dart - Flutter Navigator.pop(context) returning a black screen

Question

My Flutter Project structure is like this

Main() //Run App with MaterialApp and Routes
L HomePage() //Default route (/), with BottomNavigation
  L MoviesPage() //Default BottomNavigation Index and shows a list of movies form TMDB 
    L DetailsPage()
  L SeriesPage()
  L SupportPage()

After clicking on any movie it navigates forward to the DetailsPage() but when I call Navigator.pop from DetailsPage() it should go back to the previous screen but it doesn't.

The Navigator.canPop(context) return false But the hardware back button works absolutely fine, so how do I fix it?

main.dart

class BerryMain extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
      home: Inferno(
        {
          '/': (context, argumets) => HomePage(),
          '/detailspage': (context, arguments) => DetailsPage(arguments),
        },
      ).home(context),
    );
  }
}

homepage

class HomePage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    // TODO: implement createState
    return _HomePageState();
  }
}

class _HomePageState extends State<HomePage> {
  int _currentIndex = 0;
  final List<Widget> _childnav = [MoviesPage(), SeriesPage(), SupportPage()];

  void onTabPressed(...)

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      appBar: AppBar(
        title: Text('...'),
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.search),
            onPressed: () {},
          )
        ],
      ),
      body: _childnav[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        onTap: onTabPressed,
        currentIndex: _currentIndex, //this property defines current active tab
        items: [
          BottomNavigationBarItem(
              icon: Icon(Icons.movie), title: Text('Movies')),
          BottomNavigationBarItem(icon: Icon(Icons.tv), title: Text('Series')),
          BottomNavigationBarItem(icon: Icon(Icons.help), title: Text('Help'))
        ],
      ),
    );
  }
}

MoviesPage

//Inside ListView Builder
Virgil.pushNamed(context, '/detailspage', arguments: args);

DetailsPage

//Inside MaterialApp > Scaffold > SliverAppbar > BackButton
Navigator.pop(context)

I'm using Virgil but I don't think it is the problem.

Answer 1

This can happen if your MoviesPage has another MaterialApp widget. Most of the time you want to use Scaffold as a top widget for a new page/screen, but if you accidentally use MaterialApp instead, nothing warns you.

What happens, is that MaterialApp creates a new Navigator, so if you switch from one page with MaterialApp to another, you now have two Navigators in the widget tree.

The call Navigator.of(context) looks for the closest Navigator, so it'll use the one, newly created in your MoviesPage. As the history of your route transitions is stored in a first Navigator, this one can't pop back –?it has empty route history.

Hence, the black screen.

Long story short, to fix this, just use Scaffold as a top widget instead of MaterialApp in all nested screens.