Patent Publication Number: US-2016232879-A1

Title: Method and electronic device for displaying screen

Description:
PRIORITY 
     This application claims priority under 35 U.S.C. §119(a) to Korean Application Serial No. 10-2015-0018047, which was filed in the Korean Intellectual Property Office on Feb. 5, 2015, the entire content of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure relates generally to a method and an electronic device for displaying a screen, and more particularly, to a method and an electronic device for displaying a screen including an object. 
     2. Description of the Related Art 
     Technologies that provide virtual reality services using electronic devices, such as display devices, are actively being developed. A display device may split one screen into left and right sides, and display images corresponding to left and right eyes on the split screens, respectively. A Head Mounted Theater (HMT) device, which can be combined with a display device that provides images displayed on the split screens in order to combine the split images into a user&#39;s whole view, is an example of a device that is being developed. Accordingly, a virtual reality service may be provided to a user through the user&#39;s whole view. 
     A display device may change a screen in response to a wearer&#39;s motion and provide the changed screen. For example, when the display device detects a right rotation, the display device may provide a screen, which is configured relatively in the right side of the currently displayed screen. However, an electronic device may not display an object, which has been conventionally displayed, by providing another screen. Further, a user should perform an operation for switching the screen to search for a particular object. 
     SUMMARY 
     The present disclosure is made to address at least the problems and/or disadvantages described above and to provide at least the advantages described below. 
     Accordingly, an aspect of the present disclosure is to provide a method and an apparatus for displaying a screen to solve the above-described problems and/or other problems. 
     Another aspect of the present disclosure is to provide a method and an electronic device for displaying a screen, which can track a particular object, such that a user can simply select the particular object without performing a plurality of screen switching operations. 
     In accordance with an aspect of the present disclosure, a method is provided for displaying a screen by an electronic device. The method includes displaying a first screen including a first object; detecting a screen switching event to switch from the displayed first screen to a second screen; and when the second screen does not include the first object, displaying at least a part of the first object on the second screen. 
     In accordance with another aspect of the present disclosure, an electronic device is provided. The electronic device includes a display that displays a first screen including a first object; and a processor that detects a screen switching event to switch the display from displaying the first screen to a second screen, and when the second screen does not include the first object, controls the display to display at least a part of the first object on the second screen. 
     In accordance with another aspect of the present disclosure, a method is provided for displaying a screen by an electronic device. The method includes displaying a first screen including a first object; detecting a screen switching event for switching from the first screen to a second screen; and when the second screen does not include the first object, displaying a location of the first object. 
     In accordance with another aspect of the present disclosure, an electronic device is provided. The electronic device includes a display that displays a first screen including a first object; and a processor that detects a screen switching event for switching from the first screen to a second screen, and when the second screen does not include the first object, controls the display to display a location of the first object. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  illustrates a network environment including an electronic device according to an embodiment of the present disclosure; 
         FIG. 2  illustrates a program module according to an embodiment of the present disclosure; 
         FIG. 3A  is a perspective view illustrating an electronic device and a viewing device according to an embodiment of the present disclosure; 
         FIG. 3B  illustrates a display method of an electronic device according to an embodiment of the present disclosure; 
         FIG. 3C  is a conceptual diagram of a screen viewed by a user according to an embodiment of the present disclosure; 
         FIG. 4A  is a perspective view illustrating a user wearing an HMT device according to an embodiment of the present disclosure; 
         FIGS. 4B to 4E  are conceptual diagrams illustrating screen switching operations of an electronic device according to an embodiment of the present disclosure; 
         FIG. 5A  is a conceptual diagram illustrating an entire screen for a virtual reality service according to an embodiment of the present disclosure; 
         FIG. 5B  illustrates an electronic device according to an embodiment of the present disclosure; 
         FIG. 5C  is a conceptual diagram illustrating a screen viewed by a user according to an embodiment of the present disclosure; 
         FIG. 5D  is a conceptual diagram illustrating an entire screen for a virtual reality service according to an embodiment of the present disclosure; 
         FIG. 5E  illustrates an electronic device according to an embodiment of the present disclosure; 
         FIG. 5F  is a conceptual diagram illustrating a screen viewed by a user according to an embodiment of the present disclosure; 
         FIG. 5G  is a conceptual diagram illustrating an entire screen according to an embodiment of the present disclosure; 
         FIG. 6  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure; 
         FIGS. 7A and 7B  are conceptual diagrams illustrating a screen according to an embodiment of the present disclosure; 
         FIGS. 8A and 8B  are conceptual diagrams illustrating movement of a location of an object on an entire screen according to an embodiment of the present disclosure; 
         FIG. 9  is a flowchart illustrating a process of changing a location of an object to be tracked according to an embodiment of the present disclosure; 
         FIG. 10  is a conceptual diagram illustrating a change in a partial screen of an entire screen according to an embodiment of the present disclosure; 
         FIGS. 11A and 11B  are conceptual diagrams illustrating movement of an object to be tracked on an entire screen according to an embodiment of the present disclosure; 
         FIG. 12A  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure; 
         FIG. 12B  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure; 
         FIG. 13  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure; 
         FIGS. 14A and 14B  are conceptual diagrams illustrating an entire screen and a display screen according to an embodiment of the present disclosure; 
         FIGS. 15A to 15C  illustrate an entire screen and a display screen corresponding to a backward screen switching event according to an embodiment of the present disclosure; 
         FIG. 16  is a conceptual diagram illustrating a screen according to an embodiment of the present disclosure; 
         FIGS. 17A and 17B  are conceptual diagrams illustrating a method of displaying of an object to be tracked according to movement of a user&#39;s view in a z axis direction according to an embodiment of the present disclosure; 
         FIG. 18  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure; 
         FIGS. 19 and 20  are conceptual diagrams illustrating a method of displaying a location of an object to be tracked according to an embodiment of the present disclosure; 
         FIGS. 21A and 21B  are conceptual diagrams illustrating an electronic device according to an embodiment of the present disclosure; 
         FIGS. 22A and 22B  are conceptual diagrams illustrating a method of displaying a screen by an electronic device according to an embodiments of the present disclosure; and 
         FIG. 23  is a block diagram of an electronic device according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, various embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that there is no intent to limit the present disclosure to the particular forms disclosed herein; rather, the present disclosure should be construed to cover various modifications, equivalents, and/or alternatives of embodiments of the present disclosure. In describing the drawings, similar reference numerals may be used to designate similar constituent elements. 
     Herein, terms are used merely for the purpose of describing particular embodiments and are not intended to limit the scope of other embodiments. For example, as used herein, singular forms may include plural forms as well unless the context clearly indicates otherwise. Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as those commonly understood by a person skilled in the art to which the present disclosure pertains. Terms that are defined in a general dictionary are to be interpreted to have the same meanings as the contextual meanings in the relevant field of the art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined as such herein. 
     As used herein, the expression “have”, “may have”, “include”, or “may include” refers to the existence of a corresponding feature (e.g., a numeral, a function, an operation, or a constituent element such as a component), and does not exclude one or more additional features. 
     As used herein, the expression “A or B”, “at least one of A and/or B”, or “one or more of A and/or B” may include any or all possible combinations of items enumerated together. For example, the expression “A or B”, “at least one of A and B”, or “at least one of A or B” may include (1) at least one A, (2) at least one B, or (3) both at least one A and at least one B. 
     The expression “a first”, “a second”, “the first”, or “the second” used herein may modify various elements regardless of the order and/or importance thereof, but does not limit the corresponding elements. The expressions above are used merely for the purpose of distinguishing an element from the other elements. For example, a first user device and a second user device may indicate different user devices, regardless of an order or importance thereof. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the present disclosure. 
     When an element (e.g., a first element) is referred to as being (operatively or communicatively) “connected” or “coupled” to another element (e.g., a second element), it may be directly connected or directly coupled to the second element or another element (e.g., a third element) may be interposer therebetween. However, when the first element is referred to as being “directly connected” or “directly coupled” to the second element, there are no elements interposed therebetween. 
     Herein, the expression “configured to” may be interchangeable with, for example, “suitable for”, “having the capacity to”, “designed to”, “adapted to”, “made to”, or “capable of” according to the situation. The term “configured to” may not necessarily imply “specifically designed to” in hardware. 
