How to navigate to specific MaterialPageRoute in app from a notification in Flutter

There aren't very many cases where a GlobalKey is a good idea to use, but this might be one of them.

When you build your MaterialApp (which I assume you're using), you can pass in a navigatorKey parameter which specifies the key to use for the navigator. You can then use this key to access the navigator's state. That would look something like this:

class _AppState extends State<App> {
  final GlobalKey<NavigatorState> navigatorKey = GlobalKey(debugLabel: "Main Navigator");

  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      navigatorKey: navigatorKey,
      home: new Scaffold(
        endDrawer: Drawer(),
        appBar: AppBar(),
        body: new Container(),
      ),
    );
  }
}

And then to use it you access the navigatorKey.currentContext:

_goToDeeplyNestedView() {
  navigatorKey.currentState.push(
    MaterialPageRoute(builder: (_) => DeeplyNestedView())
  );
}

Initialize navigatorState globalkey

final GlobalKey<NavigatorState> navigatorKey = GlobalKey(debugLabel: "Main Navigator");

navigatorKey.currentState.push(
    MaterialPageRoute(builder: (_) => classname())
  );