So I love the idea of the new Sticky Header. Before it, I used a Sliver AppBar to create a search field on my homepage that stuck to the top of the screen when a user scrolled. While it was great, it was limited, since the only thing we could place in the background of the appbar when expanded was a single image. With the new Sticky Header, I can create that same search field effect, but with a background that I can do more with. For instance, I placed my Sticky Header in a Stack with a PageView. With the PageView, I can add all sorts of swipe-able content behind my search field, rather than just a single image. The problem now is that, unlike the Sliver AppBar, there is no option to add a clean solid background color that fades in behind the search field when collapsed. So now, as you scroll, you see the content behind the search field.
My question is: is there a way to set a conditional visibility based on the screen position of a widget? My vision is to place a solid background behind the search field that is only visible once the Sticky Header has reached the top of the screen.