     Alternatively, in some situations, the expression “a device configured to” may mean that the device, together with other devices or components, “is able to”. 
     For example, the phrase “a processor adapted (or configured) to perform A, B, and C” may mean a dedicated processor (e.g., an embedded processor) for performing only the corresponding operations or a generic-purpose processor (e.g., a central processing unit (CPU) or an application processor (AP)) that can perform the corresponding operations by executing one or more software programs stored in a memory device. 
     An electronic device according to various embodiments of the present disclosure may include a smartphone, a tablet personal computer (PC), a mobile phone, a video phone, an electronic book (e-book) reader, a desktop PC, a laptop PC, a netbook computer, a personal digital assistant (PDA), a portable multimedia player (PMP), an MP3 player, a mobile medical appliance, a camera, and a wearable device (e.g., a head-mounted-device (HMD) such as electronic glasses, electronic clothes, an electronic bracelet, an electronic necklace, an electronic appcessory, electronic tattoos, or a smart watch). 
     The electronic device may also be a smart home appliance, such as a television, a Digital Video Disk (DVD) player, an audio device, a refrigerator, an air conditioner, a vacuum cleaner, an oven, a microwave oven, a washing machine, an air cleaner, a set-top box, a home automation control panel, a security control panel, a TV box (e.g., Samsung HomeSync®, Apple TV®, or Google TV®), a game console (e.g., Xbox® and PlayStation®), an electronic dictionary, an electronic key, a camcorder, and an electronic photo frame. 
     The electronic device may also include various medical devices, such as various portable medical measuring devices (e.g., a blood glucose monitoring device, a heart rate monitoring device, a blood pressure measuring device, a body temperature measuring device, etc.), a Magnetic Resonance Angiography (MRA) device, a Magnetic Resonance Imaging (MRI) device, a Computed Tomography (CT) machine, and an ultrasonic machine, a navigation device, a Global Positioning System (GPS) receiver, an Event Data Recorder (EDR), a Flight Data Recorder (FDR), a Vehicle Infotainment Device, an electronic device for a ship (e.g., a navigation device for a ship, and a gyro-compass), avionics, security devices, an automotive head unit, a robot for home or industry, an automatic teller machine (ATM) in a bank, point of sales (POS) device in a shop, or an internet of things (IoT) device (e.g., a light bulb, various sensors, an electric or gas meter, a sprinkler device, a fire alarm, a thermostat, a streetlamp, a toaster, a sporting goods, a hot water tank, a heater, a boiler, etc.). 
     The electronic device may also include furniture, a building/structure, an electronic board, an electronic signature receiving device, a projector, or various kinds of measuring instruments (e.g., a water meter, an electric meter, a gas meter, and a radio wave meter). 
     Further, the electronic device may be a flexible device. 
     The electronic device may also be a combination of one or more of the aforementioned various devices. However, the electronic device is also not limited to the aforementioned devices, and may include a new electronic device according to the development of technology. 
     As used herein, the term “user” may indicate a person who uses an electronic device or a device (e.g., an artificial intelligence electronic device) that uses an electronic device. 
       FIG. 1  illustrates a network environment including an electronic device according to an embodiment of the present disclosure. 
     Referring to  FIG. 1 , an electronic device  101  within a network environment  100  includes a bus  110 , a processor  120 , a memory  130 , an input/output interface  150 , a display  160 , a communication module  170 , and a sensing module  180 . Alternatively, the electronic device  101  may omit at least one of the above elements and/or further include other elements. 
     The bus  110  may include a circuit for connecting the elements  120  to  180  and transmitting communication between the elements (for example, control messages and/or data). 
     The processor  120  may include one or more of a CPU, an AP, and a Communication Processor (CP). The processor  120  may control, for example, one or more other elements of the electronic device  101  and/or process an operation or data related to communication. The processor  120  may be referred to as a controller or may include a controller as a part thereof. 
     The memory  130  may include a volatile memory and/or a non-volatile memory. The memory  130  may store, for example, instructions or data related to at least one other element of the electronic device  101 . The memory  130  stores software and/or a program  140 . 
     In  FIG. 1 , the program  140  includes a kernel  141 , middleware  143 , an Application Programming Interface (API)  145 , and an application program (or “application”)  147 . At least some of the kernel  141 , the middle  143 , and the API  145  may be referred to as an Operating System (OS). 
     The kernel  141  may control or manage system resources (for example, the bus  110 , the processor  120 , and the memory  130 ) that are used to execute an operation or a function implemented in the other programs (for example, the middleware  143 , the API  145 , and the application programs  147 ). Further, the kernel  141  may provide an interface through which the middleware  143 , the API  145 , or the application program  147  may access individual elements of the electronic device  101  to control or manage system resources. 
     The middleware  143  may serve as a relay for allowing the API  145  or the application programs  147  to communicate with the kernel  141  to exchange data. Further, in regard to task requests received from the application program  147 , the middleware  143  may perform a control (for example, scheduling or load balancing) for the task requests using a method of assigning at least one application a priority for using the system resources (for example, the bus  110 , the processor  120 , or the memory  130 ) of the electronic device  101 . 
     The API  145  is an interface by which the applications  147  control functions provided from the kernel  141  or the middleware  143 , and may include at least one interface or function (for example, instructions) for file control, window control, image processing, or text control. 
     The input/output interface  150  may serve as an interface for transmitting commands or data input from the user or an external device to other element(s) of the electronic device  101 . Further, the input/output interface  150  may output commands or data received from another element(s) of the electronic device  101  to the user or an external device. 
     The display  160  may include a Liquid Crystal Display (LCD), a Light Emitting Diode (LED) display, an Organic Light Emitting Diode (OLED) display, a Micro Electro Mechanical System (MEMS) display, or an electronic paper display. The display  160  may display various types of content (for example, text, images, videos, icons, or symbols) to users. The display  160  may include a touch screen for receiving a touch input, a gesture input, a proximity input, and/or a hovering input using an electronic pen or a user&#39;s body part. 
     The communication module  170  may configure communication between, for example, the electronic device  101  and an external device, such as an external electronic device  102 , an external electronic device  104 , or a server  106 . For example, the communication module  170  may be connected to a network  162  through wireless or wired communication to communicate with the external electronic device  104  or the server  106 . 
     The wireless communication may use, for example, at least one of Long-Term Evolution (LTE), LTE-Advanced (LTE-A), code division multiple access (CDMA), wideband CDMA (WCDMA), Universal Mobile Telecommunications System (UMTS), wireless broadband (WiBro), and Global System for Mobile Communications (GSM), for example, as a cellular communication protocol. For example, the wired communication may include at least one of a Universal Serial Bus (USB), a High Definition Multimedia Interface (HDMI), Recommended Standard 232 (RS-232), and a Plain Old Telephone Service (POTS). 
     The network  162  may include at least one of communication networks such as a computer network (for example, a local area network (LAN) or a wide area network (WAN)), the Internet, and a telephone network. 
     Each of the external electronic devices  102  and  104  may be the same or different type of device as the electronic device  101 . 
     The server  106  may include a group of one or more servers. 
     All or some of the operations performed by the electronic device  101  may be performed by another electronic device or a plurality of electronic devices  102  or  104 , or the server  106 . 
     When the electronic device  101  should perform some functions or services automatically or by request, the electronic device  101  may send a request for performing at least some of the functions related to the functions or services to another device  102  or  104 , or the server  106  instead of performing the functions or services by itself. The another electronic device may carry out the requested function or the additional function and transfer the result, obtained by carrying out the function, to the electronic device  101 . The electronic device  101  may provide the requested functions or services based on the received result as it is or after additionally processing the received result. To achieve this, for example, cloud computing, distributed computing, or client-server computing technology may be used. 
     The sensing module  180  may support driving of the electronic device  101  by performing at least one of the operations (or functions) implemented in the electronic device  101 . 
     The sensing module  180  may measure a physical quantity or detect an operation state of the electronic device  101 , and may convert the measured or detected information into an electrical signal. For example, the sensing module  180  may include at least one of a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor (for example, a Red, Green, and Blue (RGB) sensor), a bio sensor, a temperature/humidity sensor, an illumination sensor, and ultra violet (UV) sensor. Additionally or alternatively, the sensing module  180  may include an E-nose sensor, an electromyography (EMG) sensor, an electroencephalogram (EEG) sensor, an electrocardiogram (ECG) sensor, an infrared (IR) sensor, an iris sensor, and/or a fingerprint sensor. 
