Co-ordinates of the ACTION_UP and ACTION_POINTER_UP event

Question

I am trying to check what is touching the screen whenever it is pressed, a pointer is moved, or a touch is released.

The problem is that when a touch is released, getPointerCount() includes the pointer that just left the screen in its count. And so when I try to gather all the current X and Y values, it includes an x/y pair that has left the screen.

I am currently doing something like:

int count = e.getPointerCount();
for(i = 0; i < count; i++) {
    x = e.getX(i); 
    y = e.getY(i); 
    /* do stuff with them */ 
}

Is there a way of getting the X and Y coordinates of that pointer that left the screen, or remove the pointer that left the screen and get only coordinates that are touching the screen?

Thanks

Answer 1

Have you tried using the onTouchEvent in your application?

import android.view.MotionEvent;

...

private int mActivePointerId;

protected void onCreate(Bundle savedInstanceState){
    ...
}

public boolean onTouchEvent(MotionEvent event){

    // Get the pointer ID
    mActivePointerId = event.getPointerId(0);

    // ... Many touch events later...

    // Use the pointer ID to find the index of the active pointer 
    // and fetch its position

    int pointerIndex = event.findPointerIndex(mActivePointerId);

    // Get the pointer's current position
    float x = event.getX(pointerIndex);
    float y = event.getY(pointerIndex);

    return true;

}

Answer 2

I think the method you want is getActionIndex() . From the documentation, it seems that when getActionMasked() returns ACTION_POINTER_UP , this method will return the corresponding pointer index and you can then ignore it in your loop (or do something else with it).