PATENT DOCUMENT

Publication Number: US-12189748-B2
Application Number: US-202418436612-A
Country: US
Kind Code: B2

Title: Implementation of biometric authentication

Abstract:
An electronic device performs techniques related to receiving a request to perform an operation that requires authentication, in response to receiving the request to perform the operation that requires authentication, attempting to authenticate a user, if authentication is successful, performing the operation, and if authentication is not successful and that a set of error condition criteria is met: displaying an indication of a location of the one or more biometric sensors, wherein the indication is a graphical indicator that is displayed at a respective location on the display that is a first distance from a first edge of the electronic device, and wherein the respective location on display is a second distance from a second edge of the electronic device, wherein the second edge is opposite from the first edge, and wherein the second distance is greater than the first distance, and forgoing performing the operation.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 one or more biometric sensors; 
 a display; 
 one or more processors; and 
 memory storing one or more programs configured to be executed by the one or more processors, the one or more programs including instructions for:
 receiving a request to perform an operation that requires authentication; and 
 in response to receiving the request to perform the operation that requires authentication, attempting to authenticate a user;
 in accordance with a determination that authentication is successful, performing the operation; and 
 in accordance with a determination that authentication is not successful and that a set of error condition criteria is met:
 displaying, via the display, an indication of a location of the one or more biometric sensors on the electronic device, wherein the indication is a graphical indicator that is displayed at a respective location on the display that is a first distance from a first edge of the electronic device, wherein the first edge of the electronic device corresponds to the location of the one or more biometric sensors on the electronic device, and wherein the respective location on display is a second distance from a second edge of the electronic device, wherein the second edge is opposite from the first edge, and wherein the second distance is greater than the first distance; and 
 forgoing performing the operation. 
 
 
 
 
     
     
       2. The electronic device of  claim 1 , wherein the request to perform the operation that requires authentication is received while the electronic device is in an unlocked state. 
     
     
       3. The electronic device of  claim 1 , the one or more programs further including instructions for:
 in accordance with a determination that authentication is not successful and that the set of error condition criteria is not met:
 forgoing displaying, on the display, the indication of the location of the one or more biometric sensors on the electronic device; and 
 forgoing performing the operation. 
 
 
     
     
       4. The electronic device of  claim 1 , the one or more programs further including instructions for:
 subsequent to displaying the indication of the location of the one or more biometric sensors on the electronic device, in accordance with a determination that the set of error condition criteria is no longer met, retrying authentication. 
 
     
     
       5. The electronic device of  claim 1 , wherein the set of error condition criteria includes a criterion that is met when the one or more biometric sensors are occluded. 
     
     
       6. The electronic device of  claim 1 , wherein attempting to authenticate the user includes:
 obtaining data via the one or more biometric sensors; and 
 determining that at least a portion of a biometric feature, determined based on the data obtained from the one or more biometric sensors that corresponds to the biometric feature, satisfies authentication criteria. 
 
     
     
       7. The electronic device of  claim 6 , wherein:
 the one or more biometric sensors includes a camera; and 
 the data obtained by the one or more biometric sensors that corresponds to the biometric feature includes data obtained using the camera. 
 
     
     
       8. The electronic device of  claim 6 , wherein:
 the biometric feature corresponds to a face; 
 the data obtained from the one or more biometric sensors that corresponds to the biometric feature includes data associated with a portion of the face; and 
 the authentication criteria includes a requirement that the data associated with the face match biometric data associated with an authorized face in order for the authentication criteria to be met. 
 
     
     
       9. The electronic device of  claim 1 , the one or more programs further including instructions for:
 prior to receiving the request to perform the operation that requires authentication, displaying, via the display, an application user interface corresponding to an application, wherein the application user interface includes a first affordance for performing an operation that requires authentication. 
 
     
     
       10. The electronic device of  claim 9 , the one or more programs further including instructions for:
 while attempting to authenticate the user and while displaying the application user interface, displaying a biometric authentication interface. 
 
     
     
       11. The electronic device of  claim 10 , wherein the biometric authentication interface is at least partially translucent. 
     
     
       12. The electronic device of  claim 10 , wherein the biometric authentication interface is displayed over a portion of the application user interface. 
     
     
       13. The electronic device of  claim 1 , wherein performing the operation includes transitioning the electronic device from a locked state to an unlocked state. 
     
     
       14. The electronic device of  claim 1 , wherein performing the operation includes autofilling fillable fields with credential information. 
     
     
       15. The electronic device of  claim 14 , wherein the credential information includes information associated with log-in information. 
     
     
       16. The electronic device of  claim 1 , wherein the indication of the location of the one or more biometric sensors includes a graphical indicator. 
     
     
       17. A non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of an electronic device with one or more biometric sensors and a display, the one or more programs including instructions for:
 receiving a request to perform an operation that requires authentication; and 
 in response to receiving the request to perform the operation that requires authentication, attempting to authenticate a user;
 in accordance with a determination that authentication is successful, performing the operation; and 
 in accordance with a determination that authentication is not successful and that a set of error condition criteria is met:
 displaying, via the display, an indication of a location of the one or more biometric sensors on the electronic device, wherein the indication is a graphical indicator that is displayed at a respective location on the display that is a first distance from a first edge of the electronic device, wherein the first edge of the electronic device corresponds to the location of the one or more biometric sensors on the electronic device, and wherein the respective location on display is a second distance from a second edge of the electronic device, wherein the second edge is opposite from the first edge, and wherein the second distance is greater than the first distance; and 
 forgoing performing the operation. 
 
 
 
     
     
       18. A method, comprising:
 at an electronic device with one or more biometric sensors and a display:
 receiving a request to perform an operation that requires authentication; and 
 in response to receiving the request to perform the operation that requires authentication, attempting to authenticate a user;
 in accordance with a determination that authentication is successful, performing the operation; and 
 in accordance with a determination that authentication is not successful and that a set of error condition criteria is met:
 displaying, via the display, an indication of a location of the one or more biometric sensors on the electronic device, wherein the indication is a graphical indicator that is displayed at a respective location on the display that is a first distance from a first edge of the electronic device, wherein the first edge of the electronic device corresponds to the location of the one or more biometric sensors on the electronic device, and wherein the respective location on display is a second distance from a second edge of the electronic device, wherein the second edge is opposite from the first edge, and wherein the second distance is greater than the first distance; and 
 forgoing performing the operation. 
 
 
 
 
     
     
       19. The non-transitory computer-readable storage medium of  claim 17 , wherein the request to perform the operation that requires authentication is received while the electronic device is in an unlocked state. 
     
     
       20. The non-transitory computer-readable storage medium of  claim 17 , the one or more programs further including instructions for:
 in accordance with a determination that authentication is not successful and that the set of error condition criteria is not met:
 forgoing displaying, on the display, the indication of the location of the one or more biometric sensors on the electronic device; and 
 forgoing performing the operation. 
 
 
     
     
       21. The non-transitory computer-readable storage medium of  claim 17 , the one or more programs further including instructions for:
 subsequent to displaying the indication of the location of the one or more biometric sensors on the electronic device, in accordance with a determination that the set of error condition criteria is no longer met, retrying authentication. 
 
     
     
       22. The non-transitory computer-readable storage medium of  claim 17 , wherein the set of error condition criteria includes a criterion that is met when the one or more biometric sensors are occluded. 
     
     
       23. The non-transitory computer-readable storage medium of  claim 17 , wherein attempting to authenticate the user includes:
 obtaining data via the one or more biometric sensors; and 
 determining that at least a portion of a biometric feature, determined based on the data obtained from the one or more biometric sensors that corresponds to the biometric feature, satisfies authentication criteria. 
 
     
     
       24. The non-transitory computer-readable storage medium of  claim 23 , wherein:
 the one or more biometric sensors includes a camera; and 
 the data obtained by the one or more biometric sensors that corresponds to the biometric feature includes data obtained using the camera. 
 
     
     
       25. The non-transitory computer-readable storage medium of  claim 23 , wherein:
 the biometric feature corresponds to a face; 
 the data obtained from the one or more biometric sensors that corresponds to the biometric feature includes data associated with a portion of the face; and 
 the authentication criteria includes a requirement that the data associated with the face match biometric data associated with an authorized face in order for the authentication criteria to be met. 
 
     
     
       26. The non-transitory computer-readable storage medium of  claim 17 , the one or more programs further including instructions for:
 prior to receiving the request to perform the operation that requires authentication, displaying, via the display, an application user interface corresponding to an application, wherein the application user interface includes a first affordance for performing an operation that requires authentication. 
 
     
     
       27. The non-transitory computer-readable storage medium of  claim 26 , the one or more programs further including instructions for:
 while attempting to authenticate the user and while displaying the application user interface, displaying a biometric authentication interface. 
 
     
     
       28. The non-transitory computer-readable storage medium of  claim 27 , wherein the biometric authentication interface is at least partially translucent. 
     
     
       29. The non-transitory computer-readable storage medium of  claim 27 , wherein the biometric authentication interface is displayed over a portion of the application user interface. 
     
     
       30. The non-transitory computer-readable storage medium of  claim 17 , wherein performing the operation includes transitioning the electronic device from a locked state to an unlocked state. 
     
     
       31. The non-transitory computer-readable storage medium of  claim 17 , wherein performing the operation includes autofilling fillable fields with credential information. 
     
     
       32. The non-transitory computer-readable storage medium of  claim 31 , wherein the credential information includes information associated with log-in information. 
     
     
       33. The non-transitory computer-readable storage medium of  claim 17 , wherein the indication of the location of the one or more biometric sensors includes a graphical indicator. 
     
     
       34. The method of  claim 18 , wherein the request to perform the operation that requires authentication is received while the electronic device is in an unlocked state. 
     
     
       35. The method of  claim 18 , further comprising:
 in accordance with a determination that authentication is not successful and that the set of error condition criteria is not met:
 forgoing displaying, on the display, the indication of the location of the one or more biometric sensors on the electronic device; and 
 forgoing performing the operation. 
 
 
     
     
       36. The method of  claim 18 , further comprising:
 subsequent to displaying the indication of the location of the one or more biometric sensors on the electronic device, in accordance with a determination that the set of error condition criteria is no longer met, retrying authentication. 
 
     
     
       37. The method of  claim 18 , wherein the set of error condition criteria includes a criterion that is met when the one or more biometric sensors are occluded. 
     
     
       38. The method of  claim 18 , wherein attempting to authenticate the user includes:
 obtaining data via the one or more biometric sensors; and 
 determining that at least a portion of a biometric feature, determined based on the data obtained from the one or more biometric sensors that corresponds to the biometric feature, satisfies authentication criteria. 
 
     
     
       39. The method of  claim 38 , wherein:
 the one or more biometric sensors includes a camera; and 
 the data obtained by the one or more biometric sensors that corresponds to the biometric feature includes data obtained using the camera. 
 
     
     
       40. The method of  claim 38 , wherein:
 the biometric feature corresponds to a face; 
 the data obtained from the one or more biometric sensors that corresponds to the biometric feature includes data associated with a portion of the face; and 
 the authentication criteria includes a requirement that the data associated with the face match biometric data associated with an authorized face in order for the authentication criteria to be met. 
 
     
     
       41. The method of  claim 18 , further comprising:
 prior to receiving the request to perform the operation that requires authentication, displaying, via the display, an application user interface corresponding to an application, wherein the application user interface includes a first affordance for performing an operation that requires authentication. 
 
     
     
       42. The method of  claim 41 , further comprising:
 while attempting to authenticate the user and while displaying the application user interface, displaying a biometric authentication interface. 
 
     
     
       43. The method of  claim 42 , wherein the biometric authentication interface is at least partially translucent. 
     
     
       44. The method of  claim 42 , wherein the biometric authentication interface is displayed over a portion of the application user interface. 
     
     
       45. The method of  claim 18 , wherein performing the operation includes transitioning the electronic device from a locked state to an unlocked state. 
     
     
       46. The method of  claim 18 , wherein performing the operation includes autofilling fillable fields with credential information. 
     
     
       47. The method of  claim 46 , wherein the credential information includes information associated with log-in information. 
     
     
       48. The method of  claim 18 , wherein the indication of the location of the one or more biometric sensors includes a graphical indicator.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 17/496,716, titled “IMPLEMENTATION OF BIOMETRIC AUTHENTICATION,” filed Oct. 7, 2021, which is a continuation of U.S. patent application Ser. No. 16/369,355, now U.S. Pat. No. 11,170,085, titled “IMPLEMENTATION OF BIOMETRIC AUTHENTICATION,” filed Mar. 29, 2019, which claims priority to U.S. Provisional Patent Application Ser. Nos. 62/679,955, titled “IMPLEMENTATION OF BIOMETRIC AUTHENTICATION,” filed Jun. 3, 2018; and 62/752,234, titled “IMPLEMENTATION OF BIOMETRIC AUTHENTICATION,” filed Oct. 29, 2018. All of these applications are incorporated by reference herein in their entirety. 
     This application is related to U.S. Provisional Patent Application Ser. Nos. 62/556,413, titled “FACE ENROLLMENT AND AUTHENTICATION,” filed Sep. 9, 2017; 62/557,130, titled “IMPLEMENTATION OF BIOMETRIC AUTHENTICATION,” filed Sep. 11, 2017; 62/581,025, titled “IMPLEMENTATION OF BIOMETRIC AUTHENTICATION,” filed Nov. 2, 2017; and 62/679,955, titled “IMPLEMENTATION OF BIOMETRIC AUTHENTICATION,” filed Jun. 3, 2018. 
    
    
     FIELD 
     The present disclosure relates generally to biometric authentication, and more specifically to interfaces and techniques for enrollment and authentication of biometric features. 
     BACKGROUND 
     Biometric authentication, for instance of a face, iris, or fingerprint, using electronic devices is a convenient and efficient method of authenticating users of the electronic devices. Biometric authentication allows a device to quickly and easily verify the identity of any number of users. 
     BRIEF SUMMARY 
     Some techniques for implementing biometric authentication using electronic devices, however, are generally cumbersome. When a user fails to enroll a biometric feature for biometric authentication or fails to perform biometric authentication, a user is often unaware of the underlying cause for the failure. Thus, the user can be discouraged from using biometric authentication altogether. Moreover, when the user performs additional attempts to enroll a biometric feature or biometrically authenticate after a failure, the user often does so without having the knowledge to correct the underlying cause of the failure. In view of the foregoing drawbacks, existing techniques require more time than necessary, wasting both user time and device energy. This latter consideration is particularly significant in the operation of battery-operated devices. 
     Accordingly, the present technique provides electronic devices with faster, more efficient methods and interfaces for implementing biometric authentication. Such methods and interfaces optionally complement or replace other methods for implementing biometric authentication. Such methods and interfaces reduce the cognitive burden on a user and produce a more efficient human-machine interface. For battery-operated computing devices, such methods and interfaces conserve power and increase the time between battery charges. Such methods and interfaces also reduce the number of unnecessary, extraneous, or repetitive input required at computing devices, such as smartphones and smartwatches. 
     In accordance with some examples, a method is described, the method comprising: at an electronic device with a display and one or more input devices: receiving, via the one or more input devices, a request to perform an operation that requires authentication; and in response to the request to perform the operation that requires authentication: in accordance with a determination that authentication is successful, performing the operation; and in accordance with a determination that authentication is not successful and that a set of error condition criteria is met: displaying, on the display, an indication of an error condition, wherein the indication includes information about the cause of the error condition; and forgoing performing the operation. 
     In accordance with some examples, a non-transitory computer-readable medium is described, the non-transitory computer-readable storage medium comprising one or more programs configured to be executed by one or more processors of an electronic device with a display and one or more input devices, the one or more programs including instructions for: receiving, via the one or more input devices, a request to perform an operation that requires authentication; and in response to the request to perform the operation that requires authentication: in accordance with a determination that authentication is successful, performing the operation; and in accordance with a determination that authentication is not successful and that a set of error condition criteria is met: displaying, on the display, an indication of an error condition, wherein the indication includes information about the cause of the error condition; and forgoing performing the operation. 
     In accordance with some examples, a transitory computer-readable medium is described, the transitory computer-readable storage medium comprising one or more programs configured to be executed by one or more processors of an electronic device with a display and one or more input devices, the one or more programs including instructions for: receiving, via the one or more input devices, a request to perform an operation that requires authentication; and in response to the request to perform the operation that requires authentication: in accordance with a determination that authentication is successful, performing the operation; and in accordance with a determination that authentication is not successful and that a set of error condition criteria is met: displaying, on the display, an indication of an error condition, wherein the indication includes information about the cause of the error condition; and forgoing performing the operation. 
     In accordance with some examples, an electronic device is described, the electronic device comprising: one or more input devices; a display; one or more processors; and memory storing one or more programs configured to be executed by the one or more processors, the one or more programs including instructions for: receiving, via the one or more input devices, a request to perform an operation that requires authentication; and in response to the request to perform the operation that requires authentication: in accordance with a determination that authentication is successful, performing the operation; and in accordance with a determination that authentication is not successful and that a set of error condition criteria is met: displaying, on the display, an indication of an error condition, wherein the indication includes information about the cause of the error condition; and forgoing performing the operation. 
     In accordance with some examples, an electronic device is described, the electronic device comprising: one or more input devices; a display; means for receiving, via the one or more input devices, a request to perform an operation that requires authentication; and means for, in response to the request to perform the operation that requires authentication: in accordance with a determination that authentication is successful, performing the operation; and in accordance with a determination that authentication is not successful and that a set of error condition criteria is met: displaying, on the display, an indication of an error condition, wherein the indication includes information about the cause of the error condition; and forgoing performing the operation. 
     In accordance with some examples, a method is described, the method comprising: at an electronic device with a display and a biometric sensor at a first portion of the electronic device: detecting the existence of an error condition that prevents the biometric sensor from obtaining biometric information about a user of the device; in response to detecting the existence of the error condition, displaying, on the display, an error indication, wherein the error indication is displayed at a location that is proximate to the first portion of the electronic device, including: in accordance with a determination that a user interface of the electronic device is in a first orientation relative to the biometric sensor, displaying the error indication at a first location in the user interface that is proximate to the first portion of the electronic device; and in accordance with a determination that the user interface of the electronic device is in a second orientation relative to the biometric sensor, displaying the error indication at a second location in the user interface that is proximate to the first portion of the electronic device, the first orientation being different from the second orientation. 
     In accordance with some examples, a non-transitory computer-readable medium is described, the non-transitory computer-readable storage medium comprising one or more programs configured to be executed by one or more processors of an electronic device with a display and a biometric sensor at a first portion of the electronic device, the one or more programs including instructions for: detecting the existence of an error condition that prevents the biometric sensor from obtaining biometric information about a user of the device; in response to detecting the existence of the error condition, displaying, on the display, an error indication, wherein the error indication is displayed at a location that is proximate to the first portion of the electronic device, including: in accordance with a determination that a user interface of the electronic device is in a first orientation relative to the biometric sensor, displaying the error indication at a first location in the user interface that is proximate to the first portion of the electronic device; and in accordance with a determination that the user interface of the electronic device is in a second orientation relative to the biometric sensor, displaying the error indication at a second location in the user interface that is proximate to the first portion of the electronic device, the first orientation being different from the second orientation. 
     In accordance with some examples, a transitory computer-readable medium is described, the transitory computer-readable storage medium comprising one or more programs configured to be executed by one or more processors of an electronic device with a display and a biometric sensor at a first portion of the electronic device, the one or more programs including instructions for: detecting the existence of an error condition that prevents the biometric sensor from obtaining biometric information about a user of the device; in response to detecting the existence of the error condition, displaying, on the display, an error indication, wherein the error indication is displayed at a location that is proximate to the first portion of the electronic device, including: in accordance with a determination that a user interface of the electronic device is in a first orientation relative to the biometric sensor, displaying the error indication at a first location in the user interface that is proximate to the first portion of the electronic device; and in accordance with a determination that the user interface of the electronic device is in a second orientation relative to the biometric sensor, displaying the error indication at a second location in the user interface that is proximate to the first portion of the electronic device, the first orientation being different from the second orientation. 
     In accordance with some examples, an electronic device is described, the electronic device comprising: a biometric sensor at a first portion of the electronic device; a display; one or more processors; and memory storing one or more programs configured to be executed by the one or more processors, the one or more programs including instructions for: detecting the existence of an error condition that prevents the biometric sensor from obtaining biometric information about a user of the device; in response to detecting the existence of the error condition, displaying, on the display, an error indication, wherein the error indication is displayed at a location that is proximate to the first portion of the electronic device, including: in accordance with a determination that a user interface of the electronic device is in a first orientation relative to the biometric sensor, displaying the error indication at a first location in the user interface that is proximate to the first portion of the electronic device; and in accordance with a determination that the user interface of the electronic device is in a second orientation relative to the biometric sensor, displaying the error indication at a second location in the user interface that is proximate to the first portion of the electronic device, the first orientation being different from the second orientation. 
     In accordance with some examples, an electronic device is described, the electronic device comprising: a biometric sensor at a first portion of the electronic device; a display; means for detecting the existence of an error condition that prevents the biometric sensor from obtaining biometric information about a user of the device; means for, in response to detecting the existence of the error condition, displaying, on the display, an error indication, wherein the error indication is displayed at a location that is proximate to the first portion of the electronic device, including: in accordance with a determination that a user interface of the electronic device is in a first orientation relative to the biometric sensor, displaying the error indication at a first location in the user interface that is proximate to the first portion of the electronic device; and in accordance with a determination that the user interface of the electronic device is in a second orientation relative to the biometric sensor, displaying the error indication at a second location in the user interface that is proximate to the first portion of the electronic device, the first orientation being different from the second orientation. 
     In accordance with some examples, a method is described, the method comprising: at an electronic device with a display and one or more biometric sensors: displaying, on the display, a biometric enrollment user interface for initiating biometric enrollment with the one or more biometric sensors; while displaying the biometric enrollment user interface, receiving input corresponding for a request to initiate biometric enrollment; and in response to receiving the input: in accordance with a determination that an orientation of the electronic device satisfies a set of enrollment criteria, initiating a process for enrolling a biometric feature with the one or more biometric sensors; and in accordance with a determination that the orientation of the electronic device does not satisfy the set of enrollment criteria, outputting one or more prompts to change the orientation of the electronic device to a different orientation that satisfies the set of enrollment criteria. 
     In accordance with some examples, a non-transitory computer-readable medium is described, the non-transitory computer-readable storage medium comprising one or more programs configured to be executed by one or more processors of an electronic device with a display and one or more biometric sensors, the one or more programs including instructions for: displaying, on the display, a biometric enrollment user interface for initiating biometric enrollment with the one or more biometric sensors; while displaying the biometric enrollment user interface, receiving input corresponding for a request to initiate biometric enrollment; and in response to receiving the input: in accordance with a determination that an orientation of the electronic device satisfies a set of enrollment criteria, initiating a process for enrolling a biometric feature with the one or more biometric sensors; and in accordance with a determination that the orientation of the electronic device does not satisfy the set of enrollment criteria, outputting one or more prompts to change the orientation of the electronic device to a different orientation that satisfies the set of enrollment criteria. 
     In accordance with some examples, a transitory computer-readable medium is described, the transitory computer-readable storage medium comprising one or more programs configured to be executed by one or more processors of an electronic device with a display and one or more biometric sensors, the one or more programs including instructions for: displaying, on the display, a biometric enrollment user interface for initiating biometric enrollment with the one or more biometric sensors; while displaying the biometric enrollment user interface, receiving input corresponding for a request to initiate biometric enrollment; and in response to receiving the input: in accordance with a determination that an orientation of the electronic device satisfies a set of enrollment criteria, initiating a process for enrolling a biometric feature with the one or more biometric sensors; and in accordance with a determination that the orientation of the electronic device does not satisfy the set of enrollment criteria, outputting one or more prompts to change the orientation of the electronic device to a different orientation that satisfies the set of enrollment criteria. 
     In accordance with some examples, an electronic device is described, the electronic device comprising: one or more biometric sensors; a display; one or more processors; and memory storing one or more programs configured to be executed by the one or more processors, the one or more programs including instructions for: displaying, on the display, a biometric enrollment user interface for initiating biometric enrollment with the one or more biometric sensors; while displaying the biometric enrollment user interface, receiving input corresponding for a request to initiate biometric enrollment; and in response to receiving the input: in accordance with a determination that an orientation of the electronic device satisfies a set of enrollment criteria, initiating a process for enrolling a biometric feature with the one or more biometric sensors; and in accordance with a determination that the orientation of the electronic device does not satisfy the set of enrollment criteria, outputting one or more prompts to change the orientation of the electronic device to a different orientation that satisfies the set of enrollment criteria. 
     In accordance with some examples, an electronic device is described, the electronic device comprising: one or more biometric sensors; a display; means for displaying, on the display, a biometric enrollment user interface for initiating biometric enrollment with the one or more biometric sensors; means for, while displaying the biometric enrollment user interface, receiving input corresponding for a request to initiate biometric enrollment; and means for, in response to receiving the input: in accordance with a determination that an orientation of the electronic device satisfies a set of enrollment criteria, initiating a process for enrolling a biometric feature with the one or more biometric sensors; and in accordance with a determination that the orientation of the electronic device does not satisfy the set of enrollment criteria, outputting one or more prompts to change the orientation of the electronic device to a different orientation that satisfies the set of enrollment criteria. 
     In accordance with some examples, a method is described, the method comprising: at an electronic device with a biometric sensor and a touch-sensitive display: detecting occurrence of an error condition for detecting biometric information at the biometric sensor; in response to detecting the occurrence of the error condition, displaying, on the touch-sensitive display, an indication of a location of the biometric sensor on the electronic device; while displaying the indication of the location of the biometric sensor on the electronic device, detecting a request to unlock the electronic device using the biometric sensor; and in response to detecting the request to unlock the electronic device using the biometric sensor: in accordance with a determination that the error condition is still occurring at a respective time that occurs after detecting the request to unlock the electronic device: ceasing to display the indication of the location of the biometric sensor; and displaying a touch-based user interface for entering touch-based authentication information; and in accordance with a determination that the error condition is no longer occurring, attempting to unlock the electronic device using the biometric sensor. 
     In accordance with some examples, a non-transitory computer-readable medium is described, the non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of an electronic device with a biometric sensor and a touch-sensitive display, the one or more programs including instructions for: detecting occurrence of an error condition for detecting biometric information at the biometric sensor; in response to detecting the occurrence of the error condition, displaying, on the touch-sensitive display, an indication of a location of the biometric sensor on the electronic device; while displaying the indication of the location of the biometric sensor on the electronic device, detecting a request to unlock the electronic device using the biometric sensor; and in response to detecting the request to unlock the electronic device using the biometric sensor: in accordance with a determination that the error condition is still occurring at a respective time that occurs after detecting the request to unlock the electronic device: ceasing to display the indication of the location of the biometric sensor; and displaying a touch-based user interface for entering touch-based authentication information; and in accordance with a determination that the error condition is no longer occurring, attempting to unlock the electronic device using the biometric sensor. 
     In accordance with some examples, a transitory computer-readable medium is described, the transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of an electronic device with a biometric sensor and a touch-sensitive display, the one or more programs including instructions for: detecting occurrence of an error condition for detecting biometric information at the biometric sensor; in response to detecting the occurrence of the error condition, displaying, on the touch-sensitive display, an indication of a location of the biometric sensor on the electronic device; while displaying the indication of the location of the biometric sensor on the electronic device, detecting a request to unlock the electronic device using the biometric sensor; and in response to detecting the request to unlock the electronic device using the biometric sensor: in accordance with a determination that the error condition is still occurring at a respective time that occurs after detecting the request to unlock the electronic device: ceasing to display the indication of the location of the biometric sensor; and displaying a touch-based user interface for entering touch-based authentication information; and in accordance with a determination that the error condition is no longer occurring, attempting to unlock the electronic device using the biometric sensor. 
     In accordance with some examples, an electronic device is described, the electronic device comprising: a biometric sensor; a touch-sensitive display; one or more processors; and memory storing one or more programs configured to be executed by the one or more processors, the one or more programs including instructions for: detecting occurrence of an error condition for detecting biometric information at the biometric sensor; in response to detecting the occurrence of the error condition, displaying, on the touch-sensitive display, an indication of a location of the biometric sensor on the electronic device; while displaying the indication of the location of the biometric sensor on the electronic device, detecting a request to unlock the electronic device using the biometric sensor; and in response to detecting the request to unlock the electronic device using the biometric sensor: in accordance with a determination that the error condition is still occurring at a respective time that occurs after detecting the request to unlock the electronic device: ceasing to display the indication of the location of the biometric sensor; and displaying a touch-based user interface for entering touch-based authentication information; and in accordance with a determination that the error condition is no longer occurring, attempting to unlock the electronic device using the biometric sensor. 
     In accordance with some examples, an electronic device is described, the electronic device comprising: a biometric sensor; a touch-sensitive display; means for detecting occurrence of an error condition for detecting biometric information at the biometric sensor; means, in response to detecting the occurrence of the error condition, for displaying, on the touch-sensitive display, an indication of a location of the biometric sensor on the electronic device; means, while displaying the indication of the location of the biometric sensor on the electronic device, for detecting a request to unlock the electronic device using the biometric sensor; and means, in response to detecting the request to unlock the electronic device using the biometric sensor, for: in accordance with a determination that the error condition is still occurring at a respective time that occurs after detecting the request to unlock the electronic device: ceasing to display the indication of the location of the biometric sensor; and displaying a touch-based user interface for entering touch-based authentication information; and in accordance with a determination that the error condition is no longer occurring, attempting to unlock the electronic device using the biometric sensor. 
     Executable instructions for performing these functions are, optionally, included in a non-transitory computer-readable storage medium or other computer program product configured for execution by one or more processors. Executable instructions for performing these functions are, optionally, included in a transitory computer-readable storage medium or other computer program product configured for execution by one or more processors. 
     Thus, devices are provided with faster, more efficient methods and interfaces for implementing biometric authentication, thereby increasing the effectiveness, efficiency, and user satisfaction with such devices. Such methods and interfaces optionally complement or replace other methods for implementing biometric authentication. 
    
    
     
