在“重置墙纸”按钮上，应重置为手机的默认墙纸

Question

我创建了一个具有两个按钮的Android应用程序，分别设置墙纸和重置墙纸。在设置的WallPaper上，我在drawable文件夹中有图像，这些图像被设置为墙纸，并在一定间隔内使用WallpaperManger和服务来实现。一切正常。在单击“重置壁纸”后，我需要重置为手机的默认壁纸。在按钮上，单击“我叫stopService”以停止设置墙纸的服务。它调用destroy方法并重置墙纸，但过一会儿服务触发设置墙纸。请指导我解决此问题。

MainActivity

 @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        setWallpaperBtn = (Button)findViewById(R.id.setWallpaper);
        resetWallpaperBtn = (Button)findViewById(R.id.resetWallpaper);

        //on click of set wallpaper button
        setWallpaperBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent intent = new Intent(MainActivity.this,WallPaperService.class);
                startService(intent);
            }
        });


 WallPaperService extends Service

   @Override
    public void onCreate() {
        super.onCreate();
        myTimer=new Timer();
        myWallpaperManager =    WallpaperManager.getInstance(WallPaperService.this);
     }

 @Override
    public int onStartCommand(Intent intent, int flags, int startId){
        myTimertask = new TimerTask() {
            // Bitmap bitmap =BitmapFactory.decodeResource(getResources(),R.drawable.two);
            @Override
            public void run() {
                if (prev == 1) {
                    BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inJustDecodeBounds=true;
                    BitmapFactory.decodeResource(getResources(),R.drawable.two,options);
                    options.inSampleSize=2;
                    options.inJustDecodeBounds=false;
                    bitmap=  BitmapFactory.decodeResource(getResources(),R.drawable.two,options);
                    prev = 2;
}continues for other images...
try {
                    myWallpaperManager.setBitmap(bitmap);
                                   } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        };
        myTimer.schedule(myTimertask,interval,startInterval);
        return super.onStartCommand(intent,flags,startId);
    }


 @Override
    public void onDestroy(){
        try {
            myWallpaperManager.clear();
        } catch (IOException e) {
            e.printStackTrace();
        }
        Toast.makeText(this,"invoke destroy",Toast.LENGTH_LONG).show();
    }