Flutter - how to hide global bottom navigation bar? - flutter

Question

On one of the pages, nested inside one of bottom navigation bar pages I want to hide the bottom navigation bar, which is set as global. To be clear, I'm talking about this bar:
I can't just use Navigator.pushNamed because I'm creating viewModel and passing arguments in this way:
openConversation(BuildContext context) async {
Navigator.of(context).push(MaterialPageRoute(
builder: (context) => ChangeNotifierProvider(
create: (context) => ConversationVM(...),
child: ConversationScreen(
(...)
),
),
));
}
I've tried to set the Scaffold parameter bottomNavigationBar to null, but without effect, I need to resolve that problem somewhere higher.
Nav bar snippet:
class NavigationBar extends StatefulWidget {
static String id = 'navigation_screen';
#override
State<StatefulWidget> createState() {
return _NavigationBarState();
}
}
class _NavigationBarState extends State<NavigationBar> {
//track the index of our currently selected tab
int _currentIndex = 0;
//st of widgets that we want to render
final List<Object> _children = [
PostedQueries(),
];
#override
Widget build(BuildContext context) {
return Scaffold(
//body of our scaffold which is the widget that gets displayed between our app bar and bottom navigation bar.
body: _children[_currentIndex], // new
bottomNavigationBar: BottomNavigationBar(
onTap: onTabTapped,
// new
currentIndex: _currentIndex,
// new
unselectedItemColor: Colors.grey,
selectedItemColor: Colors.deepOrange,
items: [
BottomNavigationBarItem(
icon: new Icon(Icons.home),
label: ('Home'),
),
],
),
);
}
void onTabTapped(int index) {
setState(() {
_currentIndex = index;
});
}
}