[Android General] Diablo67:
Page:6 Android Terms,Slang & Definitions Continued...

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Screen size:Actual physical size, measured as the screen's diagonal.

For simplicity, Android groups all actual screen sizes into four generalized sizes: small, normal, large, and extra large.

Screen density

The quantity of pixels within a physical area of the screen; usually referred to as dpi (dots per inch). For example, a "low" density screen has fewer pixels within a given physical area, compared to a "normal" or "high" density screen.

For simplicity, Android groups all actual screen densities into four generalized densities: low, medium, high, and extra high.

Orientation:The orientation of the screen from the user's point of view. This is either landscape or portrait, meaning that the screen's aspect ratio is either wide or tall, respectively. Be aware that not only do different devices operate in different orientations by default, but the orientation can change at runtime when the user rotates the device.

Pixel Density:is a measurement of the resolution of devices in various contexts: typically computer displays, image scanners, and digital camera image sensors.

Density-Independent Pixel (dp):A virtual pixel unit that you should use when defining UI layout, to express layout dimensions or position in a density-independent way.

The density-independent pixel is equivalent to one physical pixel on a 160 dpi screen, which is the baseline density assumed by the system for a "medium" density screen. At runtime, the system transparently handles any scaling of the dp units, as necessary, based on the actual density of the screen in use. The conversion of dp units to screen pixels is simple: px = dp * (dpi / 160). For example, on a 240 dpi screen, 1 dp equals 1.5 physical pixels. You should always use dp units when defining your application's UI, to ensure proper display of your UI on screens with different densities.

Android Resolution:Android runs on a variety of devices that offer different screen sizes and densities. For applications, the Android system provides a consistent development environment across devices and handles most of the work to adjust each application's user interface to the screen on which it is displayed. At the same time, the system provides APIs that allow you to control your application's UI for specific screen sizes and densities, in order to optimize your UI design for different screen configurations. For example, you might want a UI for tablets that's different from the UI for handsets.

LDPI:Resources for low-density (ldpi) screens (~120dpi).

MDPI:Resources for medium-density (mdpi) screens (~160dpi).

HDPI:Resources for high-density (hdpi) screens (~240dpi).

XHDPI:Resources for extra high-density (xhdpi) screens (~320dpi).

NODPI:Resources for all densities. These are density-independent resources. The system does not scale resources tagged with this qualifier, regardless of the current screen's density.

TVDPI:Resources for screens somewhere between mdpi and hdpi; approximately 213dpi. This is not considered a "primary" density group. It is mostly intended for televisions and most apps shouldn't need it—providing mdpi and hdpi resources is sufficient for most apps and the system will scale them as appropriate. If you find it necessary to provide tvdpi resources, you should size them at a factor of 1.33*mdpi. For example, a 100px x 100px image for mdpi screens should be 133px x 133px for tvdpi.

Dex:Dalvik Executable. Compiled Android application code file. Android programs are compiled into .dex files, which are in turn zipped into a single .apk file on the device. .dex files can be created by automatically translating compiled applications written in the Java programming language.

Action:An action is a description of something that an Intent sender wants done. An action is a string value assigned to an Intent. Action strings can be defined by Android or by a third-party developer. For example, android.intent.action.VIEW for a Web URL, or com.example.rumbler.SHAKE_PHONE for a custom application to vibrate the phone.

Activity:An activity is a single screen in an application, with supporting Java code, derived from the Activity class. Most commonly, an activity is visibly represented by a full screen window that can receive and handle UI events and perform complex tasks, because of the Window it uses to render its window. Though an Activity is typically full screen, it can also be floating or transparent.

AndroidManifest.xml:Every application must have an AndroidManifest.xml file (with precisely that name) in its root directory of the source tree. The manifest presents essential information about the application to the Android system, information the system must have before it can run any of the application’s code.

Application:From a component perspective, an Android application consists of one or more activities, services, listeners, and intent receivers. From a source file perspective, an Android application consists of code, resources, assets, and a single manifest. During compilation, these files are packaged in a single file called an application package file (.apk).

Broadcast Receiver:An application class that listens for Intents that are broadcast, rather than being sent to a single target application/activity. The system delivers a broadcast Intent to all interested broadcast receivers, which handle the Intent sequentially.

Canvas:A drawing surface that handles compositing of the actual bits against a Bitmap or Surface object. It has methods for standard computer drawing of bitmaps, lines, circles, rectangles, text, and so on, and is bound to a Bitmap or Surface. Canvas is the simplest, easiest way to draw 2D objects on the screen. However, it does not support hardware acceleration, as OpenGL ES does. The base class is Canvas.

