Flutter - how to get current context? - firebase

Question

I am using Firebase cloud messaging for notifications, and i want to show a dialog or snackbar once i receive a notification when i am inside the application, my problem is that i am initializing the firebase configuration at the top of my widget tree (Splash screen once the app is starting)
_fireBaseMessaging.configure(
onMessage: (Map<String, dynamic> message) async {
dynamic data = message['data'];
................ // Adding a snackbar/alertdialog here doesn't work
},
);
obviously if i set a dialog or snackbar it won't show since i need the context of my current page, is there any way to get the current context?
I also tried putting it inside the build widget of my splash screen but still the dialog isn't showing once i am on another page.
#override
Widget build(BuildContext context) {
_fireBaseMessaging.configure(
onMessage: (Map<String, dynamic> message) async {
print("onMessage: $message");
dynamic data = message['data'];
if (data['id'] == '1') {
newPro = true;
} else if (data['id'] == '2') {
print("THIS WORKS!!!");
showDialog(
context: context,
builder: (context) => AlertDialog(
content: ListTile(
title: Text("TEST"),
subtitle: Text("TEST"),
),
actions: <Widget>[
FlatButton(
child: Text("OK"),
onPressed: () => Navigator.pop(context),
)
],
));
}
},
);

Answer 1

I had the exact same issue, but I found a brilliant thread on GitHub. Basically, you can create a navigatorKey and pass that in to MaterialApp, and then use that navigatorKey to change route.
See how in this thread: https://github.com/brianegan/flutter_redux/issues/5#issuecomment-361215074

Answer 2

I ended up using Overlay support:
https://pub.dev/packages/overlay_support
It is basically called at the very beginning of my tree just like wrapping providers at the main.dart, it worked like a charm, nothing else worked at all!
Also here is a tutorial that helped me a lot:
https://medium.com/flutter-community/in-app-notifications-in-flutter-9c1e92ea10b3

Answer 3

Because it makes me uncomfortable to have the answer embedded in a link, here is the answer (credit to xqwzts on Github).
Use a GlobalKey you can access from anywhere to navigate:
Create the key:
final GlobalKey<NavigatorState> navigatorKey = new GlobalKey<NavigatorState>();
Pass it to your App:
new MaterialApp(
title: 'MyApp',
onGenerateRoute: generateRoute,
navigatorKey: navigatorKey,
);
Push routes:
navigatorKey.currentState.pushNamed('/someRoute');

Answer 4

An elegant solution to this problem is to use GlobalKey. That'll let you find the current BuildContext and do things with it.
You make a file called eg. global.dart looking like this:
import 'package:flutter/material.dart';
class GlobalVariable {
static final GlobalKey<NavigatorState> navState = GlobalKey<NavigatorState>();
}
You use this in your main() and MaterialApp() like this:
import 'global.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'fcm.dart'; // My Firebase Cloud Messaging code
import 'package:flutter/material.dart';
import 'package:firebase_core/firebase_core.dart';
import 'screens/welcome_screen.dart';
void main() {
print('Running main()');
WidgetsFlutterBinding.ensureInitialized();
Firebase.initializeApp();
initializeFcm('', GlobalVariable.navState); // Sending the global key when initializing Firebase Cloud Messaging
FirebaseMessaging.onBackgroundMessage(firebaseMessagingBackgroundHandler);
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: WelcomeScreen(),
navigatorKey: GlobalVariable.navState, // Putting the global key in the MaterialApp
);
}
}
Then, in the file that handles Firebase Cloud Messaging, which I've named fcm.dart, you'll be able to use the GlobalKey to find the current context and use it, for example like this:
import 'package:blackbox/global.dart';
import 'online_screens/game_hub_screen.dart';
import 'package:flutter/material.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
void initializeFcm(String token, GlobalKey myGlobalKey) async {
print('Initializing Firebase Cloud Messaging...');
await Firebase.initializeApp();
FirebaseMessaging.onMessageOpenedApp.listen((remoteMsg) {
// Using the currentContext found with GlobalKey:
Navigator.push(GlobalVariable.navState.currentContext, MaterialPageRoute(builder: (context) {
return GameHubScreen();
}));
});
}

Answer 5

do the initializing inside a build method of your first widget in the tree ! which normally it called an App widget and it is StateLess StateFull widget and inside the build method you have access to the BuildContext