調用后動態壁紙其實是顯示在Activity的后面，而Activity則是透明顯示，這樣就可以看到下面的動態壁紙，如果Activity不是透明的則什么也看不到。
代碼中有用到兩個接口
IWallpaperService mService;
IWallpaperEngine mEngine;
我們可以看到該目錄下面有三個aidl接口，分別是
interface IWallpaperConnection {
void attachEngine(IWallpaperEngine engine);
ParcelFileDescriptor setWallpaper(String name);
}
oneway interface IWallpaperService {
void attach(IWallpaperConnection connection,
IBinder windowToken, int windowType, boolean isPreview,
int reqWidth, int reqHeight);
}
oneway interface IWallpaperEngine {
void setDesiredSize(int width, int height);
void setVisibility(boolean visible);
void dispatchPointer(in MotionEvent event);
void dispatchWallpaperCommand(String action, int x, int y, int z, in Bundle extras);
void destroy();
}
定義壁紙管理和壁紙信息變量
private WallpaperManager mWallpaperManager = null;
private WallpaperInfo mWallpaperInfo = null;
private WallpaperConnection mWallpaperConnection = null;
private Intent mWallpaperIntent;
初始化這些變量
mWallpaperManager = WallpaperManager.getInstance(this);
mWallpaperInfo = mWallpaperManager.getWallpaperInfo();//如果返回null則說明當前不是動態壁紙
mWallpaperIntent = new Intent(WallpaperService.SERVICE_INTERFACE);
mWallpaperIntent.setClassName(mWallpaperInfo.getPackageName(), mWallpaperInfo.getServiceName());
綁定動態壁紙服務
bindService(mIntent, this, Context.BIND_AUTO_CREATE);
IWallpaperService mService;//這里有一個adil接口
在連接監聽中試著attach
public void onServiceConnected(ComponentName name, IBinder service) {
mService = IWallpaperService.Stub.asInterface(service);
try {
mService.attach(this, view.getWindowToken(),
// WindowManager.LayoutParams.TYPE_APPLICATION_MEDIA_OVERLAY,
WindowManager.LayoutParams.TYPE_APPLICATION_MEDIA,
true, root.getWidth(), root.getHeight());
} catch (RemoteException e) {
Log.w("", "Failed attaching wallpaper; clearing", e);
}
}
在bindService的時候發現總是失敗，后來發現是權限問題，只有擁有系統權限的apk才可以使用WallpaperService.SERVICE_INTERFACE服務，所以問題就變成了怎么獲取系統權限。