Content Provider:A data-abstraction layer that you can use to safely expose your application’s data to other applications. A content provider is built on the ContentProvider class, which handles content query strings of a specific format to return data in a specific format.

Cachesd:Moves Dalvik cache files to the ext2/ext3/ext4 partition on your secure digital card. Creates Dalvik Cache to SD flag.

Cachesdreset:Performs the same function as cachesd, plus erases the contents of Dalvik-Cache, forcing a rebuild on reboot.

Cachepart:Moves Dalvik cache files to the /cache partition in your phone. Creates Dalvik Cache to Cache Partition flag.

Cachepartreset:Performs the same function as cachepart, plus erases the contents of Dalvik-Cache, forcing a rebuild on reboot.

Convert-ext3:Converts an EXT2 partition to an EXT3 partition.

Note: Boot process will take longer due to the conversion.

Convert-ext4:Converts an EXT3 partition to an EXT4 partition.

Note:You must execute a2sd convert-ext3 first if you are trying to convert from EXT2 to EXT4. Boot process will take longer due to the conversion.

Data:The data partition on the device contains the user-related data, such as installed applications and settings for those apps, as well as your SQLite database containing Android settings and messages. Normally, the directory /data/app is off-limits through the ‘adb shell’ command, as well as other terminal applications that can run on the device, since this directory contains the apk files for apps. On a rooted phone, using the ‘su’ command will allow full access to this partition. This partition can be flashed using Fastboot or Nandroid.

DDMS:Dalvik Debug Monitor Service, a GUI debugging application included with the SDK. It provides screen capture, log dump, and process examination capabilities. If you are developing in Eclipse using the ADT Plugin, DDMS is integrated into your development environment.

Dialog:A floating window that that acts as a lightweight form. A dialog can have button controls only and is intended to perform a simple action (such as button choice) and perhaps return a value. A dialog is not intended to persist in the history stack, contain complex layout, or perform complex actions. Android provides a default simple dialog for you with optional buttons, though you can define your own dialog layout. The base class for dialogs is Dialog.

Drawable:A compiled visual resource that can be used as a background, title, or other part of the screen. A drawable is typically loaded into another UI element, for example as a background image. A drawable is not able to receive events, but does assign various other properties such as “state” and scheduling, to enable subclasses such as animation objects or image libraries. Many drawable objects are loaded from drawable resource files — xml or bitmap files that describe the image. Drawable resources are compiled into subclasses of android.graphics.drawable.

Datasd:Moves /data/data to the SD card.

F2FS (Flash-Friendly File System) was created by Kim Jaegeuk at Samsung for the Linux operating system kernel. The motivation for it was to build a file system that from the start takes into account the characteristics of NAND flash memory-based storage devices, which have been widely used in computer systems ranging from mobile devices to servers. Samsung chose a log-structured file system approach, which it adapted to newer forms of storage. F2FS also remedies some known issues of the older log structured file systems, such as the snowball effect of wandering trees and high cleaning overhead. Because a NAND-based storage device shows different characteristics according to its internal geometry or flash memory management scheme (such as the Flash Translation Layer), Samsung also added various parameters not only for configuring on-disk layout, but also for selecting allocation and cleaning algorithms. Introduced in the second half of 2012 this new file system shows promise but is not yet generally available in any Kernels that I have seen. Samsung has submitted these patches for integration into the Linux kernel, which means it’s likely to appear on Android releases in the future.

Flash Memory:Flash memory, also known as NAND memory, is nonvolatile – keeping information even when the device is off. Flash memory in the device is equivalent to the hard drive in a computer. This is where the device’s operating system (sometimes called firmware) and applications are stored. Flash memory is slower than RAM, but is (almost always) faster than SD cards.

Fixapk:Fixes permissions on programs.

Forcecheck:Forces Darktremor Apps2SD to force check the EXT partition on the SD card when phone is rebooted.

Heapsizexx:Sets Dalvik Heap Size to xx, or heapsize0 resets heap size to default settings.

Logcat:While in adb (see ADB), type in “adb logcat > logcat.txt”. This will help you when resolving issues and bugs. There are also tools in the market you can use for this, one of which is called aLogcat. It can show different categories (severity of errors ect.) too, which is something adb logcat cannot do.

Playstore(Old:Market):The market on Android is a place where you can purchase or download applications for your phone. When you download through the market, the installation process is transparent (as in you don’t have to deal with the APK files yourself), and there is the facility to rate apps and post comments which are visible to other users. Frequently, the developers of apps actually take onboard the feedback in the comments (mainly the smaller apps with slightly less feedback to sift through).

