工具栏上的手势手势检测

Question

I'm wanting to detect someone dragging/flinging down from the toolbar, in a fashion similar to the Chrome, with the intention of closing the activity instead.

I however found that the gesture is not detected at all (I found this out due to onFling() never being called), however single/double taps are still detected detected.

Below is a snippets from the code that I used to test if it works:

@Override
protected void onCreate(Bundle savedInstanceState) {
    /*...*/
     Toolbar toolbar = (Toolbar) findViewById(R.id.wizard_toolbar);

    final GestureDetector toolbarGestureDetector = new GestureDetector(this, new GestureDetector.SimpleOnGestureListener () {
        static final int MIN_SWIPE_VELOCITY = 200;
        static final int MIN_SWIPE_DISTANCE = 200;

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

        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            Toast.makeText(EventCreationWizard.this, "You touched me!!!", Toast.LENGTH_LONG).show();
            return true;
        }

        @Override
        public boolean onDoubleTap(MotionEvent e) {
            Toast.makeText(EventCreationWizard.this, "You touched me!!! Twice!!!", Toast.LENGTH_LONG).show();
            return super.onDoubleTap(e);
        }

        @Override
        public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX, float velocityY) {
            if((event2.getY() - event2.getY() >= MIN_SWIPE_DISTANCE) && (Math.abs(velocityY) >= MIN_SWIPE_VELOCITY)) {
                Toast.makeText(EventCreationWizard.this, "You swiped me!!!", Toast.LENGTH_LONG).show();
                return true;
            }

            return false;
        }
    });
    toolbar.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent motionEvent) {
            return toolbarGestureDetector.onTouchEvent(motionEvent);
        }
    });
    setSupportActionBar(toolbar);
   /*...*/
}

Answer 1

In your onFling instead of flase return:

super.onFling(e1, e2, velocityX, velocityY);

And return true in setOnTouchListener

 toolbar.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        toolbarGestureDetector.onTouchEvent(motionEvent);
        return true;
    }
});

Answer 2

if((event2.getY() - event2.getY() >= MIN_SWIPE_DISTANCE) && (Math.abs(velocityY) >= MIN_SWIPE_VELOCITY)) {
            Toast.makeText(EventCreationWizard.this, "You swiped me!!!", Toast.LENGTH_LONG).show();
            return true;
        }

You're subtracting event2.getY() twice so it will never be more than MIN_SWIPE_DISTANCE.