       DESCRIPTION OF THE FIGURES 
       For a better understanding of the various described embodiments, reference should be made to the Description of Embodiments below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures. 
         FIG.  1 A  is a block diagram illustrating a portable multifunction device with a touch-sensitive display in accordance with some embodiments. 
         FIG.  1 B  is a block diagram illustrating exemplary components for event handling in accordance with some embodiments. 
         FIG.  1 C  is a block diagram illustrating exemplary components for generating a tactile output, in accordance with some embodiments. 
         FIG.  2    illustrates a portable multifunction device having a touch screen in accordance with some embodiments. 
         FIG.  3    is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments. 
         FIG.  4 A  illustrates an exemplary user interface for a menu of applications on a portable multifunction device in accordance with some embodiments. 
         FIG.  4 B  illustrates an exemplary user interface for a multifunction device with a touch-sensitive surface that is separate from the display in accordance with some embodiments. 
         FIGS.  4 C- 4 H  illustrate exemplary tactile output patterns that have a particular waveform, in accordance with some embodiments. 
         FIG.  5 A  illustrates a personal electronic device in accordance with some embodiments. 
         FIG.  5 B  is a block diagram illustrating a personal electronic device in accordance with some embodiments. 
         FIGS.  5 C- 5 D  illustrate exemplary components of a personal electronic device having a touch-sensitive display and intensity sensors in accordance with some embodiments. 
         FIGS.  5 E- 5 H  illustrate exemplary components and user interfaces of a personal electronic device in accordance with some embodiments. 
         FIG.  6    illustrates exemplary devices connected via one or more communication channels, in accordance with some embodiments. 
         FIGS.  7 A- 7 AD  illustrate exemplary user interfaces for providing indications of error conditions during biometric authentication, in accordance with some examples. 
         FIGS.  8 A- 8 B  are flow diagrams illustrating a method for providing indications of error conditions during biometric authentication, in accordance with some examples 
         FIGS.  9 A- 9 U  illustrate exemplary user interfaces for providing indications about the biometric sensor during biometric authentication, in accordance with some examples. 
         FIGS.  10 A- 10 C  are flow diagrams illustrating a method for providing indications about the biometric sensor during biometric authentication, in accordance with some examples. 
         FIGS.  11 A- 11 S  illustrate exemplary user interfaces for orienting the device to enroll a biometric feature, in accordance with some examples 
         FIGS.  12 A- 12 C  are flow diagrams illustrating a method for orienting the device to enroll a biometric feature, in accordance with some examples. 
         FIGS.  13 A- 13 Z  illustrate exemplary user interfaces for providing an indication of the location of the biometric sensor to correct a detected error condition, in accordance with some examples. 
         FIGS.  14 A- 14 B  are flow diagrams illustrating a method for providing an indication of the location of the biometric sensor to correct a detected error condition, in accordance with some examples. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following description sets forth exemplary methods, parameters, and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure but is instead provided as a description of exemplary embodiments. 
     There is a need for electronic devices that provide efficient methods and interfaces for implementing biometric authentication of biometric features. For example, there is a need for electronic devices that provide a convenient and efficient method for enrolling one or more portions of a biometric feature. For another example, there is a need for electronic devices that provide a quick and intuitive technique for selectively accessing secure data in accordance with biometric authentication. For another example, there is a need for electronic devices that provide a quick and intuitive technique for enabling a function of a device in accordance with biometric authentication. Such techniques can reduce the cognitive burden on a user who enrolls a biometric feature and/or biometrically authenticates with a device, thereby enhancing overall productivity. Further, such techniques can reduce processor and battery power otherwise wasted on redundant user inputs. 
     Below,  FIGS.  1 A- 1 C,  2 ,  3 ,  4 A- 4 B, and  5 A- 5 H  provide a description of exemplary devices for performing the techniques for implementing biometric authentication.  FIG.  6    illustrates exemplary devices connected via one or more communication channels, in accordance with some embodiments.  FIGS.  7 A- 7 AD  illustrate exemplary user interfaces for providing indications of error conditions during biometric authentication.  FIGS.  8 A- 8 B  are flow diagrams illustrating a method for providing indications of error conditions during biometric authentication. The user interfaces in  FIGS.  7 A- 7 AD  are used to illustrate the processes described below, including the processes in  8 A- 8 B.  FIGS.  9 A- 9 U  illustrate exemplary user interfaces for providing indications about the biometric sensor during biometric authentication.  FIGS.  10 A- 10 C  are flow diagrams illustrating a method for providing indications about the biometric sensor during biometric authentication. The user interfaces in  FIGS.  9 A- 9 U  are used to illustrate the processes described below, including the processes in  FIGS.  10 A- 10 C .  FIGS.  11 A- 11 S  illustrate exemplary user interfaces for orienting the device to enroll a biometric feature.  FIGS.  12 A- 12 C  are flow diagrams illustrating a method for orienting the device to enroll a biometric feature. The user interfaces in  FIGS.  11 A- 11 S  are used to illustrate the processes described below, including the processes in  FIGS.  12 A- 12 C .  FIGS.  13 A- 13 Z  illustrate exemplary user interfaces for providing an indication of the location of the biometric sensor to correct a detected error condition.  FIGS.  14 A- 14 B  are flow diagrams illustrating a method for providing an indication of the location of the biometric sensor to correct a detected error condition. The user interfaces in  FIGS.  13 A- 13 Z  are used to illustrate the processes described below, including the processes in  FIGS.  14 A- 14 B . 
     Although the following description uses terms “first,” “second,” etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first touch could be termed a second touch, and, similarly, a second touch could be termed a first touch, without departing from the scope of the various described embodiments. The first touch and the second touch are both touches, but they are not the same touch. 
     The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     The term “if” is, optionally, construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” is, optionally, construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context. 
     Embodiments of electronic devices, user interfaces for such devices, and associated processes for using such devices are described. In some embodiments, the device is a portable communications device, such as a mobile telephone, that also contains other functions, such as PDA and/or music player functions. Exemplary embodiments of portable multifunction devices include, without limitation, the iPhone®, iPod Touch®, and iPad® devices from Apple Inc. of Cupertino, California. Other portable electronic devices, such as laptops or tablet computers with touch-sensitive surfaces (e.g., touch screen displays and/or touchpads), are, optionally, used. It should also be understood that, in some embodiments, the device is not a portable communications device, but is a desktop computer with a touch-sensitive surface (e.g., a touch screen display and/or a touchpad). 
     In the discussion that follows, an electronic device that includes a display and a touch-sensitive surface is described. It should be understood, however, that the electronic device optionally includes one or more other physical user-interface devices, such as a physical keyboard, a mouse, and/or a joystick. 
     The device typically supports a variety of applications, such as one or more of the following: a drawing application, a presentation application, a word processing application, a website creation application, a disk authoring application, a spreadsheet application, a gaming application, a telephone application, a video conferencing application, an e-mail application, an instant messaging application, a workout support application, a photo management application, a digital camera application, a digital video camera application, a web browsing application, a digital music player application, and/or a digital video player application. 
     The various applications that are executed on the device optionally use at least one common physical user-interface device, such as the touch-sensitive surface. One or more functions of the touch-sensitive surface as well as corresponding information displayed on the device are, optionally, adjusted and/or varied from one application to the next and/or within a respective application. In this way, a common physical architecture (such as the touch-sensitive surface) of the device optionally supports the variety of applications with user interfaces that are intuitive and transparent to the user. 
     Attention is now directed toward embodiments of portable devices with touch-sensitive displays.  FIG.  1 A  is a block diagram illustrating portable multifunction device  100  with touch-sensitive display system  112  in accordance with some embodiments. Touch-sensitive display  112  is sometimes called a “touch screen” for convenience and is sometimes known as or called a “touch-sensitive display system.” Device  100  includes memory  102  (which optionally includes one or more computer-readable storage mediums), memory controller  122 , one or more processing units (CPUs)  120 , peripherals interface  118 , RF circuitry  108 , audio circuitry  110 , speaker  111 , microphone  113 , input/output (I/O) subsystem  106 , other input control devices  116 , and external port  124 . Device  100  optionally includes one or more optical sensors  164 . Device  100  optionally includes one or more contact intensity sensors  165  for detecting intensity of contacts on device  100  (e.g., a touch-sensitive surface such as touch-sensitive display system  112  of device  100 ). Device  100  optionally includes one or more tactile output generators  167  for generating tactile outputs on device  100  (e.g., generating tactile outputs on a touch-sensitive surface such as touch-sensitive display system  112  of device  100  or touchpad  355  of device  300 ). These components optionally communicate over one or more communication buses or signal lines  103 . 
     As used in the specification and claims, the term “intensity” of a contact on a touch-sensitive surface refers to the force or pressure (force per unit area) of a contact (e.g., a finger contact) on the touch-sensitive surface, or to a substitute (proxy) for the force or pressure of a contact on the touch-sensitive surface. The intensity of a contact has a range of values that includes at least four distinct values and more typically includes hundreds of distinct values (e.g., at least 256). Intensity of a contact is, optionally, determined (or measured) using various approaches and various sensors or combinations of sensors. For example, one or more force sensors underneath or adjacent to the touch-sensitive surface are, optionally, used to measure force at various points on the touch-sensitive surface. In some implementations, force measurements from multiple force sensors are combined (e.g., a weighted average) to determine an estimated force of a contact. Similarly, a pressure-sensitive tip of a stylus is, optionally, used to determine a pressure of the stylus on the touch-sensitive surface. Alternatively, the size of the contact area detected on the touch-sensitive surface and/or changes thereto, the capacitance of the touch-sensitive surface proximate to the contact and/or changes thereto, and/or the resistance of the touch-sensitive surface proximate to the contact and/or changes thereto are, optionally, used as a substitute for the force or pressure of the contact on the touch-sensitive surface. In some implementations, the substitute measurements for contact force or pressure are used directly to determine whether an intensity threshold has been exceeded (e.g., the intensity threshold is described in units corresponding to the substitute measurements). In some implementations, the substitute measurements for contact force or pressure are converted to an estimated force or pressure, and the estimated force or pressure is used to determine whether an intensity threshold has been exceeded (e.g., the intensity threshold is a pressure threshold measured in units of pressure). Using the intensity of a contact as an attribute of a user input allows for user access to additional device functionality that is, in some circumstances, otherwise not be accessible by the user on a reduced-size device with limited real estate for displaying affordances (e.g., on a touch-sensitive display) and/or receiving user input (e.g., via a touch-sensitive display, a touch-sensitive surface, or a physical/mechanical control such as a knob or a button). 
     As used in the specification and claims, the term “tactile output” refers to physical displacement of a device relative to a previous position of the device, physical displacement of a component (e.g., a touch-sensitive surface) of a device relative to another component (e.g., housing) of the device, or displacement of the component relative to a center of mass of the device that will be detected by a user with the user&#39;s sense of touch. For example, in situations where the device or the component of the device is in contact with a surface of a user that is sensitive to touch (e.g., a finger, palm, or other part of a user&#39;s hand), the tactile output generated by the physical displacement will be interpreted by the user as a tactile sensation corresponding to a perceived change in physical characteristics of the device or the component of the device. For example, movement of a touch-sensitive surface (e.g., a touch-sensitive display or trackpad) is, optionally, interpreted by the user as a “down click” or “up click” of a physical actuator button. In some cases, a user will feel a tactile sensation such as an “down click” or “up click” even when there is no movement of a physical actuator button associated with the touch-sensitive surface that is physically pressed (e.g., displaced) by the user&#39;s movements. As another example, movement of the touch-sensitive surface is, optionally, interpreted or sensed by the user as “roughness” of the touch-sensitive surface, even when there is no change in smoothness of the touch-sensitive surface. While such interpretations of touch by a user will be subject to the individualized sensory perceptions of the user, there are many sensory perceptions of touch that are common to a large majority of users. Thus, when a tactile output is described as corresponding to a particular sensory perception of a user (e.g., an “up click,” a “down click,” “roughness”), unless otherwise stated, the generated tactile output corresponds to physical displacement of the device or a component thereof that will generate the described sensory perception for a typical (or average) user. Using tactile outputs to provide haptic feedback to a user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some embodiments, a tactile output pattern specifies characteristics of a tactile output, such as the amplitude of the tactile output, the shape of a movement waveform of the tactile output, the frequency of the tactile output, and/or the duration of the tactile output. 
     When tactile outputs with different tactile output patterns are generated by a device (e.g., via one or more tactile output generators that move a moveable mass to generate tactile outputs), the tactile outputs can invoke different haptic sensations in a user holding or touching the device. While the sensation of the user is based on the user&#39;s perception of the tactile output, most users will be able to identify changes in waveform, frequency, and amplitude of tactile outputs generated by the device. Thus, the waveform, frequency and amplitude can be adjusted to indicate to the user that different operations have been performed. As such, tactile outputs with tactile output patterns that are designed, selected, and/or engineered to simulate characteristics (e.g., size, material, weight, stiffness, smoothness, etc.); behaviors (e.g., oscillation, displacement, acceleration, rotation, expansion, etc.); and/or interactions (e.g., collision, adhesion, repulsion, attraction, friction, etc.) of objects in a given environment (e.g., a user interface that includes graphical features and objects, a simulated physical environment with virtual boundaries and virtual objects, a real physical environment with physical boundaries and physical objects, and/or a combination of any of the above) will, in some circumstances, provide helpful feedback to users that reduces input errors and increases the efficiency of the user&#39;s operation of the device. Additionally, tactile outputs are, optionally, generated to correspond to feedback that is unrelated to a simulated physical characteristic, such as an input threshold or a selection of an object. Such tactile outputs will, in some circumstances, provide helpful feedback to users that reduces input errors and increases the efficiency of the user&#39;s operation of the device. 
     In some embodiments, a tactile output with a suitable tactile output pattern serves as a cue for the occurrence of an event of interest in a user interface or behind the scenes in a device. Examples of the events of interest include activation of an affordance (e.g., a real or virtual button, or toggle switch) provided on the device or in a user interface, success or failure of a requested operation, reaching or crossing a boundary in a user interface, entry into a new state, switching of input focus between objects, activation of a new mode, reaching or crossing an input threshold, detection or recognition of a type of input or gesture, etc. In some embodiments, tactile outputs are provided to serve as a warning or an alert for an impending event or outcome that would occur unless a redirection or interruption input is timely detected. Tactile outputs are also used in other contexts to enrich the user experience, improve the accessibility of the device to users with visual or motor difficulties or other accessibility needs, and/or improve efficiency and functionality of the user interface and/or the device. Tactile outputs are optionally accompanied with audio outputs and/or visible user interface changes, which further enhance a user&#39;s experience when the user interacts with a user interface and/or the device, and facilitate better conveyance of information regarding the state of the user interface and/or the device, and which reduce input errors and increase the efficiency of the user&#39;s operation of the device. 
       FIGS.  4 C- 4 E  provide a set of sample tactile output patterns that can be used, either individually or in combination, either as is or through one or more transformations (e.g., modulation, amplification, truncation, etc.), to create suitable haptic feedback in various scenarios and for various purposes, such as those mentioned above and those described with respect to the user interfaces and methods discussed herein. This example of a palette of tactile outputs shows how a set of three waveforms and eight frequencies can be used to produce an array of tactile output patterns. In addition to the tactile output patterns shown in this figure, each of these tactile output patterns is optionally adjusted in amplitude by changing a gain value for the tactile output pattern, as shown, for example for FullTap 80 Hz, FullTap 200 Hz, MiniTap 80 Hz, MiniTap 200 Hz, MicroTap 80 Hz, and MicroTap 200 Hz in  FIGS.  4 F- 4 H , which are each shown with variants having a gain of 1.0, 0.75, 0.5, and 0.25. As shown in  FIGS.  4 F- 4 H , changing the gain of a tactile output pattern changes the amplitude of the pattern without changing the frequency of the pattern or changing the shape of the waveform. In some embodiments, changing the frequency of a tactile output pattern also results in a lower amplitude as some tactile output generators are limited by how much force can be applied to the moveable mass and thus higher frequency movements of the mass are constrained to lower amplitudes to ensure that the acceleration needed to create the waveform does not require force outside of an operational force range of the tactile output generator (e.g., the peak amplitudes of the FullTap at 230 Hz, 270 Hz, and 300 Hz are lower than the amplitudes of the FullTap at 80 Hz, 100 Hz, 125 Hz, and 200 Hz). 
       FIGS.  4 C- 4 H  show tactile output patterns that have a particular waveform. The waveform of a tactile output pattern represents the pattern of physical displacements relative to a neutral position (e.g., x zero ) versus time that an moveable mass goes through to generate a tactile output with that tactile output pattern. For example, a first set of tactile output patterns shown in  FIG.  4 C  (e.g., tactile output patterns of a “FullTap”) each have a waveform that includes an oscillation with two complete cycles (e.g., an oscillation that starts and ends in a neutral position and crosses the neutral position three times). A second set of tactile output patterns shown in  FIG.  4 D  (e.g., tactile output patterns of a “MiniTap”) each have a waveform that includes an oscillation that includes one complete cycle (e.g., an oscillation that starts and ends in a neutral position and crosses the neutral position one time). A third set of tactile output patterns shown in  FIG.  4 E  (e.g., tactile output patterns of a “MicroTap”) each have a waveform that includes an oscillation that include one half of a complete cycle (e.g., an oscillation that starts and ends in a neutral position and does not cross the neutral position). The waveform of a tactile output pattern also includes a start buffer and an end buffer that represent the gradual speeding up and slowing down of the moveable mass at the start and at the end of the tactile output. The example waveforms shown in  FIGS.  4 C- 4 H  include x min  and x max  values which represent the maximum and minimum extent of movement of the moveable mass. For larger electronic devices with larger moveable masses, there can be larger or smaller minimum and maximum extents of movement of the mass. The examples shown in  FIGS.  4 C- 4 H  describe movement of a mass in 1 dimension, however similar principles would also apply to movement of a moveable mass in two or three dimensions. 
     As shown in  FIGS.  4 C- 4 E , each tactile output pattern also has a corresponding characteristic frequency that affects the “pitch” of a haptic sensation that is felt by a user from a tactile output with that characteristic frequency. For a continuous tactile output, the characteristic frequency represents the number of cycles that are completed within a given period of time (e.g., cycles per second) by the moveable mass of the tactile output generator. For a discrete tactile output, a discrete output signal (e.g., with 0.5, 1, or 2 cycles) is generated, and the characteristic frequency value specifies how fast the moveable mass needs to move to generate a tactile output with that characteristic frequency. As shown in  FIGS.  4 C- 4 H , for each type of tactile output (e.g., as defined by a respective waveform, such as FullTap, MiniTap, or MicroTap), a higher frequency value corresponds to faster movement(s) by the moveable mass, and hence, in general, a shorter time to complete the tactile output (e.g., including the time to complete the required number of cycle(s) for the discrete tactile output, plus a start and an end buffer time). For example, a FullTap with a characteristic frequency of 80 Hz takes longer to complete than FullTap with a characteristic frequency of 100 Hz (e.g., 35.4 ms vs. 28.3 ms in  FIG.  4 C ). In addition, for a given frequency, a tactile output with more cycles in its waveform at a respective frequency takes longer to complete than a tactile output with fewer cycles its waveform at the same respective frequency. For example, a FullTap at 150 Hz takes longer to complete than a MiniTap at 150 Hz (e.g., 19.4 ms vs. 12.8 ms), and a MiniTap at 150 Hz takes longer to complete than a MicroTap at 150 Hz (e.g., 12.8 ms vs. 9.4 ms). However, for tactile output patterns with different frequencies this rule may not apply (e.g., tactile outputs with more cycles but a higher frequency can take a shorter amount of time to complete than tactile outputs with fewer cycles but a lower frequency, and vice versa). For example, at 300 Hz, a FullTap takes as long as a MiniTap (e.g., 9.9 ms). 
     As shown in  FIGS.  4 C- 4 E , a tactile output pattern also has a characteristic amplitude that affects the amount of energy that is contained in a tactile signal, or a “strength” of a haptic sensation that can be felt by a user through a tactile output with that characteristic amplitude. In some embodiments, the characteristic amplitude of a tactile output pattern refers to an absolute or normalized value that represents the maximum displacement of the moveable mass from a neutral position when generating the tactile output. In some embodiments, the characteristic amplitude of a tactile output pattern is adjustable, e.g., by a fixed or dynamically determined gain factor (e.g., a value between 0 and 1), in accordance with various conditions (e.g., customized based on user interface contexts and behaviors) and/or preconfigured metrics (e.g., input-based metrics, and/or user-interface-based metrics). In some embodiments, an input-based metric (e.g., an intensity-change metric or an input-speed metric) measures a characteristic of an input (e.g., a rate of change of a characteristic intensity of a contact in a press input or a rate of movement of the contact across a touch-sensitive surface) during the input that triggers generation of a tactile output. In some embodiments, a user-interface-based metric (e.g., a speed-across-boundary metric) measures a characteristic of a user interface element (e.g., a speed of movement of the element across a hidden or visible boundary in a user interface) during the user interface change that triggers generation of the tactile output. In some embodiments, the characteristic amplitude of a tactile output pattern can be modulated by an “envelope” and the peaks of adjacent cycles can have different amplitudes, where one of the waveforms shown above is further modified by multiplication by an envelope parameter that changes over time (e.g., from 0 to 1) to gradually adjust amplitude of portions of the tactile output over time as the tactile output is being generated. 
     Although specific frequencies, amplitudes, and waveforms are represented in the sample tactile output patterns in  FIGS.  4 C- 4 E  for illustrative purposes, tactile output patterns with other frequencies, amplitudes, and waveforms can be used for similar purposes. For example, waveforms that have between 0.5 to 4 cycles can be used. Other frequencies in the range of 60 Hz-400 Hz can be used as well. Table 1 provides examples of particular haptic feedback behaviors, configurations, and examples of their use. 
     It should be appreciated that device  100  is only one example of a portable multifunction device, and that device  100  optionally has more or fewer components than shown, optionally combines two or more components, or optionally has a different configuration or arrangement of the components. The various components shown in  FIG.  1 A  are implemented in hardware, software, or a combination of both hardware and software, including one or more signal processing and/or application-specific integrated circuits. 
     Memory  102  optionally includes high-speed random access memory and optionally also includes non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid-state memory devices. Memory controller  122  optionally controls access to memory  102  by other components of device  100 . 
     Peripherals interface  118  can be used to couple input and output peripherals of the device to CPU  120  and memory  102 . The one or more processors  120  run or execute various software programs and/or sets of instructions stored in memory  102  to perform various functions for device  100  and to process data. In some embodiments, peripherals interface  118 , CPU  120 , and memory controller  122  are, optionally, implemented on a single chip, such as chip  104 . In some other embodiments, they are, optionally, implemented on separate chips. 
     RF (radio frequency) circuitry  108  receives and sends RF signals, also called electromagnetic signals. RF circuitry  108  converts electrical signals to/from electromagnetic signals and communicates with communications networks and other communications devices via the electromagnetic signals. RF circuitry  108  optionally includes well-known circuitry for performing these functions, including but not limited to an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC chipset, a subscriber identity module (SIM) card, memory, and so forth. RF circuitry  108  optionally communicates with networks, such as the Internet, also referred to as the World Wide Web (WWW), an intranet and/or a wireless network, such as a cellular telephone network, a wireless local area network (LAN) and/or a metropolitan area network (MAN), and other devices by wireless communication. The RF circuitry  108  optionally includes well-known circuitry for detecting near field communication (NFC) fields, such as by a short-range communication radio. The wireless communication optionally uses any of a plurality of communications standards, protocols, and technologies, including but not limited to Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), high-speed downlink packet access (HSDPA), high-speed uplink packet access (HSUPA), Evolution, Data-Only (EV-DO), HSPA, HSPA+, Dual-Cell HSPA (DC-HSPDA), long term evolution (LTE), near field communication (NFC), wideband code division multiple access (W-CDMA), code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, Bluetooth Low Energy (BTLE), Wireless Fidelity (Wi-Fi) (e.g., IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, and/or IEEE 802.11ac), voice over Internet Protocol (VoIP), Wi-MAX, a protocol for e-mail (e.g., Internet message access protocol (IMAP) and/or post office protocol (POP)), instant messaging (e.g., extensible messaging and presence protocol (XMPP), Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions (SIMPLE), Instant Messaging and Presence Service (IMPS)), and/or Short Message Service (SMS), or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document. 
     Audio circuitry  110 , speaker  111 , and microphone  113  provide an audio interface between a user and device  100 . Audio circuitry  110  receives audio data from peripherals interface  118 , converts the audio data to an electrical signal, and transmits the electrical signal to speaker  111 . Speaker  111  converts the electrical signal to human-audible sound waves. Audio circuitry  110  also receives electrical signals converted by microphone  113  from sound waves. Audio circuitry  110  converts the electrical signal to audio data and transmits the audio data to peripherals interface  118  for processing. Audio data is, optionally, retrieved from and/or transmitted to memory  102  and/or RF circuitry  108  by peripherals interface  118 . In some embodiments, audio circuitry  110  also includes a headset jack (e.g.,  212 ,  FIG.  2   ). The headset jack provides an interface between audio circuitry  110  and removable audio input/output peripherals, such as output-only headphones or a headset with both output (e.g., a headphone for one or both ears) and input (e.g., a microphone). 
     I/O subsystem  106  couples input/output peripherals on device  100 , such as touch screen  112  and other input control devices  116 , to peripherals interface  118 . I/O subsystem  106  optionally includes display controller  156 , optical sensor controller  158 , intensity sensor controller  159 , haptic feedback controller  161 , depth camera controller  169 , and one or more input controllers  160  for other input or control devices. The one or more input controllers  160  receive/send electrical signals from/to other input control devices  116 . The other input control devices  116  optionally include physical buttons (e.g., push buttons, rocker buttons, etc.), dials, slider switches, joysticks, click wheels, and so forth. In some alternate embodiments, input controller(s)  160  are, optionally, coupled to any (or none) of the following: a keyboard, an infrared port, a USB port, and a pointer device such as a mouse. The one or more buttons (e.g.,  208 ,  FIG.  2   ) optionally include an up/down button for volume control of speaker  111  and/or microphone  113 . The one or more buttons optionally include a push button (e.g.,  206 ,  FIG.  2   ). 
     A quick press of the push button optionally disengages a lock of touch screen  112  or optionally begins a process that uses gestures on the touch screen to unlock the device, as described in U.S. patent application Ser. No. 11/322,549, “Unlocking a Device by Performing Gestures on an Unlock Image,” filed Dec. 23, 2005, U.S. Pat. No. 7,657,849, which is hereby incorporated by reference in its entirety. A longer press of the push button (e.g.,  206 ) optionally turns power to device  100  on or off. The functionality of one or more of the buttons are, optionally, user-customizable. Touch screen  112  is used to implement virtual or soft buttons and one or more soft keyboards. 
     Touch-sensitive display  112  provides an input interface and an output interface between the device and a user. Display controller  156  receives and/or sends electrical signals from/to touch screen  112 . Touch screen  112  displays visual output to the user. The visual output optionally includes graphics, text, icons, video, and any combination thereof (collectively termed “graphics”). In some embodiments, some or all of the visual output optionally corresponds to user-interface objects. 
     Touch screen  112  has a touch-sensitive surface, sensor, or set of sensors that accepts input from the user based on haptic and/or tactile contact. Touch screen  112  and display controller  156  (along with any associated modules and/or sets of instructions in memory  102 ) detect contact (and any movement or breaking of the contact) on touch screen  112  and convert the detected contact into interaction with user-interface objects (e.g., one or more soft keys, icons, web pages, or images) that are displayed on touch screen  112 . In an exemplary embodiment, a point of contact between touch screen  112  and the user corresponds to a finger of the user. 
     Touch screen  112  optionally uses LCD (liquid crystal display) technology, LPD (light emitting polymer display) technology, or LED (light emitting diode) technology, although other display technologies are used in other embodiments. Touch screen  112  and display controller  156  optionally detect contact and any movement or breaking thereof using any of a plurality of touch sensing technologies now known or later developed, including but not limited to capacitive, resistive, infrared, and surface acoustic wave technologies, as well as other proximity sensor arrays or other elements for determining one or more points of contact with touch screen  112 . In an exemplary embodiment, projected mutual capacitance sensing technology is used, such as that found in the iPhone® and iPod Touch® from Apple Inc. of Cupertino, California. 
     A touch-sensitive display in some embodiments of touch screen  112  is, optionally, analogous to the multi-touch sensitive touchpads described in the following U.S. Pat. No. 6,323,846 (Westerman et al.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No. 6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1, each of which is hereby incorporated by reference in its entirety. However, touch screen  112  displays visual output from device  100 , whereas touch-sensitive touchpads do not provide visual output. 
     A touch-sensitive display in some embodiments of touch screen  112  is described in the following applications: (1) U.S. patent application Ser. No. 11/381,313, “Multipoint Touch Surface Controller,” filed May 2, 2006; (2) U.S. patent application Ser. No. 10/840,862, “Multipoint Touchscreen,” filed May 6, 2004; (3) U.S. patent application Ser. No. 10/903,964, “Gestures For Touch Sensitive Input Devices,” filed Jul. 30, 2004; (4) U.S. patent application Ser. No. 11/048,264, “Gestures For Touch Sensitive Input Devices,” filed Jan. 31, 2005; (5) U.S. patent application Ser. No. 11/038,590, “Mode-Based Graphical User Interfaces For Touch Sensitive Input Devices,” filed Jan. 18, 2005; (6) U.S. patent application Ser. No. 11/228,758, “Virtual Input Device Placement On A Touch Screen User Interface,” filed Sep. 16, 2005; (7) U.S. patent application Ser. No. 11/228,700, “Operation Of A Computer With A Touch Screen Interface,” filed Sep. 16, 2005; (8) U.S. patent application Ser. No. 11/228,737, “Activating Virtual Keys Of A Touch-Screen Virtual Keyboard,” filed Sep. 16, 2005; and (9) U.S. patent application Ser. No. 11/367,749, “Multi-Functional Hand-Held Device,” filed Mar. 3, 2006. All of these applications are incorporated by reference herein in their entirety. 
     Touch screen  112  optionally has a video resolution in excess of 100 dpi. In some embodiments, the touch screen has a video resolution of approximately 160 dpi. The user optionally makes contact with touch screen  112  using any suitable object or appendage, such as a stylus, a finger, and so forth. In some embodiments, the user interface is designed to work primarily with finger-based contacts and gestures, which can be less precise than stylus-based input due to the larger area of contact of a finger on the touch screen. In some embodiments, the device translates the rough finger-based input into a precise pointer/cursor position or command for performing the actions desired by the user. 
     In some embodiments, in addition to the touch screen, device  100  optionally includes a touchpad for activating or deactivating particular functions. In some embodiments, the touchpad is a touch-sensitive area of the device that, unlike the touch screen, does not display visual output. The touchpad is, optionally, a touch-sensitive surface that is separate from touch screen  112  or an extension of the touch-sensitive surface formed by the touch screen. 
     Device  100  also includes power system  162  for powering the various components. Power system  162  optionally includes a power management system, one or more power sources (e.g., battery, alternating current (AC)), a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator (e.g., a light-emitting diode (LED)) and any other components associated with the generation, management and distribution of power in portable devices. 
     Device  100  optionally also includes one or more optical sensors  164 .  FIG.  1 A  shows an optical sensor coupled to optical sensor controller  158  in I/O subsystem  106 . Optical sensor  164  optionally includes charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) phototransistors. Optical sensor  164  receives light from the environment, projected through one or more lenses, and converts the light to data representing an image. In conjunction with imaging module  143  (also called a camera module), optical sensor  164  optionally captures still images or video. In some embodiments, an optical sensor is located on the back of device  100 , opposite touch screen display  112  on the front of the device so that the touch screen display is enabled for use as a viewfinder for still and/or video image acquisition. In some embodiments, an optical sensor is located on the front of the device so that the user&#39;s image is, optionally, obtained for video conferencing while the user views the other video conference participants on the touch screen display. In some embodiments, the position of optical sensor  164  can be changed by the user (e.g., by rotating the lens and the sensor in the device housing) so that a single optical sensor  164  is used along with the touch screen display for both video conferencing and still and/or video image acquisition. 
     Device  100  optionally also includes one or more contact intensity sensors  165 .  FIG.  1 A  shows a contact intensity sensor coupled to intensity sensor controller  159  in I/O subsystem  106 . Contact intensity sensor  165  optionally includes one or more piezoresistive strain gauges, capacitive force sensors, electric force sensors, piezoelectric force sensors, optical force sensors, capacitive touch-sensitive surfaces, or other intensity sensors (e.g., sensors used to measure the force (or pressure) of a contact on a touch-sensitive surface). Contact intensity sensor  165  receives contact intensity information (e.g., pressure information or a proxy for pressure information) from the environment. In some embodiments, at least one contact intensity sensor is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system  112 ). In some embodiments, at least one contact intensity sensor is located on the back of device  100 , opposite touch screen display  112 , which is located on the front of device  100 . 
     Device  100  optionally also includes one or more proximity sensors  166 .  FIG.  1 A  shows proximity sensor  166  coupled to peripherals interface  118 . Alternately, proximity sensor  166  is, optionally, coupled to input controller  160  in I/O subsystem  106 . Proximity sensor  166  optionally performs as described in U.S. patent application Ser. No. 11/241,839, “Proximity Detector In Handheld Device”; Ser. No. 11/240,788, “Proximity Detector In Handheld Device”; Ser. No. 11/620,702, “Using Ambient Light Sensor To Augment Proximity Sensor Output”; Ser. No. 11/586,862, “Automated Response To And Sensing Of User Activity In Portable Devices”; and Ser. No. 11/638,251, “Methods And Systems For Automatic Configuration Of Peripherals,” which are hereby incorporated by reference in their entirety. In some embodiments, the proximity sensor turns off and disables touch screen  112  when the multifunction device is placed near the user&#39;s ear (e.g., when the user is making a phone call). 
     Device  100  optionally also includes one or more tactile output generators  167 .  FIG.  1 A  shows a tactile output generator coupled to haptic feedback controller  161  in I/O subsystem  106 . Tactile output generator  167  optionally includes one or more electroacoustic devices such as speakers or other audio components and/or electromechanical devices that convert energy into linear motion such as a motor, solenoid, electroactive polymer, piezoelectric actuator, electrostatic actuator, or other tactile output generating component (e.g., a component that converts electrical signals into tactile outputs on the device). Contact intensity sensor  165  receives tactile feedback generation instructions from haptic feedback module  133  and generates tactile outputs on device  100  that are capable of being sensed by a user of device  100 . In some embodiments, at least one tactile output generator is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system  112 ) and, optionally, generates a tactile output by moving the touch-sensitive surface vertically (e.g., in/out of a surface of device  100 ) or laterally (e.g., back and forth in the same plane as a surface of device  100 ). In some embodiments, at least one tactile output generator sensor is located on the back of device  100 , opposite touch screen display  112 , which is located on the front of device  100 . 
     Device  100  optionally also includes one or more accelerometers  168 .  FIG.  1 A  shows accelerometer  168  coupled to peripherals interface  118 . Alternately, accelerometer  168  is, optionally, coupled to an input controller  160  in I/O subsystem  106 . Accelerometer  168  optionally performs as described in U.S. Patent Publication No. 20050190059, “Acceleration-based Theft Detection System for Portable Electronic Devices,” and U.S. Patent Publication No. 20060017692, “Methods And Apparatuses For Operating A Portable Device Based On An Accelerometer,” both of which are incorporated by reference herein in their entirety. In some embodiments, information is displayed on the touch screen display in a portrait view or a landscape view based on an analysis of data received from the one or more accelerometers. Device  100  optionally includes, in addition to accelerometer(s)  168 , a magnetometer and a GPS (or GLONASS or other global navigation system) receiver for obtaining information concerning the location and orientation (e.g., portrait or landscape) of device  100 . 
     In some embodiments, device  100  also includes (or is in communication with) one or more fingerprint sensors. The one or more fingerprint sensors are coupled to peripherals interface  118 . Alternately, the one or more fingerprint sensors are, optionally, coupled to an input controller  160  in I/O subsystem  106 . However, in one common embodiment, fingerprint identification operations are performed using secured dedicated computing hardware (e.g., one or more processors, memory and/or communications busses) that has additional security features so as to enhance security of the fingerprint information determined by the one or more fingerprint sensors. As used herein, a fingerprint sensor is a sensor that is capable of distinguishing fingerprint features (sometimes called “minutia features”) of the ridges and valleys of skin such as those found on the fingers and toes of humans. A fingerprint sensor can use any of a variety of techniques to distinguish the fingerprint features, including but not limited to: optical fingerprint imaging, ultrasonic fingerprint imaging, active capacitance fingerprint imaging and passive capacitance fingerprint imaging. In addition to distinguishing fingerprint features in fingerprints, in some embodiments, the one or more fingerprint sensors are capable of tracking movement of fingerprint features over time and thereby determining/characterizing movement of the fingerprint over time on the one or more fingerprint sensors. While the one or more fingerprint sensors can be separate from the touch-sensitive surface (e.g., Touch-Sensitive Display System  112 ), it should be understood that in some implementations, the touch-sensitive surface (e.g., Touch-Sensitive Display System  112 ) has a spatial resolution that is high enough to detect fingerprint features formed by individual fingerprint ridges and is used as a fingerprint sensor instead of, or in addition to, the one or more fingerprint sensors. In some embodiments, device  100  includes a set of one or more orientation sensors that are used to determine an orientation of a finger or hand on or proximate to the device (e.g., an orientation of a finger that is over one or more fingerprint sensors). Additionally, in some embodiments, the set of one or more orientation sensors are used in addition to or instead of a fingerprint sensor to detect rotation of a contact that is interacting with the device (e.g., in one or more of the methods described below, instead of using a fingerprint sensor to detect rotation of a fingerprint/contact, the set of one or more orientation sensors is used to detect rotation of the contact that includes the fingerprint, with or without detecting features of the fingerprint). 
     In some embodiments, features of fingerprints and comparisons between features of detected fingerprints and features of stored fingerprints are performed by secured dedicated computing hardware (e.g., one or more processors, memory and/or communications busses) that are separate from processor(s)  120 , so as to improve security of the fingerprint data generated, stored and processed by the one or more fingerprint sensors. In some embodiments, features of fingerprints and comparisons between features of detected fingerprints and features of enrolled fingerprints are performed by processor(s)  120  using a fingerprint analysis module. 
     In some embodiments, during an enrollment process, the device (e.g., a fingerprint analysis module or a separate secure module in communication with the one or more fingerprint sensors) collects biometric information about one or more fingerprints of the user (e.g., identifying relative location of a plurality of minutia points in a fingerprint of the user). After the enrollment process has been completed the biometric information is stored at the device (e.g., in a secure fingerprint module) for later use in authenticating detected fingerprints. In some embodiments, the biometric information that is stored at the device excludes images of the fingerprints and also excludes information from which images of the fingerprints could be reconstructed so that images of the fingerprints are not inadvertently made available if the security of the device is compromised. In some embodiments, during an authentication process, the device (e.g., a fingerprint analysis module or a separate secure module in communication with the one or more fingerprint sensors) determines whether a finger input detected by the one or more fingerprint sensors includes a fingerprint that matches a previously enrolled fingerprint by collecting biometric information about a fingerprint detected on the one or more fingerprint sensors (e.g., identifying relative locations of a plurality of minutia points in the fingerprint detected on the one or more fingerprint sensors) and comparing the biometric information that corresponds to the detected fingerprint to biometric information that corresponds to the enrolled fingerprints(s). In some embodiments, comparing the biometric information that corresponds to the detected fingerprint to biometric information that corresponds to the enrolled fingerprints(s) includes comparing a type and location of minutia points in the biometric information that corresponds to the detected fingerprint to a type and location of minutia points in the biometric information that corresponds to the enrolled fingerprints. However the determination as to whether or not a finger input includes a fingerprint that matches a previously enrolled fingerprint that is enrolled with the device is, optionally, performed using any of a number of well-known fingerprint authentication techniques for determining whether a detected fingerprint matches an enrolled fingerprint. 
     Device  100  optionally also includes one or more depth camera sensors  175 .  FIG.  1 A  shows a depth camera sensor coupled to depth camera controller  169  in I/O subsystem  106 . Depth camera sensor  175  receives data from the environment to create a three dimensional model of an object (e.g., a face) within a scene from a viewpoint (e.g., a depth camera sensor). In some embodiments, in conjunction with imaging module  143  (also called a camera module), depth camera sensor  175  is optionally used to determine a depth map of different portions of an image captured by the imaging module  143 . In some embodiments, a depth camera sensor is located on the front of device  100  so that the user&#39;s image with depth information is, optionally, obtained for video conferencing while the user views the other video conference participants on the touch screen display and to capture selfies with depth map data. In some embodiments, the depth camera sensor  175  is located on the back of device, or on the back and the front of the device  100 . In some embodiments, the position of depth camera sensor  175  can be changed by the user (e.g., by rotating the lens and the sensor in the device housing) so that a depth camera sensor  175  is used along with the touch screen display for both video conferencing and still and/or video image acquisition. 
     In some embodiments, the software components stored in memory  102  include operating system  126 , communication module (or set of instructions)  128 , contact/motion module (or set of instructions)  130 , graphics module (or set of instructions)  132 , text input module (or set of instructions)  134 , Global Positioning System (GPS) module (or set of instructions)  135 , and applications (or sets of instructions)  136 . Furthermore, in some embodiments, memory  102  ( FIG.  1 A ) or  370  ( FIG.  3   ) stores device/global internal state  157 , as shown in  FIGS.  1 A and  3   . Device/global internal state  157  includes one or more of: active application state, indicating which applications, if any, are currently active; display state, indicating what applications, views or other information occupy various regions of touch screen display  112 ; sensor state, including information obtained from the device&#39;s various sensors and input control devices  116 ; and location information concerning the device&#39;s location and/or attitude. 
     Operating system  126  (e.g., Darwin, RTXC, LINUX, UNIX, OS X, iOS, WINDOWS, or an embedded operating system such as VxWorks) includes various software components and/or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.) and facilitates communication between various hardware and software components. 
     Communication module  128  facilitates communication with other devices over one or more external ports  124  and also includes various software components for handling data received by RF circuitry  108  and/or external port  124 . External port  124  (e.g., Universal Serial Bus (USB), FIREWIRE, etc.) is adapted for coupling directly to other devices or indirectly over a network (e.g., the Internet, wireless LAN, etc.). In some embodiments, the external port is a multi-pin (e.g., 30-pin) connector that is the same as, or similar to and/or compatible with, the 30-pin connector used on iPod® (trademark of Apple Inc.) devices. 
     Contact/motion module  130  optionally detects contact with touch screen  112  (in conjunction with display controller  156 ) and other touch-sensitive devices (e.g., a touchpad or physical click wheel). Contact/motion module  130  includes various software components for performing various operations related to detection of contact, such as determining if contact has occurred (e.g., detecting a finger-down event), determining an intensity of the contact (e.g., the force or pressure of the contact or a substitute for the force or pressure of the contact), determining if there is movement of the contact and tracking the movement across the touch-sensitive surface (e.g., detecting one or more finger-dragging events), and determining if the contact has ceased (e.g., detecting a finger-up event or a break in contact). Contact/motion module  130  receives contact data from the touch-sensitive surface. Determining movement of the point of contact, which is represented by a series of contact data, optionally includes determining speed (magnitude), velocity (magnitude and direction), and/or an acceleration (a change in magnitude and/or direction) of the point of contact. These operations are, optionally, applied to single contacts (e.g., one finger contacts) or to multiple simultaneous contacts (e.g., “multitouch”/multiple finger contacts). In some embodiments, contact/motion module  130  and display controller  156  detect contact on a touchpad. 
     In some embodiments, contact/motion module  130  uses a set of one or more intensity thresholds to determine whether an operation has been performed by a user (e.g., to determine whether a user has “clicked” on an icon). In some embodiments, at least a subset of the intensity thresholds are determined in accordance with software parameters (e.g., the intensity thresholds are not determined by the activation thresholds of particular physical actuators and can be adjusted without changing the physical hardware of device  100 ). For example, a mouse “click” threshold of a trackpad or touch screen display can be set to any of a large range of predefined threshold values without changing the trackpad or touch screen display hardware. Additionally, in some implementations, a user of the device is provided with software settings for adjusting one or more of the set of intensity thresholds (e.g., by adjusting individual intensity thresholds and/or by adjusting a plurality of intensity thresholds at once with a system-level click “intensity” parameter). 
     Contact/motion module  130  optionally detects a gesture input by a user. Different gestures on the touch-sensitive surface have different contact patterns (e.g., different motions, timings, and/or intensities of detected contacts). Thus, a gesture is, optionally, detected by detecting a particular contact pattern. For example, detecting a finger tap gesture includes detecting a finger-down event followed by detecting a finger-up (liftoff) event at the same position (or substantially the same position) as the finger-down event (e.g., at the position of an icon). As another example, detecting a finger swipe gesture on the touch-sensitive surface includes detecting a finger-down event followed by detecting one or more finger-dragging events, and subsequently followed by detecting a finger-up (liftoff) event. 
     Graphics module  132  includes various known software components for rendering and displaying graphics on touch screen  112  or other display, including components for changing the visual impact (e.g., brightness, transparency, saturation, contrast, or other visual property) of graphics that are displayed. As used herein, the term “graphics” includes any object that can be displayed to a user, including, without limitation, text, web pages, icons (such as user-interface objects including soft keys), digital images, videos, animations, and the like. 
     In some embodiments, graphics module  132  stores data representing graphics to be used. Each graphic is, optionally, assigned a corresponding code. Graphics module  132  receives, from applications etc., one or more codes specifying graphics to be displayed along with, if necessary, coordinate data and other graphic property data, and then generates screen image data to output to display controller  156 . 
     Haptic feedback module  133  includes various software components for generating instructions used by tactile output generator(s)  167  to produce tactile outputs at one or more locations on device  100  in response to user interactions with device  100 . 
     Text input module  134 , which is, optionally, a component of graphics module  132 , provides soft keyboards for entering text in various applications (e.g., contacts module  137 , e-mail client module  140 , IM module  141 , browser module  147 , and any other application that needs text input). 
     GPS module  135  determines the location of the device and provides this information for use in various applications (e.g., to telephone module  138  for use in location-based dialing; to camera module  143  as picture/video metadata; and to applications that provide location-based services such as weather widgets, local yellow page widgets, and map/navigation widgets). 
     Applications  136  optionally include the following modules (or sets of instructions), or a subset or superset thereof:
         Contacts module  137  (sometimes called an address book or contact list);   Telephone module  138 ;   Video conference module  139 ;   E-mail client module  140 ;   Instant messaging (IM) module  141 ;   Workout support module  142 ;   Camera module  143  for still and/or video images;   Image management module  144 ;   Video player module;   Music player module;   Browser module  147 ;   Calendar module  148 ;   Widget modules  149 , which optionally include one or more of: weather widget  149 - 1 , stocks widget  149 - 2 , calculator widget  149 - 3 , alarm clock widget  149 - 4 , dictionary widget  149 - 5 , and other widgets obtained by the user, as well as user-created widgets  149 - 6 ;   Widget creator module  150  for making user-created widgets  149 - 6 ;   Search module  151 ;   Video and music player module  152 , which merges video player module and music player module;   Notes module  153 ;   Map module  154 ; and/or   Online video module  155 .       

