Touch Listeners for overlapping Views

Question

I was wondering if it is possible to have Views sitting on top of each other and separate listeners for them. Specifically, I have two views that are exactly sitting on top of each other and are the exact same dimensions, and I'm trying to implement a motion event OnTouchListener for view_one and an OnLongPressListener for view_two. However, the OnTouchListener on view_one seems to block the OnLongClickListener for view_one.

The basic goal of the code is to have multiple touch interactions doing different things:

1. Short click does one thing
2. Long press does another
3. Touch drag and release in vertical direction does another thing
4. Touch-drag in horizontal another

Etc, as many different things as possible.

Maybe I should just have one View that is for touching rather than two, and there is a way to separate out the touches and motion events. I know how to separate short and long press events, but the motion event messes things up.

I'm sure there is a much better way to do this. Any hints or suggestions are much appreciated. Is there a way to put limits on the length of slide motion and touch duration that help determine which action to take?

Answer 1

To answer the first part of your question - if the touch listener is consuming the event before it reaches view_two (the underneath view), it may be because you are consuming the touch event in your onTouchListener.

//Returns true if the listener has consumed the event, false otherwise.
public abstract boolean onTouch (View v, MotionEvent event)

Are you always returning false in this method? If not, there are events that probably won't get propagated to the next view in the hierarchy.

As for your second question - yes, you certainly can create an onTouchListener to handle all of these events. Here's an example that does short and long press (independent of how much movement there is):

private MotionEvent downEvent;

public abstract boolean onTouch (View v, MotionEvent event){
    if (downEvent == null && event.getAction == MotionEvent.ACTION_DOWN){
        downEvent = event;
        return false;
    }


    if (event.getAction == MotionEvent.ACTION_UP){
        if (event.getDownTime() > LONG_PRESS_THRESHOLD){
            ... do something ...
        } else if (event.getDownTime() > SHORT_PRESS_THRESHOLD){
            ... do something else ...
        } 
    }
}

As you can imagine, it will only take a bit more effort lines to determine if the delta X / delta Y between your down event and current event meets the threshold you determine for events 3 and 4.