Anastasia Anastasia - 4 months ago 36
Android Question

How to distinguish between move and click in onTouchEvent()?

In my application, I need to handle both move and click events.

A click is a sequence of one ACTION_DOWN action, several ACTION_MOVE actions and one ACTION_UP action. In theory, if you get an ACTION_DOWN event and then an ACTION_UP event - it means that the user has just clicked your View.

But in practice, this sequence doesn't work on some devices. On my Samsung Galaxy Gio I get such sequences when just clicking my View: ACTION_DOWN, several times ACTION_MOVE, then ACTION_UP. I.e. I get some unexpectable OnTouchEvent firings with ACTION_MOVE action code. I never (or almost never) get sequence ACTION_DOWN -> ACTION_UP.

I also cannot use OnClickListener because it does not gives the position of the click. So how can I detect click event and differ it from move?

Answer

Here's another solution that is very simple and doesn't require you to worry about the finger being moved. If you are basing a click as simply the distance moved then how can you differentiate a click and a long click.

You could put more smarts into this and include the distance moved, but i'm yet to come across an instance when the distance a user can move in 200 milliseconds should constitute a move as opposed to a click.

setOnTouchListener(new OnTouchListener() {
    private static final int MAX_CLICK_DURATION = 200;
    private long startClickTime;

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN: {
                startClickTime = Calendar.getInstance().getTimeInMillis();
                break;
            }
            case MotionEvent.ACTION_UP: {
                long clickDuration = Calendar.getInstance().getTimeInMillis() - startClickTime;
                if(clickDuration < MAX_CLICK_DURATION) {
                    //click event has occurred
                }
            }
        }
        return true;
    }
});