     Examples of other applications  136  that are, optionally, stored in memory  102  include other word processing applications, other image editing applications, drawing applications, presentation applications, JAVA-enabled applications, encryption, digital rights management, voice recognition, and voice replication. 
     In conjunction with touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , and text input module  134 , contacts module  137  are, optionally, used to manage an address book or contact list (e.g., stored in application internal state  192  of contacts module  137  in memory  102  or memory  370 ), including: adding name(s) to the address book; deleting name(s) from the address book; associating telephone number(s), e-mail address(es), physical address(es) or other information with a name; associating an image with a name; categorizing and sorting names; providing telephone numbers or e-mail addresses to initiate and/or facilitate communications by telephone module  138 , video conference module  139 , e-mail client module  140 , or IM module  141 ; and so forth. 
     In conjunction with RF circuitry  108 , audio circuitry  110 , speaker  111 , microphone  113 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , and text input module  134 , telephone module  138  are optionally, used to enter a sequence of characters corresponding to a telephone number, access one or more telephone numbers in contacts module  137 , modify a telephone number that has been entered, dial a respective telephone number, conduct a conversation, and disconnect or hang up when the conversation is completed. As noted above, the wireless communication optionally uses any of a plurality of communications standards, protocols, and technologies. 
     In conjunction with RF circuitry  108 , audio circuitry  110 , speaker  111 , microphone  113 , touch screen  112 , display controller  156 , optical sensor  164 , optical sensor controller  158 , contact/motion module  130 , graphics module  132 , text input module  134 , contacts module  137 , and telephone module  138 , video conference module  139  includes executable instructions to initiate, conduct, and terminate a video conference between a user and one or more other participants in accordance with user instructions. 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , and text input module  134 , e-mail client module  140  includes executable instructions to create, send, receive, and manage e-mail in response to user instructions. In conjunction with image management module  144 , e-mail client module  140  makes it very easy to create and send e-mails with still or video images taken with camera module  143 . 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , and text input module  134 , the instant messaging module  141  includes executable instructions to enter a sequence of characters corresponding to an instant message, to modify previously entered characters, to transmit a respective instant message (for example, using a Short Message Service (SMS) or Multimedia Message Service (MMS) protocol for telephony-based instant messages or using XMPP, SIMPLE, or IMPS for Internet-based instant messages), to receive instant messages, and to view received instant messages. In some embodiments, transmitted and/or received instant messages optionally include graphics, photos, audio files, video files and/or other attachments as are supported in an MMS and/or an Enhanced Messaging Service (EMS). As used herein, “instant messaging” refers to both telephony-based messages (e.g., messages sent using SMS or MMS) and Internet-based messages (e.g., messages sent using XMPP, SIMPLE, or IMPS). 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , text input module  134 , GPS module  135 , map module  154 , and music player module, workout support module  142  includes executable instructions to create workouts (e.g., with time, distance, and/or calorie burning goals); communicate with workout sensors (sports devices); receive workout sensor data; calibrate sensors used to monitor a workout; select and play music for a workout; and display, store, and transmit workout data. 
     In conjunction with touch screen  112 , display controller  156 , optical sensor(s)  164 , optical sensor controller  158 , contact/motion module  130 , graphics module  132 , and image management module  144 , camera module  143  includes executable instructions to capture still images or video (including a video stream) and store them into memory  102 , modify characteristics of a still image or video, or delete a still image or video from memory  102 . 
     In conjunction with touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , text input module  134 , and camera module  143 , image management module  144  includes executable instructions to arrange, modify (e.g., edit), or otherwise manipulate, label, delete, present (e.g., in a digital slide show or album), and store still and/or video images. 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , and text input module  134 , browser module  147  includes executable instructions to browse the Internet in accordance with user instructions, including searching, linking to, receiving, and displaying web pages or portions thereof, as well as attachments and other files linked to web pages. 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , text input module  134 , e-mail client module  140 , and browser module  147 , calendar module  148  includes executable instructions to create, display, modify, and store calendars and data associated with calendars (e.g., calendar entries, to-do lists, etc.) in accordance with user instructions. 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , text input module  134 , and browser module  147 , widget modules  149  are mini-applications that are, optionally, downloaded and used by a user (e.g., weather widget  149 - 1 , stocks widget  149 - 2 , calculator widget  149 - 3 , alarm clock widget  149 - 4 , and dictionary widget  149 - 5 ) or created by the user (e.g., user-created widget  149 - 6 ). In some embodiments, a widget includes an HTML (Hypertext Markup Language) file, a CSS (Cascading Style Sheets) file, and a JavaScript file. In some embodiments, a widget includes an XML (Extensible Markup Language) file and a JavaScript file (e.g., Yahoo!Widgets). 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , text input module  134 , and browser module  147 , the widget creator module  150  are, optionally, used by a user to create widgets (e.g., turning a user-specified portion of a web page into a widget). 
     In conjunction with touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , and text input module  134 , search module  151  includes executable instructions to search for text, music, sound, image, video, and/or other files in memory  102  that match one or more search criteria (e.g., one or more user-specified search terms) in accordance with user instructions. 
     In conjunction with touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , audio circuitry  110 , speaker  111 , RF circuitry  108 , and browser module  147 , video and music player module  152  includes executable instructions that allow the user to download and play back recorded music and other sound files stored in one or more file formats, such as MP3 or AAC files, and executable instructions to display, present, or otherwise play back videos (e.g., on touch screen  112  or on an external, connected display via external port  124 ). In some embodiments, device  100  optionally includes the functionality of an MP3 player, such as an iPod (trademark of Apple Inc.). 
     In conjunction with touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , and text input module  134 , notes module  153  includes executable instructions to create and manage notes, to-do lists, and the like in accordance with user instructions. 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , text input module  134 , GPS module  135 , and browser module  147 , map module  154  are, optionally, used to receive, display, modify, and store maps and data associated with maps (e.g., driving directions, data on stores and other points of interest at or near a particular location, and other location-based data) in accordance with user instructions. 
     In conjunction with touch screen  112 , display controller  156 , contact/motion module  130 , graphics module  132 , audio circuitry  110 , speaker  111 , RF circuitry  108 , text input module  134 , e-mail client module  140 , and browser module  147 , online video module  155  includes instructions that allow the user to access, browse, receive (e.g., by streaming and/or download), play back (e.g., on the touch screen or on an external, connected display via external port  124 ), send an e-mail with a link to a particular online video, and otherwise manage online videos in one or more file formats, such as H.264. In some embodiments, instant messaging module  141 , rather than e-mail client module  140 , is used to send a link to a particular online video. Additional description of the online video application can be found in U.S. Provisional Patent Application No. 60/936,562, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Jun. 20, 2007, and U.S. patent application Ser. No. 11/968,067, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Dec. 31, 2007, the contents of which are hereby incorporated by reference in their entirety. 
     Each of the above-identified modules and applications corresponds to a set of executable instructions for performing one or more functions described above and the methods described in this application (e.g., the computer-implemented methods and other information processing methods described herein). These modules (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules are, optionally, combined or otherwise rearranged in various embodiments. For example, video player module is, optionally, combined with music player module into a single module (e.g., video and music player module  152 ,  FIG.  1 A ). In some embodiments, memory  102  optionally stores a subset of the modules and data structures identified above. Furthermore, memory  102  optionally stores additional modules and data structures not described above. 
     In some embodiments, device  100  is a device where operation of a predefined set of functions on the device is performed exclusively through a touch screen and/or a touchpad. By using a touch screen and/or a touchpad as the primary input control device for operation of device  100 , the number of physical input control devices (such as push buttons, dials, and the like) on device  100  is, optionally, reduced. 
     The predefined set of functions that are performed exclusively through a touch screen and/or a touchpad optionally include navigation between user interfaces. In some embodiments, the touchpad, when touched by the user, navigates device  100  to a main, home, or root menu from any user interface that is displayed on device  100 . In such embodiments, a “menu button” is implemented using a touchpad. In some other embodiments, the menu button is a physical push button or other physical input control device instead of a touchpad. 
       FIG.  1 B  is a block diagram illustrating exemplary components for event handling in accordance with some embodiments. In some embodiments, memory  102  ( FIG.  1 A ) or  370  ( FIG.  3   ) includes event sorter  170  (e.g., in operating system  126 ) and a respective application  136 - 1  (e.g., any of the aforementioned applications  137 - 151 ,  155 ,  380 - 390 ). 
     Event sorter  170  receives event information and determines the application  136 - 1  and application view  191  of application  136 - 1  to which to deliver the event information. Event sorter  170  includes event monitor  171  and event dispatcher module  174 . In some embodiments, application  136 - 1  includes application internal state  192 , which indicates the current application view(s) displayed on touch-sensitive display  112  when the application is active or executing. In some embodiments, device/global internal state  157  is used by event sorter  170  to determine which application(s) is (are) currently active, and application internal state  192  is used by event sorter  170  to determine application views  191  to which to deliver event information. 
     In some embodiments, application internal state  192  includes additional information, such as one or more of: resume information to be used when application  136 - 1  resumes execution, user interface state information that indicates information being displayed or that is ready for display by application  136 - 1 , a state queue for enabling the user to go back to a prior state or view of application  136 - 1 , and a redo/undo queue of previous actions taken by the user. 
     Event monitor  171  receives event information from peripherals interface  118 . Event information includes information about a sub-event (e.g., a user touch on touch-sensitive display  112 , as part of a multi-touch gesture). Peripherals interface  118  transmits information it receives from I/O subsystem  106  or a sensor, such as proximity sensor  166 , accelerometer(s)  168 , and/or microphone  113  (through audio circuitry  110 ). Information that peripherals interface  118  receives from I/O subsystem  106  includes information from touch-sensitive display  112  or a touch-sensitive surface. 
     In some embodiments, event monitor  171  sends requests to the peripherals interface  118  at predetermined intervals. In response, peripherals interface  118  transmits event information. In other embodiments, peripherals interface  118  transmits event information only when there is a significant event (e.g., receiving an input above a predetermined noise threshold and/or for more than a predetermined duration). 
     In some embodiments, event sorter  170  also includes a hit view determination module  172  and/or an active event recognizer determination module  173 . 
     Hit view determination module  172  provides software procedures for determining where a sub-event has taken place within one or more views when touch-sensitive display  112  displays more than one view. Views are made up of controls and other elements that a user can see on the display. 
     Another aspect of the user interface associated with an application is a set of views, sometimes herein called application views or user interface windows, in which information is displayed and touch-based gestures occur. The application views (of a respective application) in which a touch is detected optionally correspond to programmatic levels within a programmatic or view hierarchy of the application. For example, the lowest level view in which a touch is detected is, optionally, called the hit view, and the set of events that are recognized as proper inputs are, optionally, determined based, at least in part, on the hit view of the initial touch that begins a touch-based gesture. 
     Hit view determination module  172  receives information related to sub-events of a touch-based gesture. When an application has multiple views organized in a hierarchy, hit view determination module  172  identifies a hit view as the lowest view in the hierarchy which should handle the sub-event. In most circumstances, the hit view is the lowest level view in which an initiating sub-event occurs (e.g., the first sub-event in the sequence of sub-events that form an event or potential event). Once the hit view is identified by the hit view determination module  172 , the hit view typically receives all sub-events related to the same touch or input source for which it was identified as the hit view. 
     Active event recognizer determination module  173  determines which view or views within a view hierarchy should receive a particular sequence of sub-events. In some embodiments, active event recognizer determination module  173  determines that only the hit view should receive a particular sequence of sub-events. In other embodiments, active event recognizer determination module  173  determines that all views that include the physical location of a sub-event are actively involved views, and therefore determines that all actively involved views should receive a particular sequence of sub-events. In other embodiments, even if touch sub-events were entirely confined to the area associated with one particular view, views higher in the hierarchy would still remain as actively involved views. 
     Event dispatcher module  174  dispatches the event information to an event recognizer (e.g., event recognizer  180 ). In embodiments including active event recognizer determination module  173 , event dispatcher module  174  delivers the event information to an event recognizer determined by active event recognizer determination module  173 . In some embodiments, event dispatcher module  174  stores in an event queue the event information, which is retrieved by a respective event receiver  182 . 
     In some embodiments, operating system  126  includes event sorter  170 . Alternatively, application  136 - 1  includes event sorter  170 . In yet other embodiments, event sorter  170  is a stand-alone module, or a part of another module stored in memory  102 , such as contact/motion module  130 . 
     In some embodiments, application  136 - 1  includes a plurality of event handlers  190  and one or more application views  191 , each of which includes instructions for handling touch events that occur within a respective view of the application&#39;s user interface. Each application view  191  of the application  136 - 1  includes one or more event recognizers  180 . Typically, a respective application view  191  includes a plurality of event recognizers  180 . In other embodiments, one or more of event recognizers  180  are part of a separate module, such as a user interface kit or a higher level object from which application  136 - 1  inherits methods and other properties. In some embodiments, a respective event handler  190  includes one or more of: data updater  176 , object updater  177 , GUI updater  178 , and/or event data  179  received from event sorter  170 . Event handler  190  optionally utilizes or calls data updater  176 , object updater  177 , or GUI updater  178  to update the application internal state  192 . Alternatively, one or more of the application views  191  include one or more respective event handlers  190 . Also, in some embodiments, one or more of data updater  176 , object updater  177 , and GUI updater  178  are included in a respective application view  191 . 
     A respective event recognizer  180  receives event information (e.g., event data  179 ) from event sorter  170  and identifies an event from the event information. Event recognizer  180  includes event receiver  182  and event comparator  184 . In some embodiments, event recognizer  180  also includes at least a subset of: metadata  183 , and event delivery instructions  188  (which optionally include sub-event delivery instructions). 
     Event receiver  182  receives event information from event sorter  170 . The event information includes information about a sub-event, for example, a touch or a touch movement. Depending on the sub-event, the event information also includes additional information, such as location of the sub-event. When the sub-event concerns motion of a touch, the event information optionally also includes speed and direction of the sub-event. In some embodiments, events include rotation of the device from one orientation to another (e.g., from a portrait orientation to a landscape orientation, or vice versa), and the event information includes corresponding information about the current orientation (also called device attitude) of the device. 
     Event comparator  184  compares the event information to predefined event or sub-event definitions and, based on the comparison, determines an event or sub-event, or determines or updates the state of an event or sub-event. In some embodiments, event comparator  184  includes event definitions  186 . Event definitions  186  contain definitions of events (e.g., predefined sequences of sub-events), for example, event  1  ( 187 - 1 ), event  2  ( 187 - 2 ), and others. In some embodiments, sub-events in an event ( 187 ) include, for example, touch begin, touch end, touch movement, touch cancellation, and multiple touching. In one example, the definition for event  1  ( 187 - 1 ) is a double tap on a displayed object. The double tap, for example, comprises a first touch (touch begin) on the displayed object for a predetermined phase, a first liftoff (touch end) for a predetermined phase, a second touch (touch begin) on the displayed object for a predetermined phase, and a second liftoff (touch end) for a predetermined phase. In another example, the definition for event  2  ( 187 - 2 ) is a dragging on a displayed object. The dragging, for example, comprises a touch (or contact) on the displayed object for a predetermined phase, a movement of the touch across touch-sensitive display  112 , and liftoff of the touch (touch end). In some embodiments, the event also includes information for one or more associated event handlers  190 . 
     In some embodiments, event definition  187  includes a definition of an event for a respective user-interface object. In some embodiments, event comparator  184  performs a hit test to determine which user-interface object is associated with a sub-event. For example, in an application view in which three user-interface objects are displayed on touch-sensitive display  112 , when a touch is detected on touch-sensitive display  112 , event comparator  184  performs a hit test to determine which of the three user-interface objects is associated with the touch (sub-event). If each displayed object is associated with a respective event handler  190 , the event comparator uses the result of the hit test to determine which event handler  190  should be activated. For example, event comparator  184  selects an event handler associated with the sub-event and the object triggering the hit test. 
     In some embodiments, the definition for a respective event ( 187 ) also includes delayed actions that delay delivery of the event information until after it has been determined whether the sequence of sub-events does or does not correspond to the event recognizer&#39;s event type. 
     When a respective event recognizer  180  determines that the series of sub-events do not match any of the events in event definitions  186 , the respective event recognizer  180  enters an event impossible, event failed, or event ended state, after which it disregards subsequent sub-events of the touch-based gesture. In this situation, other event recognizers, if any, that remain active for the hit view continue to track and process sub-events of an ongoing touch-based gesture. 
     In some embodiments, a respective event recognizer  180  includes metadata  183  with configurable properties, flags, and/or lists that indicate how the event delivery system should perform sub-event delivery to actively involved event recognizers. In some embodiments, metadata  183  includes configurable properties, flags, and/or lists that indicate how event recognizers interact, or are enabled to interact, with one another. In some embodiments, metadata  183  includes configurable properties, flags, and/or lists that indicate whether sub-events are delivered to varying levels in the view or programmatic hierarchy. 
     In some embodiments, a respective event recognizer  180  activates event handler  190  associated with an event when one or more particular sub-events of an event are recognized. In some embodiments, a respective event recognizer  180  delivers event information associated with the event to event handler  190 . Activating an event handler  190  is distinct from sending (and deferred sending) sub-events to a respective hit view. In some embodiments, event recognizer  180  throws a flag associated with the recognized event, and event handler  190  associated with the flag catches the flag and performs a predefined process. 
     In some embodiments, event delivery instructions  188  include sub-event delivery instructions that deliver event information about a sub-event without activating an event handler. Instead, the sub-event delivery instructions deliver event information to event handlers associated with the series of sub-events or to actively involved views. Event handlers associated with the series of sub-events or with actively involved views receive the event information and perform a predetermined process. 
     In some embodiments, data updater  176  creates and updates data used in application  136 - 1 . For example, data updater  176  updates the telephone number used in contacts module  137 , or stores a video file used in video player module. In some embodiments, object updater  177  creates and updates objects used in application  136 - 1 . For example, object updater  177  creates a new user-interface object or updates the position of a user-interface object. GUI updater  178  updates the GUI. For example, GUI updater  178  prepares display information and sends it to graphics module  132  for display on a touch-sensitive display. 
     In some embodiments, event handler(s)  190  includes or has access to data updater  176 , object updater  177 , and GUI updater  178 . In some embodiments, data updater  176 , object updater  177 , and GUI updater  178  are included in a single module of a respective application  136 - 1  or application view  191 . In other embodiments, they are included in two or more software modules. 
       FIG.  1 C  is a block diagram illustrating a tactile output module in accordance with some embodiments. In some embodiments, I/O subsystem  106  (e.g., haptic feedback controller  161  ( FIG.  1 A ) and/or other input controller(s)  160  ( FIG.  1 A )) includes at least some of the example components shown in  FIG.  1 C . In some embodiments, peripherals interface  118  includes at least some of the example components shown in  FIG.  1 C . 
     In some embodiments, the tactile output module includes haptic feedback module  133 . In some embodiments, haptic feedback module  133  aggregates and combines tactile outputs for user interface feedback from software applications on the electronic device (e.g., feedback that is responsive to user inputs that correspond to displayed user interfaces and alerts and other notifications that indicate the performance of operations or occurrence of events in user interfaces of the electronic device). Haptic feedback module  133  includes one or more of: waveform module  123  (for providing waveforms used for generating tactile outputs), mixer  125  (for mixing waveforms, such as waveforms in different channels), compressor  127  (for reducing or compressing a dynamic range of the waveforms), low-pass filter  129  (for filtering out high frequency signal components in the waveforms), and thermal controller  131  (for adjusting the waveforms in accordance with thermal conditions). In some embodiments, haptic feedback module  133  is included in haptic feedback controller  161  ( FIG.  1 A ). In some embodiments, a separate unit of haptic feedback module  133  (or a separate implementation of haptic feedback module  133 ) is also included in an audio controller (e.g., audio circuitry  110 ,  FIG.  1 A ) and used for generating audio signals. In some embodiments, a single haptic feedback module  133  is used for generating audio signals and generating waveforms for tactile outputs. 
     In some embodiments, haptic feedback module  133  also includes trigger module  121  (e.g., a software application, operating system, or other software module that determines a tactile output is to be generated and initiates the process for generating the corresponding tactile output). In some embodiments, trigger module  121  generates trigger signals for initiating generation of waveforms (e.g., by waveform module  123 ). For example, trigger module  121  generates trigger signals based on preset timing criteria. In some embodiments, trigger module  121  receives trigger signals from outside haptic feedback module  133  (e.g., in some embodiments, haptic feedback module  133  receives trigger signals from hardware input processing module  146  located outside haptic feedback module  133 ) and relays the trigger signals to other components within haptic feedback module  133  (e.g., waveform module  123 ) or software applications that trigger operations (e.g., with trigger module  121 ) based on activation of a user interface element (e.g., an application icon or an affordance within an application) or a hardware input device (e.g., a home button or an intensity-sensitive input surface, such as an intensity-sensitive touch screen). In some embodiments, trigger module  121  also receives tactile feedback generation instructions (e.g., from haptic feedback module  133 ,  FIGS.  1 A and  3   ). In some embodiments, trigger module  121  generates trigger signals in response to haptic feedback module  133  (or trigger module  121  in haptic feedback module  133 ) receiving tactile feedback instructions (e.g., from haptic feedback module  133 ,  FIGS.  1 A and  3   ). 
     Waveform module  123  receives trigger signals (e.g., from trigger module  121 ) as an input, and in response to receiving trigger signals, provides waveforms for generation of one or more tactile outputs (e.g., waveforms selected from a predefined set of waveforms designated for use by waveform module  123 , such as the waveforms described in greater detail below with reference to  FIGS.  4 C- 4 D ). 
     Mixer  125  receives waveforms (e.g., from waveform module  123 ) as an input, and mixes together the waveforms. For example, when mixer  125  receives two or more waveforms (e.g., a first waveform in a first channel and a second waveform that at least partially overlaps with the first waveform in a second channel) mixer  125  outputs a combined waveform that corresponds to a sum of the two or more waveforms. In some embodiments, mixer  125  also modifies one or more waveforms of the two or more waveforms to emphasize particular waveform(s) over the rest of the two or more waveforms (e.g., by increasing a scale of the particular waveform(s) and/or decreasing a scale of the rest of the waveforms). In some circumstances, mixer  125  selects one or more waveforms to remove from the combined waveform (e.g., the waveform from the oldest source is dropped when there are waveforms from more than three sources that have been requested to be output concurrently by tactile output generator  167 ). 
     Compressor  127  receives waveforms (e.g., a combined waveform from mixer  125 ) as an input, and modifies the waveforms. In some embodiments, compressor  127  reduces the waveforms (e.g., in accordance with physical specifications of tactile output generators  167  ( FIG.  1 A ) or  357  ( FIG.  3   )) so that tactile outputs corresponding to the waveforms are reduced. In some embodiments, compressor  127  limits the waveforms, such as by enforcing a predefined maximum amplitude for the waveforms. For example, compressor  127  reduces amplitudes of portions of waveforms that exceed a predefined amplitude threshold while maintaining amplitudes of portions of waveforms that do not exceed the predefined amplitude threshold. In some embodiments, compressor  127  reduces a dynamic range of the waveforms. In some embodiments, compressor  127  dynamically reduces the dynamic range of the waveforms so that the combined waveforms remain within performance specifications of the tactile output generator  167  (e.g., force and/or moveable mass displacement limits). 
     Low-pass filter  129  receives waveforms (e.g., compressed waveforms from compressor  127 ) as an input, and filters (e.g., smooths) the waveforms (e.g., removes or reduces high frequency signal components in the waveforms). For example, in some instances, compressor  127  includes, in compressed waveforms, extraneous signals (e.g., high frequency signal components) that interfere with the generation of tactile outputs and/or exceed performance specifications of tactile output generator  167  when the tactile outputs are generated in accordance with the compressed waveforms. Low-pass filter  129  reduces or removes such extraneous signals in the waveforms. 
     Thermal controller  131  receives waveforms (e.g., filtered waveforms from low-pass filter  129 ) as an input, and adjusts the waveforms in accordance with thermal conditions of device  100  (e.g., based on internal temperatures detected within device  100 , such as the temperature of haptic feedback controller  161 , and/or external temperatures detected by device  100 ). For example, in some cases, the output of haptic feedback controller  161  varies depending on the temperature (e.g. haptic feedback controller  161 , in response to receiving same waveforms, generates a first tactile output when haptic feedback controller  161  is at a first temperature and generates a second tactile output when haptic feedback controller  161  is at a second temperature that is distinct from the first temperature). For example, the magnitude (or the amplitude) of the tactile outputs can vary depending on the temperature. To reduce the effect of the temperature variations, the waveforms are modified (e.g., an amplitude of the waveforms is increased or decreased based on the temperature). 
     In some embodiments, haptic feedback module  133  (e.g., trigger module  121 ) is coupled to hardware input processing module  146 . In some embodiments, other input controller(s)  160  in  FIG.  1 A  includes hardware input processing module  146 . In some embodiments, hardware input processing module  146  receives inputs from hardware input device  145  (e.g., other input or control devices  116  in  FIG.  1 A , such as a home button or an intensity-sensitive input surface, such as an intensity-sensitive touch screen). In some embodiments, hardware input device  145  is any input device described herein, such as touch-sensitive display system  112  ( FIG.  1 A ), keyboard/mouse  350  ( FIG.  3   ), touchpad  355  ( FIG.  3   ), one of other input or control devices  116  ( FIG.  1 A ), or an intensity-sensitive home button. In some embodiments, hardware input device  145  consists of an intensity-sensitive home button, and not touch-sensitive display system  112  ( FIG.  1 A ), keyboard/mouse  350  ( FIG.  3   ), or touchpad  355  ( FIG.  3   ). In some embodiments, in response to inputs from hardware input device  145  (e.g., an intensity-sensitive home button or a touch screen), hardware input processing module  146  provides one or more trigger signals to haptic feedback module  133  to indicate that a user input satisfying predefined input criteria, such as an input corresponding to a “click” of a home button (e.g., a “down click” or an “up click”), has been detected. In some embodiments, haptic feedback module  133  provides waveforms that correspond to the “click” of a home button in response to the input corresponding to the “click” of a home button, simulating a haptic feedback of pressing a physical home button. 
     In some embodiments, the tactile output module includes haptic feedback controller  161  (e.g., haptic feedback controller  161  in  FIG.  1 A ), which controls the generation of tactile outputs. In some embodiments, haptic feedback controller  161  is coupled to a plurality of tactile output generators, and selects one or more tactile output generators of the plurality of tactile output generators and sends waveforms to the selected one or more tactile output generators for generating tactile outputs. In some embodiments, haptic feedback controller  161  coordinates tactile output requests that correspond to activation of hardware input device  145  and tactile output requests that correspond to software events (e.g., tactile output requests from haptic feedback module  133 ) and modifies one or more waveforms of the two or more waveforms to emphasize particular waveform(s) over the rest of the two or more waveforms (e.g., by increasing a scale of the particular waveform(s) and/or decreasing a scale of the rest of the waveforms, such as to prioritize tactile outputs that correspond to activations of hardware input device  145  over tactile outputs that correspond to software events). 
     In some embodiments, as shown in  FIG.  1 C , an output of haptic feedback controller  161  is coupled to audio circuitry of device  100  (e.g., audio circuitry  110 ,  FIG.  1 A ), and provides audio signals to audio circuitry of device  100 . In some embodiments, haptic feedback controller  161  provides both waveforms used for generating tactile outputs and audio signals used for providing audio outputs in conjunction with generation of the tactile outputs. In some embodiments, haptic feedback controller  161  modifies audio signals and/or waveforms (used for generating tactile outputs) so that the audio outputs and the tactile outputs are synchronized (e.g., by delaying the audio signals and/or waveforms). In some embodiments, haptic feedback controller  161  includes a digital-to-analog converter used for converting digital waveforms into analog signals, which are received by amplifier  163  and/or tactile output generator  167 . 
     In some embodiments, the tactile output module includes amplifier  163 . In some embodiments, amplifier  163  receives waveforms (e.g., from haptic feedback controller  161 ) and amplifies the waveforms prior to sending the amplified waveforms to tactile output generator  167  (e.g., any of tactile output generators  167  ( FIG.  1 A ) or  357  ( FIG.  3   )). For example, amplifier  163  amplifies the received waveforms to signal levels that are in accordance with physical specifications of tactile output generator  167  (e.g., to a voltage and/or a current required by tactile output generator  167  for generating tactile outputs so that the signals sent to tactile output generator  167  produce tactile outputs that correspond to the waveforms received from haptic feedback controller  161 ) and sends the amplified waveforms to tactile output generator  167 . In response, tactile output generator  167  generates tactile outputs (e.g., by shifting a moveable mass back and forth in one or more dimensions relative to a neutral position of the moveable mass). 
     In some embodiments, the tactile output module includes sensor  169 , which is coupled to tactile output generator  167 . Sensor  169  detects states or state changes (e.g., mechanical position, physical displacement, and/or movement) of tactile output generator  167  or one or more components of tactile output generator  167  (e.g., one or more moving parts, such as a membrane, used to generate tactile outputs). In some embodiments, sensor  169  is a magnetic field sensor (e.g., a Hall effect sensor) or other displacement and/or movement sensor. In some embodiments, sensor  169  provides information (e.g., a position, a displacement, and/or a movement of one or more parts in tactile output generator  167 ) to haptic feedback controller  161  and, in accordance with the information provided by sensor  169  about the state of tactile output generator  167 , haptic feedback controller  161  adjusts the waveforms output from haptic feedback controller  161  (e.g., waveforms sent to tactile output generator  167 , optionally via amplifier  163 ). 
     It shall be understood that the foregoing discussion regarding event handling of user touches on touch-sensitive displays also applies to other forms of user inputs to operate multifunction devices  100  with input devices, not all of which are initiated on touch screens. For example, mouse movement and mouse button presses, optionally coordinated with single or multiple keyboard presses or holds; contact movements such as taps, drags, scrolls, etc. on touchpads; pen stylus inputs; movement of the device; oral instructions; detected eye movements; biometric inputs; and/or any combination thereof are optionally utilized as inputs corresponding to sub-events which define an event to be recognized. 
       FIG.  2    illustrates a portable multifunction device  100  having a touch screen  112  in accordance with some embodiments. The touch screen optionally displays one or more graphics within user interface (UI)  200 . In this embodiment, as well as others described below, a user is enabled to select one or more of the graphics by making a gesture on the graphics, for example, with one or more fingers  202  (not drawn to scale in the figure) or one or more styluses  203  (not drawn to scale in the figure). In some embodiments, selection of one or more graphics occurs when the user breaks contact with the one or more graphics. In some embodiments, the gesture optionally includes one or more taps, one or more swipes (from left to right, right to left, upward and/or downward), and/or a rolling of a finger (from right to left, left to right, upward and/or downward) that has made contact with device  100 . In some implementations or circumstances, inadvertent contact with a graphic does not select the graphic. For example, a swipe gesture that sweeps over an application icon optionally does not select the corresponding application when the gesture corresponding to selection is a tap. 
     Device  100  optionally also include one or more physical buttons, such as “home” or menu button  204 . As described previously, menu button  204  is, optionally, used to navigate to any application  136  in a set of applications that are, optionally, executed on device  100 . Alternatively, in some embodiments, the menu button is implemented as a soft key in a GUI displayed on touch screen  112 . 
     In some embodiments, device  100  includes touch screen  112 , menu button  204 , push button  206  for powering the device on/off and locking the device, volume adjustment button(s)  208 , subscriber identity module (SIM) card slot  210 , headset jack  212 , and docking/charging external port  124 . Push button  206  is, optionally, used to turn the power on/off on the device by depressing the button and holding the button in the depressed state for a predefined time interval; to lock the device by depressing the button and releasing the button before the predefined time interval has elapsed; and/or to unlock the device or initiate an unlock process. In an alternative embodiment, device  100  also accepts verbal input for activation or deactivation of some functions through microphone  113 . Device  100  also, optionally, includes one or more contact intensity sensors  165  for detecting intensity of contacts on touch screen  112  and/or one or more tactile output generators  167  for generating tactile outputs for a user of device  100 . 
       FIG.  3    is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments. Device  300  need not be portable. In some embodiments, device  300  is a laptop computer, a desktop computer, a tablet computer, a multimedia player device, a navigation device, an educational device (such as a child&#39;s learning toy), a gaming system, or a control device (e.g., a home or industrial controller). Device  300  typically includes one or more processing units (CPUs)  310 , one or more network or other communications interfaces  360 , memory  370 , and one or more communication buses  320  for interconnecting these components. Communication buses  320  optionally include circuitry (sometimes called a chipset) that interconnects and controls communications between system components. Device  300  includes input/output (I/O) interface  330  comprising display  340 , which is typically a touch screen display. I/O interface  330  also optionally includes a keyboard and/or mouse (or other pointing device)  350  and touchpad  355 , tactile output generator  357  for generating tactile outputs on device  300  (e.g., similar to tactile output generator(s)  167  described above with reference to  FIG.  1 A ), sensors  359  (e.g., optical, acceleration, proximity, touch-sensitive, and/or contact intensity sensors similar to contact intensity sensor(s)  165  described above with reference to  FIG.  1 A ). Memory  370  includes high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices; and optionally includes non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. Memory  370  optionally includes one or more storage devices remotely located from CPU(s)  310 . In some embodiments, memory  370  stores programs, modules, and data structures analogous to the programs, modules, and data structures stored in memory  102  of portable multifunction device  100  ( FIG.  1 A ), or a subset thereof. Furthermore, memory  370  optionally stores additional programs, modules, and data structures not present in memory  102  of portable multifunction device  100 . For example, memory  370  of device  300  optionally stores drawing module  380 , presentation module  382 , word processing module  384 , website creation module  386 , disk authoring module  388 , and/or spreadsheet module  390 , while memory  102  of portable multifunction device  100  ( FIG.  1 A ) optionally does not store these modules. 
     Each of the above-identified elements in  FIG.  3    is, optionally, stored in one or more of the previously mentioned memory devices. Each of the above-identified modules corresponds to a set of instructions for performing a function described above. The above-identified modules or programs (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules are, optionally, combined or otherwise rearranged in various embodiments. In some embodiments, memory  370  optionally stores a subset of the modules and data structures identified above. Furthermore, memory  370  optionally stores additional modules and data structures not described above. 
     Attention is now directed towards embodiments of user interfaces that are, optionally, implemented on, for example, portable multifunction device  100 . 
       FIG.  4 A  illustrates an exemplary user interface for a menu of applications on portable multifunction device  100  in accordance with some embodiments. Similar user interfaces are, optionally, implemented on device  300 . In some embodiments, user interface  400  includes the following elements, or a subset or superset thereof:
         Signal strength indicator(s)  402  for wireless communication(s), such as cellular and Wi-Fi signals;   Time  404 ;   Bluetooth indicator  405 ;   Battery status indicator  406 ;   Tray  408  with icons for frequently used applications, such as:
           Icon  416  for telephone module  138 , labeled “Phone,” which optionally includes an indicator  414  of the number of missed calls or voicemail messages;   Icon  418  for e-mail client module  140 , labeled “Mail,” which optionally includes an indicator  410  of the number of unread e-mails;   Icon  420  for browser module  147 , labeled “Browser;” and   Icon  422  for video and music player module  152 , also referred to as iPod (trademark of Apple Inc.) module  152 , labeled “iPod;” and   
           Icons for other applications, such as:
           Icon  424  for IM module  141 , labeled “Messages;”   Icon  426  for calendar module  148 , labeled “Calendar;”   Icon  428  for image management module  144 , labeled “Photos;”   Icon  430  for camera module  143 , labeled “Camera;”   Icon  432  for online video module  155 , labeled “Online Video;”   Icon  434  for stocks widget  149 - 2 , labeled “Stocks;”   Icon  436  for map module  154 , labeled “Maps;”   Icon  438  for weather widget  149 - 1 , labeled “Weather;”   Icon  440  for alarm clock widget  149 - 4 , labeled “Clock;”   Icon  442  for workout support module  142 , labeled “Workout Support;”   Icon  444  for notes module  153 , labeled “Notes;” and   Icon  446  for a settings application or module, labeled “Settings,” which provides access to settings for device  100  and its various applications  136 .   
               

