isScrolledUnder property Null safety
final
True if the FlexibleSpaceBar overlaps the primary scrollable's contents.
This value is used by the AppBar to resolve AppBar.backgroundColor against MaterialState.scrolledUnder, i.e. to enable apps to specify different colors when content has been scrolled up and behind the app bar.
Null if the caller hasn't determined if the FlexibleSpaceBar overlaps the primary scrollable's contents.
Implementation
final bool? isScrolledUnder;