You can do this with GestureDetector. This works:
GestureDetector.OnGestureListener listener = new GestureDetector.SimpleOnGestureListener() {
@Override
public void onLongPress(MotionEvent e)
{
Toast.makeText(TestXmlActivity.this, "LongClick", Toast.LENGTH_SHORT).show();
}
};
final GestureDetector gestureDetector = new GestureDetector(this, listener);
horizontalScrollView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event)
{
return gestureDetector.onTouchEvent(event);
}
});