     It should be noted that the icon labels illustrated in  FIG.  4 A  are merely exemplary. For example, icon  422  for video and music player module  152  is labeled “Music” or “Music Player.” Other labels are, optionally, used for various application icons. In some embodiments, a label for a respective application icon includes a name of an application corresponding to the respective application icon. In some embodiments, a label for a particular application icon is distinct from a name of an application corresponding to the particular application icon. 
       FIG.  4 B  illustrates an exemplary user interface on a device (e.g., device  300 ,  FIG.  3   ) with a touch-sensitive surface  451  (e.g., a tablet or touchpad  355 ,  FIG.  3   ) that is separate from the display  450  (e.g., touch screen display  112 ). Device  300  also, optionally, includes one or more contact intensity sensors (e.g., one or more of sensors  359 ) for detecting intensity of contacts on touch-sensitive surface  451  and/or one or more tactile output generators  357  for generating tactile outputs for a user of device  300 . 
     Although some of the examples that follow will be given with reference to inputs on touch screen display  112  (where the touch-sensitive surface and the display are combined), in some embodiments, the device detects inputs on a touch-sensitive surface that is separate from the display, as shown in  FIG.  4 B . In some embodiments, the touch-sensitive surface (e.g.,  451  in  FIG.  4 B ) has a primary axis (e.g.,  452  in  FIG.  4 B ) that corresponds to a primary axis (e.g.,  453  in  FIG.  4 B ) on the display (e.g.,  450 ). In accordance with these embodiments, the device detects contacts (e.g.,  460  and  462  in  FIG.  4 B ) with the touch-sensitive surface  451  at locations that correspond to respective locations on the display (e.g., in  FIG.  4 B,  460    corresponds to  468  and  462  corresponds to  470 ). In this way, user inputs (e.g., contacts  460  and  462 , and movements thereof) detected by the device on the touch-sensitive surface (e.g.,  451  in  FIG.  4 B ) are used by the device to manipulate the user interface on the display (e.g.,  450  in  FIG.  4 B ) of the multifunction device when the touch-sensitive surface is separate from the display. It should be understood that similar methods are, optionally, used for other user interfaces described herein. 
     Additionally, while the following examples are given primarily with reference to finger inputs (e.g., finger contacts, finger tap gestures, finger swipe gestures), it should be understood that, in some embodiments, one or more of the finger inputs are replaced with input from another input device (e.g., a mouse-based input or stylus input). For example, a swipe gesture is, optionally, replaced with a mouse click (e.g., instead of a contact) followed by movement of the cursor along the path of the swipe (e.g., instead of movement of the contact). As another example, a tap gesture is, optionally, replaced with a mouse click while the cursor is located over the location of the tap gesture (e.g., instead of detection of the contact followed by ceasing to detect the contact). Similarly, when multiple user inputs are simultaneously detected, it should be understood that multiple computer mice are, optionally, used simultaneously, or a mouse and finger contacts are, optionally, used simultaneously. 
       FIG.  5 A  illustrates exemplary personal electronic device  500 . Device  500  includes body  502 . In some embodiments, device  500  can include some or all of the features described with respect to devices  100  and  300  (e.g.,  FIGS.  1 A- 4 B ). In some embodiments, device  500  has touch-sensitive display screen  504 , hereafter touch screen  504 . Alternatively, or in addition to touch screen  504 , device  500  has a display and a touch-sensitive surface. As with devices  100  and  300 , in some embodiments, touch screen  504  (or the touch-sensitive surface) optionally includes one or more intensity sensors for detecting intensity of contacts (e.g., touches) being applied. The one or more intensity sensors of touch screen  504  (or the touch-sensitive surface) can provide output data that represents the intensity of touches. The user interface of device  500  can respond to touches based on their intensity, meaning that touches of different intensities can invoke different user interface operations on device  500 . 
     Exemplary techniques for detecting and processing touch intensity are found, for example, in related applications: International Patent Application Serial No. PCT/US2013/040061, titled “Device, Method, and Graphical User Interface for Displaying User Interface Objects Corresponding to an Application,” filed May 8, 2013, published as WIPO Publication No. WO/2013/169849, and International Patent Application Serial No. PCT/US2013/069483, titled “Device, Method, and Graphical User Interface for Transitioning Between Touch Input to Display Output Relationships,” filed Nov. 11, 2013, published as WIPO Publication No. WO/2014/105276, each of which is hereby incorporated by reference in their entirety. 
     In some embodiments, device  500  has one or more input mechanisms  506  and  508 . Input mechanisms  506  and  508 , if included, can be physical. Examples of physical input mechanisms include push buttons and rotatable mechanisms. In some embodiments, device  500  has one or more attachment mechanisms. Such attachment mechanisms, if included, can permit attachment of device  500  with, for example, hats, eyewear, earrings, necklaces, shirts, jackets, bracelets, watch straps, chains, trousers, belts, shoes, purses, backpacks, and so forth. These attachment mechanisms permit device  500  to be worn by a user. 
       FIG.  5 B  depicts exemplary personal electronic device  500 . In some embodiments, device  500  can include some or all of the components described with respect to  FIGS.  1 A,  1 B , and  3 . Device  500  has bus  512  that operatively couples I/O section  514  with one or more computer processors  516  and memory  518 . I/O section  514  can be connected to display  504 , which can have touch-sensitive component  522  and, optionally, intensity sensor  524  (e.g., contact intensity sensor). In addition, I/O section  514  can be connected with communication unit  530  for receiving application and operating system data, using Wi-Fi, Bluetooth, near field communication (NFC), cellular, and/or other wireless communication techniques. Device  500  can include input mechanisms  506  and/or  508 . Input mechanism  506  is, optionally, a rotatable input device or a depressible and rotatable input device, for example. Input mechanism  508  is, optionally, a button, in some examples. 
     Input mechanism  508  is, optionally, a microphone, in some examples. Personal electronic device  500  optionally includes various sensors, such as GPS sensor  532 , accelerometer  534 , directional sensor  540  (e.g., compass), gyroscope  536 , motion sensor  538 , and/or a combination thereof, all of which can be operatively connected to I/O section  514 . 
     Memory  518  of personal electronic device  500  can include one or more non-transitory computer-readable storage mediums, for storing computer-executable instructions, which, when executed by one or more computer processors  516 , for example, can cause the computer processors to perform the techniques described below, including methods  800 ,  1000 ,  1200 , and  1400  ( FIGS.  8 ,  10 ,  12 , and  14   ). A computer-readable storage medium can be any medium that can tangibly contain or store computer-executable instructions for use by or in connection with the instruction execution system, apparatus, or device. In some examples, the storage medium is a transitory computer-readable storage medium. In some examples, the storage medium is a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium can include, but is not limited to, magnetic, optical, and/or semiconductor storages. Examples of such storage include magnetic disks, optical discs based on CD, DVD, or Blu-ray technologies, as well as persistent solid-state memory such as flash, solid-state drives, and the like. Personal electronic device  500  is not limited to the components and configuration of  FIG.  5 B , but can include other or additional components in multiple configurations. 
     As used here, the term “affordance” refers to a user-interactive graphical user interface object that is, optionally, displayed on the display screen of devices  100 ,  300 , and/or  500  ( FIGS.  1 A,  3 , and  5 A- 5 B ). For example, an image (e.g., icon), a button, and text (e.g., hyperlink) each optionally constitute an affordance. 
     As used herein, the term “focus selector” refers to an input element that indicates a current part of a user interface with which a user is interacting. In some implementations that include a cursor or other location marker, the cursor acts as a “focus selector” so that when an input (e.g., a press input) is detected on a touch-sensitive surface (e.g., touchpad  355  in  FIG.  3    or touch-sensitive surface  451  in  FIG.  4 B ) while the cursor is over a particular user interface element (e.g., a button, window, slider, or other user interface element), the particular user interface element is adjusted in accordance with the detected input. In some implementations that include a touch screen display (e.g., touch-sensitive display system  112  in  FIG.  1 A  or touch screen  112  in  FIG.  4 A ) that enables direct interaction with user interface elements on the touch screen display, a detected contact on the touch screen acts as a “focus selector” so that when an input (e.g., a press input by the contact) is detected on the touch screen display at a location of a particular user interface element (e.g., a button, window, slider, or other user interface element), the particular user interface element is adjusted in accordance with the detected input. In some implementations, focus is moved from one region of a user interface to another region of the user interface without corresponding movement of a cursor or movement of a contact on a touch screen display (e.g., by using a tab key or arrow keys to move focus from one button to another button); in these implementations, the focus selector moves in accordance with movement of focus between different regions of the user interface. Without regard to the specific form taken by the focus selector, the focus selector is generally the user interface element (or contact on a touch screen display) that is controlled by the user so as to communicate the user&#39;s intended interaction with the user interface (e.g., by indicating, to the device, the element of the user interface with which the user is intending to interact). For example, the location of a focus selector (e.g., a cursor, a contact, or a selection box) over a respective button while a press input is detected on the touch-sensitive surface (e.g., a touchpad or touch screen) will indicate that the user is intending to activate the respective button (as opposed to other user interface elements shown on a display of the device). 
     As used in the specification and claims, the term “characteristic intensity” of a contact refers to a characteristic of the contact based on one or more intensities of the contact. In some embodiments, the characteristic intensity is based on multiple intensity samples. The characteristic intensity is, optionally, based on a predefined number of intensity samples, or a set of intensity samples collected during a predetermined time period (e.g., 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10 seconds) relative to a predefined event (e.g., after detecting the contact, prior to detecting liftoff of the contact, before or after detecting a start of movement of the contact, prior to detecting an end of the contact, before or after detecting an increase in intensity of the contact, and/or before or after detecting a decrease in intensity of the contact). A characteristic intensity of a contact is, optionally, based on one or more of: a maximum value of the intensities of the contact, a mean value of the intensities of the contact, an average value of the intensities of the contact, a top 10 percentile value of the intensities of the contact, a value at the half maximum of the intensities of the contact, a value at the 90 percent maximum of the intensities of the contact, or the like. In some embodiments, the duration of the contact is used in determining the characteristic intensity (e.g., when the characteristic intensity is an average of the intensity of the contact over time). In some embodiments, the characteristic intensity is compared to a set of one or more intensity thresholds to determine whether an operation has been performed by a user. For example, the set of one or more intensity thresholds optionally includes a first intensity threshold and a second intensity threshold. In this example, a contact with a characteristic intensity that does not exceed the first threshold results in a first operation, a contact with a characteristic intensity that exceeds the first intensity threshold and does not exceed the second intensity threshold results in a second operation, and a contact with a characteristic intensity that exceeds the second threshold results in a third operation. In some embodiments, a comparison between the characteristic intensity and one or more thresholds is used to determine whether or not to perform one or more operations (e.g., whether to perform a respective operation or forgo performing the respective operation), rather than being used to determine whether to perform a first operation or a second operation. 
       FIG.  5 C  illustrates detecting a plurality of contacts  552 A- 552 E on touch-sensitive display screen  504  with a plurality of intensity sensors  524 A- 524 D.  FIG.  5 C  additionally includes intensity diagrams that show the current intensity measurements of the intensity sensors  524 A- 524 D relative to units of intensity. In this example, the intensity measurements of intensity sensors  524 A and  524 D are each 9 units of intensity, and the intensity measurements of intensity sensors  524 B and  524 C are each 7 units of intensity. In some implementations, an aggregate intensity is the sum of the intensity measurements of the plurality of intensity sensors  524 A- 524 D, which in this example is 32 intensity units. In some embodiments, each contact is assigned a respective intensity that is a portion of the aggregate intensity.  FIG.  5 D  illustrates assigning the aggregate intensity to contacts  552 A- 552 E based on their distance from the center of force  554 . In this example, each of contacts  552 A,  552 B, and  552 E are assigned an intensity of contact of 8 intensity units of the aggregate intensity, and each of contacts  552 C and  552 D are assigned an intensity of contact of 4 intensity units of the aggregate intensity. More generally, in some implementations, each contact j is assigned a respective intensity Ij that is a portion of the aggregate intensity, A, in accordance with a predefined mathematical function, Ij=A·(Dj/ΣDi), where Dj is the distance of the respective contact j to the center of force, and ΣDi is the sum of the distances of all the respective contacts (e.g., i=1 to last) to the center of force. The operations described with reference to  FIGS.  5 C- 5 D  can be performed using an electronic device similar or identical to device  100 ,  300 , or  500 . In some embodiments, a characteristic intensity of a contact is based on one or more intensities of the contact. In some embodiments, the intensity sensors are used to determine a single characteristic intensity (e.g., a single characteristic intensity of a single contact). It should be noted that the intensity diagrams are not part of a displayed user interface, but are included in  FIGS.  5 C- 5 D  to aid the reader. 
     In some embodiments, a portion of a gesture is identified for purposes of determining a characteristic intensity. For example, a touch-sensitive surface optionally receives a continuous swipe contact transitioning from a start location and reaching an end location, at which point the intensity of the contact increases. In this example, the characteristic intensity of the contact at the end location is, optionally, based on only a portion of the continuous swipe contact, and not the entire swipe contact (e.g., only the portion of the swipe contact at the end location). In some embodiments, a smoothing algorithm is, optionally, applied to the intensities of the swipe contact prior to determining the characteristic intensity of the contact. For example, the smoothing algorithm optionally includes one or more of: an unweighted sliding-average smoothing algorithm, a triangular smoothing algorithm, a median filter smoothing algorithm, and/or an exponential smoothing algorithm. In some circumstances, these smoothing algorithms eliminate narrow spikes or dips in the intensities of the swipe contact for purposes of determining a characteristic intensity. 
     The intensity of a contact on the touch-sensitive surface is, optionally, characterized relative to one or more intensity thresholds, such as a contact-detection intensity threshold, a light press intensity threshold, a deep press intensity threshold, and/or one or more other intensity thresholds. In some embodiments, the light press intensity threshold corresponds to an intensity at which the device will perform operations typically associated with clicking a button of a physical mouse or a trackpad. In some embodiments, the deep press intensity threshold corresponds to an intensity at which the device will perform operations that are different from operations typically associated with clicking a button of a physical mouse or a trackpad. In some embodiments, when a contact is detected with a characteristic intensity below the light press intensity threshold (e.g., and above a nominal contact-detection intensity threshold below which the contact is no longer detected), the device will move a focus selector in accordance with movement of the contact on the touch-sensitive surface without performing an operation associated with the light press intensity threshold or the deep press intensity threshold. Generally, unless otherwise stated, these intensity thresholds are consistent between different sets of user interface figures. 
     An increase of characteristic intensity of the contact from an intensity below the light press intensity threshold to an intensity between the light press intensity threshold and the deep press intensity threshold is sometimes referred to as a “light press” input. An increase of characteristic intensity of the contact from an intensity below the deep press intensity threshold to an intensity above the deep press intensity threshold is sometimes referred to as a “deep press” input. An increase of characteristic intensity of the contact from an intensity below the contact-detection intensity threshold to an intensity between the contact-detection intensity threshold and the light press intensity threshold is sometimes referred to as detecting the contact on the touch-surface. A decrease of characteristic intensity of the contact from an intensity above the contact-detection intensity threshold to an intensity below the contact-detection intensity threshold is sometimes referred to as detecting liftoff of the contact from the touch-surface. In some embodiments, the contact-detection intensity threshold is zero. In some embodiments, the contact-detection intensity threshold is greater than zero. 
     In some embodiments described herein, one or more operations are performed in response to detecting a gesture that includes a respective press input or in response to detecting the respective press input performed with a respective contact (or a plurality of contacts), where the respective press input is detected based at least in part on detecting an increase in intensity of the contact (or plurality of contacts) above a press-input intensity threshold. In some embodiments, the respective operation is performed in response to detecting the increase in intensity of the respective contact above the press-input intensity threshold (e.g., a “down stroke” of the respective press input). In some embodiments, the press input includes an increase in intensity of the respective contact above the press-input intensity threshold and a subsequent decrease in intensity of the contact below the press-input intensity threshold, and the respective operation is performed in response to detecting the subsequent decrease in intensity of the respective contact below the press-input threshold (e.g., an “up stroke” of the respective press input). 
       FIGS.  5 E- 5 H  illustrate detection of a gesture that includes a press input that corresponds to an increase in intensity of a contact  562  from an intensity below a light press intensity threshold (e.g., “IT L ”) in  FIG.  5 E , to an intensity above a deep press intensity threshold (e.g., “IT D ”) in  FIG.  5 H . The gesture performed with contact  562  is detected on touch-sensitive surface  560  while cursor  576  is displayed over application icon  572 B corresponding to App  2 , on a displayed user interface  570  that includes application icons  572 A- 572 D displayed in predefined region  574 . In some embodiments, the gesture is detected on touch-sensitive display  504 . The intensity sensors detect the intensity of contacts on touch-sensitive surface  560 . The device determines that the intensity of contact  562  peaked above the deep press intensity threshold (e.g., “IT D ”). Contact  562  is maintained on touch-sensitive surface  560 . In response to the detection of the gesture, and in accordance with contact  562  having an intensity that goes above the deep press intensity threshold (e.g., “IT D ”) during the gesture, reduced-scale representations  578 A- 578 C (e.g., thumbnails) of recently opened documents for App  2  are displayed, as shown in  FIGS.  5 F- 5 H . In some embodiments, the intensity, which is compared to the one or more intensity thresholds, is the characteristic intensity of a contact. It should be noted that the intensity diagram for contact  562  is not part of a displayed user interface, but is included in  FIGS.  5 E- 5 H  to aid the reader. 
     In some embodiments, the display of representations  578 A- 578 C includes an animation. For example, representation  578 A is initially displayed in proximity of application icon  572 B, as shown in  FIG.  5 F . As the animation proceeds, representation  578 A moves upward and representation  578 B is displayed in proximity of application icon  572 B, as shown in  FIG.  5 G . Then, representations  578 A moves upward,  578 B moves upward toward representation  578 A, and representation  578 C is displayed in proximity of application icon  572 B, as shown in  FIG.  5 H . Representations  578 A- 578 C form an array above icon  572 B. In some embodiments, the animation progresses in accordance with an intensity of contact  562 , as shown in  FIGS.  5 F- 5 G , where the representations  578 A- 578 C appear and move upwards as the intensity of contact  562  increases toward the deep press intensity threshold (e.g., “IT D ”). In some embodiments, the intensity, on which the progress of the animation is based, is the characteristic intensity of the contact. The operations described with reference to  FIGS.  5 E- 5 H  can be performed using an electronic device similar or identical to device  100 ,  300 , or  500 . 
     In some embodiments, the device employs intensity hysteresis to avoid accidental inputs sometimes termed “jitter,” where the device defines or selects a hysteresis intensity threshold with a predefined relationship to the press-input intensity threshold (e.g., the hysteresis intensity threshold is X intensity units lower than the press-input intensity threshold or the hysteresis intensity threshold is 75%, 90%, or some reasonable proportion of the press-input intensity threshold). Thus, in some embodiments, the press input includes an increase in intensity of the respective contact above the press-input intensity threshold and a subsequent decrease in intensity of the contact below the hysteresis intensity threshold that corresponds to the press-input intensity threshold, and the respective operation is performed in response to detecting the subsequent decrease in intensity of the respective contact below the hysteresis intensity threshold (e.g., an “up stroke” of the respective press input). Similarly, in some embodiments, the press input is detected only when the device detects an increase in intensity of the contact from an intensity at or below the hysteresis intensity threshold to an intensity at or above the press-input intensity threshold and, optionally, a subsequent decrease in intensity of the contact to an intensity at or below the hysteresis intensity, and the respective operation is performed in response to detecting the press input (e.g., the increase in intensity of the contact or the decrease in intensity of the contact, depending on the circumstances). 
     For ease of explanation, the descriptions of operations performed in response to a press input associated with a press-input intensity threshold or in response to a gesture including the press input are, optionally, triggered in response to detecting either: an increase in intensity of a contact above the press-input intensity threshold, an increase in intensity of a contact from an intensity below the hysteresis intensity threshold to an intensity above the press-input intensity threshold, a decrease in intensity of the contact below the press-input intensity threshold, and/or a decrease in intensity of the contact below the hysteresis intensity threshold corresponding to the press-input intensity threshold. Additionally, in examples where an operation is described as being performed in response to detecting a decrease in intensity of a contact below the press-input intensity threshold, the operation is, optionally, performed in response to detecting a decrease in intensity of the contact below a hysteresis intensity threshold corresponding to, and lower than, the press-input intensity threshold. 
     As used herein, an “installed application” refers to a software application that has been downloaded onto an electronic device (e.g., devices  100 ,  300 , and/or  500 ) and is ready to be launched (e.g., become opened) on the device. In some embodiments, a downloaded application becomes an installed application by way of an installation program that extracts program portions from a downloaded package and integrates the extracted portions with the operating system of the computer system. 
     As used herein, the terms “open application” or “executing application” refer to a software application with retained state information (e.g., as part of device/global internal state  157  and/or application internal state  192 ). An open or executing application is, optionally, any one of the following types of applications:
         an active application, which is currently displayed on a display screen of the device that the application is being used on;   a background application (or background processes), which is not currently displayed, but one or more processes for the application are being processed by one or more processors; and   a suspended or hibernated application, which is not running, but has state information that is stored in memory (volatile and non-volatile, respectively) and that can be used to resume execution of the application.       

