Flutter Navigator.pop(context) returning a black screen

 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.

class Page2 extends StatelessWidget {

  const Page2({Key? key}) : super(key: key);
  
  @override

  Widget build(BuildContext context) {

    return Page2Stateful(title: 'Page 2'); //MaterialApp(.......

  }

}