     The sensing module  180  may process at least some of the information obtained from other elements (for example, at least one of the processor  120 , the memory  130 , the input/output interface  150 , and the communication module  170 ) and utilize the same in various manners. For example, the sensing module  180  may control at least some functions of the electronic device  101  by using the processor  120  or independently therefrom so that the electronic device  101  may interwork with other electronic devices  102  or  104 , or the server  106 ). The sensing module  180  may be integrated into the processor  120  or the communication module  170 . Alternatively, at least one element of the sensing module  180  may be included in the server  106 , and at least one operation implemented in the sensing module  180  may be supported by the server  106 . 
     The display  160  may display a first screen including a first object. The processor  120  may make a control to detect a screen switching event for switching the screen of the display from the first screen to a second screen and, when the second screen does not include the first object, to display at least a part of the first object on the second screen. 
     The sensing module  180  may detect movement of the electronic device  101 . In this case, the screen switching event may be the movement of the electronic device. 
     The processor  120  may make a control to switch the first screen corresponding to a first part of a preset entire screen to the second screen corresponding to a second part of the preset entire screen, based on at least one of a degree and a direction of the movement and to display the switched second screen. 
     The processor  120  may make a control to display the second screen such that at least a part of the first object contacts the boundary of the second screen. 
     The processor  120  may make a control to display the second screen such that at least the part of the first object contacts the boundary of the second screen from a time point when the first object contacts the boundary of the second screen by the screen switching corresponding to the screen switching event. 
     The processor  120  may make a control to detect a backward screen switching event for the screen switching in a direction opposite to the direction of the screen switching corresponding to the screen switching event and to display the first object in response to the backward screen switching event. 
     The processor  120  may also make a control to display the first object at a preset location of the second screen and make a control to change and display a location of the first object on a preset entire screen according to the screen switching event. 
     The first screen may include a left eye image and a right eye image to provide a virtual reality service. 
     The display  160  may display the first screen including the first object. The processor  20  may make a control to detect the screen switching event for switching the screen of the display  120  from the first screen to the second screen and, when the second screen does not include the first object, to display the location of the first object. 
     The processor  120  may make a control to display at least one of an indicator, which indicates the location of the first object, and map information, which shows a relative location of the first object. 
       FIG. 2  illustrates a program module according to an embodiment of the present disclosure. For example, the program module illustrated in  FIG. 2  may be used as the program  140  illustrated in  FIG. 1 . 
     Referring to  FIG. 2 , a program module  210  includes an OS for controlling resources related to an electronic device in which it is installed and/or various applications executed in the OS. For example, the OS may be Android®, iOS®, Windows®, Symbian®, Tizen®, Bada®, etc. 
     The programming module  210  includes a kernel  220 , middleware  230 , an API  260 , and applications  270 . At least some of the program module  210  may be preloaded in the electronic device or downloaded from a server. 
     The kernel  220  includes a system resource manager  221  and a device driver  223 . The system resource manager  221  may control, allocate, or collect the system resources. The system resource manager  221  may include a process manager, a memory manager, and/or a file system manager. The device driver  223  may include a display driver, a camera driver, a Bluetooth driver, a shared-memory driver, a USB driver, a keypad driver, a Wi-Fi driver, an audio driver, or an Inter-Process Communication (IPC) driver. 
     The middleware  230  may provide a function required by the applications  270  in common or provide various functions to the applications  270  through the API  260 , such that the applications  270  efficiently use limited system resources of the electronic device. The middleware  230  includes a runtime library  235 , an application manager  241 , a window manager  242 , a multimedia manager  243 , a resource manager  244 , a power manager  245 , a database manager  246 , a package manager  247 , a connectivity manager  248 , a notification manager  249 , a location manager  250 , a graphic manager  251 , and a security manager  252 . 
     The run time library  235  may include a library module that a compiler uses in order to add new functions through a programming language while the application  270  is executed. The run time library  235  may perform input/output management, memory management, and/or a function for an arithmetic function. 
     The application manager  241  may manage a life cycle of at least one application among the applications  270 . 
     The window manager  242  may manage a graphical user interface (GUI) resource used in a screen. 
     The multimedia manager  243  may detect a format required for reproducing various media files and encode or decode a media file using a codec appropriate for the corresponding format. 
     The resource manager  244  may manage resources such as a source code, a memory, or a storage space of at least one application among the applications  270 . 
     The power manager  245  may operate together with a Basic Input/Output System (BIOS), in order to manage a battery or power and may provide power information for the operation of the electronic device. 
     The database manager  246  may generate, search for, and/or change a database to be used by at least one of the applications  270 . 
     The package manager  247  may manage the installation or updating of applications distributed in the form of a package file. 
     The connectivity manager  248  may manage, for example, a wireless connection of Wi-Fi or Bluetooth. 
     The notification manager  249  may display or notify an event such as a received message, an appointment, a proximity notification, etc., to a user. 
     The location manager  250  may manage location information of the electronic device. 
     The graphic manager  251  may manage graphic effects to be provided to a user and user interfaces related to the graphic effects. 
     The security manager  252  may provide various security functions required for system security or user authentication. 
     When the electronic device has a call function, the middleware  230  may further include a telephony manager for managing a voice call function or a video call function of the electronic device. 
     The middleware  230  may include a middleware module for forming a combination of various functions of the aforementioned elements. The middleware  230  may provide a module specialized for each type of operating system in order to provide a differentiated function. In addition, a few existing elements may be dynamically removed from the middleware  230 , or new elements may be added to the middleware  230 . 
     The API  260 , which is a set of API programming functions, may be provided in a different configuration for each OS. For example, using Android® or iOS®, an API set may be provided for each platform. When using Tizen®, two or more API sets may be provided for each platform. 
     The applications  270  include a home application  271 , a dialer application  272 , a short message service/multimedia messaging service (SMS/MMS) application  273 , an Instant Message (IM) application  274 , a browser application  275 , a camera application  276 , an alarm application  277 , a contact information application  278 , a voice dial application  279 , an e-mail application  280 , a calendar application  281 , a media player application  282 , an album application  283 , and a clock application  284 . Alternatively, some these applications may be removed from the applications  270 . Further, other applications may be included in the applications  270 , such as a health care application (for example, an application for measuring an amount of exercise or blood sugar), and an environmental information application (for example, an application for providing atmospheric pressure, humidity, or temperature information). 
     The applications  270  may also include an information exchange application that supports information exchange between the electronic device and an external electronic device. The information exchange application may include, for example, a notification relay application for transmitting particular information to the external electronic device, or a device management application for managing the external electronic device. 
     For example, the notification relay application may include a function of transferring, to the external electronic device, notification information generated from other applications of the electronic device (for example, the SMS/MMS application  273 , the e-mail application  280 , a health management application, or an environmental information application). 
     Further, the notification relay application may receive notification information from an external electronic device and provide the received notification information to a user. 
     The device management application may manage (for example, install, delete, or update) a function for at least a part of the external electronic device communicating with the electronic device (for example, turning on/off the external electronic device itself (or some elements thereof) or adjusting brightness (or resolution) of a display), applications executed in the external electronic device, or services provided from the external electronic device (for example, a telephone call service or a message service). 
     The applications  270  may include an application (for example, a health management application) designated according to attributes of the external electronic device (for example, attributes of the electronic device such as the type of electronic device which corresponds to a mobile medical device). 
     The applications  270  may include an application received from the external electronic device. The applications  270  may also include a preloaded application or a third party application that can be downloaded from the server. 
     Names of the elements of the program module  210  may change depending on the type of OS. 
     At least some of the program module  210  may be implemented in software, firmware, hardware, or a combination of two or more thereof. At least some of the programming module  210  may be implemented (for example, executed) by a processor. At least some of the programming module  210  may include, for example, a module, program, routine, sets of instructions, process, etc., for performing one or more functions. 
       FIG. 3A  is a perspective view illustrating an electronic device and a viewing device according to an embodiment of the present disclosure. 
     Referring to  FIG. 3A , the electronic device  301  includes a display and stores a virtual reality application that can provide a display similar to an actual reality to the user. For example, the virtual reality application displays a left eye image and a right eye image corresponding to each of the user&#39;s eyes based on a stereo scheme. 
