How to change view after hide SliverPersistentHeader - flutter

Question

I need AppBar that shows other view on up scrolling.
Is it possible?
Bellow is my attempts to realize it. But...
This is what I need:
when scrolled down:
and when up scrolled
but I have now this:
Here is how I do this:
class DetailedEvent extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: CustomScrollView(
slivers: <Widget>[
SliverPersistentHeader(
pinned: true,
floating: false,
delegate: _SliverAppBarDelegate(),//HERE IS CUSTOM HEADER CLASS
)
This class used in MainPage:
class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
double scrollAnimationValue(double shrinkOffset) {
double maxScrollAllowed = maxExtent - minExtent;
return ((maxScrollAllowed - shrinkOffset) / maxScrollAllowed)
.clamp(0, 1)
.toDouble();
}
#override
Widget build(
BuildContext context,
double shrinkOffset,
bool overlapsContent,
) {
final tableTitleStyle =
TextStyle(color: AppColors.appWhiteDarker, fontSize: 16);
final tableValueStyle = TextStyle(color: AppColors.pureWhite, fontSize: 16);
final double visibleMainHeight = max(maxExtent - shrinkOffset, minExtent);
final double animationVal = scrollAnimationValue(shrinkOffset);
return Container(
height: visibleMainHeight,
width: MediaQuery.of(context).size.width,
child: Stack(
fit: StackFit.expand,
children: <Widget>[
...,
Positioned(
bottom: 0.0,
child: SizedBox(
width: MediaQuery.of(context).size.width,
child: Column(
mainAxisSize: MainAxisSize.max,
children: <Widget>[...],
),
),
)
],
),
);
}
#override...
}