detect touched item changed without lifting up finger (swipe)
gridview.setOnTouchListener(new OnTouchListener(){
@Override
public boolean onTouch(View v, MotionEvent event) {

        if(event.getAction() == MotionEvent.ACTION_MOVE){
            gridview.requestFocusFromTouch();
            gridview.setSelection(gridview.pointToPosition((int)event.getX(),(int)event.getY()));
            return true;
        }
        if(event.getAction() == MotionEvent.ACTION_UP){
            gridview.clearFocus();
            return true;
        }

        return false;
    }
});