     The viewing device  302  may be an HMT device, which may be worn on a user&#39;s head even as the user moves. Further, the viewing device  102  receives the electronic device  301  such that the user may view an image displayed on the electronic device  301  through the viewing device  102 . 
     The viewing device  302  includes a housing  350  that is worn on the user&#39;s head, a blackout part  330  that is fixed to the housing at an area corresponding to locations of the user&#39;s eyes, and at least one input button  321  provided on the housing  350 . The viewing device  302  also includes an input pad  325  for receiving a swipe input from the user. 
     The user may make the blackout part  330  fit closely to each of the user&#39;s eyes and, accordingly, the user may view the images provided by the virtual reality application provided from the electronic device  301 , without any interference from external light. 
     The electronic device  301  may be received by, e.g., coupled to, the viewing device  302 . The electronic device  301  may be connected to the viewing device  302  through a wire or wirelessly. For example, although the electronic device  301  may be connected to the viewing device  302  based on a USB, it is only an example and there is no limitation on the connection if data transmission/reception between the two devices  301  and  302  is possible through the connection. 
     According to another embodiment, the electronic device  301  may be simply physically coupled to the viewing device  302 . 
       FIG. 3B  illustrates a display method of an electronic device according to an embodiment of the present disclosure. 
     Referring to  FIG. 3B , the electronic device  301  displays a left eye image  361  and a right eye image  362  on the display  360 . The left eye image  361  includes a first object  363  and the right eye image  362  includes a second object  364 . The first object  363  corresponds to a left eye  701  and the second object  364  corresponds to a right eye  702 . 
     In  FIG. 3B , an InterPupillary Distance (IPD) corresponding to a distance between the left eye  701  and the right eye  702  may be D. 
     The left eye image  361  and the right eye image  362  may correspond to both of the user&#39;s eyes to provide a feeling of depth to the user. For example, the left eye image  361  and the right eye image  362  may be images for the virtual reality service, and may be images configured to give a three-dimensional effect to a part of the entire screen for the virtual reality service. 
     The electronic device  301  displays the first object  363  and the second object  364  with a predetermined distance therebetween. The user views an object image  367 , which exists at the intersection of a straight line passing through a left eye  701  and the first object  363  and a straight line passing through a right eye  702  and the second object  364 . For example, the user views an object image which exists at a location spaced apart from the user by L 1 . 
     Accordingly, the electronic device  301  may display the first object  363  and the second object  364 , which have a loop shape. 
       FIG. 3C  is a conceptual diagram illustrating a screen viewed by a user according to an embodiment of the present disclosure. 
     Referring to  FIG. 3C , the user views a screen  370  including a loop-shaped image  371 . 
       FIG. 4A  is a perspective view illustrating a user wearing an HMT device according to an embodiment of the present disclosure. 
     Referring to  FIG. 4A , the user wears the viewing device  302  coupled to the electronic device  301 , and the user may view an image displayed on the display of the electronic device  301 . 
     As described above, the electronic device  301  may display a left eye image and a right eye image on left and right parts of the display. The left eye image may be incident on the user&#39;s left eye and the right eye image may be incident on the user&#39;s right eye. For example, the left eye image and the right eye image may be incident on the user&#39;s whole view through both eyes. The user may receive a virtual reality service through the viewing device  302  by viewing the images incident on both eyes. 
     The virtual reality application executed by the electronic device  301  may display a binocular image on the display. The virtual reality application may change and display the binocular image according to a motion (yaw, pitch, and/or roll) of the user or the viewing device  302 . 
     The viewing device  302  may receive a command by at least one of the input button  321  and the input pad  325  from the user. For example, the electronic device  301  may acquire a focus control command or a focus adjustment command from the viewing device  302 . Further, the user may directly input the focus control command or the focus adjustment command into the electronic device  301 . 
     For example, when the user inputs a swipe gesture in a first direction of the input pad  325 , the electronic device  301  may perform a control command corresponding to the swipe gesture. 
       FIGS. 4B, 4C, 4D, and 4E  are conceptual diagrams illustrating screen switching operations of an electronic device according to an embodiment of the present disclosure. 
     Referring to  FIG. 4B , the user looks in a first direction  411  while wearing the electronic device  301 . As described above, the electronic device  301  displays a left eye image and a right eye image that are combined for the user in a first virtual screen  421 . The first virtual screen  421  may be a screen corresponding to a part of the entire screen configured in the virtual reality service. 
     When the user turns his head in a right direction  401 , the electronic device  301  senses the rotation in the right direction  401 . As illustrated in  FIGS. 4C to 4E , as the user turns his head in a second direction  412 , a third direction  413 , and a fourth direction  414 , from the first direction  411 , the electronic device  301  senses the rotation  401  and changes the display accordingly. Specifically, the electronic device  301  displays a second virtual screen  422  in accordance with the second direction  412 , a third virtual screen  423  in accordance with the third direction  413 , and a fourth virtual screen  424  in accordance with the fourth direction  414 . More specifically, the electronic device  301  displays different left and right eye images for displaying each of the virtual screens  422  to  424 . 
     Each of the first virtual screen  421  to the fourth virtual screen  424  may be a partial screen of an entire screen for the virtual reality service. 
     As illustrated in  FIGS. 4B to 4E , the second virtual screen  422  is a screen for a foreground arranged relatively to the right of the first virtual screen  421 , the third virtual screen  423  is a screen for a foreground arranged relatively to the right of the second virtual screen  422 , and the fourth virtual screen  424  is a screen for a foreground arranged relatively to the right side of the third virtual screen  423 . Accordingly, as the user turns his head in the right direction  401 , the user may sequentially view the foregrounds arranged relatively on the right side. 
       FIG. 5A  is a conceptual diagram illustrating an entire screen for a virtual reality service according to an embodiment of the present disclosure. 
     Referring to  FIG. 5A , the entire screen is configured in three dimensions and includes objects  501 ,  502 , and  503 . The first object  501  is arranged at a first location (x1, y1, z1), the second object  502  is arranged at a second location (x2, y2, z2), and the third object  503  is arranged at a third location (x3, y3, z3). The objects  501 ,  502 , and  503  are images that constitute the entire screen, and there is no limitation on the type thereof. 
     A first user view  511  may be configured on the entire screen. In  FIG. 5A , the first user view  511  includes the first object  501 . Accordingly, an electronic device may display a first screen corresponding to the first user view  511 . 
       FIG. 5B  illustrates an electronic device according to an embodiment of the present disclosure. 
     Referring to  FIG. 5B , the electronic device  301  displays a left eye image  521  and a right eye image  523  on the display  360 . The left eye image  521  includes a first object  522  and the right eye image  523  includes a second object  524 . 
       FIG. 5C  is a conceptual diagram illustrating a screen viewed by a user according to an embodiment of the present disclosure. 
     Referring to  FIG. 5C , the user views a screen  525 , which includes a first object  526 . The first object  526  is a combination of the left eye image  521  including the first object  522  and the right eye image  523  including the second object  524 . The first screen  525  may be generated by projecting the entire screen onto a plane corresponding to the first user view  511 , as illustrated in  FIG. 5A . 
     While displaying the left eye image  521  including the first object  522  and the right eye image  523  including the second object  524 , the electronic device  301  may detect a screen switching event. The screen switching event may be movement, e.g., a rotation, of the electronic device  301 . For example, the user may turn his head while wearing the electronic device  301  as illustrated in  FIGS. 4B to 4E . 
       FIG. 5D  is a conceptual diagram illustrating an entire screen for a virtual reality service according to an embodiment of the present disclosure. 
     Referring to  FIG. 5D , the electronic device  301  changes the user&#39;s view into a second user view  512 . The second user view  512  includes the second object  502  and the third object  503 . The electronic device  101  changes the user&#39;s view from the first user view  511  to the second user view  512  in accordance with a detected rotation angle of the electronic device  301 . 
     The screen switching event corresponding to the movement of the electronic device  301  is only an example, and there is no limitation on an input method, if the input method can be detected by the electronic device  301 . 