     As used herein, the term “closed application” refers to software applications without retained state information (e.g., state information for closed applications is not stored in a memory of the device). Accordingly, closing an application includes stopping and/or removing application processes for the application and removing state information for the application from the memory of the device. Generally, opening a second application while in a first application does not close the first application. When the second application is displayed and the first application ceases to be displayed, the first application becomes a background application. 
     Attention is now directed towards embodiments of user interfaces (“UI”) and associated processes that are implemented on an electronic device, such as portable multifunction device  100 , device  300 , or device  500 . 
       FIG.  6    illustrates exemplary devices connected via one or more communication channels to participate in a transaction in accordance with some embodiments. One or more exemplary electronic devices (e.g., devices  100 ,  300 , and  500 ) are configured to optionally detect input (e.g., a particular user input, an NFC field) and optionally transmit payment information (e.g., using NFC). The one or more electronic devices optionally include NFC hardware and are configured to be NFC-enabled. 
     The electronic devices (e.g., devices  100 ,  300 , and  500 ) are optionally configured to store payment account information associated with each of one or more payment accounts. Payment account information includes, for example, one or more of: a person&#39;s or company&#39;s name, a billing address, a login, a password, an account number, an expiration date, a security code, a telephone number, a bank associated with the payment account (e.g., an issuing bank), and a card network identifier. In some examples, payment account information includes include an image, such as a picture of a payment card (e.g., taken by the device and/or received at the device). In some examples, the electronic devices receive user input including at least some payment account information (e.g., receiving user-entered credit, debit, account, or gift card number and expiration date). In some examples, the electronic devices detect at least some payment account information from an image (e.g., of a payment card captured by a camera sensor of the device). In some examples, the electronic devices receive at least some payment account information from another device (e.g., another user device or a server). In some examples, the electronic device receives payment account information from a server associated with another service for which an account for a user or user device previously made a purchase or identified payment account data (e.g., an app for renting or selling audio and/or video files). 
     In some embodiments, a payment account is added to an electronic device (e.g., device  100 ,  300 , and  500 ), such that payment account information is securely stored on the electronic device. In some examples, after a user initiates such process, the electronic device transmits information for the payment account to a transaction-coordination server, which then communicates with a server operated by a payment network for the account (e.g., a payment server) to ensure a validity of the information. The electronic device is optionally configured to receive a script from the server that allows the electronic device to program payment information for the account onto the secure element. 
     In some embodiments, communication among electronic devices  100 ,  300 , and  500  facilitates transactions (e.g., generally or specific transactions). For example, a first electronic device (e.g.,  100 ) can serve as a provisioning or managing device, and can send notifications of new or updated payment account data (e.g., information for a new account, updated information for an existing account, and/or an alert pertaining to an existing account) to a second electronic device (e.g.,  500 ). In another example, a first electronic device (e.g.,  100 ) can send data to a second election device, wherein the data reflects information about payment transactions facilitated at the first electronic device. The information optionally includes one or more of: a payment amount, an account used, a time of purchase, and whether a default account was changed. The second device (e.g.,  500 ) optionally uses such information to update a default payment account (e.g., based on a learning algorithm or explicit user input). 
     Electronic devices (e.g.,  100 ,  300 ,  500 ) are configured to communicate with each other over any of a variety of networks. For example, the devices communicate using a Bluetooth connection  608  (e.g., which includes a traditional Bluetooth connection or a Bluetooth Low Energy connection) or using a WiFi network  606 . Communications among user devices are, optionally, conditioned to reduce the possibility of inappropriately sharing information across devices. For example, communications relating to payment information requires that the communicating devices be paired (e.g., be associated with each other via an explicit user interaction) or be associated with a same user account. 
     In some embodiments, an electronic device (e.g.,  100 ,  300 ,  500 ) is used to communicate with a point-of-sale (POS) payment terminal  600 , which is optionally NFC-enabled. The communication optionally occurs using a variety of communication channels and/or technologies. In some examples, electronic device (e.g.,  100 ,  300 ,  500 ) communicates with payment terminal  600  using an NFC channel  610 . In some examples, payment terminal  600  communicates with an electronic device (e.g.,  100 ,  300 ,  500 ) using a peer-to-peer NFC mode. Electronic device (e.g.,  100 ,  300 ,  500 ) is optionally configured transmit a signal to payment terminal  600  that includes payment information for a payment account (e.g., a default account or an account selected for the particular transaction). 
     In some embodiments, proceeding with a transaction includes transmitting a signal that includes payment information for an account, such as a payment account. In some embodiments, proceeding with the transaction includes reconfiguring the electronic device (e.g.,  100 ,  300 ,  500 ) to respond as a contactless payment card, such as an NFC-enabled contactless payment card, and then transmitting credentials of the account via NFC, such as to payment terminal  600 . In some embodiments, subsequent to transmitting credentials of the account via NFC, the electronic device reconfigures to not respond as a contactless payment card (e.g., requiring authorization before again reconfigured to respond as a contactless payment card via NFC). 
     In some embodiments, generation of and/or transmission of the signal is controlled by a secure element in the electronic device (e.g.,  100 ,  300 ,  500 ). The secure element optionally requires a particular user input prior to releasing payment information. For example, the secure element optionally requires detection that the electronic device is being worn, detection of a button press, detection of entry of a passcode, detection of a touch, detection of one or more option selections (e.g., received while interacting with an application), detection of a fingerprint signature, detection of a voice or voice command, and or detection of a gesture or movement (e.g., rotation or acceleration). In some examples, if a communication channel (e.g., an NFC communication channel) with another device (e.g., payment terminal  600 ) is established within a defined time period from detection of the input, the secure element releases payment information to be transmitted to the other device (e.g., payment terminal  600 ). In some examples, the secure element is a hardware component that controls release of secure information. In some examples, the secure element is a software component that controls release of secure information. 
     In some embodiments, protocols related to transaction participation depend on, for example, device types. For example, a condition for generating and/or transmitting payment information can be different for a wearable device (e.g., device  500 ) and a phone (e.g., device  100 ). For example, a generation and/or transmission condition for a wearable device includes detecting that a button has been pressed (e.g., after a security verification), while a corresponding condition for a phone does not require button-depression and instead requires detection of particular interaction with an application. In some examples, a condition for transmitting and/or releasing payment information includes receiving particular input on each of multiple devices. For example, release of payment information optionally requires detection of a fingerprint and/or passcode at the device (e.g., device  100 ) and detection of a mechanical input (e.g., button press) on another device (e.g., device  500 ). 
     Payment terminal  600  optionally uses the payment information to generate a signal to transmit to a payment server  604  to determine whether the payment is authorized. Payment server  604  optionally includes any device or system configured to receive payment information associated with a payment account and to determine whether a proposed purchase is authorized. In some examples, payment server  604  includes a server of an issuing bank. Payment terminal  600  communicates with payment server  604  directly or indirectly via one or more other devices or systems (e.g., a server of an acquiring bank and/or a server of a card network). 
     Payment server  604  optionally uses at least some of the payment information to identify a user account from among a database of user accounts (e.g.,  602 ). For example, each user account includes payment information. An account is, optionally, located by locating an account with particular payment information matching that from the POS communication. In some examples, a payment is denied when provided payment information is not consistent (e.g., an expiration date does not correspond to a credit, debit or gift card number) or when no account includes payment information matching that from the POS communication. 
     In some embodiments, data for the user account further identifies one or more restrictions (e.g., credit limits); current or previous balances; previous transaction dates, locations and/or amounts; account status (e.g., active or frozen), and/or authorization instructions. In some examples, the payment server (e.g.,  604 ) uses such data to determine whether to authorize a payment. For example, a payment server denies a payment when a purchase amount added to a current balance would result in exceeding an account limit, when an account is frozen, when a previous transaction amount exceeds a threshold, or when a previous transaction count or frequency exceeds a threshold. 
     In some embodiments, payment server  604  responds to POS payment terminal  600  with an indication as to whether a proposed purchase is authorized or denied. In some examples, POS payment terminal  600  transmits a signal to the electronic device (e.g.,  100 ,  300 ,  500 ) to identify the result. For example, POS payment terminal  600  sends a receipt to the electronic device (e.g.,  100 ,  300 ,  500 ) when a purchase is authorized (e.g., via a transaction-coordination server that manages a transaction app on the user device). In some instances, POS payment terminal  600  presents an output (e.g., a visual or audio output) indicative of the result. Payment can be sent to a merchant as part of the authorization process or can be subsequently sent. 
     In some embodiments, the electronic device (e.g.,  100 ,  300 ,  500 ) participates in a transaction that is completed without involvement of POS payment terminal  600 . For example, upon detecting that a mechanical input has been received, a secure element in the electronic device (e.g.,  100 ,  300 ,  500 ) releases payment information to allow an application on the electronic device to access the information (e.g., and to transmit the information to a server associated with the application). 
     In some embodiments, the electronic device (e.g.,  100 ,  300 ,  500 ) is in a locked state or an unlocked state. In the locked state, the electronic device is powered on and operational but is prevented from performing a predefined set of operations in response to the user input. The predefined set of operations optionally includes navigation between user interfaces, activation or deactivation of a predefined set of functions, and activation or deactivation of certain applications. The locked state can be used to prevent unintentional or unauthorized use of some functionality of the electronic device or activation or deactivation of some functions on the electronic device. In the unlocked state, the electronic device  100  is power on and operational and is not prevented from performing at least a portion of the predefined set of operations that cannot be performed while in the locked state. 
     When the device is in the locked state, the device is said to be locked. In some embodiments, the device in the locked state optionally responds to a limited set of user inputs, including input that corresponds to an attempt to transition the device to the unlocked state or input that corresponds to powering the device off. 
     In some examples, a secure element (e.g.,  115 ) is a hardware component (e.g., a secure microcontroller chip) configured to securely store data or an algorithm such that the securely stored data is not accessible by the device without proper authentication information from a user of the device. Keeping the securely stored data in a secure element that is separate from other storage on the device prevents access to the securely stored data even if other storage locations on the device are compromised (e.g., by malicious code or other attempts to compromise information stored on the device). In some examples, the secure element provides (or releases) payment information (e.g., an account number and/or a transaction-specific dynamic security code). In some examples, the secure element provides (or releases) the payment information in response to the device receiving authorization, such as a user authentication (e.g., fingerprint authentication; passcode authentication; detecting double-press of a hardware button when the device is in an unlocked state, and optionally, while the device has been continuously on a user&#39;s wrist since the device was unlocked by providing authentication credentials to the device, where the continuous presence of the device on the user&#39;s wrist is determined by periodically checking that the device is in contact with the user&#39;s skin). For example, the device detects a fingerprint at a fingerprint sensor (e.g., a fingerprint sensor integrated into a button) of the device. The device determines whether the fingerprint is consistent with a registered fingerprint. In accordance with a determination that the fingerprint is consistent with the registered fingerprint, the secure element provides (or releases) payment information. In accordance with a determination that the fingerprint is not consistent with the registered fingerprint, the secure element forgoes providing (or releasing) payment information. 
     Attention is now directed towards embodiments of user interfaces (“UI”) and associated processes that are implemented on an electronic device, such as portable multifunction device  100 , device  300 , or device  500 . 
       FIGS.  7 A- 7 AD  illustrate exemplary user interfaces for providing indications of error conditions during biometric authentication, in accordance with some examples. The user interfaces in these figures are used to illustrate the processes described below, including the processes in  FIGS.  8 A- 8 B . 
       FIG.  7 A  illustrates electronic device  700  (e.g., portable multifunction device  100 , device  300 , or device  500 ). In the exemplary example illustrated in  FIGS.  7 A- 7 AD , electronic device  700  is a smartphone. In other examples, electronic device  700  can be a different type of electronic device, such as a tablet (e.g., electronic device  900 ). Electronic device  700  includes display  702 , one or more input devices (e.g., touchscreen of display  702 , button  704 , and a microphone), a wireless communication radio, and biometric sensor  703 . Electronic device  700  includes biometric sensor  703 . In some examples, biometric sensor  703  includes one or more biometric sensors that can include a camera, such as a depth camera (e.g., an infrared camera), a thermographic camera, or a combination thereof. In some examples, biometric sensor  703  includes a biometric sensor (e.g., facial recognition sensor), such as those described in U.S. Ser. No. 14/341,860, “Overlapping Pattern Projector,” filed Jul. 14, 2014, U.S. Pub. No. 2016/0025993 and U.S. Ser. No. 13/810,451, “Scanning Projects and Image Capture Modules For 3D Mapping,” U.S. Pat. No. 9,098,931, which are hereby incorporated by reference in their entirety for any purpose. In some examples, biometric sensor  703  includes one or more fingerprint sensors (e.g., a fingerprint sensor integrated into a button). In some examples, electronic device  700  further includes a light-emitting device (e.g., light projector), such as an IR flood light, a structured light projector, or a combination thereof. The light-emitting device is, optionally, used to illuminate the biometric feature (e.g., the face) during capture of biometric data of biometric features by biometric sensor  703 . In some examples, electronic device  700  includes a plurality of cameras separate from biometric sensor  703 . In some examples, electronic device  700  includes only one camera separate from biometric sensor  703 . 
     At  FIG.  7 A , a user learns from notification  708  that she has received a message from John Appleseed. The user wishes to view the restricted content of notification  708  (e.g., the message from John Appleseed), but is unable to do so, as electronic device  700  is currently in a locked state. Electronic device  700  displays a locked state user interface (UI) with lock icon  706 , which provides an indication that electronic device  700  is in a locked state. Viewing the restricted content of notification  708  requires successful authentication (e.g., determining that information (or data) about a biometric feature obtained using biometric sensor  703  corresponds to (or matches) stored authorized credentials). To view the restricted content of notification  708 , the user lifts (or raises) electronic device  700  (e.g., from a substantially horizontal orientation to the orientation of the device as depicted in the user&#39;s hand in  FIG.  7 A ). Electronic device  700  detects the change in orientation of electronic device  700  and, in response, initiates biometric authentication. In some examples, after initiating biometric authentication, electronic device  700  determines that biometric authentication is successful. In some examples, upon determining that biometric authentication is successful, electronic device  700  transitions from a locked state to an unlocked state, and displays the restricted content of notification  708 . 
     After initiating biometric authentication (e.g., prior to successful authentication), electronic device  700  determines whether a face is detected by biometric sensor  703 . At  FIG.  7 B , upon determining that a face is detected, electronic device  700  displays authentication glyph  710 , which includes a plurality of rings that rotate spherically. Authentication glyph  710  provides an indication that biometric authentication is being performed. In some examples, electronic device  700  displays an animation of lock icon  706  morphing into authentication glyph  710 . In some examples, upon determining that no face is detected using biometric sensor  703 , electronic device  700  maintains a locked state, and does not display authentication glyph  710 . 
     After detecting the presence of a face, electronic device  700  determines that authentication is unsuccessful due to failure to obtain sufficient information about the user&#39;s face using biometric sensor  703 . Specifically, as depicted by  FIG.  7 B , biometric sensor  703  is positioned outside acceptable distance range  712  (e.g., above the maximum threshold range), resulting in a failure to obtain sufficient information about the user&#39;s face. Upon determining that biometric authentication is unsuccessful due to the user&#39;s face being outside acceptable distance range  712 , electronic device  700  maintains the device in a locked state and does not display the restricted content of notification  708 . In some examples, electronic device  700  maintains the device in a locked state and does not display the restricted content of notification  708  upon determining authentication is unsuccessful and that no error condition exists. In some examples, upon determining that authentication is unsuccessful (e.g., due to captured biometric information not matching an authorized biometric information profile (e.g., stored authorized credentials)) and that no error condition exists (e.g., no condition preventing capture of sufficient biometric information), electronic device  700  maintains a locked state and automatically retries biometric authentication. In some examples, while retrying biometric authentication, electronic device  700  continues to display authentication glyph  710  in  FIG.  7 B . 
     As depicted in  FIGS.  7 C- 7 G , upon determining that biometric authentication is unsuccessful due to the user&#39;s face being outside acceptable distance range  712 , electronic device  700  displays an animation of authentication glyph  710  morphing into error indication  714 A such that error indication  714 A replaces the display of authentication glyph  710 . At  FIG.  7 G , electronic device  700  displays error indication  714 A, which prompts the user to take an action to correct the error condition underlying error indication  714 A. Specifically, error indication  714 A prompts the user to move her face closer to biometric sensor  703 . Error indication  714 A also suggests to the user that the user&#39;s face is too far away from biometric sensor  703 , which is the cause of error indication  714 A. As long as the user&#39;s face is outside acceptable distance range  712 , electronic device  700  will continue to determine that error indication  714 A exists. Upon determining that error indication  714 A still exists, electronic device  700  does not attempt retrying biometric authentication. It is noted that electronic device  700  displays error indication  714 A at a position coinciding with the position of lock icon  706  in  FIG.  7 A . Further, electronic device  700  displays error indication  714 A on a portion of display  702  that is adjacent to biometric sensor  703  to suggest to the user that error indication  714 A is associated with (or corresponds to) biometric sensor  703 . 
     As depicted in  FIG.  7 H , after being prompted to correct error indication  714 A, the user moves her face closer to biometric sensor  703  such that the user&#39;s face is within acceptable distance range  712 . At  FIG.  7 H , electronic device determines that error indication  714 A no longer exists. Upon determining that error indication  714 A no longer exists, electronic device  700  enables biometric authentication on the device and automatically retries biometric authentication using biometric sensor  703 . 
     In response to automatically retrying biometric authentication, electronic device  700  displays error indication  714 A with a shimmer effect (e.g., animating the error indication such that one or more portions of the error indication moves side to side so as produce an effect where the error indication appears to shine) to indicate that electronic device  700  is attempting to biometrically authenticate the user again.  FIGS.  7 H- 7 L  depict an animation of error indication  714 A with the shimmer effect. In some examples, instead of displaying error indication  714 A with a shimmer effect, electronic device  700  displays (e.g., replaces display of error indication  714 A with) authentication glyph  710  to indicate that electronic device  700  is attempting to biometrically authenticate the user again. Accordingly, in some examples, electronic device  700  displays an animation of authentication glyph  710  morphing into lock icon  706  instead of error indication  714 A morphing into lock icon  706 . 
     At  FIG.  7 L , after retrying biometric authentication, electronic device  700  successfully biometrically authenticates the user. In response to successful biometric authentication, electronic device  700  transitions the device from a locked state to an unlocked state. While transitioning from a locked state to an unlocked state, electronic device  700  displays an animation of error indication  714 A morphing into lock icon  706 , as depicted in  FIGS.  7 L- 7 N . After displaying an animation of error indication  714 A morphing into lock icon  706 , electronic device  700  displays an animation of lock icon  706  transitioning to unlock icon  716 , as depicted in  FIGS.  7 N- 70   . Unlock icon  716  provides an indication that electronic device  700  is in an unlocked state. Additionally, as depicted in  FIG.  70   , electronic device  700  displays the restricted content (e.g., “Hey, is our meeting still on?”) of notification  708  in response to biometric authentication being successful. 
     At  FIG.  7 P , instead of determining that the user&#39;s face is outside acceptable distance range  712  as discussed above with respect to  FIG.  7 B , electronic device  700  determines that biometric authentication is not available on the device. Upon determining that biometric authentication is not available, electronic device  700  displays error indication  714 B in  FIG.  7 P , which provides an indication that biometric authentication is not currently available on the device. Biometric authentication can be unavailable for a variety of reasons, including that biometric authentication has failed more than a predefined number of times (e.g., 5, 10, 15) since the last successful authentication. 
     Due to biometric authentication being unavailable, a user must use an alternative method to authenticate the user. For example, the user can authenticate by entering a passcode at electronic device  700 . While displaying error indication  714 B in  FIG.  7 P , electronic device  700  receives input  720  at error indication  714 B. 
     At  FIG.  7 Q , in response to receiving input  720  at error indication  714 B, electronic device  700  displays passcode entry UI  722 A with a plurality of entry affordances for entering a passcode (or password). 
     In some examples, instead of determining that authentication is successful as a result of retrying biometric authentication, as discussed above with respect to  FIGS.  7 L- 70   , electronic device  700  determines that authentication is unsuccessful. In some examples, upon determining that authentication is unsuccessful, electronic device  700  maintains a locked state, and displays an animation of lock icon  706  in  FIG.  7 R  alternating between different positions to simulate a “shake” effect. The shake animation provides an indication to the user that biometric authentication has failed and that electronic device  700  remains in a locked state. 
     After determining that authentication is unsuccessful, a user can perform an action at electronic device  700  to trigger retrying biometric authentication. At  FIG.  7 S , a user triggers retrying biometric authentication by swiping up starting from a region near the bottom edge of display  702 . Electronic device  700  receives input  724 , and in response, retries biometric authentication. In some examples, after retrying biometric authentication, electronic device  700  determines that authentication is successful. In some examples, upon determining that authentication is successful as a result of retrying biometric authentication, electronic device  700  transitions from a locked state to an unlocked state. 
     At  FIGS.  7 S- 7 T , electronic device  700  determines that authentication is unsuccessful as a result of retrying biometric authentication, in response to input  724 . Upon determining that authentication is unsuccessful as a result of retrying biometric authentication, electronic device  700  displays passcode entry UI  722 B in  FIG.  7 T  and/or maintains a locked state. 
     At  FIG.  7 U , electronic device  700  determines that authentication is successful as a result of retrying biometric authentication at passcode entry UI  722 B. Upon determining that authentication is successful, electronic device transitions from a locked state to an unlocked state, as depicted in  FIGS.  7 U- 7 W . In some examples, at  FIG.  7 U , electronic device determines that authentication is not successful as a result of retrying biometric authentication at passcode entry UI  722 B. In some examples, upon making this determination, electronic device maintains a locked state. 
       FIGS.  7 X- 7 AD  illustrate various error conditions that electronic device  700  can detect while attempting to biometrically authenticate a user. Instead of displaying error indication  714 A as described above with respect to  FIG.  7 G , electronic device  700  can display any one of the error indications described below (e.g., error indication  714 C-I).  FIGS.  7 X- 7 AD  also depict electronic device  700  coaching a user (e.g., via error indication  714 C-I) to take an action to correct the detected error condition so that electronic device  700  can retry biometrically authenticating the user. 
     At  FIG.  7 X , a user&#39;s face is positioned too close to biometric sensor  703 . As a result, electronic device  700  determines that the user&#39;s face is positioned outside acceptable distance range  712  (e.g., below the minimum threshold range). Upon determining that the user&#39;s face is positioned outside acceptable distance range  712 , electronic device  700  displays error indication  714 C, which prompts the user to move her face farther away from biometric sensor  703 . Error indication  714 C also provides an indication of the cause of the error condition (e.g., an indication that the user&#39;s face is too close to biometric sensor  703 .) 
     At  FIG.  7 Y , a user&#39;s hand is covering biometric sensor  703 . As a result, electronic device  700  determines that an object (e.g., a user&#39;s hand) is covering biometric sensor  703  such that the sensor is unable to obtain any information about the user&#39;s face. Upon determining that an object is covering biometric sensor  703 , electronic device  700  displays error indication  714 D, which prompts the user to move her hand away from biometric sensor  703 . Error indication  714 D also provides an indication of the cause of the error condition (e.g., an indication that biometric sensor  703  is covered). 
     At  FIG.  7 Z , a user is not looking at electronic device  700 . As a result, electronic device  700  determines that the user&#39;s eyes are not looking at the device. Upon determining that the user&#39;s eyes are not looking at the device, electronic device  700  displays error indication  714 E, which prompts the user to look at the device to correct the error condition. Error indication  714 E also provides an indication of the cause of the error condition (e.g., an indication that the user is not looking at the device. 
     At  FIG.  7 AA , a user&#39;s face is within field of view  728 , but the user is wearing a hat. As a result, electronic device  700  determines that a portion of the user&#39;s face is obscured (or occluded). For example, electronic device  700  obtains partial information about a user&#39;s face using biometric sensor  703 , where the partial information is below the threshold amount needed for comparison with the stored authorized credentials. Upon determining that a portion of the user&#39;s face is obscured, electronic device  700  displays error indication  714 F, which prompts the user to remove the hat. Error indication  714 F also provides an indication of the cause of the error condition (e.g., an indication that a portion of the user&#39;s face is obscured). 
     At  FIG.  7 AB , a user&#39;s face is outside field of view  728  of biometric sensor  703 . As a result, electronic device  700  determines that the user&#39;s face is outside field of view  728  of biometric sensor  703 . In some examples, the user&#39;s face is outside field of view  728  when more than a threshold portion of the face is outside the field of view. In some examples, the user&#39;s face is outside field of view  728  when no face is detected within the field of view. Upon determining that the user&#39;s face is outside field of view  728 , electronic device  700  displays error indication  714 G, which prompts the user to move her face to within field of view  728 . Error indication  714 G also provides an indication of the cause of the error condition (e.g., an indication that the user&#39;s face is outside field of view  728 ). 
     At  FIG.  7 AC , a user&#39;s face is within field of view  728 , but is turned away from biometric sensor  703 . As a result, electronic device  700  determines that the user&#39;s face is turned away from biometric sensor  703 . Upon determining that the user&#39;s face is turned away from biometric sensor  703 , electronic device  700  displays error indication  714 H, which prompts the user to turn her face towards the sensor. Error indication  714 H also provides an indication of the cause of the error condition (e.g., an indication that the user&#39;s face is turned away from biometric sensor  703 ). 
     At  FIG.  7 AD , a user&#39;s face is positioned appropriately within the field of view and acceptable distance range of biometric sensor  703 . However, the lighting conditions of the environment in which the user is located are not suitable for performing biometric authentication. Specifically, the amount of light is so great that it interferes with performing biometric authentication. As a result, electronic device  700  determines (e.g., via one or more ambient light sensors) that the amount of light exceeds a predefined threshold. Upon determining that the amount of light exceeds the threshold, electronic device  700  displays error indication  714 I, which prompts the user to seek improved lighting conditions with a lower amount of light. Error indication  714 I also provides an indication of the cause of the error condition (e.g., an indication that the light conditions are not suitable for performing biometric authentication). 
       FIGS.  8 A- 8 B  are flow diagrams illustrating a method for providing indications of error conditions during biometric authentication, in accordance with some examples. Method  800  is performed at an electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) with a display (e.g.,  702 ) and one or more input devices (e.g., an accelerometer (e.g.,  168 ), a touchscreen of a display (e.g.,  702 )). In some examples, the electronic device includes one or more biometric sensors (e.g., a fingerprint sensor, a contactless biometric sensor (e.g., a biometric sensor that does not require physical contact, such as a thermal or optical facial recognition sensor), an iris scanner). In some examples, the one or more biometric sensors include one or more cameras. Some operations in method  800  are, optionally, combined, the orders of some operations are, optionally, changed, and some operations are, optionally, omitted. 
     As described below, method  800  provides an intuitive way for providing indications of error conditions during biometric authentication. The method reduces the cognitive burden on a user for performing biometric authentication, thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to perform biometric authentication faster and more efficiently conserves power and increases the time between battery charges. 
     The electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) receives ( 802 ), via the one or more input devices (e.g., an accelerometer (e.g.,  168 ), a touchscreen of a display (e.g.,  702 )), a request to perform an operation that requires authentication (e.g., biometric authentication). In some examples, the request to perform an operation that requires authentication includes a request to unlock the device (e.g., a swipe at a predefined location). In some examples, the request is triggered by lifting the device from a substantially horizontal position. 
     In response ( 804 ) to the request to perform the operation that requires authentication (e.g., biometric authentication) and in accordance ( 806 ) with a determination that authentication (e.g., biometric authentication) is successful, the electronic device performs the operation. In some examples, authentication is successful when a user input (e.g., data obtained from one or more biometric sensors that correspond to a biometric feature (e.g., face, finger) of a user, passcode) corresponds to (e.g., matches) an authorized credential (e.g., an enrolled fingerprint, face, or passcode). In some examples, a user input corresponds to an authorized credential when the user input matches the authorized credential. 
     In response ( 804 ) to the request to perform the operation that requires authentication (e.g., biometric authentication) and in accordance ( 808 ) with a determination that authentication (e.g., biometric authentication) is not successful and that a set of error condition criteria is met (e.g., an error condition exists), the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) displays ( 810 ), on the display (e.g.,  702 ), an indication of an error condition (e.g.,  714 A-I) (e.g., of the set of error condition criteria) and forgoes ( 816 ) performing the operation. The indication includes ( 812 ) information about the cause of the error condition. In some examples, authentication is not successful when a user input (e.g., data obtained from one or more biometric sensors that correspond to a biometric feature (e.g., face, finger) of a user, passcode) does not correspond to (e.g., match) an authorized credential (e.g., an enrolled fingerprint, face, or passcode). In some examples, a user input does not correspond to an authorized credential when the user input does not match the authorized credential. In some examples, the set of error condition criteria includes only one criterion. Displaying the indication of the error condition provides the user with feedback about the current state of the device (e.g., that an error condition is preventing successful biometric authentication) and prompts the user to take further action to correct the error condition. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. Moreover, forgoing performing the operation when biometric authentication has failed and an error condition is detected enhances security and reduces the instances of multiple resource-intensive re-attempts of biometric authentication that is likely to fail due to the error condition. Providing improved security enhances the operability of the device and makes the user-device interface more efficient (e.g., by restricting unauthorized access) which, additionally, reduces power usage and improves battery life of the device by limiting the performance of restricted operations. 
     In some examples, in response ( 804 ) to the request to perform the operation that requires authentication and in accordance ( 826 ) with a determination that authentication (e.g., biometric authentication) is not successful and that the set of error condition criteria is not met, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) forgoes ( 828 ) displaying, on the display (e.g.,  702 ), the indication of the error condition and forgoes ( 830 ) performing the operation. 
     In some examples, the indication (e.g.,  714 A-I) of the error condition includes ( 814 ) an indication of a user action (e.g., visible indication (e.g., graphic or text)) that can be performed to correct the error condition (e.g., for a subsequent authentication attempt). In some examples, the indication of the user action indicates how to correct the error condition for a subsequent authentication attempt. Displaying an indication of a user action that can be performed to correct the error condition provides feedback to the user as to what course of action to take so that the user can be biometrically authenticated in a subsequent authentication attempt. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. 
     In some examples, the indication (e.g.,  714 A-I) of the error condition includes information (e.g., an indication of a user action and/or device condition, visible indication (e.g., graphic or text)) about a cause of the error condition. Displaying an indication of the cause of the error condition provides feedback to the user as to what course of action to take so that the user can be biometrically authenticated in a subsequent authentication attempt. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. 
     In some examples, the set of error condition criteria includes a requirement that is met when a biometric feature (e.g., a fingerprint, a face) of a first type (e.g., a type that corresponds to authorized biometric features) is detected using one or more biometric sensors (e.g.,  703 ) of the electronic device. In some examples, the indication of the error condition (e.g.,  714 A-I) is not displayed if a potentially valid biometric feature is not detected (e.g., signifying that a user is not currently engaging with the device). Forgoing displaying the indication of the error condition when no biometric feature is detected prevents potentially confusing the user, for it is likely that the user did not intend to perform biometric authentication if no biometric feature is detected. Thus, forgoing displaying the indication in this scenario makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, in accordance with a determination that authentication (e.g., biometric authentication) is successful, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) forgoes displaying, on the display (e.g.,  702 ), the indication of the error condition (e.g.,  714 A-I). 
     In some examples, subsequent to displaying the indication of the error condition (e.g.,  714 A-I) and in accordance with a determination that the set of error condition criteria continues to be met, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) forgoes ( 818 ) attempting (and, optionally, disabling further attempts at) biometric authentication on the electronic device (e.g., biometric authentication functionality is not available on the device while the set of error conditions are met). In some examples, subsequent to displaying the indication of the error condition and in accordance with a determination that the set of error condition criteria is no longer met, the electronic device enables ( 822 ) retrying biometric authentication on the electronic device (e.g., the error condition is no longer present (e.g., has been corrected (e.g., due to the user taking an action to correct the error condition))). Automatically retrying biometric authentication when the set of error condition criteria is no longer met allows the user to quickly attempt to biometrically authenticate herself without requiring that the user explicitly request biometric authentication. Performing an optimized operation when a set of conditions has been met without requiring further user input enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, subsequent to displaying the indication of the error condition and in response to the determination that the set of error condition criteria is no longer met, the electronic device retries ( 824 ) authentication (e.g., biometric authentication) (e.g., automatically retrying authentication). In some examples, retrying authentication includes attempting to match biometric information obtained by one or more biometric sensors with authorized credentials (e.g., stored data that has been authorized for use in biometric authentication). In some examples, the determination that the error condition is not met occurs subsequent to (or in response to) receiving an input to correct the error condition. In some examples, retrying authentication occurs (or only occurs) in accordance with a determination that the error condition is not met due to detecting a user input that causes the error condition to not be met. 
     In some examples, subsequent to the determination that the set of error condition criteria is no longer met (e.g., detecting that the error condition has been corrected), the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) receives, via the one or more input devices, an input (e.g.,  724 ,  726 ) corresponding to a request to retry authentication. In some examples, the input is a touch gesture input (e.g., tap, a swipe (e.g., an upward swipe)) or an activation of a hardware button (e.g., power button). In some examples, in response to receiving the input corresponding to the request to retry authentication, the electronic device retries authentication (e.g., biometric authentication) (e.g., automatically retrying authentication). In some examples, retrying authentication includes attempting to match biometric information obtained by one or more biometric sensors with authorized credentials (e.g., stored data that has been authorized for use in biometric authentication). In some examples, retrying authentication includes using one or more biometric sensors to obtain data of a biometric feature (e.g., face, fingerprint) of the user. 
     In some examples, displaying the indication of the error condition (e.g.,  714 A-I) includes an animation (e.g., shimmering) indicating that an attempt to authenticate is ongoing. In some examples, the attempt to authenticate includes attempting to detect biometric information using one or more biometric sensors. Displaying a shimmering animation indicating that an attempt to authenticate is ongoing provides feedback to the user as to the current state of the device and that no further action is required at this time. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication 
     In some examples, subsequent to (or in response to) receiving the request to perform the operation that requires authentication and prior to displaying the indication of the error condition (e.g.,  714 A-I), the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) performs authentication. In some examples, while performing authentication, electronic device  700  displays, on the display (e.g.,  702 ), a first indication (e.g.,  710 ,  714 A-I) (e.g., rings that rotate around a sphere, a user interface object that shimmers, where the user interface object includes the indication of the error condition) that the electronic device is using one or more biometric sensors (e.g.,  703 ) of the electronic device to obtain information about a biometric feature. In some examples, displaying the indication of the error condition includes replacing the display of the first indication with the display of the indication of the error condition. Displaying an indication that biometric authentication is occurring provides the user with feedback about the current state of the device (e.g., biometric authentication is being performed) and that the user does not need to take any action at this time. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, while performing the authentication, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) displays, on the display (e.g.,  702 ), a first lock icon (e.g.,  706 ) (e.g., an icon indicative of the locked state of the electronic device) and a first animation that transitions from the first lock icon to the first indication. In some examples, subsequent to displaying the indication of the error condition (e.g., and in accordance with a determination that authentication is successful) and subsequent to displaying the first animation, the electronic device displays, on the display (e.g.,  702 ), a second animation that transitions from the indication of the error condition to an unlock icon (e.g.,  716 ) (e.g., an icon indication of the locked state of the electronic device). In some examples, the first animation and the second animation show a morphing from one object to the next object. In some examples, the second animation includes displaying a first lock icon subsequent to the indication of the error condition and prior to the unlock icon. 
     In some examples, subsequent to displaying the indication of the error condition, the electronic device displays, on the display (e.g.,  702 ), an animation that transitions from the indication of the error condition to a second lock icon (e.g.,  706 ) or from a second indication (e.g.,  710 ,  714 A-I) (e.g., rings that rotate around a sphere) that the electronic device is using one or more biometric sensors of the electronic device to obtain information about a biometric feature to the second lock icon (e.g., an icon indicative of the locked state of the electronic device). In some examples, the second lock icon is the first lock icon. In some examples, the second indication is the first indication. 
     In some examples, while retrying authentication and subsequent to displaying the indication of the error condition and in accordance with a determination that the error condition is absent, the electronic device displays, on the display, a third indication (e.g.,  710 ,  714 A-I) (e.g., rings that rotate around a sphere, a user interface object that shimmers, where the user interface object includes the indication of the error condition) that the electronic device is using one or more biometric sensors of the electronic device to obtain information about a biometric feature. In some examples, the third indication is the first indication. 
     In some examples, prior to displaying the indication of the error condition, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) displays, on the display (e.g.,  702 ), a third lock icon (e.g.,  706 ) at a location on the display (e.g., an icon indicative of the locked state of the electronic device). In some examples, the indication of the error condition (e.g.,  714 A-I) is displayed proximate to (e.g., near, adjacent to, at, within a predetermined distance of) the location on the display. In some examples, the third lock icon is the first lock icon and/or the second lock icon. 
     In some examples, when the electronic device is in a locked state while receiving the request to perform the operation that requires authentication and in accordance with the determination that authentication is successful, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) transitions from the locked state to an unlocked state. In some examples, the operation that requires authentication is transitioning the electronic device from a locked state to an unlocked state. In some examples, when the electronic device is in a locked state while receiving the request to perform the operation that requires authentication and in accordance with the determination that authentication is not successful, the electronic device maintains the locked state. Maintaining the device in the locked state when authentication is unsuccessful enhances device security by preventing fraudulent and/or unauthorized access to the device. Improving security measures of the device enhances the operability of the device by preventing unauthorized access to content and operations and, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more efficiently. 
     In some examples, when the electronic device is in a locked state while receiving the request to perform the operation that requires authentication and in accordance with the determination that authentication is not successful, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) maintains the locked state and retries authentication (e.g., biometric authentication) (e.g., automatically retrying authentication). In some examples, retrying authentication includes attempting to obtain information about a biometric feature (e.g., face, fingerprint) using one or more biometric sensors of the electronic device. In some examples, retrying authentication includes attempting to match biometric information obtained by one or more biometric sensors with authorized credentials (e.g., stored data that has been authorized for use in biometric authentication). In some examples, after retrying authentication and in accordance with a determination that authentication resulting from retrying authentication is successful, the electronic device transitions from the locked state to an unlocked state. In some examples, after retrying authentication and in accordance with a determination that authentication resulting from retrying authentication is not successful, the electronic device maintains the locked state. 
     In some examples, subsequent to (or in response to) receiving the request to perform the operation that requires authentication, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) attempts authentication (e.g., biometric authentication). In some examples, while attempting authentication, the electronic device displays, on the display (e.g.,  702 ), a third indication (e.g.,  710 ,  714 A-I) (e.g., rings that rotate around a sphere) that the electronic device is using one or more biometric sensors of the electronic device to obtain information about a biometric feature (e.g., face, fingerprint). In some examples, the indication is a scanning animation. In some examples, the third indication is the first indication and/or the second indication. In some examples, while retrying authentication, the electronic device maintains display of the third indication on the display (e.g.,  702 ). 
     In some examples, in accordance with the determination that authentication resulting from retrying authentication is not successful, the electronic device displays, on the display (e.g.,  702 ), an animation with a lock icon (e.g.,  706 ) (e.g., an icon indicative of the locked state of the electronic device) alternating between a first position and a second position, the second position being different from the first position. In some examples, the animation with the lock icon is an animation of the lock icon shaking (e.g., side to side, rotating back and forth). In some examples, the electronic device displays an animation involving the lock icon to indicate that biometric authentication has failed. In some examples, a tactile output is provided in combination with the shaking lock icon. In some examples, no tactile output is provided. In some examples, in accordance with a determination that the biometric information captured using the one or more biometric sensors does not correspond to or does not match the authorization credentials, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) maintains the locked state of the electronic device. Displaying an animation of the lock icon shaking provides the user with feedback about the current state of the device (e.g., that biometric authentication has failed) and prompts the user to take further action. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) includes a biometric sensor (e.g.,  703 ) and the set of error condition criteria includes one or more of the following error condition criterions:
         A distance of the biometric feature from the biometric sensor exceeds a first predetermined threshold distance (e.g., the biometric feature (e.g., face) is too far from the biometric sensor) or exceeds the maximum of a distance range (e.g.,  712 ). In some examples, exceeding the first predetermined threshold or the maximum of a distance range is highly correlated with degradation or reduced accuracy of the information about the biometric feature obtained by the biometric sensor). In some examples, the user can correct this error condition by moving the user&#39;s face closer to the biometric sensor.   A distance of the biometric feature from the biometric sensor is below a second predetermined threshold distance (e.g., the biometric feature (e.g., face) is too close to the biometric sensor) or falls below the minimum of a distance range (e.g.,  712 ). In some examples, falling below the second predetermined threshold or the minimum of a distance range is highly correlated with degradation or reduced accuracy of the information about the biometric feature obtained by the biometric sensor. In some examples, the user can correct this error condition by moving the user&#39;s face farther away from the biometric sensor.   The biometric sensor (e.g.,  703 ) is occluded (e.g., partially occluded, fully occluded, occluded to a degree sufficient to inhibit operation of the sensor) (e.g., occluded by a portion of the user (e.g., a hand), while interacting with the electronic device). In some examples, the user can correct this error condition by moving the user&#39;s hand away from the biometric sensor.   A sub-portion of a detected biometric feature (e.g., eyes of a detected face) is not oriented towards the biometric sensor (e.g., one or more eyes are not focused on the electronic device (e.g., biometric sensor)). In some examples, the user can correct this error condition by opening the user&#39;s eyes or looking at the electronic device (e.g., biometric sensor).   At least a portion of the detected biometric feature is occluded (e.g., partially occluded, fully occluded, occluded to a degree sufficient to result in incomplete information about the biometric feature). In some examples, the user can correct this error condition by removing the accessory (e.g., sunglasses) or article of clothing (e.g., scarf, hat) that is blocking the user&#39;s face.   No biometric feature is detected within a field of view (e.g.,  728 ) of the biometric sensor.   A pose (e.g., an orientation with respect to the biometric sensor) of the detected biometric feature exceeds a threshold range (e.g., the biometric feature (e.g., face) is turned away from the biometric sensor). In some examples, exceeding the threshold range is highly correlated with degradation or reduced accuracy of the information about the biometric feature obtained by the biometric sensor. In some examples, the user can correct this error condition by turning the user&#39;s face toward the electronic device (e.g., biometric sensor).   The electronic device detects (e.g., via one or more ambient light sensors) an amount of light (e.g., ambient light) that exceeds a predetermined light threshold (e.g., exceeding the predetermined light threshold is highly correlated with degradation or reduced accuracy of the information about the biometric feature obtained by the biometric sensor). In some examples, the user can correct this error condition by turning the user&#39;s back towards the sun so as to reduce the amount of light detected by the electronic device or move to a new location that has less ambient light (e.g., indoors).       

