Scenario

I am using the firebase_messaging package to handle notifications for my Flutter project. I have a Nested Navigation flow implemented, implementation similar to here.

Problem

I am able to handle notifications when the app is in the foreground or in the background, for nested navigation routes. However, I am facing difficulty handling notifications when the app is in the terminated state. I have tried following the Firebase documentation

Code

In my MaterialApp widget in app.dart, I’ve omitted the routes parameter, and have populated the onGenerateRoute parameter with:

NavigationService.dart

  Route<dynamic> onGenerateRoute(RouteSettings settings) {
    String path = settings.name!;
    Object? arguments = settings.arguments;
    if (settings.arguments == null) {
      Uri uri = Uri.parse(settings.name!);
      path = uri.path;
      arguments = uri.queryParameters;
    }
    if (_appRoutes[path] != null) {
      if (Platform.isIOS) {
        return CupertinoPageRoute(
          settings: settings,
          builder: (_) => _appRoutes[path]!(arguments),
        );
      }
      return MaterialPageRoute(
        settings: settings,
        builder: (_) => _appRoutes[path]!(arguments),
      );
    } else {
      print('route: $path');
      throw SystemException('onGenerateRoute: Route not found');
    }
  }

Each of my nested navigation services also contain their own implementation of onGenerateRoute, which checks against specific routes that they contain.

When I attempt to navigate to a “nested route”, ie. /profile, I get the following error message, even though my ProfileNavigationService contains the route

I/flutter ( 8088): route: /profile
I/flutter ( 8088): onGenerateRoute: Route not found     
I/flutter ( 8088): #0      NavigationService.onGenerateRoute (package:vibefam/routes/navigation_service.dart:359)
I/flutter ( 8088): #1      _WidgetsAppState._onGenerateRoute (package:flutter/src/widgets/app.dart:1482)        
I/flutter ( 8088): #2      NavigatorState._routeNamed (package:flutter/src/widgets/navigator.dart:4447)

This is how I’ve set up my notification listeners:

  Future<void> _setupNotificationHandler() async {
    // handles interaction when app is terminated
    RemoteMessage? initialMessage =
        await FirebaseMessaging.instance.getInitialMessage();

    if (initialMessage != null) {
      _handleMessage(initialMessage);
    }
    // handles interaction when app is in the background
    FirebaseMessaging.onMessageOpenedApp.listen(_handleMessage);
  }

  void _handleMessage(RemoteMessage message) {
    String? parsedRoute = NotificationUtil.getRoute(message);
    if (parsedRoute == null) {
      return;
    }

    Uri uri = Uri.parse(parsedRoute);
    String path = uri.path;
    Map<String, dynamic> params = uri.queryParameters;
    if (!NestedRouteHandler.hasNestedRoute(path)) {
      NavigationService.of(context).navigateTo(path, arguments: params);
      return;
    }
    NestedRouteHandler.navigate(context, path, params);
  }

  @override
  void initState() {
    super.initState();
    _setupNotificationHandler();
  }