     The detected rotation angle may include two angles of a spherical coordinate system, which are orthogonal to each other, e.g., a first angle (θ) on an xy plane with a z axis as an axis of rotation and a second angle (φ) formed with the xy plane. The electronic device  301  may rotate the first user view  511  at the rotation angle of the electronic device  301  to determine the second user view  512 . Alternatively, the electronic device  301  may determine the screen rotation angle by using the rotation angle of the electronic device  301 , and rotate the first user view  511  at the screen rotation angle to determine the second user view  512 . 
     The electronic device  301  displays a second screen corresponding to the second user view  512 . 
       FIG. 5E  illustrates an electronic device according to an embodiment of the present disclosure. 
     Referring to  FIG. 5E , the electronic device  301  displays a left eye image  531  and a right eye image  534  corresponding to the second screen  512 . The left eye image  531  includes a second object  532  for the left eye and a third object  533  for the left eye, and the right eye image  534  includes a second object  535  for the right eye and a third object  536  for the right eye. 
       FIG. 5F  is a conceptual diagram illustrating a screen viewed by a user according to an embodiment of the present disclosure. 
     Referring to  FIG. 5F , the user views a screen  537 , which includes a second object  538  and a third object  539 . The second object  538  and the third object  539  are combinations of the left eye image  531  including the second object  532  for the left eye and the third object  533  for the left eye, and the right eye image  534  including the second object  535  for the right eye and the third object  536  for the right eye, respectively. 
       FIG. 5G  is a conceptual diagram illustrating an entire screen according to an embodiment of the present disclosure. 
     Referring to  FIG. 5G , the electronic device  301  configures an entire screen  540  in a rotation angle coordinate system. The entire screen  540  configured in the rotation angle coordinate system includes a horizontal axis as a first angle ( 0 ) and a vertical axis as a 15 second angle (φ). The electronic device  301  may initially display a first screen  551 , which is a first part of the entire screen  540 . The first screen  551  includes a first object  541 . More specifically, the electronic device  301  displays a left eye image and a right eye image corresponding to the first screen  551 . 
     The electronic device  301  detects a rotation and determines a second screen  552  in response to the detected rotation. The electronic device  301  adjusts the display screen from the first screen  551  to the second screen  552  in the entire screen  540 , in response to the rotation of the electronic device  101 . The second screen  552  includes a second object  542  and a third object  543 . The electronic device  301  displays a left eye image and a right eye image corresponding to the second screen  552 . 
       FIG. 6  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure. 
       FIGS. 7A and 7B  are conceptual diagrams illustrating a screen according to an embodiment of the present disclosure. 
       FIGS. 8A and 8B  are conceptual diagrams illustrating movement of a location of an object on an entire screen according to an embodiment of the present disclosure. 
     Referring to  FIG. 6 , in step  610 , the electronic device displays a first screen including a first object. The electronic device may configure the first object as an object to be tracked. The object to be tracked may be preset or may be designated in the electronic device. 
     In step  620 , the electronic device detects a screen switching event. For example, the screen switching event may be a movement of the electronic device. The electronic device may switch from the first screen to a second screen in response to the screen switching event. For example, the electronic device may rotate the first screen within the entire screen according to the rotation of the electronic device. 
     In step  630 , the electronic device determines whether the first object is included in the second screen. When the first object is not included in the second screen, the electronic device displays at least a part of the first object in the second screen in step  640 . However, when the first object is included in the second screen, the electronic device displays the second screen in step  650 . 
     For example, as illustrated in  FIG. 7A , the electronic device may switch and display the display screen corresponding to a part of the entire screen according to the screen switching event. 
     In response to the electronic device detecting a rightward rotation, the electronic device sequentially switches the screen from the first screen  511  illustrated in  FIG. 5A  to the second screen  512  illustrated  FIG. 5D . Accordingly, the electronic device may sequentially display a plurality of screens  701  to  706 . 
     More specifically, the electronic device sequentially displays left eye images and right eye images corresponding to the plurality of screens  701  to  706 . 
     The screen  701  and the screen  702  include a first object  711 . This corresponds to the first object  501  being included in a part corresponding to a user&#39;s view angle. 
     According to the rotation of the user&#39;s view, the first object  501  may contact a boundary of a user&#39;s view  801 , as illustrated in  FIG. 8A . The electronic device may display a part  712  of the first object. Thereafter, the electronic device may display a screen  705  including only a second object  713  and may display a screen  706  including the second object  713  and a third object  714 . 
     The electronic device may also display a plurality of screens  721  to  726  as illustrated in  FIG. 7B . More specifically, the electronic device may sequentially display left eye images and right eye images corresponding to the plurality of screens  721  to  726 . 
     As illustrated in  FIG. 7B , the electronic device may also display the part  712  of the first object on the screen  724  corresponding to the view angle at which the first object  501  is not viewed on the entire screen. For example, the electronic device may maintain the displaying of the part  712  of the first object on the third screen. Thereafter, the electronic device may display a screen  725  including the second object  713  and may display a screen  726  including the second object  713  and the third object  714 . The electronic device continues to display the part  712  of the first object on each of the screen  725  and the screen  726 . That is, the electronic device displays as if the first object  501  is being dragged, even though the screen is switched. 
     Displaying only the part  712  of the first object is only an example, and the electronic device may display an entirety of the first object or display another object which may replace the first object. 
     Alternatively, the electronic device may change attributes of the first object, such as a color or transparency, and display the changed first object. 
     Further, displaying the first object at a location out of the user&#39;s view angle is only an example, and the electronic device may display the first object at a predetermined location of the screen. 
     Referring to  FIGS. 8A and 8B , the electronic device may change a first view angle  801  to a second view angle  802  in response to the screen switching event. The first object  501  may contact a boundary of the first view angle  801 . The electronic device may display, for example, the screen  723  of  FIG. 7B , according to the first view angle  801 . 
     The electronic device may change the location of the first object  501  according to the second view angle  802 . For example, the electronic device may change the location of the first object  501  from (x1, y1, z1) to (x4, y4, z4). 
     The electronic device may change the location of the first object  501  according to the rotation of the electronic device. The electronic device may display the first object  501  at the location of (x4, y4, z4), the second object  502  at the location of (x2, y2, z2), and the third object  503  at the location of (x3, y3, z3) on one screen, like screen  726  of  FIG. 7B . 
     When the rotation of the electronic device corresponds to (θ, φ), the electronic device may rotate the location of (x1, y1, z1) by (θ, φ) to determine the location as (x4, y4, z4). 
       FIG. 9  is a flowchart illustrating a process of changing a location of an object to be tracked according to an embodiment of the present disclosure. 
     Referring to  FIG. 9 , in step  910 , the electronic device detects a screen switching event for changing a user&#39;s view from a first screen to a second screen. For example, the electronic device may detect a movement of the electronic device. 
     In step  920 , the electronic device displays a first object on a preset area of the second screen. 
     For example, the electronic device may display the first object  711  at the center of all screens  1001  to  1006  as illustrated in  FIG. 10 . 
     More specifically, the electronic device detects the screen switching event while the screen  1001  including the first object  711  is displayed. The electronic device always displays the first object  711  at a preset location, for example, a center or an edge, while displaying the remaining parts except for the first object  711  as illustrated in screens  1002  to  1006 . That is, the electronic device displays the first object  711  as it is floating. Accordingly, the user may always view the object to be tracked. 
     The electronic device may overlappingly display the first object  711  and another object when the location of the first object  711  overlaps a location of the other object. 
     While the first object  711  overlaps the other object, the electronic device may move the location of the first object  711  to another location and display the moved first object  711 . 
       FIGS. 11A and 11B  are conceptual diagrams illustrating movement of an object to be tracked on an entire screen according to an embodiment of the present disclosure. 
     Referring to  FIG. 11A , the electronic device may display the screen  1001  of  FIG. 10  on the entire screen according to a first user view  1101 . The electronic device may detect a screen detection event, e.g., a rotation of the electronic device by (θ, φ). 
     The electronic device may rotate a location of the first object  501  according to the detected rotation as illustrated in  FIG. 11B . When the rotation of the electronic device corresponds to (θ, φ), the electronic device may rotate the location of (x1, y1, z1) by (θ, φ) to determine the location (x5, y5, z5). That is, the electronic device may rotate the location of the first object as much as the electronic device rotates. Accordingly, the electronic device may display screen  1006  of  FIG. 10  in accordance with a second user view  1102 . 
