Gadgetbridge/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/SwipeEvents.java

/*  Copyright (C) 2020-2021 Petr Vaněk

    This file is part of Gadgetbridge.

    Gadgetbridge is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Gadgetbridge is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
package nodomain.freeyourgadget.gadgetbridge.util;

import android.content.Context;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;

//simple swipe detector based on GestureDetector, inspired by https://stackoverflow.com/a/19506010
public class SwipeEvents implements View.OnTouchListener {

    private final GestureDetector gestureDetector;

    public SwipeEvents(Context context) {
        gestureDetector = new GestureDetector(context, new GestureListener());
    }

    public void onSwipeLeft() {
    }

    public void onSwipeRight() {
    }

    public boolean onTouch(View v, MotionEvent event) {
        return gestureDetector.onTouchEvent(event);
    }
    private final class GestureListener extends GestureDetector.SimpleOnGestureListener {

        private static final int SWIPE_DISTANCE_THRESHOLD = 100;
        private static final int SWIPE_VELOCITY_THRESHOLD = 100;

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

        @Override
        public boolean onSingleTapConfirmed(MotionEvent e) {
            return false;
        }

        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            if (e1 == null || e2 == null){
                return false;
            }
            float distanceX = e2.getX() - e1.getX();
            float distanceY = e2.getY() - e1.getY();
            if (Math.abs(distanceX) > Math.abs(distanceY) && Math.abs(distanceX) > SWIPE_DISTANCE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                if (distanceX > 0)
                    onSwipeRight();
                else
                    onSwipeLeft();
                return true;
            }
            return false;
        }
    }
}