Navigation Setup

main.dart

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
      //...
      child: MaterialApp(
        navigatorKey: NavigatorHolder.navigatorKey,
        home: MyHomePage(),
        routes: {
          '/all-emotions': (BuildContext context) => MyHomePage(),
          '/list-emotions': (BuildContext context) => EmotionsList(),
          '/add-emotion': (BuildContext context) => AddDetail(),
          '/view-saved-emotion': (BuildContext context) => ViewDetail(),
        },
      ),
    );
  }
  //...
}