How to show/hide bottom navigation bar in some screen? - flutter

Question

This blog shows how to preserve page state using PageStorage
This blog shows multiple navigation for each screen. The bottom nav bar here persist on all screens
But how do you make BottomNavigationBar show/hide in some screens? Say, login/register/successful screens? Tried to create a stateful widget for BottomNavigationBar but selectedIndex for the nav bar gets reset every time I use it. I can't seem to make it work.
class App extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Text('app_screen'),
bottomNavigationBar: AppBottomNavigationController(),
);
}
}
app_bottom_navigation_controller.dart
class AppBottomNavigationController extends StatefulWidget {
#override
_AppBottomNavigationControllerState createState() =>
_AppBottomNavigationControllerState();
}
class _AppBottomNavigationControllerState
extends State<AppBottomNavigationController> {
int currentIndex = 0;
final List<Widget> pages = [];
final PageStorageBucket bucket = PageStorageBucket();
#override
void initState() {
pages.addAll([
HomeScreen(
key: PageStorageKey('home_screen'),
),
SearchScreen(
key: PageStorageKey('search_screen'),
),
AccountScreen(
key: PageStorageKey('account_screen'),
)
]);
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: PageStorage(
child: pages[currentIndex],
bucket: bucket,
),
bottomNavigationBar: _bottomNavigationBar(currentIndex),
);
}
Widget _bottomNavigationBar(int selectedIndex) {
return BottomNavigationBar(
currentIndex: selectedIndex,
onTap: (index) => setState(() => currentIndex = index),
items: [
BottomNavigationBarItem(
icon: Icon(Icons.home),
title: Text('Home'),
),
BottomNavigationBarItem(
icon: Icon(Icons.search),
title: Text('Search'),
),
BottomNavigationBarItem(
icon: Icon(Icons.person),
title: Text('Account'),
),
],
);
}
}
Then under account.dart screen, I have account_bag.dart and account_successful.dart screens. I would like to have my account_bag.dart screen to have the bottom nav bar while the account_successful.dart does not.