static private int getAction(int index, MotionEvent event)
    {
        int action = event.getActionMasked();
        if (action == MotionEvent.ACTION_MOVE) {
            int hsz = event.getHistorySize();
            if (hsz > 0) {
                float x = event.getX(index);
                float y = event.getY(index);
                for (int h = 0; h < hsz; ++h) {
                    if ( event.getHistoricalX(index, h) != x ||
                         event.getHistoricalY(index, h) != y )
                        return 1;
                }
                return 2;
            }
            return 1;
        }
        if (action == MotionEvent.ACTION_DOWN || action == MotionEvent.ACTION_POINTER_DOWN && index == event.getActionIndex()) {
            return 0;
        } else if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_POINTER_UP && index == event.getActionIndex()) {
            return 3;
        }
        return 2;
    }