如何在Android上在主屏幕上拖动图像？

我开发了一个可以在Android手机的主屏幕上设置图像的服务。现在我想将该图像移动到设备屏幕上。我应该如何做到这一点？\n感谢您的答复。\n提前致谢。\n这是我的代码。\n

public class FeatureService extends Service
{
private WindowManager windowManager;
private ImageView dialerImage;
@Nullable
@Override
public IBinder onBind(Intent intent)
{
    return null;
}
@Override
public void onCreate()
{
    super.onCreate();
    windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
    dialerImage = new ImageView(this);
    dialerImage.setImageResource(R.drawable.dialer);
    final WindowManager.LayoutParams params = new WindowManager.LayoutParams(
            WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.TYPE_PHONE,
            WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
            PixelFormat.TRANSLUCENT);
    params.gravity = Gravity.TOP | Gravity.LEFT;
    params.x = 0;
    params.y = 100;
    windowManager.addView(dialerImage, params);
    dialerImage.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v)
        {
            Intent i= new Intent(getApplicationContext(), MainActivity.class);
            i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(i);
            return;
        }
    });
    dialerImage.setOnLongClickListener(new View.OnLongClickListener()
    {
        @Override
        public boolean onLongClick(View v)
        {
            dialerImage.setOnTouchListener(new View.OnTouchListener()
            {
                private int initialX;
                private int initialY;
                private float initialTouchX;
                private float initialTouchY;
                @Override
                public boolean onTouch(View v, MotionEvent event)
                {
                    switch (event.getAction())
                    {
                        case MotionEvent.ACTION_UP:
                        {
                            return false;
                        }
                        case MotionEvent.ACTION_DOWN:
                        {
                            initialX = params.x;
                            initialY = params.y;
                            initialTouchX = event.getRawX();
                            initialTouchY = event.getRawY();
                            return false;
                        }
                        case MotionEvent.ACTION_MOVE:
                        {
                            params.x = initialX + (int) (event.getRawX() - initialTouchX);
                            params.y = initialY + (int) (event.getRawY() - initialTouchY);
                            windowManager.updateViewLayout(dialerImage, params);
                            return false;
                        }
                    }
                    return true;
                }
            });
            return false;
        }
    });
}
@Override
public void onDestroy()
{
    super.onDestroy();
    if (dialerImage != null) windowManager.removeView(dialerImage);
}
}

\n现在我想在长按时移动我的图像，第一次点击图像时可以正常工作。但是一旦我移动图像第二次长按拖动就不起作用了。\n第二次开始，只需触摸图像即可移动，长按不起作用。