android - 如何让 GestureDetector 正常工作

Question

到目前为止，我的 Activity 中有这段代码:

private class SwipeGestureDetector extends SimpleOnGestureListener {
    // Swipe properties, you can change it to make the swipe 
    // longer or shorter and speed
    private static final int SWIPE_MIN_DISTANCE = 120;
    private static final int SWIPE_MAX_OFF_PATH = 200;
    private static final int SWIPE_THRESHOLD_VELOCITY = 200;

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
      try {
        float diffAbs = Math.abs(e1.getY() - e2.getY());
        float diff = e1.getX() - e2.getX();
        Log.d("MainDisplayActivity", "Gesture class is running");
        if (diffAbs > SWIPE_MAX_OFF_PATH)
          return false;

        // Left swipe
        if (diff > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
           MainDisplayActivity.this.onLeftSwipe();

        // Right swipe
        } else if (-diff > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
          MainDisplayActivity.this.onRightSwipe();

        }

      } catch (Exception e) {
        Log.e("YourActivity", "Error on gestures");

      }
      return false;
    }

  }//end of SwipeGestureDetector class

  //methods called by SwipeGestureDetector when the approrpiate swipes occured
  private void onLeftSwipe() {
        Toast.makeText(this, "Successfully have the swipe working for left", Toast.LENGTH_SHORT).show();
  }

  private void onRightSwipe() {
      Toast.makeText(this, "Successfully have the swipe working for right", Toast.LENGTH_SHORT).show();
  }

我有这个全局的:private GestureDetector gestureDetector;

在 onCreate 上我有这个，因为我看到人们这样做:

gestureDetector = new GestureDetector(this, new SwipeGestureDetector());
    ((LinearLayout)findViewById(R.id.parent_main_display)).setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            return gestureDetector.onTouchEvent(event);
        }
    });

不太确定自己做错了什么，但滑动时没有任何反应。有什么想法吗？

Answer 1

你应该覆盖下一个

@Override
 public boolean onDown(MotionEvent e) {
  return true;
 }

 @Override
 public boolean onSingleTapUp(MotionEvent e) {
  return true;
 }

onFling 也应该返回 true