When an app is installed from the market, it is copied to ‘/data/app/apkname.apk’, as the act of ‘installing’. An app can store its data in the folder ‘/data/data/apkname’. It is possible to clear the data stored by an application by using the Manage Applications feature in Settings | Applications | Manage Applications.

Intent:A message object that you can use to launch or communicate with other applications/activities asynchronously. An Intent object is an instance of Intent. It includes several criteria fields that you can supply, to determine what application/activity receives the Intent and what the receiver does when handling the Intent. Available criteria include the desired action, a category, a data string, the MIME type of the data, a handling class, and others. An application sends an Intent to the Android system, rather than sending it directly to another application/activity. The application can send the Intent to a single target application or it can send it as a broadcast, which can in turn be handled by multiple applications sequentially. The Android system is responsible for resolving the best-available receiver for each Intent, based on the criteria supplied in the Intent and the Intent Filters defined by other applications.

Intent Filter:A message object that you can use to launch or communicate with other applications/activities asynchronously. An Intent object is an instance of Intent. It includes several criteria fields that you can supply, to determine what application/activity receives the Intent and what the receiver does when handling the Intent. Available criteria include the desired action, a category, a data string, the MIME type of the data, a handling class, and others. An application sends an Intent to the Android system, rather than sending it directly to another application/activity. The application can send the Intent to a single target application or it can send it as a broadcast, which can in turn be handled by multiple applications sequentially. The Android system is responsible for resolving the best-available receiver for each Intent, based on the criteria supplied in the Intent and the Intent Filters defined by other applications.

Layout Resource:An XML file that describes the layout of an Activity screen.

Lowmem-Moderate:Sets the internal memory killer to the following

settings:

Foreground Apps: 1536 pages / 6 MB

Visible Apps: 3072 pages / 12 MB

Secondary Server: 4096 pages / 16 MB

Hidden Apps: 7680 pages / 30 MB

Content Provider: 8960 pages / 35 MB

Empty App: 10240 pages / 40 MB

Lowmem-Optimum:Sets the internal memory killer to the following

settings:

Foreground Apps: 1536 pages / 6 MB

Visible Apps: 2048 pages / 8 MB

Secondary Server: 4096 pages / 16 MB

Hidden Apps: 10240 pages / 40 MB

Content Provider: 12800 pages / 50 MB

Empty App: 15360 pages / 60 MB

Lowmem-Strict:Sets the internal memory killer to the following

settings:

Foreground Apps: 1536 pages / 6 MB

Visible Apps: 2048 pages / 8 MB

Secondary Server: 4096 pages / 16 MB

Hidden Apps: 15360 pages / 60 MB

Content Provider: 17920 pages / 70 MB

Empty App: 20480 pages / 80 MB

Lowmem-Aggressive:Sets the internal memory killer to the following

settings:

Foreground Apps: 1536 pages / 6 MB

Visible Apps: 3072 pages / 12 MB

Secondary Server: 4096 pages / 16 MB

Hidden Apps: 21000 pages / 82 MB

Content Provider: 23000 pages / 90 MB

Empty App: 25000 pages / 98 MB

Lowmem-Extreme: Sets the internal memory killer to the following

settings:

Foreground Apps: 1536 pages / 6 MB

Visible Apps: 3072 pages / 12 MB

Secondary Server: 4096 pages / 16 MB

Hidden Apps: 38400 pages / 150 MB

Content Provider: 40960 pages / 160 MB

Empty App: 43520 pages / 170 MB

Lowmem-Ultimate:Sets the internal memory killer to the following

settings:

Foreground Apps: 1536 pages / 6 MB

Visible Apps: 3072 pages / 12 MB

Secondary Server: 4096 pages / 16 MB

Hidden Apps: 51200 pages / 200 MB

Content Provider: 57600 pages / 225 MB

Empty App: 64000 pages / 250 MB

Lowmem-Default:Sets the internal memory killer back to phone default settings.

Manifest File:An XML file that each application must define, to describe the application’s package name, version, components (activities, intent filters, services), imported libraries, and describes the various activities, and so on.

Nocache:Moves Dalvik cache files to the internal phone storage. Removes all Dalvik Cache flags.

Nocachereset:Performs the same function as nocache, plus erases the contents of Dalvik-Cache, forcing a rebuild on reboot.

Nodata:Restores /data/data to the internal storage.

Noswap: Creates the No Swap flag. Prevents A2SD from activating the swap partition.

