You can do two different things to have scrolling button, depending what do you mean.
- If you want to have a scroll button, you should create
UIScrollBar
component, which you will attach to youUIScrollView
as a horizontal or vertical scroll bar. See NGUI examples included to the package. - If you want to have a object on your list, which clicked will allow you to drag the
UIScrollView
, you should attach to this gameObject aUIDragScrollView
component. It will allow you to drag-to-scroll behavior, similar to mobile list dragging experience. Again, such example should be included to the package.
EDIT: After your question clarification, the answer should be a bit different.
You should write a script, with a reference to your UIScrollView
and then you should call on it MoveRelative( Vector3 relative ) or MoveAbsolute( Vector3 absolute ), which will move the scroll view.