     In some examples, the set of error condition criteria can be a first subset of the error conditions listed above. For example, the first subset can include one or more error condition criterion selected from the group consisting of: the distance of the biometric feature exceeds a first predetermined threshold distance, the distance of the biometric feature is below a second predetermined threshold distance, the biometric feature is out of the field of view of the biometric sensor, and the pose of the biometric feature exceeds a threshold range. The first subset is focused on guiding the user to correct error conditions involving the positioning and/or orientation of the face. As a further example, a second subset can include one or more error condition criterion selected from the group consisting of: the biometric sensor is occluded, and no biometric feature is detected within a field of view of the biometric sensor. The second subset is focused on guiding the user to correct error conditions where the biometric sensor is unable to obtain any information about the biometric feature of the user. For another example, a third subset can include one or more error condition criterion selected from the group consisting of: the pose of the detected biometric feature exceeds a threshold range and the biometric sensor is occluded. The third subset is focused on the error conditions that are likely to occur for devices of a certain form factor/size (e.g., a tablet device (e.g., iPad)). 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) includes a biometric sensor (e.g.,  703 ) at a portion (e.g., a location) of the electronic device (e.g., a portion that is not on the display). In some examples, in response to the request to perform the operation that requires authentication, the electronic device displays, on the display (e.g.,  702 ), a progress indicator (e.g.,  714 A-I) proximate to (e.g., adjacent to, near, within a predetermined distance of) the portion of the electronic device, the progress indicator including the indication of the error condition. Displaying the progress indicator near the biometric sensor provides the user with feedback as to the association of the biometric sensor with the processes occurring at the device (e.g., attempted authentication). Specifically, the user becomes aware of the biometric sensor during biometric authentication such that the user is less likely to perform an action that interferes with the biometric sensor or alternatively, the user is prompted to take corrective action. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, the indication of the error condition (e.g.,  714 B) includes an indication that biometric authentication is currently not enabled on the electronic device in accordance with a determination that biometric authentication is currently not enabled on the electronic device. In some examples, biometric authentication can become unavailable (or not enabled on the electronic device) when one or more of the following conditions have been met: the electronic device has not been successfully authenticated since being turned on or restarted; the electronic device has not been unlocked for more than a predetermined amount of time (e.g., 48 hours); the passcode has not been used to unlock the device for more than a predetermined amount of time (e.g., 156 hours); biometric authentication using a biometric feature (e.g., face, fingerprint) has not been used to unlock device for more than predetermined amount of time (e.g., 4 hours); the electronic device has received a remote lock command; biometric authentication has failed more than a predetermined number of times (e.g., 5, 10, 15) since the last successful authentication with the device; the electronic device has received a power off and/or emergency SOS command, and an explicit request by the user to disable biometric authentication has been detected. Displaying an indication that biometric authentication is currently not enabled provides feedback to the user of the current state of the device and prompts the user to pursue an alternative method to authenticate herself. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, the indication that biometric authentication is currently not enabled includes an affordance (e.g.,  714 B) (e.g., the indication is an affordance). In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) receives an input (e.g.,  720 ) corresponding to the affordance and in response to receiving the input corresponding to the affordance, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) displays, on the display (e.g.,  702 ), a credential entry user interface (e.g.,  722 A) with a plurality of character entry keys. In some examples, the credential entry user interface includes a virtual keypad or virtual keyboard. In some examples, the virtual keypad or virtual keyboard includes a plurality of character entry keys. 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  700 ) detects a condition that triggers attempting authentication (e.g., biometric authentication). In some examples, the request to perform an operation that requires authentication includes a request to unlock the device (e.g., a swipe at a predefined location). In some examples, in response to detecting the condition that triggers attempting authentication (e.g., biometric authentication) and in accordance with a determination that the condition corresponds to an alert (e.g.,  708 ) generated by the device without user input directed to the device (e.g., based on the satisfaction of criteria other than detection of user input) while a biometric feature is available for detection by the one or more biometric sensors (e.g., a face is detected in the field of view of one or more face detection sensors such as a depth camera), the electronic device displays a fifth indication (e.g.,  710 ) (e.g., rings that rotate around a sphere) that the electronic device is using the one or more biometric sensors of the electronic device to obtain information about a biometric feature. In some examples, in accordance with a determination that the condition corresponds to an alert generated by the device without user input directed to the device (e.g., based on the satisfaction of criteria other than detection of user input) while a biometric feature is not available for detection by the one or more biometric sensors (e.g., no face is detected in the field of view of one or more face detection sensors such as a depth camera), the electronic device forgoes displaying the fifth indication (e.g., rings that rotate around a sphere) that the electronic device is using the one or more biometric sensors of the electronic device to obtain information about a biometric feature. In some examples, in accordance with a determination that the condition corresponds to a user input directed to the device (e.g., a request that is not associated with a notification; a request that is a touch gesture input (e.g., tap, a swipe (e.g.,  724 ) (e.g., an upward swipe) or an activation of a hardware button (e.g., power button) or sensor data indicative of movement (e.g., lifting) of the device)), the electronic device displays the fifth indication that the electronic device is using one or more biometric sensors of the electronic device to obtain information about a biometric feature (e.g., without regard to whether or not the biometric feature is available for detection by the one or more biometric sensors). Forgoing displaying the indication when no face is detected prevents potentially confusing the user, for it is likely that the user does not intend to initiate biometric authentication if no biometric feature is detected. Thus, forgoing displaying the indication in this scenario makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     Note that details of the processes described above with respect to method  800  (e.g.,  FIGS.  8 A- 8 B ) are also applicable in an analogous manner to the methods described below. For example, method  1000 , method  1200 , and/or method  1400  optionally include one or more of the characteristics of the various methods described above with reference to method  800 . For example, the error indications (e.g.,  714 A-I) as described with respect to method  800  can be used to provide indications of error conditions during biometric authentication that is performed in processes described with respect to method  1000 , method  1200 , and method  1400 . For brevity, these details are not repeated below. 
       FIGS.  9 A- 9 U  illustrate exemplary user interfaces for providing indications about the biometric sensor during biometric authentication, in accordance with some examples. The user interfaces in these figures are used to illustrate the processes described below, including the processes in  FIGS.  10 A- 10 C . 
       FIG.  9 A  illustrates electronic device  900  (e.g., portable multifunction device  100 , device  300 , device  500 ). In the exemplary examples illustrated in  FIGS.  9 A- 9 U , electronic device  900  is a tablet computer. In other examples, electronic device  900  can be a different type of electronic device, such as a smartphone (e.g., electronic device  700 ). Electronic device  900  includes display  902 , one or more input devices (e.g., touchscreen of display  902 , button  904 , and a microphone), a wireless communication radio, and biometric sensor  903 . Electronic device  900  includes biometric sensor  903 . In some examples, biometric sensor  903  includes one or more biometric sensors that can include a camera, such as an infrared camera, a thermographic camera, or a combination thereof. In some examples, biometric sensor  903  includes some or all of the features of biometric sensor  703 . In some examples, biometric sensor  903  includes one or more fingerprint sensors (e.g., a fingerprint sensor integrated into a button). In some examples, electronic device  900  further includes a light-emitting device (e.g., light projector), such as an IR flood light, a structured light projector, or a combination thereof. The light-emitting device is, optionally, used to illuminate the biometric feature (e.g., the face) during capture of biometric data of biometric features by biometric sensor  903 . In some examples, electronic device  900  includes a plurality of cameras separate from biometric sensor  903 . In some examples, electronic device  900  includes only one camera separate from biometric sensor  903 . 
     At  FIG.  9 A , a user wishes to purchase goods using payment information stored on electronic device  900 . As depicted in  FIG.  9 A , electronic device  900  is in a split screen (e.g., multitasking) mode. While in the split screen mode, electronic device  900  concurrently displays app store user interface (UI)  906  in left region  907  of display  902  and browser UI  908  in right region  909  of display  902 . While concurrently displaying app store UI  906  and browser UI  908 , electronic device  900  receives input  910  at purchase affordance  912 . 
     At  FIG.  9 B , in response to receiving input  910  at purchase affordance  912 , electronic device  900  swaps the applications being displayed in left region  907  and right region  909  of display  902 . Specifically, electronic device  900  displays browser UI  908  in left region  907 , and displays app store UI  906  in right region  909 . Electronic device  900  swaps the applications in order to place the application associated with the goods being purchased in the region that is closer to biometric sensor  903 . By placing browser UI  908  in left region  907 , electronic device  900  provides an indication to the user of the location of biometric sensor  903 , which is used to authenticate the user prior to authorizing payment for purchasing the goods. As shown in  FIG.  9 B , swapping the applications also places the application associated with the goods being purchased in the region that is closer to button  904 . In some examples, when the button  904  and the biometric sensor  903  are not in close proximity (e.g., on the same side), electronic device  900  swaps applications, when necessary, to place the application associated with the goods being purchased in the region that is closer to the biometric sensor  903 . In some examples, when button  904  and biometric sensor  903  are not in close proximity (e.g., on the same side), electronic device  900  swaps applications, when necessary, to place the application associated with the goods being purchased in the region that is closer to the button  904 . 
     Additionally, as depicted in  FIG.  9 B , in response to receiving input  910  at purchase affordance  912 , electronic device  900  darkens browser UI  908  while darkening app store UI  906  to a greater degree than that of browser UI  908 . By darkening browser UI  908  less than app store UI  906 , electronic device  900  indicates to the user which application is associated with pay sheet interface  914  and the goods the user wishes to purchase. 
     Moreover, in response to receiving input  910  at purchase affordance  912 , electronic device  900  concurrently displays pay sheet interface  914  with information about the goods being purchased and prompt  916  to prompt the user to double-click button  904  to initiate a process for authorizing payment for the goods. Further in response to receiving input  910  at purchase affordance  912 , electronic device  900  displays dynamic indication  918  to emphasize the location of button  904 . While displaying pay sheet interface  914 , electronic device receives input  920  at button  904  (e.g., double-press of button  904 ). Prompt  916  instructs the user to provide one or more activations of button  904  (e.g., a double press of button  904 ). In some examples, prompt  916  is emphasized relative to one or more other displayed objects (on pay sheet interface  914 ). In some examples, dynamic indication  918  emphasizes the location of button  904  on the device by continuously changing in size (e.g., continuously alternating between becoming wider and becoming narrower, or otherwise continuously changing in size) adjacent to the location of button  904  on the display, thereby allowing the user to more easily locate the button corresponding to the request of prompt  916 . In some examples, pay sheet interface  914  includes the name of the application to which it corresponds (e.g., the name of the application from which the user initiated the process for authorizing payment). 
     At  FIG.  9 C , in response to receiving input  920  at button  904 , electronic device  900  initiates a process for authorizing payment for the goods. Authorizing payment for the goods requires successfully authenticating the user. As a result, in response to receiving input  920 , electronic device  900  initiates biometric authentication using biometric sensor  903 . After initiating biometric authentication, electronic device  900  displays face glyph  922 , which provides an indication that electronic device  900  is attempting to biometrically authenticate the user (e.g., attempting to obtain biometric information about the user using biometric sensor  903 ). In some examples, face glyph  922  includes a simulation of a representation of a biometric feature. In some examples, in response to receiving input  920  at button  904 , electronic device displays an animation of face glyph  922  moving from the location of prompt  916  to the location of face glyph  922 , as depicted in  FIG.  9 C . In some examples, the animation is such that face glyph  922  appears to slide out of prompt  916 . 
     At  FIG.  9 D , after displaying face glyph  922 , electronic device transitions to displaying authentication glyph  924 , which provides an indication that electronic device  900  is attempting to biometrically authenticate the user (e.g., continuing to try to obtain biometric information, attempting to match obtained information with stored authorized credentials). Authentication glyph  924  includes a plurality of rings that rotate spherically. In some examples, authentication glyph  924  provides an indication that biometric data is being processed (e.g., compared against stored authorized credentials). 
     While displaying authentication glyph  924 , electronic device  900  detects that an error condition exists (e.g., a condition that prevents biometric sensor  903  from obtaining sufficient information about the user&#39;s face). Specifically, electronic device  900  detects that biometric sensor  903  is covered by a physical object (e.g., the user&#39;s hand)). In some examples, electronic device  900  does not detect an error condition, and is able to obtain sufficient information about the user&#39;s face. In some examples, after obtaining sufficient information about the user&#39;s face and while displaying authentication glyph  924 , electronic device  900  determines whether the obtained information satisfies biometric authentication criteria (e.g., determines whether the obtained biometric information matches, within a threshold, a biometric template associated with the user (e.g., stored authorized credentials)). In some examples, upon determining that biometric authentication is successful (e.g., biometric authentication criteria is satisfied), electronic device  900  transitions to an unlocked state. 
     At  FIG.  9 E , in response to detecting that an error condition exists, electronic device  900  displays error indication  926  at a location at the top of display  902  (e.g., with respect to the ground, with respect to the user). Error indication  926  provides an indication of the error condition that currently exists. Further in response to detecting that an error conditions exists, electronic device  900  displays error icon  928  at a location of display  902  that is adjacent to biometric sensor  903 , thereby providing an indication of the location of biometric sensor  903 . By providing an indication of the location of biometric sensor  903 , error icon  928  suggests to the user the cause of the error condition. In some examples, in response to detecting that an error condition exists, electronic device  900  displays error indication  926  at a location adjacent to biometric sensor  903 . In some examples, error indication  926  includes some or all of the features of error indication  714 A, including a shimmer effect. 
     At  FIG.  9 F , further in response to detecting that an error condition exists, electronic device  900  displays an animation of pay sheet interface  914  moving from its initial location in  FIG.  9 E  to the location in  FIG.  9 F , which is closer to biometric sensor  903 . By moving pay sheet interface towards biometric sensor  903 , electronic device  900  indicates to the user the existence of error icon  928  in addition to indicating the location of biometric sensor  903  (and thus suggesting to the user the cause of the error condition). 
     In some examples, error icon  928  is displayed at different location of display  902  depending on the positioning of the user&#39;s hand on display  902 . As illustrated in  FIG.  9 F , the user&#39;s hand is covering a portion of display  902  that is adjacent to biometric sensor  903 . While the user&#39;s hand is in contact with display  902 , electronic device  900  detects an input as a result of the contact from the user&#39;s hand. In response to detecting this input, electronic device  900  displays error icon  928  at a location at which the input is not detected. As another example, in  FIG.  9 G , the user&#39;s hand is covering less of display  902  than the user&#39;s hand in  FIG.  9 F . In some examples, in response to detecting the input of the user&#39;s hand in  FIG.  9 G , electronic device  900  displays error icon  928  at a location that is different from the location in  FIG.  9 F , where the location in  FIG.  9 G  is closer to biometric sensor  903  than that of  FIG.  9 F . As yet another example, in  FIG.  9 H , the user&#39;s hand is covering a large portion of the upper-left side of display  902 . In some examples, in response to detecting the input of the user&#39;s hand in  FIG.  9 H , electronic device  900  displays error icon  928  at a location that is different from the locations in  FIGS.  9 F- 9 G . Specifically, in some examples, electronic device  900  displays error icon  928  at a location that is close to (or substantially near) biometric sensor  903  without being at a location where the input of the user&#39;s hand is detected. 
     At  FIG.  9 I , the user removes her hand such that it no longer covers biometric sensor  903 . While displaying error indication  926  and error icon  928 , electronic device  900  detects that the error condition no longer exists. 
     At  FIG.  9 J , in response to detecting that the error condition no longer exists, electronic device  900  automatically retries biometric authentication. While retrying biometric authentication, electronic device  900  displays authentication glyph  924 . While displaying authentication glyph  924 , electronic device  900  attempts to biometrically authenticate the user. Specifically, electronic device  900  obtains information about the user&#39;s face using biometric sensor  903 , and determines whether biometric authentication is successful (e.g., the obtained information matches stored authorized credentials). 
     While retrying biometric authentication, electronic device  900  determines that biometric authentication is successful. At  FIG.  9 K , upon determining biometric authentication is successful, electronic device  900  displays success glyph  930 , which provides an indication that biometric authentication was successful. In some examples, success glyph  930  replaces authentication glyph  924 . 
     At  FIG.  9 L , further in response to determining that biometric authentication is successful, electronic device  900  displays processing indicator  932 , which provides an indication that the payment transaction is being processed (e.g., electronic device  900  is transmitting payment information (e.g., credentials) to an external device (e.g., server) to authorize payment). In some examples, processing indicator  932  has a similar or identical pattern to authentication glyph  924 . 
     At  FIG.  9 M , upon receiving an indication that payment has been completed (e.g., authorized), electronic device  900  displays completed indication  934 , which provides an indication that payment has been completed. Completed indication  934  includes a checkmark to indicate completion. 
       FIGS.  9 N- 9 S  illustrate a technique for displaying error indication  926  and error icon  928  when error indication  926  and error icon  928  are to be displayed in approximately the same location. At  FIG.  9 N , a user wishes to unlock the device to access restricted content (e.g., a home screen, a most recently used application).  FIG.  9 N  depicts electronic device  900  in a portrait orientation with respect to the ground, where a user is covering biometric sensor  903  with her hand. Additionally, electronic device  900  displays locked state UI  936  with lock icon  938 . Lock icon  938  provides an indication that electronic device  900  is in a locked state. 
     While displaying locked state UI  936 , electronic device  900  receives a request to unlock the device. For example, electronic device  900  detects the user lifting the device from a substantially horizontal position. 
     At  FIG.  9 O , in response to receiving the request to unlock the device, electronic device  900  attempts to biometrically authenticate the user. While attempting to biometrically authenticate the user, electronic device  900  displays authentication glyph  924 . Additionally, while attempting to biometrically authenticate the user, electronic device  900  detects that an error condition exists (e.g., a condition that prevents biometric sensor  903  from obtaining sufficient information about the user&#39;s face). Specifically, electronic device  900  detects that biometric sensor  903  is covered by a physical object (e.g., the user&#39;s hand)). 
     At  FIG.  9 P , in response to detecting that an error condition exists, electronic device  900  displays error icon  928  at a location of display  902  that is near biometric sensor  903  (e.g., at the top of display  902 ). Further in response to detecting that an error condition exists, electronic device  900  determines that error indication  926  is to be displayed at approximately the same location as error icon  928 . Upon determining that error indication  926  is to be displayed at approximately the same location, electronic device  900  does not immediately display error indication  926 , and instead displays error indication  926  as part of an animation that transitions from error icon  928  to error indication  926  to lock icon  938 , as described below with respect to  FIGS.  9 Q- 9 R . 
     At  FIG.  9 Q , after displaying error icon  928 , electronic device  900  displays (e.g., replaces display of error icon  928  with) error indication  926 , which as discussed above, provides an indication of the cause of the error condition. 
     While displaying error indication  926 , the user removes her hand from biometric sensor  903  such that it no longer covers biometric sensor  903 . In response to detecting that the error condition no longer exists, electronic device  900  automatically retries biometric authentication. 
     At  FIGS.  9 R- 9 S , upon determining that authentication is successful as a result of retrying biometric authentication, electronic device  900  transitions from a locked state to an unlocked state. Specifically, electronic device  900  displays (e.g., replaces display of error indication  926  with) an animation of lock icon  938  transitioning to unlock icon  940 , which provides an indication to the user that electronic device  900  has transitioned to an unlocked state. In some examples, instead of successful biometric authentication, electronic device  900  determines that authentication is unsuccessful as a result of retrying biometric authentication. In some examples, upon determining that authentication is unsuccessful, electronic device  900  displays a passcode entry UI with an affordance which, when activated, triggers retrying biometric authentication. In some examples, while retrying biometric authentication, electronic device  900  darkens all portions of display  902  except for the user interface associated with retrying biometric authentication. 
       FIG.  9 T  illustrates a technique for displaying error icon  928  when error icon  928  is to be displayed at approximately the same location as one of the notifications being displayed (e.g.,  944 A-D). In some examples, a user wishes to view the restricted content of one or more of the notifications (e.g.,  944 A-D) that are displayed while electronic device  900  is in a locked state. As depicted in  FIG.  9 T , a user is covering biometric sensor  903  with her hand when the electronic device is a portrait orientation, where biometric sensor  903  is located near the bottom of the device. In some examples, while attempting to biometrically authenticate a user to access the restricted content of the notifications, electronic device  900  detects that an error condition exists as a result of the user covering biometric sensor  903  with her hand. In response to detecting that an error condition exists, electronic device  900  determines that error icon  928  is to be displayed at approximately the same location as one of the notifications (e.g.,  944 A-D). Upon making this determination and in response to detecting that the error condition exists, electronic device  900  displays UI element  942  (e.g., a background) concurrently with error icon  928  to provide a background on which to overlay the display of error icon  928 . As depicted in  FIG.  9 T , UI element  942  is opaque such that the notification on which error icon  928  is overlaid (e.g.,  944 D) is not visible to the user. In some examples, UI element  942  is transparent such that the notification on which error icon  928  is overlaid is visible to the user. 
       FIG.  9 T  also illustrates a technique for hiding unlock indication  905  of  FIG.  9 U  when error icon  928  is to be displayed at approximately the same location as unlock indication  905 . In some examples, electronic device  900  displays unlock indication  905 , which provides an indication of an approximate location on display  902  from which a user can start an upward swipe to initiate biometric authentication. In some examples, while displaying unlock indication  905 , electronic device  900  detects that an error condition exists as a result of the user covering biometric sensor  903  with her hand. In some examples, in response to detecting that an error condition exists, electronic device  900  determines that error icon  928  is to be displayed at approximately the same location as unlock indication  905 . In some examples, upon making this determination and in response to detecting that the error condition exists, electronic device  900  ceases to display unlock indication  905 , and displays error icon  928  at approximately the same location at which unlock indication  905  was displayed. 
     While displaying error icon  928 , electronic device  900  detects that the error condition no longer exists (e.g., due to the user removing her hand from biometric sensor  903 ). As depicted in  FIG.  9 U , the user has removed her hand from biometric sensor  903 . At  FIG.  9 U , upon detecting that the error condition no longer exists, electronic device  900  ceases to display error icon  928 , and re-displays unlock indication  905  at the location at which it was previously displayed. 
       FIGS.  10 A- 10 C  are flow diagrams illustrating a method for providing indications about the biometric sensor during biometric authentication, in accordance with some examples. Method  1000  is performed at an electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) with a display (e.g.,  902 ) and a biometric sensor (e.g.,  903 ) (e.g., a first biometric sensor of a device with a plurality of biometric sensors) (e.g., a fingerprint sensor, a contactless biometric sensor (e.g., a biometric sensor that does not require physical contact, such as a thermal or optical facial recognition sensor), an iris scanner) at a first portion of the electronic device (e.g., a portion that is not a part of the display). In some examples, the biometric sensor includes one or more cameras. Some operations in method  1000  are, optionally, combined, the orders of some operations are, optionally, changed, and some operations are, optionally, omitted. 
     As described below, method  1000  provides an intuitive way for providing indications about the biometric sensor during biometric authentication. The method reduces the cognitive burden on a user for performing biometric authentication, thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to perform biometric authentication faster and more efficiently conserves power and increases the time between battery charges. 
     The electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) detects ( 1002 ) (e.g., detects in response to a request to perform an operation that requires authentication) the existence of an error condition that prevents the biometric sensor from obtaining biometric information about a user of the device (e.g., a contactless biometric sensor such as a thermal or optical facial recognition sensor) is occluded (e.g., partially occluded, fully occluded, occluded to a degree sufficient to inhibit operation of the sensor) (e.g., occluded by a portion of the user (e.g., a hand), while interacting with the electronic device). 
     In response ( 1004 ) to detecting the existence of the error condition, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays, on the display (e.g.,  902 ), an error indication (e.g.,  928 ) (e.g., a graphical icon). In some examples, the error indication includes text (e.g., indicating that the sensor is occluded. In some examples, the error indication does not include text. The error indication is displayed ( 1006 ) at a location that is proximate to the first portion of the electronic device. In some examples, the location is at or near the portion of the display that is closest to the location of the biometric sensor (e.g.,  903 ). Displaying the error indication provides the user with feedback about the current state of the device (e.g., that an error condition is preventing successful biometric authentication) and prompts the user to take further action to correct the error condition. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. Displaying the error indication near the biometric sensor provides the user with feedback as to the association of the biometric sensor with the processes occurring at the device (e.g., attempted authentication). Specifically, the user becomes aware of the biometric sensor during biometric authentication such that the user is less likely to perform an action that interferes with the biometric sensor or alternatively, the user is prompted to take corrective action. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, the error indication (e.g.,  928 ) includes ( 1008 ) a biometric sensor occluded icon and a reticle, the error indication providing an indication that the biometric sensor is occluded. In some examples, the error indication is associated with the electronic device performing biometric authentication (e.g., using the biometric sensor to obtain biometric information about a biometric feature (e.g., face, fingerprint). Providing an indication that the biometric sensor is occluded provides the user with feedback about the current state of the device (e.g., that the biometric sensor is occluded) and prompts the user to take further action to correct the error condition. Providing improved feedback with instructions on proper movements of the biometric feature therefore enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device), which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In accordance ( 1010 ) with a determination that a user interface of the electronic device is in a first orientation relative to the biometric sensor, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays the error indication at a first location in the user interface that is proximate to (e.g., adjacent to, near to, within a predetermined distance of) the first portion of the electronic device. 
     In accordance ( 1012 ) with a determination that the user interface of the electronic device is in a second orientation relative to the biometric sensor, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays the error indication (e.g.,  928 ) at a second location in the user interface that is proximate to (e.g., adjacent to, near to, within a predetermined distance of) the first portion of the electronic device, the first orientation being different from the second orientation. 
     In some examples, while attempting ( 1014 ) to obtain biometric information using the biometric sensor (e.g.,  903 ), the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays ( 1016 ), on the display (e.g.,  902 ), a first progress indicator (e.g.,  924 ,  926 ,  938 ,  940 ). In some examples, the first progress indicator provides an indication of the current state of the electronic device (e.g., locked state, unlocked state, performing biometric authentication, error state, error condition). In some examples, in accordance ( 1018 ) with a determination that the user interface (e.g.,  906 ,  908 ) of the electronic device is in a third orientation relative to the biometric sensor, the user interface in the third orientation having a first top side, the electronic device displays the first progress indicator proximate to (e.g., adjacent to, near to, within a predetermined distance of) the first top side of the user interface in the third orientation. In some examples, in accordance ( 1020 ) with a determination that the user interface of the electronic device is in a fourth orientation relative to the biometric sensor, the user interface in the fourth orientation having a second top side, the electronic device displays the first progress indicator proximate to (e.g., adjacent to, near to, within a predetermined distance of) the second top side of the user interface in the fourth orientation, the third orientation being different from the fourth orientation. In some examples, the first progress indicator is displayed on the display at a location that is closest to or proximate to (e.g., adjacent to, near to, within a predetermined distance of) the biometric sensor. Displaying the first progress indicator near the top of the display regardless of orientation ensures that the user is more likely to be aware of the provided feedback to the user (e.g., the progress indicator). Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays, on the display (e.g.,  902 ), a second progress indicator (e.g.,  924 ,  926 ,  938 ,  940 ) of the electronic device. In some examples, the second progress indicator provides an indication of the current state of the electronic device (e.g., locked state, unlocked state, performing biometric authentication, error state). In some examples, the first progress indicator is the second progress indicator. In some examples, the second progress indicator is an animation with a first portion (e.g., an indication that the electronic device is performing biometric authenticating using the biometric sensor (e.g.,  924 ) (e.g., rotating rings)) and a second portion (e.g., an indication of an error condition or error state (e.g.,  926 ), an indication of the current lock or unlock state of the electronic device (e.g., lock icon (e.g.,  938 ), unlock icon (e.g.,  940 )) that is different from the first portion. In some examples, in accordance with a determination that the second progress indicator is displayed at the location that is proximate to the first portion of the electronic device, the electronic device displays the error indication (e.g.,  928 ) as part of the animation subsequent to the first portion and prior to the second portion. 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays, on the display (e.g.,  902 ), a home affordance (e.g.,  905 ) (e.g., an indication of a location of a gesture that when performed, results in displaying a home screen such as a swipe up gesture from an edge of the display or a tap gesture on the affordance) at a third location (e.g., a location proximate to a side (e.g., bottom side) of the user interface) in the user interface. In some examples, in accordance with a determination that the error indication (e.g.,  928 ) is displayed at the third location, the electronic device ceases to display the home affordance (e.g.,  905 ) while displaying the error indication at the third location. Ceasing display of the home affordance while displaying an error indication allows the user to quickly realize the home affordance is not accessible because there is an error and prompts the user to take further action to correct the error condition. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. 
     In some examples, after ceasing to display the home affordance (e.g.,  905 ), the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) detects a correction of the error condition that prevents the biometric sensor (e.g.,  903 ) from obtaining biometric information about the user of the device. In some examples, the electronic device detects the absence of the error condition subsequent to displaying the error indication (e.g.,  928 ) at the third location. In some examples, in response to detecting the correction of the error condition, the electronic device displays, on the display (e.g.,  902 ), the home affordance at the third location in the user interface (e.g., and ceases to display the error indication (e.g.,  928 )). 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) detects an input (e.g., palm, finger) at the location that is proximate to (e.g., adjacent to, near to, within a predetermined distance of) the first portion of the electronic device. In some examples, in response to detecting the input at the location that is proximate to the first portion of the electronic device, the electronic device displays, on the display, the error indication (e.g.,  928 ) at a different location. In some examples, the different location is a location at which the input is not detected. In some examples, prior to displaying the error indication at the new location, the electronic device determines the different location based on the location of the input with respect to the display. In some examples, the different location is proximate to the location that is proximate to the first portion of the electronic device. In some examples, the error indication is moved to the different location after being initially displayed at a first location that is proximate to the first portion of the electronic device. In some examples, the error indication is initially displayed at a location selected so as to be away from any regions of the display that are known to be occluded (e.g., occluded by a detected touch input). Displaying the error indication at a different location depending on the location of the input (e.g., a user&#39;s hand) provides the user with feedback about the current state of the device (e.g., that an error condition is preventing successful biometric authentication) and prompts the user to take further action to correct the error condition. Further, by adjusting the location, the device ensures that the error indication is visible to the user and thus, the user is more likely to take corrective action at the device. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays, on the display (e.g.,  902 ), a first transaction interface (e.g.,  914 ) (e.g., a transaction (or payment) interface that is separate from (or overlaid on top of) the user interface and includes transaction information such as a credit card number, billing address, etc.) at a position that is proximate to (e.g., adjacent to, near to, within a predetermined distance of) the first portion of the electronic device. In some examples, the first transaction interface is displayed in response to receiving an input (e.g.,  910 ) corresponding to an affordance (e.g.,  912 ) of the user interface (e.g.,  908 ) (e.g., an affordance for making a payment or completing a transaction). 
     In some examples, displaying the first transaction interface (e.g.,  914 ) includes displaying an animation of the first transaction interface transitioning (e.g., translating) from an initial position that is substantially centered with respect to the display to the position that is proximate to the first portion of the electronic device. In some examples, the animation includes displaying (e.g., maintaining the display of) the first transaction interface while the first transaction interface transitions (e.g., translates) from the initial position to the position that is proximate to the first portion of the electronic device. In some examples, the animation includes a visual effect where the first transaction interface appears to float while transitioning. 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays, on the display (e.g.,  902 ), a prompt (e.g.,  916 ) to provide one or more activations of a hardware button (e.g.,  904 ) of the electronic device. In some examples, the electronic device prompts the user by displaying “double click for Apple Pay”. In some examples, the prompt is displayed adjacent to the button. In some examples, the prompt is displayed when the device is displaying a transaction user interface region (e.g.,  914 ) but without receiving any indication that a transaction terminal is nearby and is requesting transaction credentials (e.g., the prompt to provide the one or more activations of the button are displayed before the device has been placed in an NFC field of an NFC reader that is requesting payment information). In some examples, the hardware button is a mechanical button or a solid state button. In some examples, the button is a switch or any other type of toggle. In some examples, the button has a fixed position relative to the electronic device, and in particular, relative to the display of the electronic device such that the electronic device may display prompts based on a position of the button. In some examples, the button is a solid-state button that operates according to capacitive and/or resistive touch, and/or is responsive to changes in the intensity of input without having a mechanical switch that is depressed to activate the button and instead monitors whether an intensity of the input is above an intensity threshold that corresponds to activation of the solid-state button. In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) receives one or more activations (e.g.,  920 ) of the hardware button of the electronic device, and in response to receiving the one or more activations of the hardware button, the electronic device displays, on the display (e.g.,  902 ), an authentication progress indicator (e.g.,  922 ,  924 ,  930 ,  932 ,  934 ). In some examples, displaying the authentication progress indicator includes displaying an animation of the authentication progress indicator transitioning from a location of the prompt (e.g.,  916 ) to a final position of the authentication progress indicator. In some examples, the authentication indicator provides a status of the authentication (e.g., in progress, successful, unsuccessful). In some examples, the animation includes displaying (e.g., maintaining the display of) the authentication progress indicator while the authentication progress indicator transitions (e.g., translates) from the location of the prompt to the final position. In some examples, the animation includes a visual effect where the authentication progress indicator appears to slide out of the prompt. In some examples, the authentication progress indicator is displayed with (or overlaid on) the user interface (e.g.,  914 ) (or the transaction user interface region). Prompting the user to activate a hardware button guides the user to perform an action at the device in order to complete a transaction. Prompting the user in this manner enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device), which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. Displaying an authentication progress indicator provides feedback to the user regarding the status of the authentication. Improved feedback enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device), which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) concurrently displays ( 1022 ), on the display (e.g.,  902 ), a first application (e.g., corresponding to  906 ,  908 ) in a first region (e.g.,  907 ,  909 ) and a second application (e.g., corresponding to  906 ,  908 ) in a second region (e.g.,  907 ,  909 ), the second application being adjacent to (e.g., next to, proximate to, within a predetermined distance of) the first application. In some examples, the electronic device displays ( 1024 ), on the display, a second transaction interface (e.g.,  914 ). In some examples, the second transaction interface is the first transaction interface. In some examples, the second transaction interface is displayed overlaid on the first application and/or the second application. In some examples, in accordance ( 1026 ) with a determination that the second transaction interface corresponds to the first application, the electronic device modifies a first visual characteristic (e.g., obscure, darken, blur) of the first application. In some examples, the second transaction interface corresponds to the first application when the first application includes information about the good or service (or transaction) that is being purchased (or completed) using (or via) the second transaction interface. In some examples, this determination is made while displaying the second transaction interface. In some examples, in accordance ( 1030 ) with a determination that the second transaction interface corresponds to the second application, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) modifies a first visual characteristic (e.g., obscure, darken, blur) of the second application. In some examples, the second transaction interface corresponds to the first application when the first application includes information about the good or service (or transaction) that is being purchased (or completed) using (or via) the second transaction interface. In some examples, this determination is made while displaying the second transaction interface. 
     In some examples, modifying the first visual characteristic of the first application includes modifying a second visual characteristic of the second application. In some examples, modifying the second visual characteristic of the second application includes increasing darkening and/or increasing blur radius of a blur effect applied to the second application to a greater degree (or amount) than with respect to the first application. In some examples, modifying the first visual characteristic of the second application includes modifying a second visual characteristic of the first application. In some examples, modifying the second visual characteristic of the first application includes increasing darkening and/or increasing blur radius of a blur effect applied to the first application to a greater degree (or amount) than with respect to the second application. Modifying the visual characteristic of one application to a greater degree than with respect to another application provides feedback to the user as to which application is more relevant at the time. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. 
     In some examples, modifying the first visual characteristic of the first application includes displaying ( 1028 ) the first application in the second region in accordance with a determination that the second region is closer (e.g., nearer) to the first portion of the electronic device (e.g., biometric sensor) than the first region. In some examples, displaying the first application in the second region includes ceasing to display the first application in the first region. In some examples, modifying the first visual characteristic of the second application includes displaying ( 1032 ) the second application in the first region in accordance with a determination that the first region is closer (e.g., nearer) to the first portion of the electronic device (e.g., biometric sensor) than the second region. In some examples, displaying the second application in the first region includes ceasing to display the second application in the second region. In some examples, the electronic device displays an animation of the first application swapping places with the second application. 
     In some examples, in accordance with the determination that the second transaction interface (e.g.,  914 ) corresponds to the first application, the second transaction interface includes an indication of the first application (e.g., the name of the first application). In some examples, in accordance with the determination that the second transaction interface corresponds to the second application, the second transaction interface includes an indication of the second application (e.g., the name of the second application). 
     Note that details of the processes described above with respect to method  1000  (e.g.,  FIGS.  10 A- 10 C ) are also applicable in an analogous manner to the methods described below/above. For example, method  800 , method  1200 , and/or method  1400  optionally include one or more of the characteristics of the various methods described above with reference to method  1000 . For example, error icon  928 , as described in method  1000 , can be used to indicate that the biometric sensor is obstructed when biometric authentication is being performed in the processes described with respect to method  800 , method  1200 , and method  1400 . For brevity, these details are not repeated below. 
