Swipe to delete listitem

marcin picture marcin · May 31, 2012 · Viewed 17.9k times · Source

I would like to implement a swipe gesture to delete rows in a ListView similar to the android notifications.

Right now all I have is a ListView with an onTouchListener - that said, I already have swipe detection working.

gestureDetector = new GestureDetector(this, new GestureListener());
onTouchListener = new TouchListener();  
listview.setOnTouchListener(onTouchListener);  

My GestureListener class:

protected class GestureListener extends SimpleOnGestureListener
{
    private static final int SWIPE_MIN_DISTANCE = 150;
    private static final int SWIPE_MAX_OFF_PATH = 100;
    private static final int SWIPE_THRESHOLD_VELOCITY = 100;

    private MotionEvent mLastOnDownEvent = null;

    @Override
    public boolean onDown(MotionEvent e)
    {
        mLastOnDownEvent = e;
        return super.onDown(e);
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
    {
        if(e1 == null){
            e1 = mLastOnDownEvent;
        }
        if(e1==null || e2==null){
            return false;
        }

        float dX = e2.getX() - e1.getX();
        float dY = e1.getY() - e2.getY();

        if (Math.abs(dY) < SWIPE_MAX_OFF_PATH && Math.abs(velocityX) >= SWIPE_THRESHOLD_VELOCITY && Math.abs(dX) >= SWIPE_MIN_DISTANCE ) {
            if (dX > 0) {
                Toast.makeText(getApplicationContext(), "Right Swipe", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(getApplicationContext(), "Left Swipe", Toast.LENGTH_SHORT).show();
            }
            return true;
        }
        else if (Math.abs(dX) < SWIPE_MAX_OFF_PATH && Math.abs(velocityY)>=SWIPE_THRESHOLD_VELOCITY && Math.abs(dY)>=SWIPE_MIN_DISTANCE ) {
            if (dY>0) {
                Toast.makeText(getApplicationContext(), "Up Swipe", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(getApplicationContext(), "Down Swipe", Toast.LENGTH_SHORT).show();
            }
            return true;
        }
        return false;
    }
}

My TouchListener class:

protected class TouchListener implements View.OnTouchListener
{
    @Override
    public boolean onTouch(View v, MotionEvent e)
    {
        if (gestureDetector.onTouchEvent(e)){
            return true;
        }else{
            return false;
        }
    }
}

Are there some tutorials / examples on that?

thanks

Answer

wdziemia picture wdziemia · May 31, 2012

If you have your swipe detection working, all that is left is to delete the item. For that, the following code will delete the item off screen.

yourListViewAdapter.yourListItems.remove(position);
yourListViewAdapter.notifyDataSetChanged();