9-Patch:A resizeable bitmap resource that can be used for backgrounds or other images on the device.

Odex:Odex stands for “Optimized Dalvik Executable” file. The Android system, as identified above, utilizes compressed data stored in the .apk file at runtime. To speed up this process, the most critical elements of application will be placed uncompressed in an .odex file, thus enabling the Android OS to quickly interpret that important information before it continues to parse the rest of the application. Stock ROMs will come from the manufacturer as “odexed”, meaning that the application(s) will have a .apk file and an .odex file, i.e. Calendar.apk and Calendar.odex.

ROW Scheduler:The ROW scheduling algorithm will be used in mobile devices as default

+block layer IO scheduling algorithm. ROW stands for "READ Over WRITE"

+which is the main requests dispatch policy of this algorithm.

Resources:Nonprogrammatic application components that are external to the compiled application code, but which can be loaded from application code using a well-known reference format. Android supports a variety of resource types, but a typical application’s resources would consist of UI strings, UI layout components, graphics or other media files, and so on. An application uses resources to efficiently support localization and varied device profiles and states. For example, an application would include a separate set of resources for each supported local or device type, and it could include layout resources that are specific to the current screen orientation (landscape or portrait). The resources of an application are always stored in the res/* subfolders of the project.

Resetcache:Clears the dalvik cache and restarts phone.

Reswap: Removes the No Swap flag. Allows A2SD to activate the swap partition.This is used if you have already executed an a2sd noswap command. Otherwise, this part is automatically performed when Apps2SD is started.

Service:An object of class Service that runs in the background (without any UI presence) to perform various persistent actions, such as playing music or monitoring network activity.

SPL:The Secondary Program Loader is a piece of bootcode that initiates the startup of the phone, displaying the initial splash screen for the device, and loading the initial files from ROM.

It checks to see if a button combination is pressed on bootup (such as that to enter Recovery Mode or the bootloader), and loads the relevant system software. If no special instruction is given by holding keys, the bootloader loads the normal system software by initializing the boot process from the boot partition.

Flashing your SPL is risky, as the process failing will probably result in a broken, or bricked phone, since the SPL is executed very early on in the boot process, and any error here will prevent access to the recovery or bootloader features.

If you do flash the SPL though, it unlocks the Carrier-ID CID from the device, essentially allowing any RUU to be installed to the device, and allows flashing alternative or custom bootscreens.

Surface:An object of type Surface representing a block of memory that gets composited to the screen. A Surface holds a Canvas object for drawing, and provides various helper methods to draw layers and resize the surface. You should not use this class directly; use SurfaceView instead.

SurfaceView:A View object that wraps a Surface for drawing, and exposes methods to specify its size and format dynamically. A SurfaceView provides a way to draw independently of the UI thread for resource-intensive operations (such as games or camera previews), but it uses extra memory as a result. SurfaceView supports both Canvas and OpenGL ES graphics. The base class is SurfaceView.

System:The /system directory on your device is where the main operational software for the Android OS is stored. It has a number of sub-directories of which /system/apps (where application apk’s are stored) is probably the only one users would have need to access. The /system folder is read-only by default and needs remounted via ‘adb’ to allow write access.

Swappyxx:Sets swap partition swappiness value to xx.

Theme:A set of properties (text size, background color, and so on) bundled together to define various default display settings. Android provides a few standard themes, listed in R.style (starting with “Theme_”).

Update.zip:An update.zip (does not have to actually be called update.zip if you have a patched Recovery image) is a file containing some files which will be copied to the phone’s internal memory. Normally, a new system update or ROM is stored in the file, but update.zip files are commonly used to install modifications such as themes or applications that are installed on the System partition to prevent uninstallation.

To flash one of these files, which commonly would contain a custom ROM for your phone, you would boot your phone to a patched recovery image (whether using Fastboot, or the home+power method if you have a patched Recovery image flashed on your phone)

Update.zip files are cryptographically signed, and more information on how to sign your own files can be found online.

URI's:Android uses URI strings as the basis for requesting data in a content provider (such as to retrieve a list of contacts) and for requesting actions in an Intent (such as opening a Web page in a browser). The URI scheme and format is specialized according to the type of use, and an application can handle specific URI schemes and strings in any way it wants. Some URI schemes are reserved by system components. For example, requests for data from a content provider must use the content://. In an Intent, a URI using an http:// scheme will be handled by the browser.

View:An object that draws to a rectangular area on the screen and handles click, keystroke, and other interaction events. A View is a base class for most layout components of an Activity or Dialog screen (text boxes, windows, and so on). It receives calls from its parent object (see viewgroup, below)to draw itself, and informs its parent object about where and how big it would like to be (which may or may not be respected by the parent).

