navigation_provider.dart

class NavigationProvider extends ChangeNotifier {
  /// [NavigationProvider] edinmek için shortcode
  static NavigationProvider of(BuildContext context) =>
      Provider.of<NavigationProvider>(context, listen: false);

  // Açılış sayfası
  int _currentScreenIndex = FIRST_SCREEN;
  int get currentTabIndex => _currentScreenIndex;

  Route<dynamic> onGenerateRoute(RouteSettings settings) {
    print('Oluşturulan rota: ${settings.name}');
    switch (settings.name) {
      case PushedScreen.route:
        return MaterialPageRoute(builder: (_) => PushedScreen());
      case SimpleScreen.route:
        return MaterialPageRoute(builder: (_) => SimpleScreen());
      default:
        return MaterialPageRoute(builder: (_) => Root());
    }
  }

  final Map<int, Screen> _screens = {
    FIRST_SCREEN: Screen(
      title: 'First',
      icon: Icons.home,
      child: FirstScreen(),
      initialRoute: FirstScreen.route,
      navigatorState: GlobalKey<NavigatorState>(),
      onGenerateRoute: (settings) {
        print('Oluşturulan rota: ${settings.name}');
        switch (settings.name) {
          case PushedScreen.route:
            return MaterialPageRoute(builder: (_) => PushedScreen());
          default:
            return MaterialPageRoute(builder: (_) => FirstScreen());
        }
      },
      scrollController: ScrollController(),
    ),
    SECOND_SCREEN: Screen(
      title: 'Second',
      icon: Icons.search,
      child: SecondScreen(),
      initialRoute: SecondScreen.route,
      navigatorState: GlobalKey<NavigatorState>(),
      onGenerateRoute: (settings) {
        print('Oluşturulan route: ${settings.name}');
        switch (settings.name) {
          default:
            return MaterialPageRoute(builder: (_) => SecondScreen());
        }
      },
      scrollController: ScrollController(),
    ),
    THIRD_SCREEN: Screen(
      title: 'Third',
      icon: Icons.favorite,
      child: ThirdScreen(),
      initialRoute: ThirdScreen.route,
      navigatorState: GlobalKey<NavigatorState>(),
      onGenerateRoute: (settings) {
        print('Oluşturulan route: ${settings.name}');
        switch (settings.name) {
          default:
            return MaterialPageRoute(builder: (_) => ThirdScreen());
        }
      },
      scrollController: ScrollController(),
    ),
    FOURTH_SCREEN: Screen(
      title: 'Fourth',
      icon: Icons.message,
      child: FourthScreen(),
      initialRoute: FourthScreen.route,
      navigatorState: GlobalKey<NavigatorState>(),
      onGenerateRoute: (settings) {
        print('Oluşturulan route: ${settings.name}');
        switch (settings.name) {
          case SimpleScreen.route:
            return MaterialPageRoute(builder: (_) => SimpleScreen());
          default:
            return MaterialPageRoute(builder: (_) => FourthScreen());
        }
      },
      scrollController: ScrollController(),
    ),
  };

  List<Screen> get screens => _screens.values.toList();

  Screen get currentScreen => _screens[_currentScreenIndex];

//...