Flutter sample to use multiple navigators with `bottomNavigationBar`

multiple_navigators.dart

class MyComponentHomePage extends StatefulWidget {
  const MyComponentHomePage();

  @override
  State<MyComponentHomePage> createState() => _StateHomePage();
}

class _StateHomePage extends State<MyComponentHomePage> {
  final _keys = [
    GlobalKey<NavigatorState>(),
    null,
    GlobalKey<NavigatorState>(),
  ];
  var _index = 1;

  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      onWillPop: () async {
        if (_index != 1) {
          return !await _keys[_index]!.currentState!.maybePop();
        }
        return true;
      },
      child: Scaffold(
        body: child: IndexedStack(
          index: _index,
          children: [
            /// Simply use Navigator.push() inside MyComponentPlaylist()
            Navigator(
              key: _keys[0],
              onGenerateRoute: (settings) => MaterialPageRoute(
                builder: (context) => const MyComponentPlaylist(),
              ),
            ),
            MyComponentPlayer(),
            Navigator(
              key: _keys[2],
              onGenerateRoute: (settings) => MaterialPageRoute(
                builder: (context) => const MyComponentLibrary(),
              ),
            ),
          ],
        ),
        bottomNavigationBar: NavigationBar(
          selectedIndex: _index,
          onDestinationSelected: (value) => setState(() {
            _index = value;
          }),
          destinations: const [
            NavigationDestination(
              icon: Icon(Icons.queue_music),
              label: 'Playlist',
            ),
            NavigationDestination(
              icon: Icon(Icons.music_note_outlined),
              selectedIcon: Icon(Icons.music_note),
              label: 'Player',
            ),
            NavigationDestination(
              icon: Icon(Icons.library_music_outlined),
              selectedIcon: Icon(Icons.library_music),
              label: 'Library',
            ),
          ],
        ),
      );
    );
  }
}