Starting with Android 2.1 (API Level 7), users can now enjoy live +wallpapers — richer, animated, interactive backgrounds — on +their home screens. A live wallpaper is very similar to a normal Android +application and has access to all the facilities of the platform: SGL (2D +drawing), OpenGL (3D drawing), GPS, accelerometers, network access, etc. The +live wallpapers included on Nexus One demonstrate the use of some of these APIs +to create fun and interesting user experiences. For instance, the Grass +wallpaper uses the phone's location to compute sunrise and sunset times in order +to display the appropriate sky.
+ +
+
+Creating your own live wallpaper is easy, especially if you have had
+previous experience with SurfaceView or Canvas.
+To learn how to create a live wallpaper, you should check out the CubeLiveWallpaper sample code.
In terms of implementation, a live wallpaper is very similar to a regular
+Android service. The
+only difference is the addition of a new method, onCreateEngine(), whose goal is to create a
+WallpaperService.Engine. The engine is responsible for
+handling the lifecycle and drawing of a wallpaper. The system provides a surface
+on which you can draw, just like you would with a SurfaceView.
+Drawing a wallpaper can be very expensive so you should optimize your code
+as much as possible to avoid using too much CPU, not only for battery life
+but also to avoid slowing down the rest of the system. That is also why the
+most important part of the lifecycle of a wallpaper is when it becomes invisible.
+When invisible, such as when the user launches an application that covers
+the home screen, a wallpaper must stop all activity.
The engine can also implement several methods to interact with the user
+or the home application. For instance, if you want your wallpaper to scroll
+along when the user swipes from one home screen to another, you can use onOffsetsChanged().
+To react to touch events, simply implement onTouchEvent(MotionEvent).
+Finally, applications can send arbitrary commands to the live wallpaper.
+Currently, only the standard home application sends commands to the onCommand()
+method of the live wallpaper:
-
+
android.wallpaper.tap: When the user taps an empty space +on the workspace. This command is interpreted by the Nexus and Water live +wallpapers to make the wallpaper react to user interaction. For instance, +if you tap an empty space on the Water live wallpaper, new ripples appear +under your finger.
+android.home.drop: When the user drops an icon or a widget +on the workspace. This command is also interpreted by the Nexus and Water +live wallpapers.
+
If you are developing a live wallpaper, remember that the feature is +supported only on Android 2.1 (API level 7) and higher versions of the platform. +To ensure that your application can only be installed on devices that support +live wallpapers, remember to add the following to the application's manifest +before publishing to Android Market:
+ +-
+
<uses-sdk android:minSdkVersion="7" />, which indicates +to Android Market and the platform that your application requires Android 2.1 or +higher. For more information, see the API +Levels and the documentation for the +<uses-sdk>+element.
+<uses-feature android:name="android.software.live_wallpaper" />, +which tells Android Market that your application includes a live wallpaper +Android Market uses this feature as a filter, when presenting users lists of +available applications. When you declaring this feature, Android Market +displays your application only to users whose devices support live wallpapers, +while hiding it from other devices on which it would not be able to run. For +more information, see the documentation for the +<uses-feature>+element.
+
Many great live wallpapers are already available on Android Market and +we can't wait to see more!
diff --git a/docs/html/resources/resources_toc.cs b/docs/html/resources/resources_toc.cs index e337e385b9a42..097202924d35f 100644 --- a/docs/html/resources/resources_toc.cs +++ b/docs/html/resources/resources_toc.cs @@ -83,6 +83,9 @@