Question

I am working on a multitouch program that needs to record only the movements made by the second finger or index pointer.
Now the documentation says that we can use MotionEvent.ACTION_POINTER_INDEX_MASK and & it with action and shift by INDEX_SHIFT to get the pointer that made the action like going up or down. But this technique does not work on move.

Is there anyway that we can detect the move action made by a certain pointer alone?

Thx,

Answer 1

yes, you can have something like this in your View class:

@Override
public boolean onTouchEvent(MotionEvent event) {
    switch (event.getActionMasked()) {
        case MotionEvent.ACTION_MOVE:
            if(event.getPointerCount()>1){
                //where 1 is the index of the second finger
                final int Y = event.getY(1); 
                final int X = event.getX(1); 
            }
            break;
    }
}

so depending on what finger you want to get the movent you can set the get to that index. Rember that values may be from 0 (the first pointer that is down) to getPointerCount()-1.
I tested this on 2.2 Gingerbread so I hope it be useful for you 🙂