Android: How to handle right to left swipe gestures

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日久生厌
日久生厌 2020-11-21 06:18

I want my app to recognize when a user swipes from right to left on the phone screen.

How to do this?

22条回答
  •  挽巷
    挽巷 (楼主)
    2020-11-21 07:00

    In order to have Click Listener, DoubleClick Listener, OnLongPress Listener, Swipe Left, Swipe Right, Swipe Up, Swipe Down on Single View you need to setOnTouchListener. i.e,

    view.setOnTouchListener(new OnSwipeTouchListener(MainActivity.this) {
    
                @Override
                public void onClick() {
                    super.onClick();
                    // your on click here
                }
    
                @Override
                public void onDoubleClick() {
                    super.onDoubleClick();
                    // your on onDoubleClick here
                }
    
                @Override
                public void onLongClick() {
                    super.onLongClick();
                    // your on onLongClick here
                }
    
                @Override
                public void onSwipeUp() {
                    super.onSwipeUp();
                    // your swipe up here
                }
    
                @Override
                public void onSwipeDown() {
                    super.onSwipeDown();
                    // your swipe down here.
                }
    
                @Override
                public void onSwipeLeft() {
                    super.onSwipeLeft();
                    // your swipe left here.
                }
    
                @Override
                public void onSwipeRight() {
                    super.onSwipeRight();
                    // your swipe right here.
                }
            });
    
    }
    

    For this you need OnSwipeTouchListener class that implements OnTouchListener.

    public class OnSwipeTouchListener implements View.OnTouchListener {
    
    private GestureDetector gestureDetector;
    
    public OnSwipeTouchListener(Context c) {
        gestureDetector = new GestureDetector(c, new GestureListener());
    }
    
    public boolean onTouch(final View view, final MotionEvent motionEvent) {
        return gestureDetector.onTouchEvent(motionEvent);
    }
    
    private final class GestureListener extends GestureDetector.SimpleOnGestureListener {
    
        private static final int SWIPE_THRESHOLD = 100;
        private static final int SWIPE_VELOCITY_THRESHOLD = 100;
    
        @Override
        public boolean onDown(MotionEvent e) {
            return true;
        }
    
        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            onClick();
            return super.onSingleTapUp(e);
        }
    
        @Override
        public boolean onDoubleTap(MotionEvent e) {
            onDoubleClick();
            return super.onDoubleTap(e);
        }
    
        @Override
        public void onLongPress(MotionEvent e) {
            onLongClick();
            super.onLongPress(e);
        }
    
        // Determines the fling velocity and then fires the appropriate swipe event accordingly
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            boolean result = false;
            try {
                float diffY = e2.getY() - e1.getY();
                float diffX = e2.getX() - e1.getX();
                if (Math.abs(diffX) > Math.abs(diffY)) {
                    if (Math.abs(diffX) > SWIPE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                        if (diffX > 0) {
                            onSwipeRight();
                        } else {
                            onSwipeLeft();
                        }
                    }
                } else {
                    if (Math.abs(diffY) > SWIPE_THRESHOLD && Math.abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
                        if (diffY > 0) {
                            onSwipeDown();
                        } else {
                            onSwipeUp();
                        }
                    }
                }
            } catch (Exception exception) {
                exception.printStackTrace();
            }
            return result;
        }
    }
    
    public void onSwipeRight() {
    }
    
    public void onSwipeLeft() {
    }
    
    public void onSwipeUp() {
    }
    
    public void onSwipeDown() {
    }
    
    public void onClick() {
    
    }
    
    public void onDoubleClick() {
    
    }
    
    public void onLongClick() {
    
    }
    }
    

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