The list below defines some of the basic terminology of the Android platform.
Android application package file. Each Android application is compiled and packaged in a single file that includes all of the application’s code (.dex files), resources, assets, and manifest file. The application package file can have any name but must use the. apk extension. For example: myExampleAppname. apk. For convenience, an application package file is often referred to as an “.apk”.
Compiled Android application code file.
Android programs are compiled into. dex (Dalvik Executable) 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.
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.
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.
Android Debug Bridge, a command-line debugging application included with the SDK. It provides tools to browse the device, copy tools on the device, and forward ports for debugging. If you are developing in Eclipse using the ADT Plugin, adb is integrated into your development environment. See Android Debug Bridge for more information.
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).
Related: .apk, Activity
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.
Related: Drawable, OpenGL ES.
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. See Content Providers topic for more information.
Related: URI Usage in Android
The Android platform’s virtual machine. The Dalvik VM is an interpreter-only virtual machine that executes files in the Dalvik Executable (.dex) format, a format that is optimized for efficient storage and memory-mappable execution. The virtual machine is register-based, and it can run classes compiled by a Java language compiler that have been transformed into its native format using the included “dx” tool.