       FIG. 12A  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure. 
     Referring to  FIG. 12A , in step  1210 , the electronic device identifies a boundary of the user&#39;s view corresponding to the displayed screen. The boundary of the user&#39;s view may be a boundary of the screen displayed on the electronic device. Alternatively, the boundary of the user&#39;s view may be configured in a predetermined part within the screen displayed on the electronic device. 
     In step  1220 , the electronic device determines whether the first object, which is the object to be tracked, contacts the boundary. As described above, the electronic device may change the user&#39;s view according to the screen switching event, and also change the boundary of the user&#39;s view. The electronic device may determine whether the first object contacts the changed boundary. When the first object contacts the boundary, the first object may not be displayed thereafter, so that the electronic device may determine whether the first object contacts the boundary. 
     When the first object does not contact the boundary in step  1220 , the electronic device maintains the location of the first object in step  1230 . 
     When the first object contacts the boundary in step  1220 , the electronic device changes the location of the first object according to the movement of the boundary in step  1240 . The electronic device may detect the rotation of the electronic device and change the location of the first object based on the detected rotation. That is, even when the screen is switched, the electronic device may display the screen such that the first object contacts the boundary. Accordingly, the electronic device may continue to display the first object as if it is being dragged from a time point where the first object contacts the boundary, even though the screen is being switched. 
       FIG. 12B  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure. 
     Referring to  FIG. 12B , in step  1250 , the electronic device detects movement of the user&#39;s view corresponding to the displayed screen. The electronic device may detect the screen switching event and detect the movement of the user&#39;s view on the entire screen in response to the screen switching event. For example, the electronic device may detect the rotation of the electronic device and rotate the user&#39;s view according to the rotation of the electronic device. 
     In step  1260 , the electronic device changes the location of the first object according to the movement of the user&#39;s view and display the changed first object. For example, the electronic device may change the location of the first object by rotating the first object according to the rotation of the user&#39;s view. Accordingly, the electronic device may display the first object as if it is being floated. 
       FIG. 13  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure. 
     Referring to  FIG. 13 , in step  1310 , the electronic device displays a first screen including a first object. 
     In step  1320 , the electronic device detects a screen switching event in a first direction. For example, the electronic device may detect a screen switching event to a second screen arranged in the first direction from the first screen on the entire screen. 
     In step  1330 , the electronic device displays the second screen including at least a part of the first object. According to the present embodiment, it is assumed that the second screen, which is the part of the entire screen, does not actually include the first object. Further, the first object may be an object to be tracked. Accordingly, the electronic device may display at least the part of the first object on the second screen. For example, the electronic device may change the location of the first object from (x1, y1, z1) to (x4, y4, z4) as illustrated in  FIG. 8B . 
     In step  1340 , the electronic device detects a screen switching event in a second direction. For example, the electronic device may detect a screen switching event from the second screen to a third screen arranged in the second direction from the second screen on the entire screen. The third screen may be a screen arranged between the first screen and the second screen on the entire screen. Alternatively, the third screen may be the first screen. The screen switching event in the second direction may be called a backward screen switching event. 
     In step  1350 , the electronic device displays the third screen including the first object. 
       FIGS. 14A and 14B  are conceptual diagrams illustrating an entire screen and a display screen according to an embodiment of the present disclosure. 
     Referring to  FIG. 14A , the electronic device may rotate a user&#39;s view  1401  on the entire screen according to a backward screen switching event. For example, the electronic device may determine the user&#39;s view  1401  by rotating the user&#39;s view  802  of  FIG. 8B . The user&#39;s view  1401  may include the first object  501  and the second object  502 . The electronic device  101  may rotate the user&#39;s view  802  while maintaining (x4, y4, z4) as the location of the first object  501  on the entire screen according to the backward screen switching event. That is, even though the first object  501  contacts the boundary of the user&#39;s view, if the backward screen switching event is detected, the electronic device may maintain the location of the first object  501  on the entire screen. 
     The electronic device may switch the screen  726  corresponding to the user&#39;s view  802  to the screen  727  corresponding to the user&#39;s view  1401  as illustrated in  FIG. 14B . The screen  727  corresponding to the user&#39;s view  1401  includes the first object  715 . As described above, the user may easily view the object to be tracked without the turn his head again back to an initial location, in order to view the object to be tracked again. 
       FIGS. 15A to 15C  illustrate an entire screen and a display screen corresponding to a backward screen switching event according to an embodiment of the present disclosure. 
     Referring to  FIG. 15A , the electronic device may rotate the user&#39;s view  1401  on the entire screen according to a backward screen switching event. For example, the electronic device may determine the user&#39;s view  1401  by rotating the user&#39;s view  802  of  FIG. 8B . The user&#39;s view  1401  includes the first object  501  and the second object  502 . The electronic device may rotate the location of the first object  501  from (x4, y4, z4) to (x6, y6, z6) according to the backward screen switching event. That is, when the first object  501  contacts the boundary of the user&#39;s view, the electronic device may change the location of the first object  501  according to the backward screen switching event. Accordingly, the electronic device may continually display the first object  501  as if it is backwardly dragged, even though the screen is switched. 
     Referring to  FIG. 15B , the electronic device may rotate a user&#39;s view  1501  until the user&#39;s view includes (x1, y1, z1), which is the initial location of the first object  501 , according to the backward screen switching event. The electronic device may store the initial location of the first object  501 . Further, when the first object  501  backwardly moves and reaches the initial location, the electronic device may display the initial location. 
     Accordingly, as illustrated in  FIG. 15C , the electronic device may display the screen  726  including the part  712  of the first object, the second object  713 , and the third object  714 . The electronic device may display the screen  728  including the second object  713  according to the backward screen switching event, and in this case, may also display the part  712  of the first object. The electronic device may display the screen  729  including the first object  715 . 
       FIG. 16  is a conceptual diagram illustrating a screen according to an embodiment of the present disclosure. 
     In  FIG. 16 , it is assumed that the first object  712  and the second object  713  are configured as objects to be tracked. That is,  FIG. 16  illustrates a method of displaying a screen for a plurality of objects to be tracked. 
     Referring to  FIG. 16 , the electronic device may display the screen  726  including the part  712  of the first object, the second object  713 , and the third object  714 . More specifically, the electronic device may display a left eye image and a right eye image corresponding to the screen  726 . For example, the electronic device may display the screen  726  corresponding to the user&#39;s view  802  of  FIG. 8B . 
     As illustrated in  FIG. 8B , the electronic device  101  displays the screen including the first object  501  arranged at (x4, y4, z4), the second object  502  arranged at (x2, y2, z2), and the third object  503  arranged at (x3, y3, z3). The electronic device may move the location of the first object on the entire screen from (x1, y1, z1) to (x4, y4, z4) while rotating the user&#39;s view  801  of  FIG. 8A . According to the change in the location on the entire screen, the object may be fixedly displayed at a predetermined location on the screen displayed on the electronic device. 
     The electronic device may detect a screen switching event for further rotating the user&#39;s view  802  in a right direction. The electronic device  101  may display screens  1601  and  1603  including a part  1602  of the second object from a time point, when the second object contacts the boundary of the user&#39;s view. When display areas of the part  712  of the first object and the part  1602  of the second object overlap each other, the electronic device  101  may overlappingly display the two objects. 
     Thereafter, the electronic device may detect a backward screen switching event. In response to the backward screen switching event, the electronic device may display the screen  1604  including the first object  1611 , the second object  1612 , and the third object  714 . When the backward screen switching event is detected, the electronic device may display the screen  1604  while maintaining the locations of the first object  1611  and the second object  1612 , which are the objects to be tracked on the entire screen. 
       FIGS. 17A and 17B  are conceptual diagrams illustrating a method of displaying an object to be tracked according to movement of a user&#39;s view in a z axis direction according to an embodiment of the present disclosure. 
     Referring to  FIG. 17A , the entire screen include a first object  1703  and a second object  1704 . The first object  1703  is arranged at (x7, y7, z7), and the second object  1704  is arranged at (x8, y8, z8). The screen switching event may be an event for moving the user&#39;s view from a first user&#39;s view  1701  to a second user&#39;s view  1702 . 
