Question

I have a project using a ViewPager which works correctly:
I can page from view to view by flicking left and right.

On one page of the ViewPager, I have a custom view and I am trying to add below it another view (LinearLayout) that is touch sensitive and that will not “page” the ViewPager. Like this:

<LinearLayout >

    <myView />

    <LinearLayout> // The touch sensitive region
    </LinearLayout>

</LinearLayout>

After my view has been inflated and added to the ViewPager, I call setOnTouchListener() to attach a listener to the internal LinearLayout. The listener returns “true”.

Unfortunateley when I move horizontally in that view, I move to another page.
The events I get are:
ACTION_DOWN, ACTION_MOVE (n times) and finally ACTION_CANCEL. Although I stayed within the view.

It seems that the event has gone up the view hierarchy and processed by the ViewPager.

Is there a logical explanation to this behaviour ?

Answer 1

I have found a workaround by intercepting events at the Activity level, overriding dispatchTouchEvent().

In there, I call super.dispatchTouchEvent() for processing all events unless the user is touching my touch sensitive view. I test if the user is on the correct page and at the right location. In that case I process the event myself.

@Override
public boolean dispatchTouchEvent (MotionEvent ev) {


    if ( pager.getCurrentPosition()!=0 ) { // Test ViewPager page
            super.dispatchTouchEvent(ev);
    }   
    else {

        int[] xy = new int[2];
        findViewById(R.id.myTouchControl).getLocationOnScreen(xy);
        int topOfView = xy[1];

        if ( ev.getY() > topOfView ) {
            // Custom processing
            ...

        } else {
            // Standard processing
            super.dispatchTouchEvent(ev);
        }
    }
    return false;
}