flutter_nav_tut

.\lib\main.dart

// ...
class Main extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      // ...
      routes: {
        '/newPage': (context) => NewPage(title: "Via routed navigation!"),
      },
    );
  }
}
// ...
class _MainPageState extends State<MainPage> {
  // ...
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      // ...
      drawer: Drawer(
        child: ListView(
          children: <Widget>[
            // ...
            ListTile(
              // ...
              onTap: () {
                Navigator.of(context).pop();
                Navigator.push(
                    context,
                    MaterialPageRoute(
                        builder: (BuildContext context) =>
                            NewPage(title: "Via MaterialPageRoute")));
              },
            ),
          ],
        ),
      ),
    );
  }
}