     Referring to  FIG. 17B , the electronic device may display a screen  1710  including a first object  1711  and a second object  1712  according to the first user view  1701 . The electronic device may display the first object  1711  to be larger than the second object  1712  according to a distance from the user&#39;s view  1701  of the first object  1703  and the second object  1704  on the entire screen. 
     The electronic device may display a screen  1720  including a second object  1722  according to the changed second user view  1702 . The second object  1722  within the screen  1720  may be displayed to be larger than the second object  1712  within the screen  1710 . The electronic device may display a part  1721  of the first object, which is the object to be tracked. The electronic device may display the part  1721  of the first object from a time point when the first object  1703  contacts the boundary of the user&#39;s view. Further, the electronic device may display the first object  1703  while moving the location of the first object  1703  on the entire screen from the time point when the first object  1703  contacts the boundary of the user&#39;s view. 
       FIG. 18  is a flowchart illustrating a method of displaying a screen according to an embodiment of the present disclosure. 
     Referring to  FIG. 18 , in step  1810 , the electronic device displays a first screen including a first object. 
     In step  1820 , the electronic device detects a screen switching event for switching the screen from a first screen to a second screen. 
     In step  1830 , the electronic device determines whether the first object is included in the second screen. 
     When the first object is not included in the second screen, the electronic device additionally displays the location of the first object on the second screen in step  1840 . 
     When the first object is included in the second screen, the electronic device displays the second screen in step  1850 . 
       FIGS. 19 and 20  are conceptual diagrams illustrating a method of displaying a location of an object to be tracked according to an embodiment of the present disclosure. 
     Referring to  FIG. 19 , the electronic device may display a second screen  1900  including a second object  1901  and a third object  1902 . An object to be tracked may not be included within the second screen  1900 . The electronic device may display, by arrows  1911  to  1916 , a relative location of the object to be tracked based on the second screen  1900  of the entire screen. When one of the arrows  1911  to  1916  is designated, the electronic device may display a screen including the object to be tracked. 
     Referring to  FIG. 20 , the electronic device may display a second screen  2000  including a second object  2001  and a third object  2002 . An object to be tracked may not be included within the second screen  2000 . The electronic device may display a corresponding mini map  2010  on the entire screen. The second screen  2011  and a location of the object  2012  to be tracked may be displayed on the mini map  2010 . When one location is designated on the mini map  2010 , the electronic device may display a screen including the designated location. Particularly, when the object  2012  to be tracked is designated on the mini map  2010 , the electronic device may display a screen including the object to be tracked. 
       FIGS. 21A and 21B  are conceptual diagrams illustrating an electronic device according to an embodiment of the present disclosure. 
     Referring to  FIG. 21A , an electronic device  2100 , i.e., a glasses type wearable electronic device, includes a transparent display  2110 . The transparent display  2110  allows light from the outside to pass through, and the user may view an object  2101  outside the electronic device  2100 . The user may view the external object  2101  in an area  2111  of the transparent display  2110 . The electronic device  101  may photograph the external object  2101  and display an additional information object  2112  on the transparent display  2110  by analyzing the photographed image. Accordingly, the electronic device  2100  may provide an augmented reality service for the external object. 
     Referring to  FIG. 21B , the user may turn his head to view an external object  2102 . The external object  2101  may be out of the user&#39;s view in  FIG. 21B , while the user views the external object  2102  in an area  2121  of the transparent display  2110 . The electronic device  2100  may photograph the external object  2102  and display an additional information object  2122  on the transparent display  2110  by analyzing the photographed image. Additionally, the electronic device  2100  may display at least a part  2113  of the additional information object corresponding to the external object  2101  on the transparent display  2100 . 
       FIGS. 22A and 22B  are conceptual diagrams illustrating a method of displaying a screen by an electronic device according to an embodiment of the present disclosure. 
     Referring to  FIG. 22A , the electronic device  2250  may display a first menu screen  2200  including a first object  2201 , a second object  2202 , and a third object  2203 . In  FIG. 22A , it is assumed that the third object  2203  is an object to be tracked. 
       FIG. 22B  illustrates an entire screen configured in a two dimensional plane. The entire screen includes a first page  2230 , a second page  2240 , and a third page  2250 . The first page  2230  includes a first object  2231 , a second object  2232 , and a third object  2233 . The second page  2240  includes a fourth object  2241 , a fifth object  2242 , and a sixth object  2243 . The third page  2250  includes a seventh object  2251 , an eighth object  2252 , and a ninth object  2253 . For example, the first object  2231  to the ninth object  2253  may be icons for executing applications. 
     As illustrated in  FIG. 22A , the user may input a leftward flick gesture  2205 . The flick gesture  2205  may be a screen switching event, and the electronic device  2250  may switch the first menu screen  2200  to the second menu screen  2210  in response to the screen switching event. The second menu screen  2210  may correspond to the second page  2240  of the entire screen. The second menu screen  2210  includes a fourth object  2211 , a fifth object  2212 , and a sixth object  2213 . Further, the electronic device  2250  may display the third object  2204 , which is the object to be tracked, on the second menu screen  2210 . 
     Thereafter, as illustrated in  FIG. 22A , the user may input another leftward flick gesture  2215 . The flick gesture  2215  may be a screen switching event, and the electronic device  2250  may switch the second menu screen  2210  to the third menu screen  2220  in response to the screen switching event. The third menu screen  2220  corresponds to the third page  2250  of the entire screen. The third menu screen  2220  includes a seventh object  2221 , an eighth object  2222 , and a ninth object  2223 . Additionally, the electronic device  2250  continues to display the third object  2204 , which is the object to be tracked, on the third menu screen  2220 . 
       FIG. 23  is a block diagram illustrating an electronic device according to an embodiment of the present disclosure. 
     Referring to  FIG. 23 , an electronic device  2301  includes an AP  2310 , a communication module  2320 , a Subscriber Identification Module (SIM) card  2324 , a memory  2330 , a sensor module  2340 , an input device  2350 , a display  2360 , an interface  2370 , an audio module  2380 , a camera module  2391 , a power management module  2395 , a battery  2396 , an indicator  2397 , and a motor  2398 . 
     The AP  2310  may control a plurality of hardware or software components connected the AP  2310  by driving an operating system or an application program and perform a variety of data processing and calculations. The AP  2310  may be implemented by, for example, a System on Chip (SoC). The AP  2310  may further include a Graphics Processing Unit (GPU) and/or an image signal processor. Alternatively, the AP  2310  may also include at least some of the components illustrated in  FIG. 23 , e.g., a cellular module  2321 . The AP  2310  may load instructions or data, received from at least one other component (for example, a non-volatile memory), in a volatile memory to process the loaded instructions or data, and may store various types of data in a non-volatile memory. 
     The communication module  2320  may have a configuration equal or similar to the communication module  170  illustrated in  FIG. 1 . 
     The communication module  2320  includes a cellular module  2321 , a Wi-Fi module  2323 , a Bluetooth (BT) module  2325 , a GPS module  2327 , an NFC module  2328 , and a Radio Frequency (RF) module  2329 . 
     The cellular module  2321  may provide a voice call, video call, text message services, or Internet services through, for example, a communication network. The cellular module  2321  may distinguish between and authenticate electronic devices within a communication network using a subscriber identification module (for example, the SIM card  2324 ). The cellular module  2321  may perform at least some of the functions which may be provided by the AP  2310 . The cellular module  2321  may include a CP. 
     The Wi-Fi module  2323 , the BT module  2325 , the GPS module  2327 , and the NFC module  2328  may include a processor for processing data transmitted/received through the corresponding module. At least some (two or more) of the cellular module  2321 , the Wi-Fi module  2323 , the BT module  2325 , the GPS module  2327 , and the NFC module  2328  may be included in one Integrated Chip (IC) or IC package. 
     The RF module  2329  may transmit/receive RF signals, for example, communication signals. The RF module  2329  may include a transceiver, a Power Amp Module (PAM), a frequency filter, a Low Noise Amplifier (LNA) and/or an antenna. At least one of the cellular module  2321 , the Wi-Fi module  2323 , the BT module  2325 , the GPS module  2327 , and the NFC module  2328  may transmit/receive an RF signal through a separate RF module. 
     The SIM card  2324  may include a subscriber identification module and/or an embedded SIM, and contain unique identification information (for example, an Integrated Circuit Card Identifier (ICCID)) or subscriber information (for example, an International Mobile Subscriber Identity (IMSI)). 