ViewGroup:A container object that groups a set of child Views. The viewgroup is responsible for deciding where child views are positioned and how large they can be, as well as for calling each to draw itself when appropriate. Some viewgroups are invisible and are for layout only, while others have an intrinsic UI (for instance, a scrolling list box). Viewgroups are all in the widget package, but extend ViewGroup.

Widget:One of a set of fully implemented View subclasses that render form elements and other UI components, such as a text box or popup menu. Because a widget is fully implemented, it handles measuring and drawing itself and responding to screen events. Widgets are all in the android.widget package.

Window:In an Android application, an object derived from the abstract class Window that specifies the elements of a generic window, such as the look and feel (title bar text, location and content of menus, and so on). Dialog and Activity use an implementation of this class to render a window. You do not need to implement this class or use windows in your application.

glibc: (GNU C Library)Any Unix-like operating system needs a C library: the library which defines the ``system calls'' and other basic facilities such as open, malloc, printf, exit...

The GNU C Library is used as the C library in the GNU systems and most systems with the Linux kernel.

Libhybris:a way to load Android libraries while overriding some Bionic symbols with those symbols from glibc.

Bloatware:Software or 'apps' that you don't need, but come preinstalled to a device's /system partition, meaning that you cannot remove them unless the device has been rooted. Usually, these are apps are sponsored by a company and included by a carrier for profit. For example, the Photobucket app included on the G2 by TMobile.

Compile:It translates (a android program)from a high-level language into another language, usually machine language.

Decompile:To convert executable (ready-to-run) program code (sometimes called object code ) into some form of higher-level programming language so that it can be read by a human.

Deodex:Deodexing is basically repackaging of these APKs in a certain way, such that they are reassembled into classes.dex files. By doing that, all pieces of an application package are put together back in one place, thus eliminating the worry of a modified APK conflicting with some separate odexed parts.

GNU:A recursive acronym for “GNU's Not Unix!”; it is pronounced g-noo, as one syllable with no vowel sound between the g and the n. The GNU Project was launched in 1984 to develop a complete Unix-like operating system which is free software: the GNU system. “Free software” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech”, not as in “free beer”.

API:An application programming interface (API) is a specification intended to be used as an interface by software components to communicate with each other. An API may include specifications for routines, data structures, object classes, and variables. An API specification can take many forms, including an International Standard such as POSIX, vendor documentation such as the Microsoft Windows API, the libraries of a programming language, e.g. Standard Template Library in C++ or Java API.

An API differs from an application binary interface (ABI) in that an API is source code based while an ABI is a binary interface. For instance POSIX is an API, while the Linux Standard Base is an ABI.

Odex:In Android file system, applications come in packages with the extension .apk. These application packages, or APKs contain certain .odex files whose supposed function is to save space. These ‘odex’ files are actually collections of parts of an application that are optimized before booting. Doing so speeds up the boot process, as it preloads part of an application. On the other hand, it also makes hacking those applications difficult because a part of the coding has already been extracted to another location before execution.

Open Source:Open-source refers to software with publicly available source code. In the context of Android, Open-source refers to the approach to the design, development, and distribution of software. This offers accessibility to a software's source code for modification, improvement, bug-fixing, and security-enhancement. CyanogenMod is based on this principle.

Port:To Take a rom or app from one phone and program it to work on a different one.

Swap:Swap is, in short, virtual RAM. With swap, a small portion of the hard drive is set aside and used like RAM. The computer will attempt to keep as much information as possible in RAM until the RAM is full. At that point, the computer will begin moving inactive blocks of memory (called pages) to the hard disk, freeing up RAM for active processes. If one of the pages on the hard disk needs to be accessed again, it will be moved back into RAM, and a different inactive page in RAM will be moved onto the hard disk ('swapped'). The trade off is disks and SD cards are considerably slower than physical RAM, so when something needs to be swapped, there is a noticeable performance hit.

Unlike traditional swap, Android's Memory Manager kills inactive processes to free up memory. Android signals to the process, then the process will usually write out a small bit of specific information about its state (for example, Google Maps may write out the map view coordinates; Browser might write the URL of the page being viewed) and then the process exits. When you next access that application, it is restarted: the application is loaded from storage, and retrieves the state information that it saved when it last closed. In some applications, this makes it seem as if the application never closed at all. This is not much different from traditional swap, except that Android apps are specially programed to write out very specific information, making Android's Memory Manager more efficient that swap.

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