       FIGS.  11 A- 11 S  illustrate exemplary user interfaces for orienting the device to enroll a biometric feature (e.g., a face for later use in biometric authentication), in accordance with some examples. The user interfaces in these figures are used to illustrate the processes described below, including the processes in  FIGS.  12 A- 12 C . 
       FIG.  11 A  illustrates electronic device  900  (e.g., portable multifunction device  100 , device  300 , device  500 ). In the exemplary examples illustrated in  FIGS.  11 A- 11 S , electronic device  900  is a tablet computer. In other examples, electronic device  900  can be a different type of electronic device, such as a smartphone (e.g., electronic device  700 ). Electronic device  900  includes display  902 , one or more input devices (e.g., touchscreen of display  902 , button  904 , and a microphone), a wireless communication radio, and biometric sensor  903 . Electronic device  900  includes biometric sensor  903 . In some examples, biometric sensor  903  includes one or more biometric sensors that can include a camera, such as an infrared camera, a thermographic camera, or a combination thereof. In some examples, biometric sensor  903  includes some or all of the features of biometric sensor  703 . In some examples, biometric sensor  903  includes one or more fingerprint sensors (e.g., a fingerprint sensor integrated into a button). In some examples, electronic device  900  further includes a light-emitting device (e.g., light projector), such as an IR flood light, a structured light projector, or a combination thereof. The light-emitting device is, optionally, used to illuminate the biometric feature (e.g., the face) during capture of biometric data of biometric features by biometric sensor  903 . In some examples, electronic device  900  includes a plurality of cameras separate from biometric sensor  903 . In some examples, electronic device  900  includes only one camera separate from biometric sensor  903 . 
     At  FIG.  11 A , a user wishes to set up biometric (e.g., face) authentication on electronic device  900 . Successfully setting up biometric authentication on the device enables a user to perform operations on the device that require authentication (e.g., unlocking the device) by presenting the user&#39;s face for biometric authentication. To set up biometric authentication on the electronic device, a user must first enroll her face. The process for enrolling the face can include some or all of the features (or processes) of  FIGS.  11 A- 11 O . 
     As illustrated in  FIG.  11 A , electronic device  900  displays introduction user interface (UI)  1106  with initiate affordance  1108 . Electronic device  900  receives input  1110  at initiate affordance  1108  to start the process of enrolling the user&#39;s face for biometric authentication. 
     At  FIG.  11 B , in response to receiving input  1110  at initiate affordance  1108 , electronic device  900  determines that the orientation of the device is not suitable for enrolling the user&#39;s face. In some examples, a suitable orientation for enrolling the user&#39;s face is a portrait orientation that is upright (e.g., vertical), where the portrait orientation is such that biometric sensor  903  is at the top of the device (e.g., the side of the device that is farthest away from the ground). In response to determining that the orientation of the device is not suitable for enrolling the user&#39;s face, electronic device  900  displays (e.g., replaces display of introduction UI  1106  with) one or more prompts to prompt the user to orient electronic device  900  to a suitable orientation. More specifically, electronic device  900  determines that electronic device  900  is in a substantially horizontal orientation (e.g., approximately parallel to the ground). As a result, as depicted in  FIG.  11 B , electronic device  900  displays prompt  1112 A to prompt the user to lift electronic device  900  to an upright position. 
     In some examples, in response to receiving input  1110  at initiate affordance  1108 , electronic device determines that the orientation of the device is suitable for enrolling the user&#39;s face. In some examples, upon determining that the orientation is suitable for enrolling the user&#39;s face, electronic device  900  automatically initiates a process for enrolling the user&#39;s face, as described below with respect to  FIG.  11 D . 
     At  FIG.  11 C , in response to determining that electronic device  900  is in an upright position but not in a portrait orientation (e.g., the user has lifted the device off the table in response to prompt  1112 A), electronic device  900  displays (e.g., replaces display of prompt  1112 A with) prompt  1112 B to prompt the user to rotate electronic device  900  to a portrait orientation (e.g., with the biometric sensor  903  at the top). Specifically, prompt  1112 B prompts the user to rotate in a specific direction (e.g., using text and/or an arrow) such that minimal rotation is required to achieve the desired (or suitable) orientation. For example, prompt  1112 B prompts the user to rotate electronic device  900  clockwise because rotating clockwise requires less rotation to achieve the desired orientation than rotating the device counterclockwise. In some examples, prompt  1112 B includes an animation of a representation of electronic device  900  rotating clockwise 90 degrees to indicate to the user the action needed to orient the device to a suitable orientation for enrolling the user&#39;s face. 
     In some examples, electronic device  900  displays a different prompt based on the orientation of the device. For example, if biometric sensor  903  is located adjacent to the right edge of the device (e.g., with respect to the user), electronic device  900  displays prompt  1112 C in  FIG.  11 Q . In some examples, prompt  1112 C prompts the user to rotate the device counterclockwise (e.g., via text and/or a pictorial illustration of the direction in which to rotate the device). In some examples, prompt  1112 C includes an animation of a representation of electronic device  900  rotating counterclockwise 90 degrees to indicate to the user the action needed to orient the device to a suitable orientation for enrolling the user&#39;s face. As another example, if biometric sensor  903  is located adjacent to the bottom edge of the device (e.g., with respect to the user), electronic device  900  displays prompt  1112 D in  FIG.  11 R . In some examples, prompt  1112 D prompts the user to rotate the device 180 degrees (e.g., via text and/or a pictorial illustration of the direction in which to rotate the device). In some examples, prompt  1112 D includes an animation of a representation of electronic device  900  rotating clockwise or counterclockwise 180 degrees to indicate to the user the action needed to orient the device to a suitable orientation for enrolling the user&#39;s face. 
     At  FIG.  11 D , in response to determining that electronic device  900  is in a suitable orientation, electronic device  900  automatically initiates a process for enrolling the user&#39;s face. As illustrated in  FIGS.  11 D- 11 F , after initiating the process for enrolling the user&#39;s face, electronic device  900  displays face enrollment UI  1114 . Face enrollment UI  1114  includes a facial image of the user. In some examples, the facial image is an image of the user captured by one or more cameras on device  900 . For example, the facial image optionally is live preview of the image data captured by the one or more cameras (e.g., a digital viewfinder) that updates continuously as the field of view of the camera and/or the field of view&#39;s contents change. In some examples, background content is removed such that only the user&#39;s face is visible in the facial image. Face enrollment UI  1114  also optionally includes an orientation guide that is superimposed (e.g., overlaid) on the facial image. The orientation guide is, optionally, a set of curved lines that extend into a virtual z-dimension (e.g., along an axis normal to the plane of the display) and intersect over the center of the facial image. Thus, the curved lines of the orientation guide appear to bulge outwards relative to the plane of display  902  to give a sense of the position of the user&#39;s head in three-dimensional space. 
     Face enrollment UI  1114  also includes an enrollment progress meter. The enrollment progress meter includes a set of display elements (e.g., progress elements) that are arranged around the facial image and the orientation guide. In the example of  FIG.  11 D , the progress elements are a set of lines that extend radially outward from the facial image arranged in a circular pattern. In some examples, the progress elements indicate an orientation of the user&#39;s face needed to enroll corresponding facial features. For example, progress elements in the upper portion of the enrollment progress meter optionally move, fill in, elongate, and/or change color when the user&#39;s head is tilted upwards, which allows the one or more cameras on device  900  to capture image data of the under-side of the user&#39;s face. In some examples, device  900  displays progress elements in the enrollment progress meter in an unenrolled state (e.g., the progress elements are greyed out, unchanged). 
     Face enrollment UI  1114  also includes a text prompt, which instructs the user to move (e.g., rotate and/or tilt) their head in a circular motion during the enrollment process. In some examples, the text prompt is optionally accompanied by tactile and/or auditory prompt depending on device settings and/or user selections. In some examples, device  900  displays the text prompt on face enrollment UI  1114  through the facial enrollment process. 
     In some examples, instead of automatically initiating a process for enrolling the user&#39;s face (and displaying face enrollment UI  1114 ), electronic device  900  displays enrollment introduction UI  1146  in  FIG.  11 S  in response to determining that electronic device  900  is in a suitable orientation. Enrollment introduction UI  1146  includes a face glyph (e.g., a representation of a biometric feature (e.g., face)), and an enrollment progress meter. The enrollment progress meter includes a set of display elements (e.g., progress elements) that are arranged around the glyph. In some examples, the progress elements includes some or all of the features of the progress elements described above with respect to  FIG.  11 D . In some examples, to trigger display of face enrollment UI  1114  and proceed with enrollment of the user&#39;s face, the user activates continue affordance  1148  on enrollment introduction UI  1146 . For example, as shown in  FIG.  11 S , electronic device  900  detects activation (e.g., selection) of continue affordance  1148  via input  1150  (e.g., tap gesture). In some examples, in response to detecting activation of continue affordance  1148 , electronic device  900  initiates the process for enrolling the user&#39;s face, as described above with respect to  FIG.  11 D . 
     At  FIG.  11 G , after successfully completing the enrollment of the user&#39;s face, electronic device  900  displays (e.g., replaces display of face enrollment UI  1114  with) scan completion interface  1116 , which includes continue affordance  1118 . Scan completion interface  1116  includes a facial image and a success-state meter. In the example of  FIG.  11 G , the facial image is blurred, faded, darkened or otherwise obscured to indicate that additional image data is no longer being collected as part of the facial scan. In some examples, the success-state meter is a solid, continuous green circle surrounding the facial image that provides a visual indication that the first scan is complete. To provide a further visual notification, scan completion interface  1116  also includes a text prompt (e.g., a completion message). 
     After completing enrollment of the user&#39;s face, a second iteration of the enrollment process is performed without requiring that the user re-orient the device. As depicted in  FIG.  11 G , while displaying scan completion interface  1116 , electronic device  900  receives input  1120  at continue affordance  1118  to initiate the second iteration of the enrollment process. 
     At  FIG.  11 H , in response to receiving input  1120  at continue affordance  1118 , electronic device  900  initiates a second iteration of the enrollment process, analogous to the processes described above with respect to  FIGS.  11 D- 11 F . Electronic device  900  initiates the second iteration without prompting the user to re-orient the device to an orientation different from its current orientation. Initiating the second iteration of the enrollment process includes displaying second face enrollment UI  1122 . Second face enrollment UI  1122  includes some or all of the features of face enrollment UI  1114 . 
     At  FIG.  11 I , after successfully completing the second iteration of the enrollment process, electronic device  900  displays (e.g., replaces display of second face enrollment UI  1122  with) second scan completion interface  1124 , which includes continue affordance  1126 . Second scan completion interface  1124  includes some or all of the features of scan completion interface  1116 . As illustrated in  FIG.  11 I , electronic device  900  receives input  1128  at continue affordance  1126 . 
     At  FIG.  11 J , in response to receiving input  1128  at continue affordance  1126 , electronic device  900  displays (e.g., replaces display of second scan completion interface  1124  with) enrollment completion interface  1130 , providing an indication to the user that biometric authentication has been successfully set up on electronic device  900 . Enrollment completion interface  1130  includes a biometric authentication glyph. For example, the biometric authentication glyph is, optionally, a line drawing of all or part of a face (e.g., a stylized face graphic). In the example of  FIG.  11 J , enrollment completion interface  1130  also includes a text prompt indicating that the enrollment process is complete and face authentication at the device is set-up and/or enabled. In some examples, enrollment completion interface  1130  also includes a completion affordance, activation of which causes device  900  to exit face authentication set-up. In some examples, enrollment completion interface  1130  includes a visual indication (e.g., checkmark) that the enrollment process is complete. 
     At  FIG.  11 K , after biometric authentication has been set up on electronic device  900 , a user can unlock electronic device  900  (e.g., transition the device from a locked state to an unlocked state) using biometric authentication by presenting the user&#39;s face to biometric sensor  903 . In some examples, the user initiates biometric authentication to unlock the device by lifting (or raising) electronic device  900  (e.g., from a substantially horizontal orientation). While electronic device  900  is being lifted, electronic device  900  detects a change in orientation of the device, and in response, initiates biometric authentication to unlock the device. It is noted that while electronic device  900  is in a locked state, electronic device  900  displays locked state interface  1132  including biometric sensor indicator  1134 , which provides an indication to the user of the location of biometric sensor  903 , and lock icon  1136 , which provides an indication that electronic device  900  is in a locked state. In some examples, electronic device  900  does not display biometric sensor indicator  1134  while electronic device  900  is in a locked state. 
     As depicted in  FIG.  11 L , when electronic device  900  initiates biometric authentication, the user is holding electronic device  900  such that the user&#39;s face is outside field of view  1138  of biometric sensor  903 . In some examples, the user&#39;s face is outside field of view  1138  when more than a threshold portion of the face is outside the field of view. In some examples, the user&#39;s face is outside field of view  1138  when no face is detected within the field of view. While attempting to biometrically authenticate the user&#39;s face, electronic device  900  is unable to obtain sufficient information about the user&#39;s face using biometric sensor  903 . As a result, electronic device  900  does not have sufficient information for comparison with the stored authorized credentials, which were generated from the enrollment process described above with respect to  FIGS.  11 D- 11 J . 
     At  FIG.  11 M , upon determining that the user&#39;s face is outside field of view  1138 , electronic device  900  displays error indication  1140 , which provides an indication to the user that the user&#39;s face is outside field of view  1138 . (Error indication  1140  includes some or all of the features of error indication  714 G.) Additionally, upon determining that the user&#39;s face is outside field of view  1138 , electronic device  900  does not automatically retry authentication. In some examples, electronic device  900  also displays biometric sensor indicator  1134 . In some examples, if sufficient information had been obtained but authentication nevertheless failed (e.g., the obtained information did not match the stored authorized credentials), electronic device  900  automatically retries biometric authentication. 
     As depicted in  FIG.  11 N , after learning from error indication  1140  that the user&#39;s face is outside field of view  1138  of biometric sensor  903 , the user moves her face into field of view  1138  such that the user&#39;s face is within field of view  1138 . In response to detecting that the cause of error indication  1140  has been corrected (e.g., detects more than a threshold amount of the user&#39;s face), electronic device  900  automatically retries biometric authentication. Upon determining that authentication is successful as a result of retrying biometric authentication (e.g., the information obtained using biometric sensor  903  matches the stored authorized credentials), electronic device  900  transitions from a locked state to an unlocked state. After transitioning to the unlocked state, electronic displays unlocked state interface  1142 . 
     In some examples, while displaying unlocked state interface  1142 , electronic device  900  receives a request (e.g., an upward swipe starting from within a region adjacent to the bottom edge of display  902 ) to access restricted content on the device (e.g., home screen  1144  of  FIG.  11 O , the most recently used application). In response to receiving the request to access restricted content, electronic device  900  displays home screen  1144 , including a plurality of icons that, when activated, result in launching an application corresponding to the activated icon. In some examples, instead of displaying home screen  1144 , electronic device  900  displays the most recently used application (e.g., a user interface of the application). It is noted that the above processes described above with respect to  FIGS.  11 K- 11 O  are performed when electronic device  900  is in a landscape orientation. However, in some examples, some or all of the processes described above with respect to  FIGS.  11 K- 11 N  can be performed when electronic device  900  is in a portrait orientation. 
     In some examples, instead of transitioning to an unlocked state as described with respect to  FIG.  11 N , electronic device  900  maintains a locked state if the obtained information does not match the stored authorized credentials. In some examples, as depicted in  FIG.  11 P , upon determining that the obtained information does not match the stored authorized credentials, electronic device  900  displays locked state interface  1132  while alternating the position of lock icon  1136  such that it simulates a “shake” effect, thereby providing an indication to the user that electronic device  900  remains in a locked state. 
       FIGS.  12 A- 12 C  are flow diagrams illustrating a method for orienting the device to enroll a biometric feature (e.g., a face for later use in biometric authentication), in accordance with some examples. Method  1200  is performed at an electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) with a display (e.g.,  902 ) and one or more biometric sensors (e.g.,  903 ) (e.g., a biometric sensor of a device with a plurality of biometric sensors) (e.g., a fingerprint sensor, a contactless biometric sensor (e.g., a biometric sensor that does not require physical contact, such as a thermal or optical facial recognition sensor), an iris scanner). In some examples, the one or more biometric sensors include one or more cameras. Some operations in method  1200  are, optionally, combined, the orders of some operations are, optionally, changed, and some operations are, optionally, omitted. 
     As described below, method  1200  provides an intuitive way for prompting a user to orient a device to enroll a biometric feature. The method reduces the cognitive burden on a user for enrolling a biometric feature (e.g., a face for later use in biometric authentication), thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to enroll a biometric feature faster and more efficiently conserves power and increases the time between battery charges. 
     The electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) displays ( 1202 ), on the display (e.g.,  902 ), a biometric enrollment user interface (e.g.,  1106 ) for initiating biometric enrollment with the one or more biometric sensors. 
     While displaying ( 1204 ) the biometric enrollment user interface, the electronic device receives input (e.g.,  1110 ) (e.g., touch gesture (e.g., tap), spoken user input) corresponding to a request to initiate biometric enrollment. 
     In response ( 1206 ) to receiving the input (e.g.,  1110 ) and in accordance ( 1208 ) with a determination that an orientation of the electronic device (e.g., current orientation, an orientation of the electronic device at (or near) the time of the input) satisfies a set of enrollment criteria, the electronic device initiates a process for enrolling a biometric feature with the one or more biometric sensors (e.g.,  903 ). In some examples, the set of enrollment criteria includes whether the electronic device is oriented in a portrait orientation with respect to a frame of reference (e.g., Earth, ground), whether the one or more biometric sensors are oriented (or located) at a particular side of the electronic device in the portrait orientation (e.g., the side furthest away from Earth), or whether the electronic device is oriented such that it is not approximately parallel with respect to the ground. In some examples, the set of enrollment criteria includes whether the electronic device is in a certain (e.g., proper) orientation relative to a biometric feature (e.g., face) (e.g., a primary plane of the device (e.g., a plane defined by the display of the device) is facing the biometric feature). In some examples, initiating a process for enrolling a biometric feature includes capturing data corresponding to a face of a user using the one or more biometric sensors. In some examples, the set of enrollment criteria includes a requirement that the device is in an orientation that is suitable for enrolling a biometric feature for biometric authentication. In some examples, initiating a process for enrolling a biometric feature includes (or triggers) displaying a enrollment user interface (e.g.,  1114 ) for capturing information about a biometric feature. 
     In response ( 1206 ) to receiving the input (e.g.,  1110 ) and in accordance ( 1222 ) with a determination that the orientation of the electronic device does not satisfy the set of enrollment criteria, outputting one or more prompts (e.g.,  1112 A-B) (e.g., a visual, audio and/or tactile prompt) to change the orientation of the electronic device to a different orientation that satisfies the set of enrollment criteria. Outputting one or more prompts when the set of enrollment criteria are not satisfied provides the user with feedback as to what corrective actions to take to continue enrolling a biometric feature. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. 
     In some examples, outputting the one or more prompts includes outputting ( 1224 ) a first prompt (e.g.,  1112 A) to orient the electronic device to an initial orientation. In some examples, the initial orientation is an orientation such that the electronic device is not approximately parallel with respect to the ground. In some examples, the initial orientation is an orientation such that the electronic device is approximately parallel to the force of gravity. In some examples, the set of enrollment criteria includes a requirement that a primary plane of a device be substantially aligned with a predetermined plane (e.g., a plane that is substantially normal to the ground) such that the display of the device is substantially vertical. In some examples, the set of enrollment criteria includes a requirement that the primary plane of the device is not substantially aligned with a (second) predetermined plane (e.g., a plane that is substantially parallel to the ground) such that the device is not resting on a horizontal surface while attempting to enroll a biometric feature. In some examples, outputting the one or more prompts includes, subsequent to outputting the first prompt (e.g.,  1112 A), outputting ( 1226 ) a second prompt (e.g.,  1112 B) to orient the electronic device to the different orientation that satisfies the set of enrollment criteria, the first prompt being different from the second prompt. In some examples, the electronic device outputs the first prompt without outputting the second prompt. In some examples, the electronic device ceases outputting the first prompt when the orientation of the electronic device changes to the initial orientation. In some examples, the electronic device outputs the second prompt when the orientation of the electronic device changes to the initial orientation. In some examples, the electronic device outputs the second prompt without outputting the first prompt (e.g., when the electronic device is already in the initial orientation). In some examples, the set of enrollment criteria includes whether the electronic device is oriented in a portrait orientation with respect to a frame of reference (e.g., Earth, ground), whether the one or more biometric sensors are oriented (or located) at a particular side of the electronic device in the portrait orientation (e.g., the side furthest away from Earth), or whether the electronic device is oriented such that it is not approximately parallel with respect to the ground. Outputting the first prompt without outputting the second prompt provides improved feedback to the user as it reduces the chances of confusion when the user is taking corrective actions to trigger enrollment of a biometric feature. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. 
     In some examples, outputting the one or more prompts includes outputting a third prompt (e.g.,  1112 B) to rotate the electronic device (e.g., about an axis perpendicular to the electronic device) to the different orientation that satisfies the set of enrollment criteria, the third prompt being based on the orientation of the electronic device while receiving the input. In some examples, the third prompt is the second prompt. In some examples, in accordance with a determination that the orientation of the electronic device is in a first orientation, the electronic device outputs a first rotation prompt to rotate the electronic device to the different orientation that satisfies the set of enrollment criteria. In some examples, in accordance with a determination that the orientation of the electronic device is in a second orientation that is different from the first orientation, the electronic device outputs a second rotation prompt to rotate the electronic device to the different orientation that satisfies the set of enrollment criteria, the second rotation prompt being different from the first rotation prompt. In some examples, the first rotation prompt or the second rotation prompt is the second prompt. In some examples, the set of enrollment criteria includes whether the electronic device is oriented in a portrait orientation with respect to a frame of reference (e.g., Earth, ground), whether the one or more biometric sensors are oriented (or located) at a particular side of the electronic device in the portrait orientation (e.g., the side furthest away from Earth), or whether the electronic device is oriented such that it is not approximately parallel with respect to the ground. Outputting a prompt based on the orientation of the device provides feedback to the user as to an efficient process for achieving a suitable orientation of the device for enrolling a biometric feature. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, outputting the one or more prompts includes outputting a fourth prompt (e.g.,  1112 B) to rotate (e.g., along an axis parallel to a primary plane (e.g., a plane defined by the display of the device) of the device) the electronic device (e.g., about an axis perpendicular to the electronic device) to the different orientation that satisfies the set of enrollment criteria, the fourth prompt being based on an alignment of a primary plane of the device (e.g., a plane defined by the display of the device) to a predetermined plane (e.g., a plane that is substantially normal to the ground; a plane that is substantially parallel to the ground). In some examples, the electronic device outputs the fourth prompt in accordance with a determination that the electronic device is oriented substantially parallel to the ground. In some examples, the set of enrollment criteria includes a requirement that a primary plane of a device be substantially aligned with a predetermined plane (e.g., a plane that is substantially normal to the ground) such that the display of the device is substantially vertical. In some examples, the set of enrollment criteria includes a requirement that the primary plane of the device is not substantially aligned with a (second) predetermined plane (e.g., a plane that is substantially parallel to the ground) such that the device is not resting on a horizontal surface while attempting to enroll a biometric feature. 
     In some examples, the orientation of the electronic device (e.g.,  900 ) does not satisfy the set of enrollment criteria due to the orientation resulting in the one or more biometric sensors (e.g.,  903 ) being located (substantially) near (at or adjacent to) the right side of the electronic device (e.g., located (substantially) to the right of the center of the electronic device). In some examples, the location of the biometric sensor is with respect to the user. In some examples, the one or more prompts (e.g.,  1112 C) includes an animation of a representation of a device rotating by less than a first amount in a first direction (e.g., approximately 90 degrees counter-clockwise (e.g., to the left)). In some examples, the animation shows the representation rotating counter-clockwise such that the representation ends in a portrait orientation with the representation of a biometric sensor located near the top side of the representation. In some examples, the one or more prompts includes a textual indication and/or a pictorial illustration of the direction (and/or amount (e.g., degrees)) in which to rotate the device. Displaying an animation of a representation of a device rotating provides the user with feedback as to what corrective action to take to continue enrolling a biometric feature. Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, the orientation of the electronic device (e.g.,  900 ) does not satisfy the set of enrollment criteria due to the orientation resulting in the one or more biometric sensors (e.g.,  903 ) being located (substantially) near (at or adjacent to) the left side of the electronic device (e.g., located (substantially) to the left of the center of the electronic device. In some examples, the location of the biometric sensor is with respect to the user. In some examples, the one or more prompts (e.g.,  1112 B) includes an animation of a representation of a device rotating by less than the first amount in a second direction that is different from the first direction (e.g., approximately 90 degrees clockwise (e.g., to the right). In some examples, the animation shows the representation rotating clockwise such that the representation ends in a portrait orientation with the representation of a biometric sensor located near the top side of the representation. In some examples, the one or more prompts includes a textual indication and/or a pictorial illustration of the direction (and/or amount (e.g., degrees)) in which to rotate the device. 
     In some examples, the orientation of the electronic device (e.g.,  900 ) does not satisfy the set of enrollment criteria due to the orientation resulting in the one or more biometric sensors (e.g.,  903 ) being located (substantially) near (at or adjacent to) the bottom side of the electronic device (e.g., located (substantially) below the center of the electronic device). In some examples, the location of the biometric sensor is with respect to the user. In some examples, the one or more prompts (e.g.,  1112 D) includes an animation of a representation of a device rotating by more than the first amount (e.g., rotating upside down or approximately 180 degrees either clockwise or counterclockwise (e.g., to the right or to the left). In some examples, the animation shows the representation rotating clockwise or counter-clockwise 180 degrees such that the representation ends in a portrait orientation with the representation of a biometric sensor located near the top side of the representation. In some examples, the one or more prompts includes a textual indication and/or a pictorial illustration of the direction (and/or amount (e.g., degrees)) in which to rotate the device. 
     In some examples, subsequent to outputting the one or more prompts (e.g.,  1112 B-D) to change the orientation of the electronic device to a different orientation that satisfies the set of enrollment criteria, the electronic device detects a change in orientation of the electronic device. In some examples, in response to detecting the change in orientation of the electronic device: in accordance with a determination that the orientation of the electronic device still does not satisfy the set of enrollment criteria, the electronic device outputs one or more new prompts (e.g.,  1112 B-D) to change the orientation of the electronic device to a different orientation that satisfies the set of enrollment criteria. In some examples, the one or more new prompts (e.g.,  1112 B-D) are different from the one or more prompts described above. In some examples, the one or more new prompts (e.g.,  1112 B-D) can include any one of the animations described above (e.g., rotate clockwise, rotate counter-clockwise, rotate 180 degrees). In some examples, in response to detecting the change in orientation of the electronic device: in accordance with a determination that the orientation of the electronic device satisfies the set of enrollment criteria, the electronic device initiates a process for enrolling a biometric feature with the one or more biometric sensors, such as by displaying a biometric enrollment introduction interface (e.g.,  1146 ). 
     In some examples, subsequent to initiating the process for enrolling the biometric feature (e.g., subsequent to successfully enrolling a biometric feature), the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) receives a request to perform an operation that requires authentication (e.g., a request to unlock the device (e.g., perform a swipe at a predefined location)). In some examples, the electronic device receives the request to perform the operation that requires authentication subsequent to performing (or completing) biometric enrollment. In some examples, the electronic device receives the request to perform the operation that requires authentication subsequent to outputting the one or more prompts (e.g.,  1112 A-B) (e.g., a visual, audio and/or tactile prompt) to change the orientation of the electronic device to the different orientation that satisfies the set of enrollment criteria. In some examples, in response to receiving the request to perform the operation that requires authentication, the electronic device attempts authentication using the one or more biometric sensors (e.g.,  903 ) (e.g., that includes obtaining data by the one or more biometric sensors). In some examples, after attempting (e.g., unsuccessfully attempting) authentication using the one or more biometric sensors and in accordance with a determination that data obtained by the one or more biometric sensors corresponds to less than a threshold amount of a biometric feature (e.g., part of a face/fingerprint, not a whole face/fingerprint) (e.g., due to the face being outside the field of view (e.g.,  1138 ), the electronic device forgoes retrying authentication. In some examples, the electronic device forgoes automatically retrying authentication. In some examples, after attempting authentication using the one or more biometric sensors, the electronic device forgoes retrying authentication due to biometric authentication having failed more than a predetermined number of times (e.g., 5, 10, 15) since the last successful authentication with the device. In some examples, the electronic device forgoes retrying authentication without an explicit request to perform an operation that requires authentication (e.g., a request to unlock the device (e.g., perform a swipe at a predefined location)). In some examples, after an initial attempt at authentication does not succeed, the electronic device retries biometric authentication if a determination is not made that data obtained by the one or more biometric sensors corresponds to only a portion of a biometric feature. Forgoing retrying authentication when less than a threshold amount of a biometric feature is obtained avoids the user consuming the permitted number of attempts on repeated requests (e.g., repeated requests of the same type), thereby conserving at least one attempt for requests for other operations that require biometric authentication. Conserving at least one attempt enhances the operability of the device and makes the user-device interface more efficient (e.g., by avoiding exhaustion of authentication attempts on repeated, similar requests) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, after attempting (e.g., unsuccessfully attempting) authentication using the one or more biometric sensors and in accordance with a determination that the data obtained by the one or more biometric sensors corresponds to not less (e.g., more) than the threshold amount of the biometric feature, the electronic device retries authentication. Automatically retrying authentication when a threshold amount of the biometric feature is obtained provides the user the ability to attempt authentication when the conditions are appropriate without requiring the user to explicitly request retrying authentication. Performing an operation when a set of conditions has been met without requiring further user input enhances the operability of the device (e.g., increases the chances of successful authentication) and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, in accordance with a determination that authentication resulting from retrying authentication is successful, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) performs an operation corresponding to the request. In some examples, in accordance with a determination that authentication resulting from retrying authentication is not successful, the electronic device forgoes performing the operation corresponding to the request. In some examples, authentication is successful when the biometric information captured using the one or more biometric sensors corresponds to (or matches) authorized credentials (e.g., stored information about a biometric feature (e.g., face, fingerprint) that are authorized for use in biometric authentication). In some examples, authentication is unsuccessful when the biometric information captured using the one or more biometric sensors does not correspond to (or match) authorized credentials (e.g., stored information about a biometric feature (e.g., face, fingerprint) that are authorized for use in biometric authentication). Forgoing performing the operation when authentication is not successful enhances device security by preventing fraudulent and/or unauthorized access to the device. Improving security measures of the device enhances the operability of the device by preventing unauthorized access to content and operations and, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more efficiently. 
     In some examples, subsequent to outputting the one or more prompts (e.g.,  1112 A-B) (e.g., a visual, audio and/or tactile prompt) to change the orientation of the electronic device to the different orientation that satisfies the set of enrollment criteria, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) detects ( 1228 ) that the current orientation of the electronic device satisfies the set of enrollment criteria. In some examples, in response ( 1230 ) to determining that the current orientation of the electronic device satisfies the set of enrollment criteria, the electronic device initiates the process for enrolling the biometric feature with the one or more biometric sensors. In some examples, the set of enrollment criteria includes whether the electronic device is oriented in a portrait orientation with respect to a frame of reference (e.g., Earth, ground), whether the one or more biometric sensors are oriented (or located) at a particular side of the electronic device in the portrait orientation (e.g., the side furthest away from Earth), or whether the electronic device is oriented such that it is not approximately parallel with respect to the ground. In some examples, the set of enrollment criteria includes a requirement that a primary plane of a device be substantially aligned with a predetermined plane (e.g., a plane that is substantially normal to the ground) such that the display of the device is substantially vertical. In some examples, the set of enrollment criteria includes a requirement that the primary plane of the device is not substantially aligned with a (second) predetermined plane (e.g., a plane that is substantially parallel to the ground) such that the device is not resting on a horizontal surface while attempting to enroll a biometric feature. In some examples, the set of enrollment criteria includes whether the electronic device is in a certain (e.g., proper) orientation relative to a biometric feature (e.g., face) (e.g., a primary plane of the device (e.g., a plane defined by the display of the device) is facing the biometric feature). 
     In some examples, initiating the process for enrolling a biometric feature with the one or more biometric sensors includes displaying a biometric enrollment introduction interface (e.g.,  1146 ). In some examples, the biometric enrollment interface includes concurrently displaying a representation of a simulation of a biometric feature and a simulated progress indicator. 
     In some examples, initiating the process for enrolling the biometric feature with the one or more biometric sensors includes successfully enrolling the biometric feature. In some examples, subsequent to successfully enrolling the biometric feature, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) outputs ( 1212 ) a prompt (e.g., corresponding to  1122 ) to enroll the biometric feature for a second time with the one or more biometric sensors. In some examples, the electronic device outputs the prompt to enroll the biometric feature without prompting to change the orientation of the electronic device. 
     In some examples, initiating the process for enrolling the biometric feature with the one or more biometric sensors includes ( 1210 ) successfully enrolling the biometric feature. In some examples, subsequent to successfully enrolling the biometric feature, the electronic device (e.g.,  100 ,  300 ,  500 ,  900 ) receives ( 1214 ) a request to perform an operation that requires authentication (e.g., a request to unlock the device (e.g., perform a swipe at a predefined location), request to access home screen (e.g.,  1144 )). In some examples, in response ( 1216 ) to receiving the request to perform the operation that requires authentication and in accordance ( 1218 ) with a determination that data obtained by the one or more biometric sensors corresponds to (e.g., matches) the enrolled biometric feature, the electronic device performs the operation that requires authentication. In some examples, in response to receiving the request to perform the operation that requires authentication, the electronic device performs authentication (or attempts to authenticate) using the one or more biometric sensor (e.g.,  903 ). In some examples, in response ( 1216 ) to receiving the request to perform the operation that requires authentication and in accordance ( 1220 ) with a determination that data obtained by the one or more biometric sensors does not correspond to (e.g., does not match) the enrolled biometric feature, the electronic device forgoes performing the operation that requires authentication. 
       FIGS.  13 A- 13 Z  illustrate exemplary user interfaces for prompting a user to correct an error condition that is detected while attempting to biometrically authenticate the user, in accordance with some examples. The user interfaces in these figures are used to illustrate the processes described below, including the processes in  FIGS.  14 A- 14 B . 
       FIG.  13 A  illustrates electronic device  900  (e.g., portable multifunction device  100 , device  300 , device  500 ). In the exemplary examples illustrated in  FIGS.  13 A- 13 Z , electronic device  900  is a tablet computer. In other examples, electronic device  900  can be a different type of electronic device, such as a smartphone (e.g., electronic device  700 ). Electronic device  900  includes display  902 , one or more input devices (e.g., touchscreen of display  902 , button  904 , and a microphone), a wireless communication radio, and biometric sensor  903 . Electronic device  900  includes biometric sensor  903 . In some examples, biometric sensor  903  includes one or more biometric sensors that can include a camera, such as an infrared camera, a thermographic camera, or a combination thereof. In some examples, biometric sensor  903  includes some or all of the features of biometric sensor  703 . In some examples, biometric sensor  903  includes one or more fingerprint sensors (e.g., a fingerprint sensor integrated into a button). In some examples, electronic device  900  further includes a light-emitting device (e.g., light projector), such as an IR flood light, a structured light projector, or a combination thereof. The light-emitting device is, optionally, used to illuminate the biometric feature (e.g., the face or an iris) during capture of biometric data of biometric features by biometric sensor  903 . In some examples, electronic device  900  includes a plurality of cameras separate from biometric sensor  903 . In some examples, electronic device  900  includes only one camera separate from biometric sensor  903 . 
       FIGS.  13 A- 13 J  illustrate a scenario where electronic device  900  detects an error condition while attempting to unlock the device using biometric sensor  903 . A user wishes to access restricted content on electronic device  900 . For example, the restricted content can be home screen  1324 A of  FIG.  13 G , the most recently used application, or the content associated with notifications  1306 ,  1308 , and/or  1310 . To access the restricted content, the user must unlock the device, which requires successful authentication of the user. 
     To initiate the process of accessing restricted content on electronic device  900 , the user lifts (or raises) electronic device  900  (e.g., from a substantially horizontal orientation to the orientation of the device as depicted in the user&#39;s hand in  FIG.  13 A ). Due to the change in orientation of the device, electronic device  900  detects (e.g., via accelerometer  168 ) a request to perform an operation that requires authentication (e.g., a request to unlock the device). In response to detecting the request to unlock the device, electronic device  900  attempts to biometrically authenticate the user using biometric sensor  903 . Attempting to biometrically authenticate the user using biometric sensor  903  includes attempting to capture information about a potentially valid biometric feature (e.g., a biometric feature that can be used for biometric authentication) using biometric sensor  903  and/or determining whether the captured information about the potentially valid biometric feature corresponds to, or matches, stored authorized credentials (e.g., a biometric template). 
     As depicted in  FIG.  13 A , the user&#39;s face is not substantially facing biometric sensor  903 , largely due to the orientation in which electronic device  900  is being held. In particular, the orientation of the device results in biometric sensor  903  being located adjacent to the bottom edge of electronic device  900  (e.g., with respect to the user) and having only a partial view of the user&#39;s face, due to the angle of the device relative to the user (e.g., the chin and nose of the user are visible to the sensor from the bottom of the user&#39;s face, but the eyes and mouth are not visible or are visible at an angle that makes it difficult to consistently recognize the features when the face was enrolled from an angle where the eyes and mouth were closer to being directly facing the camera). While attempting to biometrically authenticate the user using biometric sensor  903 , electronic device  900  detects that an error condition has occurred. In some examples, detecting that an error condition has occurred requires determining that a potentially valid biometric feature is not substantially facing biometric sensor  903 . For example, electronic device  900  detects the presence of a face, but determines that the face is directed to a location that is substantially above biometric sensor  903 . Given the orientation of the face, biometric sensor  903  can capture some information about the face. For example, biometric sensor  903  captures information about the lower portion of the face (e.g., chin, bottom of the nose, etc.), but not the upper portion (e.g., eyes, eyebrows, upper portion of the nose, etc.). However, electronic device  900  does not use this information to biometrically authenticate the user (e.g., determine whether the captured information matches stored authorized credentials). In some examples, electronic device  900  does not use this information for biometrically authenticating the user because information captured while the face is not substantially facing biometric sensor  903  is highly correlated with degradation or reduced accuracy of the captured information. 
