Android Open Source - texting Swipe Gesture Listener

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License

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Free to use, distribute, do anything.

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Java Source Code

package com.skk.texting.gesture;
/*from w ww .j  a v  a2 s  . co m*/
import android.view.GestureDetector;
import android.view.MotionEvent;
import com.skk.texting.constants.ApplicationConstants;

public class SwipeGestureListener extends GestureDetector.SimpleOnGestureListener {
    private static final float THRESHOLD_DISTANCE = 100;
    private SwipeGestureHandler handler;
    protected MotionEvent lastDownEvent = null;

    public SwipeGestureListener(SwipeGestureHandler handler) {
        this.handler = handler;
    }

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

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        //Determining left or right is more important for this application as up and down are anyways ignored
        e1 = (e1 == null)? lastDownEvent : e1;
        e1 = (e1 == null)? MotionEventRecorder.replayEvent(ApplicationConstants.RECORDED_START_SWIPE) : e1;

        Direction swipeDirection = horizontalDirection(e1, e2);
        swipeDirection = swipeDirection.equals(Direction.None) ? verticalDirection(e1, e2) : swipeDirection;

        switch (swipeDirection){
            case Right:
                return handler.onSwipeRight();
            case Left:
                return handler.onSwipeLeft();
            case Up:
                return handler.onSwipeUp();
            case Down:
                return handler.onSwipeDown();
        }
        return false;
    }

    private Direction horizontalDirection(MotionEvent start, MotionEvent end) {
        float displacementX = end.getX() - start.getX();
        Direction direction = (displacementX > 0) ? Direction.Right : Direction.Left;
        return Math.abs(displacementX) >= THRESHOLD_DISTANCE ? direction : Direction.None;
    }

    private Direction verticalDirection(MotionEvent start, MotionEvent end) {
        float displacementY = end.getY() - start.getY();
        Direction direction = (displacementY > 0) ? Direction.Down : Direction.Up;
        return Math.abs(displacementY) >= THRESHOLD_DISTANCE ? direction : Direction.None;
    }

}

enum Direction{
    Right, Left, Up, Down, None
}

Java Source Code List