     The memory  2330  includes an internal memory  2332  or an external memory  2334 . The internal memory  2332  may include at least one of a volatile memory (e.g., a Dynamic Random Access Memory (DRAM), a Static RAM (SRAM), a Synchronous Dynamic RAM (SDRAM), etc.) and a non-volatile memory (e.g., a One Time Programmable Read Only Memory (OTPROM), a Programmable ROM (PROM), an Erasable and Programmable ROM (EPROM), an Electrically Erasable and Programmable ROM (EEPROM), a flash memory (for example, a NAND flash memory or a NOR flash memory), a hard drive, or a Solid State Drive (SSD). 
     The external memory  2334  may further include a flash drive, a Compact Flash (CF), a Secure Digital (SD), a Micro Secure Digital (Micro-SD), a Mini Secure Digital (Mini-SD), an extreme Digital (xD), a memory stick, etc. The external memory  2334  may be functionally and/or physically connected to the electronic device  2301  through various interfaces. 
     The sensor module  2340  may measure a physical quantity or detect an operation state of the electronic device  2301 , and may convert the measured or detected information to an electrical signal. The sensor module  2340  includes a gesture sensor  2340 A, a gyro sensor  2340 B, an atmospheric pressure sensor  2340 C, a magnetic sensor  2340 D, an acceleration sensor  2340 E, a grip sensor  2340 F, a proximity sensor  2340 G, a color sensor  2340 H (e.g., an RGB sensor), a biometric sensor  2340 I, a temperature/humidity sensor  2340 J, an illumination sensor  2340 K, and an Ultra Violet (UV) sensor  2340 M. Additionally or alternatively, the sensor module  2340  may include an E-nose sensor, an electromyography (EMG) sensor, an electroencephalogram (EEG) sensor, an electrocardiogram (ECG) sensor, an infrared (IR) sensor, an iris sensor, and/or a fingerprint sensor. 
     The sensor module  2340  may further include a control circuit for controlling at least one sensor included therein. 
     The electronic device  2301  may further include a processor configured to control the sensor module  2340  as a part of or separately from the AP  2310 , and may control the sensor module  2340  while the AP  2310  is in a sleep state. 
     The input device  2350  includes a touch panel  2352 , a (digital) pen sensor  2354 , a key  2356 , and an ultrasonic input device  2358 . The touch panel  2352  may use at least one of a capacitive type, a resistive type, an infrared type, and an ultrasonic type. The touch panel  2352  may further include a control circuit. The touch panel  2352  may further include a tactile layer, and provide a tactile reaction to a user. 
     The (digital) pen sensor  2354  may include a recognition sheet which is a part of the touch panel or a separate recognition sheet. The key  2356  may include a physical button, an optical key, and/or a keypad. 
     The ultrasonic input unit  2358  may input data through an input device that generates an ultrasonic signal, and the electronic device  2301  may identify data by detecting a sound wave with a microphone  2388 ). 
     The display  2360  includes a panel  2362 , a hologram device  2364 , and a projector  2366 . The panel  2362  may be flexible, transparent, or wearable. The panel  2362  may also be configured to be integrated with the touch panel  2352  as a single module. 
     The hologram device  2364  may show a stereoscopic image in the air by using interference of light. 
     The projector  2366  may project light onto a screen to display an image. For example, the screen may be located inside or outside the electronic device  2301 . 
     The display  2360  may further include a control circuit for controlling the panel  2362 , the hologram device  2364 , or the projector  2366 . 
     The interface  2370  includes an HDMI  2372 , a USB  2374 , an optical interface  2376 , and a D-subminiature (D-sub)  2378 . Additionally or alternatively, the interface  2370  may include a Mobile High-definition Link (MHL) interface, a Secure Digital (SD) card/Multi-Media Card (MMC) interface, or an Infrared Data Association (IrDA) standard interface. 
     The audio module  2380  may bilaterally convert a sound and an electrical signal. The audio module  2380  may process sound information input or output through, e.g., a speaker  2382 , a receiver  2384 , earphones  2386 , and the microphone  2388 . 
     The camera module  2391  is a device that may photograph a still image and a dynamic image. The camera module  291  may include one or more image sensors (e.g., a front sensor or a back sensor), a lens, an Image Signal Processor (ISP) or a flash (for example, LED or xenon lamp). 
     The power management module  2395  may manage power of the electronic device  2301 . The power management module  2395  may include a Power Management Integrated Circuit (PMIC), a charger IC, or a battery gauge. The PMIC may have a wired and/or wireless charging scheme. Examples of the wireless charging method may include a magnetic resonance method, a magnetic induction method, an electromagnetic method, etc. Additional circuits (e.g., a coil loop, a resonance circuit, a rectifier, etc.) for wireless charging may be further included. The battery gauge may measure the remaining amount of battery  2396 , a charging voltage and current, or temperature. The battery  2396  may include a rechargeable battery and/or a solar battery. 
     The indicator  2397  may indicate particular status of the electronic device  2301  or a part thereof (e.g., the AP  2310 ), such as a booting status, a message status, a charging status, etc. 
     The motor  2398  may convert an electrical signal into mechanical vibrations, and may generate a vibration or haptic effect. Although not illustrated, the electronic device  2301  may include a processing device (for example, a GPU) for supporting mobile TV. The processing device for supporting mobile TV may process media data according to a standard of Digital Multimedia Broadcasting (DMB), Digital Video Broadcasting (DVB), media flow, etc. 
     Each of the elements of the electronic device according to the present disclosure may be implemented by one or more elements and the name of the corresponding element may vary depending on a type of the electronic device. In various embodiments, the electronic device may include at least one of the above-described elements. Some of the above-described elements may be omitted from the electronic device, or the electronic device may further include additional elements. Further, some of the elements of the electronic device according to the various embodiments of the present disclosure may be combined to form a single entity, and thus, may equivalently execute functions of the corresponding elements prior to the combination. 
     The term “module” as used herein may, for example, mean a unit including one of hardware, software, and firmware or a combination of two or more of them. The “module” may be interchangeably used with, for example, the term “unit”, “logic”, “logical block”, “component”, or “circuit”. The “module” may be the smallest unit of an integrated component or a part thereof. The “module” may be the smallest unit that performs one or more functions or a part thereof. The “module” may be mechanically or electronically implemented. For example, the “module” according to the present disclosure may include at least one of an Application-Specific Integrated Circuit (ASIC) chip, a Field-Programmable Gate Arrays (FPGA), and a programmable-logic device for performing operations which has been known or are to be developed hereinafter. 
     According to various embodiments, at least some of the devices (for example, modules or functions thereof) or the method (for example, operations) according to the present disclosure may be implemented by a command stored in a computer-readable storage medium in a programming module form. When the command is executed by one or more processors (for example, the processor  120 ), the one or more processors may execute a function corresponding to the command. The computer-readable storage medium may be, for example, the memory  130 . 
     The computer readable recoding medium may include a hard disk, a floppy disk, magnetic media (e.g., a magnetic tape), optical media (e.g., a Compact Disc ROM (CD-ROM) and a DVD), magneto-optical media (e.g., a floptical disk), a hardware device (e.g., a ROM, a Random Access Memory (RAM), a flash memory), etc. 
     In addition, the program instructions may include high class language codes, which can be executed in a computer by using an interpreter, as well as machine codes made by a compiler. The aforementioned hardware device may be configured to operate as one or more software modules in order to perform the operation of the present invention, and vice versa. 
     The programming module according to the present disclosure may include one or more of the aforementioned elements or may further include other additional elements, or some of the aforementioned elements may be omitted. Operations executed by a module, a programming module, or other element elements according to various embodiments of the present disclosure may be executed sequentially, in parallel, repeatedly, or in a heuristic manner. Further, some operations may be executed according to another order or may be omitted, or other operations may be added. 
     According to various embodiments of the present disclosure, a storage medium having commands stored therein is provided. The commands are configured to allow one or more processors to perform one or more operations when being executed by the one or more processors. The one or more operations may include: displaying a first screen including a first object; detecting a screen switching event to switch the screen of the electronic device from the first screen to a second screen; and when the second screen does not include the first object, displaying at least a part of the first object on the second screen. 
     While the present disclosure has been particularly shown and described with reference to certain embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims and their equivalents.