     In some examples, detecting that the error condition has occurred requires determining that electronic device  900  is in an orientation that results in biometric sensor  903  being located adjacent to the bottom edge of the device (e.g., with respect to the user). In some examples, detecting that the error condition has occurred requires detecting that display  902  is on (e.g., active). In other words, if electronic device  900  detects that display  902  is off (e.g., inactive), electronic device  900  will not detect an error condition even if biometric sensor  903  is occluded. In some examples, detecting that the error condition has occurred requires detecting a request to unlock the device. In some examples, a request to unlock the device is, or includes, a request to initiate (or attempt) biometric authentication. In some examples, detecting that the error condition has occurred requires determining that a maximum (e.g., threshold) number of failed biometric authentication attempts has not been reached (e.g., at least one biometric authentication attempt is available). 
     In some examples, if a maximum number of failed attempts has been reached, the device does not perform biometric authentication until successful non-biometric authentication (e.g., passcode authentication) has been performed. In some examples, a request to perform an operation that requires authentication (e.g., a request to unlock the device) after the maximum number of failed biometric authentication attempts has been reached triggers display of an alternative authentication user interface (e.g., passcode entry UI  1320 A). 
     At  FIG.  13 A , in response to detecting that the error condition has occurred, electronic device  900  maintains a locked state. Because electronic device  900  is in a locked state, the user is unable to access the restricted content. Electronic device  900  displays locked state UI  1300 A with lock icon  1302 , which provides an indication that the device is in a locked state. 
     Further in response to detecting that an error condition has occurred, electronic device  900  initially displays location indication  1304 A (e.g., location indication  1304 A was not displayed prior to detecting the error condition). Electronic device  900  displays location indication  1304 A adjacent to lock icon  1302 . Location indication  1304 A includes an indication of a user action that can be performed to correct the detected error condition (e.g., for a subsequent biometric authentication attempt). In some examples, location indication  1304 A includes an indication of the location of biometric sensor  903  on the device. In some examples, location indication  1304 A includes a visual indication (e.g., text, arrow) describing or indicating the location of biometric sensor  903 . For example, location indication  1304 A can be an animated arrow, as described below with respect to location indication  1318  in  FIGS.  13 C- 13 D . 
     At  FIG.  13 B , the user still wishes to access restricted content on electronic device  900 , so the user attempts to unlock the device via a swipe gesture despite not having corrected the error condition. Electronic device  900  displays unlock indication  905  in a predefined region adjacent to the bottom edge of display  902  (e.g., with respect to the user). Unlock indication  905  provides an indication of an approximate location on display  902  from which a user can start an upward swipe gesture to attempt to unlock the electronic device. 
     While displaying locked state UI  1300 A with location indication  1304 A, electronic device  900  detects a request to unlock the electronic device. Detecting a request to unlock the device includes receiving input  1312 A starting at a location of display  902 , and determining that input  1312 A is an upward swipe gesture that starts within a predefined region adjacent to the bottom edge of display  902 . 
     At  FIG.  13 C , in response to detecting the request to unlock the device, electronic device  900  displays (e.g., replaces display of locked state UI  1300 A with) interstitial interface  1314 A. Interstitial interface  1314 A indicates to the user that electronic device  900  has not yet completed biometric authentication (e.g., is attempting to biometrically authenticate the user using biometric sensor  903 ). Displaying interstitial interface  1314 A includes ceasing to display unlock indication  905 . In some examples, displaying interstitial interface  1314 A includes sliding the locked state UI  1300 A in an upward direction to display (e.g., reveal) interstitial interface  1314 A. 
     Further in response to detecting the request to unlock the device, electronic device  900  determines whether the error condition is still occurring. Upon a determination that the error condition is still occurring at a time immediately after the request to unlock the device, electronic device  900  maintains display of location indication  1304 A and initially displays location indication  1318 . Electronic device  900  displays location indication  1318  at a location on display  902  that is adjacent to biometric sensor  903  such that location indication  1318  is pointing at biometric sensor  903 . As depicted in  FIGS.  13 C- 13 D , location indication  1318  includes a visual arrow that is animated in a manner where it appears to bounce near biometric sensor  903 . Similar to location indication  1304 A, location indication  1318  is a prompt to the user to take an action that corrects the error condition. For example, upon seeing location indication  1318 , a user turns their head toward biometric sensor  903  such that their face is substantially directed to (or facing) biometric sensor  903 . 
     At  FIG.  13 E , upon a determination that the error condition is still occurring after a predetermined amount of time has elapsed (e.g., 1, 3, or 5 seconds since receiving the request and/or since displaying the interstitial interface  1314 A) and/or a determination that biometric authentication has not successfully completed, electronic device  900  displays (e.g., replaces display of interstitial interface  1314  with) passcode entry UI  1320 A. Passcode entry UI  1320 A includes a plurality of entry affordances for entering a passcode (or password). Displaying passcode entry UI  1320 A includes again initially displaying unlock indication  905  and maintaining display of lock icon  1302 . Further upon a determination that the error condition is still occurring after a predetermined amount of time has elapsed, electronic device  900  ceases displaying location indication  1304 A. In some examples, upon a determination that the error condition is still occurring (e.g., immediately after detecting the request to unlock the device, after a predetermined amount of time has elapsed (e.g., 1, 3, or 5 seconds since receiving the request and/or since displaying the interstitial interface  1314 A)) and/or a determination that biometric authentication has not successfully completed, electronic device  900  forgoes attempting to unlock the device and/or attempting to biometrically authenticate the user. 
     At  FIG.  13 F , electronic device  900  continues to determine whether the error condition is still occurring while displaying passcode entry UI  1320 A. The user turns their head to a new orientation in which the user&#39;s face is substantially facing biometric sensor  903  (e.g., the user looks down to begin entering their passcode). Due to the turning of the user&#39;s head, electronic device  900  determines that the error condition is no longer occurring. In particular, electronic device  900  determines that a potentially valid biometric feature is substantially facing biometric sensor  903 . In some examples, the user can correct the detected error condition by turning the user&#39;s face toward biometric sensor  903 , or re-orienting the device to a new orientation in which the user&#39;s face is substantially facing biometric sensor  903  (e.g., rotating the device so that a face detection sensor is on a right edge, left edge, or top edge of the device as opposed to being on a bottom edge of the device). 
     Upon a determination that the error condition is no longer occurring, electronic device  900  attempts to unlock the device using biometric sensor  903 . Upon a determination that the captured information about the user&#39;s face corresponds to stored authorized credentials, electronic device  900  transitions from a locked state to an unlocked state. Transitioning to an unlocked state includes displaying (e.g., replacing display of lock icon  1302  with) unlock icon  1322 , which provides an indication that electronic device  900  has successfully been unlocked. Transitioning to an unlocked state further includes displaying (e.g., replacing display of passcode entry UI  1320 A with) home screen  1324 A of  FIG.  13 G  or a most recently used application, or an application selected based on other criteria (such as an application corresponding to a selected or recently received notification or an application that the user was using on another related device). In some examples, attempting to unlock the device includes attempting to biometrically authenticate a user. Attempting to biometrically authenticate the user using biometric sensor  903  includes attempting to capture information about a potentially valid biometric feature (e.g., a biometric feature that can be used for biometric authentication) using biometric sensor  903  and/or determining whether the captured information about the potentially valid biometric feature corresponds to, or matches, stored authorized credentials (e.g., a biometric template). In some examples, attempting to capture information about a potentially valid biometric feature includes powering on biometric sensor  903 . In some examples, electronic device  900  determines whether captured information about a potentially valid biometric feature matches stored authorized credentials if, or when, electronic device  900  successfully captures information about a potentially valid biometric feature. In some examples, if electronic device  900  does not, or fails to, capture information about a potentially valid biometric feature, electronic device  900  forgoes determining whether captured information about a potentially valid biometric feature matches stored authorized credentials. 
     Upon a determination that the captured information about the user&#39;s face does not correspond to stored authorized credentials, electronic device  900  maintains the locked state. For example, electronic device  900  maintains display of passcode entry UI  1320 A with lock icon  1302 , as depicted in  FIG.  13 E . 
     As described above with respect to  FIGS.  13 A- 13 D , the user does not correct the error condition while electronic device  900  displays locked state UI  1300 A and/or interstitial UI  1314 A. In some examples, instead of failing to correct the error condition in  FIGS.  13 A- 13 D , the user corrects the error condition by turning their head to a new orientation in which the user&#39;s face is substantially facing biometric sensor  903 , as depicted in  FIG.  13 H . While location indication  1304 A of  FIGS.  13 A- 13 D  is displayed (e.g., after detecting a request to perform an operation that requires authentication, after detecting a request to unlock the device, and/or before passcode entry UI  1320 A is displayed), electronic device  900  determines whether the error condition is still occurring. In some examples, electronic device  900  determines that the error condition is no longer occurring. In particular, electronic device  900  determines that a potentially valid biometric feature is substantially facing biometric sensor  903 . Upon a determination that the error condition is no longer occurring, electronic device  900  attempts to unlock the device using biometric sensor  903 . 
     In some examples, upon a determination that the captured information about the user&#39;s face does not correspond to stored authorized credentials, electronic device  900  maintains the locked state. For example, electronic device  900  displays (e.g., replaces display of interstitial interface  1314  with) passcode entry UI  1320 A of  FIG.  13 E . 
     In some examples, the user does not correct the error condition and/or otherwise fails to successfully complete biometric authentication. Instead, while displaying passcode entry  1320 A of  FIG.  13 E , electronic device  900  receives, via display  902 , a sequence of one or more characters that corresponds to a password or passcode, as depicted in  FIG.  13 I . As an example, electronic device  900  receives character input  1326 , which is a portion of the sequence of one or more characters. 
     At  FIG.  13 J , in some examples, upon a determination that the sequence of one or more characters corresponds to stored authorized credentials, electronic device  900  transitions from a locked state to an unlocked state. Transitioning to an unlocked state can include displaying (e.g., replacing display of lock icon  1302  with) unlock icon  1322 , which provides an indication that electronic device  900  has successfully been unlocked. Transitioning to an unlocked state can include displaying (e.g., replacing display of passcode entry UI  1320 A with) home screen  1324 A of  FIG.  13 G  or the most recently used application. 
     In some examples, upon a determination that the sequence of one or more characters does not correspond to stored authorized credentials, electronic device  900  maintains the locked state. For example, electronic device  900  maintains display of passcode entry UI  1320 A of  FIG.  13 E . 
       FIGS.  13 K- 13 P  illustrate another scenario where electronic device  900  detects an error condition while attempting to unlock the device using biometric sensor  903 .  FIG.  13 K  depicts processes that are analogous to the processes described above with respect to  FIG.  13 A . To initiate the process of accessing restricted content on electronic device  900 , the user lifts (or raises) electronic device  900  (e.g., from a substantially horizontal orientation to the orientation of the device as depicted in the user&#39;s hand in  FIG.  13 K ). In some examples, due to the change in orientation of the device, electronic device  900  detects (e.g., via accelerometer  168 ) a request to perform an operation that requires authentication (e.g., a request to unlock the device). In response to detecting the request to unlock the device, electronic device  900  attempts to biometrically authenticate the user using biometric sensor  903 . 
     In some examples, while attempting to biometrically authenticate the user using biometric sensor  903 , electronic device  900  detects that an error condition has occurred. In some examples, detecting that an error condition has occurred requires determining that biometric sensor  903  is occluded (e.g., by the user&#39;s hand). Because biometric sensor  903  is occluded at  FIG.  13 K , electronic device  900  is unable to capture information about the user&#39;s face. Accordingly, electronic device  900  has no captured information for biometrically authenticating the user. The user can correct the detected error condition by moving their hand away from biometric sensor  903  such that biometric sensor  903  is no longer occluded. 
     In some examples, in response to detecting that an error condition has occurred, electronic device  900  maintains a locked state. In some examples, further in response to detecting that an error condition has occurred, electronic device  900  initially displays location indication  1304 B (e.g., location indication  1304 B were not displayed prior to detecting the error condition). In some examples, location indication  1304 B includes an indication of the location of biometric sensor  903  on the device. In some examples, electronic device  900  displays location indication  1304 B at a location on display  902  that is adjacent to biometric sensor  903 . In some examples, location indication  1304 B includes a visual indication (e.g., text, arrow) describing or indicating the location of biometric sensor  903 . For example, location indication  1304 B can be an animated arrow, as described above with respect to location indication  1318  in  FIGS.  13 C- 13 D . In some examples, electronic device  900  displays location indication  1304 C of  FIG.  13 Y  in addition to or instead of location indication  1304 B. In some examples, location indication  1304 C includes some or all of the features of error indication  928  of  FIGS.  9 E- 9 I . In some examples, electronic device  900  displays location indication  1304 D of  FIG.  13 Z  in addition to or instead of location indication  1304 B. In some examples, location indication  1304 D includes a text description of the location of biometric sensor  903  (e.g., with respect to the user and/or with respect to location indication  1304 D). 
     In some examples, further in response to detecting that an error condition has occurred, electronic device  900  initially displays error indication  1328 . In some examples, electronic device  900  displays error indication  1328  adjacent to lock icon  1302 . In some examples, error indication  1328  includes an indication of the cause of the error condition. In some examples, error indication  1328  includes an indication of a user action that can be performed to correct the detected error condition (e.g., for a subsequent biometric authentication attempt). 
       FIG.  13 L  depicts processes that are analogous to the processes described above with respect to  FIG.  13 B . At  FIG.  13 L , the user still wishes to access restricted content on electronic device  900 , so the user attempts to unlock the device via a swipe gesture despite not having corrected the error condition. In some examples, while displaying locked state UI  1300 B with location indication  1304 B, electronic device  900  detects a request to unlock the electronic device using biometric sensor  903 . Detecting a request to unlock the device includes receiving input  1312 B starting at a location of display  902 , and determining that input  1312 B is an upward swipe gesture that starts within a predefined region adjacent to the bottom edge of display  902 . Locked state UI  1300 B is a landscape version of locked state UI  1300 A, and includes some or all of the feature of locked state UI  1300 A. 
       FIG.  13 M  depicts processes that are analogous to the processes described above with respect to  FIG.  13 C . At  FIG.  13 M , in some examples, in response to detecting the request to unlock the device, electronic device  900  displays (e.g., replaces display of locked state UI  1300 B with) interstitial interface  1314 B. Interstitial interface  1314 B is a landscape version of interstitial interface  1314 A, and includes some or all of the features of interstitial interface  1314 A. 
     Further in response to receiving the request to unlock the device, electronic device  900  determines whether the error condition is still occurring. Upon a determination that the error condition is still occurring at a time immediately after the request to unlock the device, electronic device  900  maintains display of location indication  1304 B. 
       FIG.  13 N  depicts processes that are analogous to the processes described above with respect to  FIG.  13 I . At  FIG.  13 N , in some examples, upon a determination that the error condition is still occurring after a predetermined amount of time has elapsed (e.g., 1, 3, or 5 seconds), electronic device  900  displays (e.g., replaces display of interstitial interface  1314 B with) passcode entry UI  1320 B. Passcode entry UI  1320 B is a landscape version of passcode entry UI  1320 A, and includes some or all of the features of passcode entry UI  1320 A. 
     In some examples, the user does not correct the error condition. Instead, while displaying passcode entry  1320 B of  FIG.  13 N , electronic device  900  receives, via display  902 , a sequence of one or more characters that corresponds to a password or passcode. As an example, electronic device  900  receives character input  1330 , which is a portion of the sequence of one or more characters. 
       FIG.  13 O  depicts processes that are analogous to the processes described above with respect to  FIG.  13 J . At  FIG.  13 J , in some examples, upon a determination that the sequence of one or more characters corresponds to stored authorized credentials, electronic device  900  transitions from a locked state to an unlocked state. Transitioning to an unlocked state can include displaying (e.g., replacing display of lock icon  1302  with) unlock icon  1322 , which provides an indication that electronic device  900  has successfully been unlocked. Transitioning to an unlocked state can include displaying (e.g., replacing display of passcode entry UI  1320 B with) home screen  1324 B of  FIG.  13 P  or the most recently used application. 
     In some examples, upon a determination that the sequence of one or more characters does not correspond to stored authorized credentials, electronic device  900  maintains the locked state. For example, electronic device  900  maintains display of passcode entry UI  1320 B of  FIG.  13 N . 
     At  FIG.  13 Q , in some examples, while in a locked state, electronic device  900  detects the occurrence of a type of error condition that is different from the type of error conditions detected in  FIGS.  13 A and  13 K , as described above. The error conditions detected in  FIGS.  13 A and  13 K  are of the type where the location of biometric sensor  903  would be especially useful for the user to know in order to correct the error condition. In some examples, while attempting to biometrically authenticate the user using biometric sensor  903 , electronic device  900  detects an error condition of a different type (e.g., a type where knowledge of the location of biometric sensor  903  is not especially useful). At  FIG.  13 Q , electronic device  900  detects that the biometric feature is outside acceptable distance range  1303  (e.g., too far from biometric sensor  903 ). In response to detecting an error condition of a different type, electronic device  900  displays error indication  1332 , which includes some or all of the features of error indication  714 A in  FIG.  7 G . Further in response to detecting an error condition of a different type, electronic device  900  forgoes displaying an indication of the location of biometric sensor  903 . 
       FIGS.  13 R- 13 T  illustrate a scenario where electronic device  900  detects an error condition while attempting to make a payment using biometric sensor  903 . Similar to unlocking a device, as described above with respect to  FIG.  13 A , making a payment requires successful authentication of the user. 
     At  FIG.  13 R , a user wishes to purchase some items from an online retail store. In some examples, while displaying webpage  1334  of a browsing application, electronic device  900  detects a request to perform an operation that requires authentication (e.g., a request to make a payment to purchase an item). Specifically, electronic device  900  detects activation of a purchase affordance via input  1336 . 
     In some examples, upon detecting the request to make a payment, electronic device  900  attempts to biometrically authenticate the user using biometric sensor  903 . In some examples, while attempting to biometrically authenticate the user using biometric sensor  903 , electronic device  900  detects that an error condition has occurred. Similar to the error condition detected with respect to  FIG.  13 A , electronic device  900  determines that a potentially valid biometric feature is not substantially facing biometric sensor  903 . In some examples, further upon detecting the request to make a payment, electronic device  900  displays pay sheet interface  1338 , which overlaps (e.g., partially overlaps) webpage  1334 . 
     At  FIG.  13 S , upon detecting that an error condition has occurred, electronic device  900  initially displays location indication  1304 E. In some examples, electronic device  900  displays location indication  1304 E at a location on display  902  that is adjacent to biometric sensor  903  such that location indication  1304 E is pointing at biometric sensor  903 . In some examples, location indication  1304 E is an animated arrow, as described above with respect to location indication  1318  in  FIGS.  13 C- 13 D . 
     Electronic device  900  continues to determine whether the error condition is still occurring while displaying location indication  1304 E. Prompted by location indication  1304 E, the user turns their head downward to a new orientation in which the user&#39;s face is substantially facing biometric sensor  903 , as shown in  FIG.  13 T . Due to the turning of the user&#39;s head, electronic device  900  determines that the error condition is no longer occurring. In particular, electronic device  900  determines that a potentially valid biometric feature is substantially facing biometric sensor  903 . 
     In some examples, upon a determination that the error condition is no longer occurring, electronic device  900  attempts to make a payment using biometric sensor  903 . In some examples, upon a determination that the captured information about the user&#39;s face corresponds to stored authorized credentials, electronic device  900  makes the payment, as shown in  FIG.  13 T . In some examples, upon a determination that the captured information about the user&#39;s face does not correspond to stored authorized credentials, electronic device  900  forgoes making the payment. 
       FIGS.  13 U- 13 X  illustrate a scenario where electronic device  900  detects an error condition while attempting to biometrically authenticate using biometric sensor  903 , as a precursor to autofilling fillable fields (e.g., username field, password field) using stored information. Similar to unlocking a device, as described above with respect to  FIG.  13 A , autofilling fillable fields requires successful authentication of the user. 
     At  FIG.  13 U , a user wishes to autofill the username field and password field using stored log-in information. In some examples, while displaying log-in UI  1340  of a mobile application, electronic device  900  detects a request to perform an operation that requires authentication (e.g., a request to autofill). Specifically, electronic device  900  detects activation of an autofill affordance via input  1342 . 
     In some examples, upon detecting the request to autofill fillable fields, electronic device  900  attempts to biometrically authenticate the user using biometric sensor  903 . In some examples, while attempting to biometrically authenticate the user using biometric sensor  903 , electronic device  900  detects that an error condition has occurred. Similar to the error condition detected with respect to  FIG.  13 A , electronic device  900  determines that a potentially valid biometric feature is not substantially facing biometric sensor  903 . 
     At  FIG.  13 V , upon detecting that an error condition has occurred, electronic device  900  initially displays location indication  1304 E. In some examples, electronic device  900  displays location indication  1304 E at a location on display  902  that is adjacent to biometric sensor  903  such that location indication  1304 E is pointing at biometric sensor  903 . In some examples, location indication  1304 E is an animated arrow, as described above with respect to location indication  1318  in  FIGS.  13 C- 13 D . 
     Electronic device  900  continues to determine whether the error condition is still occurring while displaying location indication  1304 E. Prompted by location indication  1304 E, the user turns their head downward to a new orientation in which the user&#39;s face is substantially facing biometric sensor  903 . Due to the turning of the user&#39;s head, electronic device  900  determines that the error condition is no longer occurring. In particular, electronic device  900  determines that a potentially valid biometric feature is substantially facing biometric sensor  903 . 
     In some examples, upon a determination that the error condition is no longer occurring, electronic device  900  attempts to autofill the fillable fields using biometric sensor  903 . At  FIG.  13 W , electronic device  900  determines that the captured information about the user&#39;s face corresponds to stored authorized credentials. In some examples, upon a determination that the captured information about the user&#39;s face corresponds to stored authorized credentials, electronic device  900  autofills the fillable fields, as shown in  FIG.  13 X . In some examples, autofilling the fillable fields includes automatically logging in the user. In some examples, the user must manually log-in by activating a displayed affordance for signing in the user (e.g., the device detects a request to log-in the user after the fillable fields are autofilled). In some examples, upon a determination that the captured information about the user&#39;s face does not correspond to stored authorized credentials, electronic device  900  forgoes autofilling the fillable fields. 
       FIGS.  14 A- 14 B  are flow diagrams illustrating a method for prompting a user to correct an error condition that is detected while attempting to biometrically authenticate the user, in accordance with some examples. Method  1400  is performed at an electronic device (e.g.,  900 ) with a display (e.g.,  902 ) and one or more biometric sensors (e.g.,  903 ) (e.g., a first biometric sensor of a device with a plurality of biometric sensors) (e.g., a fingerprint sensor, a contactless biometric sensor (e.g., a biometric sensor that does not require physical contact, such as a thermal or optical facial recognition sensor), an iris scanner). In some examples, the one or more biometric sensors include one or more cameras. Some operations in method  1400  are, optionally, combined, the orders of some operations are, optionally, changed, and some operations are, optionally, omitted. 
     As described below, method  1400  provides an intuitive way for prompting a user to correct an error condition that is detected while attempting to biometrically authenticate the user. The method reduces the cognitive burden on a user performing biometric authentication, thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to perform biometric authentication faster and more efficiently conserves power and increases the time between battery charges. 
     The electronic device (e.g.,  900 ) with a biometric sensor (e.g.,  903 ) and a touch-sensitive display (e.g.,  902 ) detects ( 1402 ) occurrence of an error condition (e.g., biometric sensor is partially occluded or covered, fully occluded, occluded to a degree sufficient to inhibit operation of the sensor, biometric sensor is occluded by a portion of the user (e.g., a hand) while interacting with the electronic device, the biometric sensor is not directed to a portion of a biometric feature (e.g., face) that can be used for biometric authentication, the biometric feature is turned away from the biometric sensor, the biometric feature is not oriented such that it is substantially facing the biometric sensor) for detecting biometric information (e.g., information about, or corresponding to, a biometric feature) at the biometric sensor. In some examples, the user can correct the error condition by moving the user&#39;s hand away from the biometric sensor. In some examples, the user can correct the error condition by turning the user&#39;s face toward the biometric sensor and/or tilting/rotating the device (e.g.,  900 ) so that the biometric sensor is in a position and/or orientation in which the biometric feature is substantially facing the biometric sensor. In some examples, the device detects occurrence of an error condition while the device is in a locked state. In some examples, detecting occurrence of an error condition is, or includes, determining that a set of one or more error condition criteria has been met. In some examples, detecting occurrence of an error condition is, or includes, determining that an error condition has occurred. 
     In some examples, the occurrence of the error condition (e.g., error condition criteria) includes a requirement ( 1404 ) that the biometric sensor (e.g.,  903 ) is covered in order for the error condition to occur. In some examples, the occurrence of the error condition (e.g., error condition criteria) includes a requirement that the display (e.g.,  902 ) is on for the error condition to occur. In some examples, the occurrence of the error condition (e.g., error condition criteria) includes a requirement that an input (e.g.,  1312 A-B,  1336 ,  1342 ) corresponding to a request to attempt biometric authentication (e.g., a request to perform an operation that requires authentication) has been met in order for the error condition to occur (e.g., an upward swipe, tilting device upward, waking device by pressing a button (e.g.,  904 ) or tapping on the screen (e.g., display  902 ), tapping on screen when the display is on, activating an affordance, etc.). 
     In some examples, the occurrence of the error condition (e.g., error condition criteria) includes a requirement that a maximum number (e.g., a predetermined number) of failed authentication attempts has not yet been reached in order for the error condition to occur (e.g., the device allows only a respective number of failed authentication attempts before non-biometric authentication (e.g., password, passcode, or pattern) is required to unlock the device). In some examples, the occurrence of the error condition (e.g., error condition criteria) includes a requirement ( 1406 ) that the electronic device (e.g.,  900 ) is oriented so that the biometric sensor (e.g.,  903 ) is not directed to a portion of the biometric feature that can be used for biometric authentication in order for the error condition to occur. In some examples, in this orientation, the biometric sensor is located at (or adjacent or near) the bottom edge of the device. Requiring that a maximum number of failed authentication attempts has not yet been reached in order to detect the error condition reduces the instances of multiple resource-intensive re-attempts of biometric authentication that is likely to fail due to the error condition. This, in turn, reduces power usage and improves battery life of the device by limiting the performance of operations that are likely to fail. 
     In some examples, the occurrence of the error condition is detected when the error condition is of a first type (e.g., biometric sensor is partially occluded (or covered), fully occluded, occluded to a degree sufficient to inhibit operation of the sensor, biometric sensor is occluded by a portion of the user (e.g., a hand), while interacting with the electronic device, the biometric sensor is not directed to a portion of a biometric feature (e.g., face) that can be used for biometric authentication, the biometric feature is turned away from the biometric sensor, the biometric feature is not oriented such that it is substantially facing the biometric sensor). In some examples, the user can correct the error condition by moving the user&#39;s hand away from the biometric sensor. In some examples, the user can correct the error condition by turning the user&#39;s face toward the biometric sensor and/or tilting/rotating the device so that the biometric sensor is in a position (or orientation) in which the biometric feature is substantially facing the biometric sensor. In some examples, in response to detecting occurrence of a second type of error condition (e.g., error conditions different from the first type), the electronic device displays an indication (e.g.,  1332 ) of the occurrence of the second type of error condition (e.g., information about the cause of the error condition (e.g., device too far away, device too close)) without displaying an indication (e.g.,  1304 A-E), of the location of the biometric sensor. 
     In response to (e.g., subsequent to) detecting the occurrence of the error condition, the electronic device (e.g.,  900 ) displays ( 1408 ), on the touch-sensitive display (e.g.,  902 ), an indication (e.g.,  1304 A-E) of a location of the biometric sensor (e.g.,  903 ) on the electronic device (e.g., a textual indication (e.g.,  1304 A,  1304 D) (e.g., text stating “look down”), a graphical, visual, or pictorial indication (e.g.,  1304 B-C,  1304 E) (e.g., a visual object (e.g., arrow or other shape) that is static or animated (e.g., moves back and forth between two positions of the user interface, a bouncing object))). In some examples, in response to (e.g., subsequent to) detecting the occurrence of the error condition, the electronic device forgoes determining whether captured biometric information about a biometric feature corresponds to (or matches) stored authorized credentials (e.g., a biometric template). 
     In some examples, the indication of the location of the biometric sensor includes an indication (e.g.,  1304 A- 1304 E) of a user action that can be performed to correct the error condition (e.g., for a subsequent authentication attempt). In some examples, the indication of the user action indicates how to correct the error condition for a subsequent authentication attempt. Displaying an indication of a user action that can be performed to correct the error condition provides feedback to the user as to what course of action to take so that the user can be biometrically authenticated in a subsequent authentication attempt. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, the indication (e.g.,  1304 A-E) is located near (e.g., adjacent to) the biometric sensor. In some examples, the indication includes an instruction ( 1410 ) (e.g.,  1304 A) to change a pose (e.g., orientation) of the biometric feature toward the biometric sensor (e.g., textual indication (e.g., “look down”)). In some examples, the indication includes a text description ( 1412 ) (e.g.,  1304 D) of where the biometric sensor is located (e.g., face sensor to right, face sensor to left, face sensor down)). In some examples, the indication includes a graphical indication (e.g.,  1304 B-C,  1304 E) located near (e.g., adjacent to) the biometric sensor. In some examples, the indication includes a pictorial illustration (e.g.,  1304 B,  1304 E) of a location of the biometric sensor (e.g., an object (e.g., arrow or other shape) pointing toward the sensor). In some examples, the indication (e.g.,  1304 A-E) includes an animation that illustrates a location of the biometric sensor (e.g., an object bouncing or sliding toward the sensor, an animation pulsing or glowing near the sensor). Displaying the indication near the biometric sensor provides feedback to the user of the location of the device that is the source of the error condition. By displaying the indication near the biometric sensor, the user is prompted to remove their hand from the biometric sensor to correct the error condition. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. Displaying a pictorial illustration of the location of the biometric sensor provides feedback to the user of the location of the device that is the source of the error condition. By displaying a pictorial illustration of the location of the biometric sensor, the user is prompted to remove their hand from the biometric sensor to correct the error condition. Providing improved visual feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. In some examples, no indicator is displayed during biometric authentication. 
     While displaying the indication (e.g.,  1304 A-E) of the location of the biometric sensor (e.g.,  903 ) on the electronic device (e.g.,  900 ), the electronic device detects ( 1414 ) a request to unlock the electronic device using the biometric sensor (e.g., the request corresponds to a touch gesture input (e.g.,  1312 A-B) (e.g., swipe gesture (e.g., a contact that exceeds a threshold distance in a horizontal or vertical direction)), the request corresponds to a contact starting from an edge (e.g., bottom edge) of the display (e.g.,  902 ) or starting from within a predefined region (e.g., lower portion) of the display). In some examples, the request corresponds to a touch gesture input (e.g.,  1312 A-B) starting at a first region of the display (e.g., a region along a bottom edge of the display) and ends (or progresses through) a second region of the display (e.g., a region above the region along the bottom edge of the display). 
     In response to (e.g., subsequent to) detecting the request to unlock the electronic device (e.g.,  900 ) using the biometric sensor (e.g.,  903 ): in accordance with a determination that the error condition is still occurring at a respective time that occurs after detecting the request to unlock the electronic device (e.g., a time immediately after detecting the request to unlock the electronic device or a respective time that occurs after a delay time period such as 1, 3, or 5 seconds has elapsed): the electronic device ceases ( 1416 ) to display the indication (e.g.,  1304 A-E) of the location of the biometric sensor; and displays ( 1416 ) a touch-based user interface (e.g.,  1320 A-B) for entering touch-based authentication information (e.g., a password, passcode, swipe pattern). In some examples, while displaying the touch-based user-interface, the electronic device determines that the error condition is no longer occurring. In some examples, in accordance with a determination that the error condition is no longer occurring, the electronic device attempts to unlock the electronic device using the biometric sensor. In some examples, a determination that a set of one or more error condition criteria is still being met is (or includes) a determination that the error condition is still occurring. 
     Ceasing to display the indication (e.g., text stating “look down”) of the location of the biometric sensor after detecting a request to unlock the device improves feedback to the user by removing potential confusion resulting from displaying both the indication of the location of the biometric sensor and the passcode entry user interface. For example, if the electronic device were to continue displaying the indication of the location of the biometric sensor while also displaying, for example, a passcode entry user interface, the user is likely to become confused as to what action to take in order to perform biometric authentication (e.g., look down or enter passcode). Providing improved feedback to the user enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     Automatically displaying a touch-based user interface in accordance with a determination that the error condition is still occurring provides a user the ability to attempt non-biometric authentication when the conditions are appropriate without requiring the user to explicitly request performing non-biometric authentication. Performing an operation when a set of conditions has been met without requiring further user input enhances the operability of the device (e.g., directs the user to the action needed to authenticate) and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, while displaying the touch-based user interface (e.g.,  1320 A-B) for entering touch-based authentication information, the electronic device detects a touch input sequence (e.g., a sequence of one or more inputs (e.g.,  1326 ,  1330 ) corresponding to one or more characters, a sequence of one or more characters) on the touch-sensitive display (e.g., for inputting a password, passcode, or swipe pattern). In some examples, in response to detecting the touch input sequence: in accordance with a determination that the touch input sequence matches authorized credentials (e.g., stored authorized credentials, password, passcode, swipe pattern), the electronic device transitions the electronic device from a locked state to an unlocked state. In some examples, in response to detecting the touch input sequence: in accordance with a determination that the touch input sequence does not match authorized credentials, the electronic device maintains the electronic device in a locked state. 
     In some examples, the respective time is a time that occurs ( 1418 ) after a predetermined delay time period from when the request to unlock the electronic device using the biometric sensor was detected. 
     In response to (e.g., subsequent to) detecting the request to unlock the electronic device (e.g.,  900 ) using the biometric sensor (e.g.,  903 ): in accordance with a determination that the error condition is no longer occurring (e.g., the error condition has been corrected), the electronic device attempts ( 1420 ) to unlock the electronic device using the biometric sensor (e.g., comparing the information captured by the biometric sensor with stored authorized credentials (e.g., a biometric template associated with the user)). In some examples, if the captured information matches, within a threshold time period, the stored authorized credentials, the device transitions from a locked state to an unlocked state. In some examples, if the captured information does not match, within the threshold, the stored authorized credentials, the device maintains the locked state and/or displays the touch-based interface (e.g.,  1320 A-B) for entering touch-based authentication information. In some examples, attempting to unlock the electronic device via biometric authentication occurs without displaying the touch-based user interface for entering touch-based authentication information. In some examples, a determination that a set of one or more error condition criteria is no longer being met is (or includes) a determination that the error condition is no longer occurring. In some examples, the determination that the error condition is no longer occurring can be made at any time up to the respective time that occurs after detecting the request to unlock the electronic device. Automatically attempting to unlock the electronic device in accordance with a determination that the error condition is no longer occurring improves the chance of success of the attempt to unlock the device. For example, the device performs the attempt immediately after the device detects that the error condition has been corrected. Performing an optimized operation when a set of conditions has been met without requiring further user input enhances the operability of the device and makes the user-device interface more efficient (e.g., by helping the user to provide proper inputs and reducing user mistakes when operating/interacting with the device) which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     In some examples, attempting to unlock the electronic device (e.g.,  900 ) includes: in accordance with a determination that biometric authentication is successful (e.g., information captured using the biometric sensor (e.g.,  903 ) matches or corresponds to stored authorized credentials), unlocking the electronic device (e.g., transitioning the device from a locked state to an unlocked state). In some examples, attempting to unlock the electronic device includes: in accordance with a determination that biometric authentication is not successful (e.g., information captured using the biometric sensor (e.g.,  903 ) does not match or correspond to stored authorized credentials), displaying, on the touch-sensitive display (e.g.,  902 ), an alternative authentication user interface (e.g.,  1320 A-B) (e.g., the touch-based user interface for entering touch-based authentication information (e.g., a password, passcode, swipe pattern). In some examples, further in accordance with a determination that biometric authentication is not successful, the electronic device maintains a locked state. In some examples, attempting to unlock the electronic device includes attempting to biometrically authenticate the user using the biometric sensor. 
     In some examples, the determination that the error condition is no longer occurring is made ( 1422 ) subsequent to detecting the request to unlock the electronic device (e.g.,  900 ) using the biometric sensor (e.g.,  903 ) (e.g., after detecting the request to unlock but before the predetermined amount of time lapses) and while displaying the indication (e.g.,  1304 A-E) of the location of the biometric sensor. 
     Note that details of the processes described above with respect to method  1400  (e.g.,  FIGS.  14 A- 14 B ) are also applicable in an analogous manner to the methods described above. For example, method  800 , method  1000 , and/or method  1200  optionally include one or more of the characteristics of the various methods described above with reference to method  1400 . For example, displaying the indication of the location of the biometric sensor, as described in method  1400 , can be performed in method  800 , method  1000 , and method  1200  in response to detecting an error condition. For brevity, these details are not repeated below. 
     The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the techniques and their practical applications. Others skilled in the art are thereby enabled to best utilize the techniques and various embodiments with various modifications as are suited to the particular use contemplated. 
     Although the disclosure and examples have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosure and examples as defined by the claims. 
     One aspect of the present technology is the gathering and use of data available from various sources to improve the delivery to users of invitational content or any other content that may be of interest to them. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, twitter IDs, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information data, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to deliver targeted content that is of greater interest to the user. Accordingly, use of such personal information data enables users to calculated control of the delivered content. Further, other uses for personal information data that benefit the user are also contemplated by the present disclosure. For instance, health and fitness data may be used to provide insights into a user&#39;s general wellness, or may be used as positive feedback to individuals using technology to pursue wellness goals. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the US, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, in the case of advertisement delivery services, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In another example, users can select not to provide mood-associated data for targeted content delivery services. In yet another example, users can select to limit the length of time mood-associated data is maintained or entirely prohibit the development of a baseline mood profile. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an app that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, content can be selected and delivered to users by inferring preferences based on non-personal information data or a bare minimum amount of personal information, such as the content being requested by the device associated with a user, other non-personal information available to the content delivery services, or publicly available information.

Metadata:
Filing Date: 20240208
Publication Date: 20250107
Grant Date: 20250107
Priority Date: 20180603
Inventors: VAN OS, MARCEL
ANTON, PETER D.
DEVINE, LYNNE
MOHSENI, Daamun
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F21/316", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0484", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/45", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/316", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V40/67", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V40/166", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/32", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F21/32", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F21/32", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F21/316", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/32", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 68692668