android 还原手机默认桌面

增加权限

 <uses-permission android:name="android.permission.SET_WALLPAPER" />

@Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  mbutton = (Button) findViewById(R.id.button1);
  mbutton.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View arg0) {
   try {
    clearWallpaper();
   } catch (IOException e) {
    e.printStackTrace();
   }
   }
  });
 }
 @Override
 public void clearWallpaper() throws IOException {
  super.clearWallpaper();
 }

如果把自定义的图片变成背景可以通过

Bitmap bp = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
    setWallpaper(bp);