Transparent sticky header ui collectionview don't show cells underneath

问题

I want a sticky header that shows the views behind the collectionview, but not the collectionview cells as they pass under. Masking the collectionview masks the supplementaryview headers, and not masking them they are visible as they pass under

来源：https://stackoverflow.com/questions/44739618/transparent-sticky-header-ui-collectionview-dont-show-cells-underneath