public boolean onTouch(View v, MotionEvent event) {
  int action = event.getAction() & MotionEvent.ACTION_MASK;
  int pointerIndex = (event.getAction() & MotionEvent.ACTION_POINTER_ID_MASK) >> MotionEvent.ACTION_POINTER_ID_SHIFT;
  int actionId = event.getPointerId(pointerIndex);
  pointerCount = event.getPointerCount();
  if (actionId < MAX_POINTERS) {
    lastActions[actionId] = action;
  }
  for (int i = 0; i < pointerCount; i++) {
    int pointerId = event.getPointerId(i);
    if (pointerId < MAX_POINTERS) {
      points[pointerId] = new PointF(event.getX(i), event.getY(i));
      if (action == MotionEvent.ACTION_MOVE) {
        lastActions[pointerId] = action;
      }
    }
  }
  touchView.invalidate();
  return true;
}