Flutter FCM Navigation onResume/onLaunch - flutter

Question

In my app, I got a class "home" where the user is navigated to after he is authorized. Within "home" there is a PageView with BottomNavigationBar. When the user is getting a push notification from firebase (new message) he should be navigated to ChatHome and to the specific chat after tapping. How can I do this?
Home does look like this
#override
Widget build(BuildContext context) {
return Scaffold(
key: _scaffoldKey,
body: PageView(
children: <Widget>[
Feed(userID: widget.userID),
SearchView(),
ChatHome(),
Profile(
uid: currentUser?.uid,
auth: widget.auth,
logoutCallback: widget.logoutCallback,
),
],
controller: pageController,
onPageChanged: onPageChanged,
physics: NeverScrollableScrollPhysics(),
),
bottomNavigationBar: CupertinoTabBar(
currentIndex: pageIndex,
inactiveColor: Colors.white,
backgroundColor: Color.fromRGBO(0, 111, 123, 1),
activeColor: Color.fromRGBO(251, 174, 23, 1),
onTap: onTap,
items: [
BottomNavigationBarItem(
icon: Icon(Icons.home, size: 20),
title: Text("Home"),
),
BottomNavigationBarItem(
icon: Icon(Icons.search, size: 20),
title: Text("Search"),
),
BottomNavigationBarItem(
icon: Icon(Icons.chat, size: 20),
title: Text("Chats"),
),
BottomNavigationBarItem(
icon: Icon(Icons.profile, size: 20),
title: Text("Profile"),
),
]),
);
}
In ChatHome I got ListTiles with all the chat partners. On click the user is navigated to the specific chat.
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Chat(
chatPartnerId: chatPartner[index].uid,
chatPartnerName: chatPartner[index].username,
chatPartnerPhotoUrl: chatPartner[index].photoUrl)));
In home page, I got my onResume
I tried different things but could find a good solution
With the following code, I was able to navigate to ChatHome but the BottomNavigationBar disappeared.
onResume: (Map<String, dynamic> message) async {
final screen = message['screen'];
print(screen);
if(screen == "ChatHome"){
Navigator.pushNamed(context, '/chatHome');
}
},
The following code didn't work well as the app jumped around and always ends in home.
onResume: (Map<String, dynamic> message) async {
final screen = message['screen'];
print(screen);
if(screen == "ChatHome"){
Navigator.pushNamed(context, '/home').then((_) => pageController.jumpToPage(2));
}
},
routes: {
'/rootPage': (BuildContext context) => new RootPage(auth: new Auth()),
'/chatHome': (BuildContext context) => ChatHome(),
'/home': (BuildContext context) => Home(),
},
Any help is appreciated.

Answer 1

You need to provide a navigatorKey to your MaterialApp Widget:
final GlobalKey<NavigatorState> navigatorKey = new GlobalKey<NavigatorState>();
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
....
navigatorKey: navigatorKey,
.....
);
}
}
Then, you can use this navigatorKey to navigate in your onResume handler:
onResume: (message) async {
navigatorKey.currentState.pushNamed("/sample-route/" + message["data"]["..."])
}
For the onLaunch handler (which is called directly onLaunch, means the first app view isn't built yet which means you cannot use the navigatorKey instantly, I only found a hacky solution:
onLaunch: (message) async {
Timer.periodic(
Duration(milliseconds: 500),
(timer) {
if (navigatorKey.currentState == null) return;
navigatorKey.currentState.pushNamed("/sample-route/" + message["data"]["..."]);
timer.cancel();
},
);
}
Of course, the solution for onLaunch isn't clean, but it works.