Android: Measure/detect covered area by a finger touch on screen (NOT only touch coordinates)

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囚心锁ツ
囚心锁ツ 2020-12-17 18:37

I would like to get access to the area covered by a finger for each touch event on an Android.

Every touch event will result in a coordinate pair X and Y independent

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  •  北荒
    北荒 (楼主)
    2020-12-17 19:24

    You need to implement OnGestureListener.

    First of all, you need to register GestureDetector in onTouchEvent

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        mGestureDetector.onTouchEvent(event);
        return true;
    }
    

    In onShowPress you will get starting points

    @Override
    public void onShowPress(MotionEvent e) {
        startX = e.getX();
        startY = e.getY();
    }
    

    In onScroll you will get the end points.

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
            float distanceY) {
                endX = e2.getX();
                endY = e2.getY();
    }
    

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