從可繪制對象設置背景牆紙

Question

在我的應用中，我需要獲取設備的當前牆紙：

Wallpaper = WallpaperManager.getInstance(getApplicationContext()).peekDrawable();

不，問題在於此操作將導致UI在獲取背景時稍有滯后，此外，我需要將其設置為應用程序的背景，我已經嘗試過：

//Drawable Wallpaper defined already...

  new Thread(new Runnable() {
    public void run() {
      Wallpaper = WallpaperManager.getInstance(getApplicationContext()).peekDrawable();
    }
  }).start();
     if (Wallpaper == null)
       {                       
         //Resources res = getResources();
         //Drawable drawable1 = res.getDrawable(R.drawable.bg1);
         //getWindow().setBackgroundDrawable(drawable1);
     }
      else
        {
          Wallpaper.setAlpha(50);
          getWindow().setBackgroundDrawable(Wallpaper);
 }
      //........

但這沒用，有什么主意嗎？ 如果可能的話，請提供代碼，我還是android的新手。此外，還有更好的方法嗎？

Answer 1

請嘗試以下操作，看看是否有幫助。 我已注釋了代碼以供您擴展（如果需要）。

private class SetWallpaperTask extends AsyncTask<Void, Void, Void> {

  Drawable wallpaperDrawable;

  @Override
  protected void onPreExecute() {
    // Runs on the UI thread
    // Do any pre-executing tasks here, for example display a progress bar
    Log.d(TAG, "About to set wallpaper...");
  }

  @Override
  protected Void doInBackground(Void... params) {
    // Runs on the background thread
    WallpaperManager wallpaperManager = WallpaperManager.getInstance
      (getApplicationContext());
    wallpaperDrawable = wallpaperManager.getDrawable();
  }

  @Override
  protected void onPostExecute(Void res) {
    // Runs on the UI thread
    // Here you can perform any post-execute tasks, for example remove the
    // progress bar (if you set one).
    if (wallpaperDrawable != null) {
      wallpaperDrawable.setAlpha(50);
      getWindow().setBackgroundDrawable(wallpaperDrawable);
      Log.d(TAG, "New wallpaper set");
    } else {
      Log.d(TAG, "Wallpaper was null");
    }
  }

}

並執行此（后台）任務：

SetWallpaperTask t = new SetWallpaperTask();
t.execute();

如果仍然遇到問題，建議您遍歷SetWallpaperActivity.java示例並嘗試復制該示例。