android - 如何处理 ImageView 上的向下滑动手势

Question

我正在尝试识别图像视图上的向下滑动手势。我试过GestureDetector了，但现在不推荐使用了。我正在使用的示例代码如下。但是，它不会进入 onFling() 方法。

GestureDetector gestureDetector;
gestureDetector = new GestureDetector(new GestureListener());

        view.findViewById(R.id.imageView).setOnTouchListener(new OnTouchListener() {
            public boolean onTouch(View v, MotionEvent event) {
                if (gestureDetector.onTouchEvent(event)) {
                    System.out.println("DONE-------");
                    updateSwipeAction();
                    return true;
               }
                return false;
            }
        });

class GestureListener extends SimpleOnGestureListener {

        private static final int SWIPE_MIN_DISTANCE = 10;
        private static final int SWIPE_THRESHOLD_VELOCITY = 10;

        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE) {
                //From Right to Left
                return true;
            } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE) {
                //From Left to Right
                return true;
            }

            if (e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE) {
                //From Bottom to Top
                return true;
            } else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE) {
                //From Top to Bottom
                return true;
            }
            return false;
        }

        @Override
        public boolean onDown(MotionEvent e) {
            //always return true since all gestures always begin with onDown and<br>
            //if this returns false, the framework won't try to pick up onFling for example.
            return true;
        }
    }

Answer 1

试试这个，实现 ongestureListener 并且有一个 onscroll 方法你可以直接访问

@SuppressLint("NewApi")

public class AndroidExplorer extends Activity implements    
     android.view.GestureDetector.OnGestureListener

    {
    private Handler mHandler = new Handler();
    @Override
    protected void onCreate(Bundle mybundle) 
    {
    // TODO Auto-generated method stub  
    super.onCreate(mybundle);
    setContentView(R.layout.main);
    }
    @Override
    public boolean onDown(MotionEvent e) {
        // TODO Auto-generated method stub
        return false;
    }
    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
            float velocityY) {
        // TODO Auto-generated method stub
        return false;
    }
    @Override
    public void onLongPress(MotionEvent e) {
        // TODO Auto-generated method stub

    }
    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
            float distanceY) {
        // TODO Auto-generated method stub
        return false;
    }
    @Override
    public void onShowPress(MotionEvent e) {
        // TODO Auto-generated method stub

    }
    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        // TODO Auto-generated method stub
        return false;
    }




}