Adding Padding to fast scroller in List View

I have added a header for the StickyHeaderlistview to show/hide the view when scrolling up and down using Flexible space ObservableView.But the problem is scroller starts from the top of the header view and header

almost contains a size of 300dp . Here the header is acting as flexible space. so when scrolling up we cant find the start of scrollbar.it is under the show/hide view. Is there any way to set the start of scroll after that headerview or add any padding or offset to scrollbar.

thanks.