[Migration] FCM Null Safety 적용

Flutter 2.2로의 마이그레이션을 하게 되면서 기존의 방법으로는 FCM을 사용할 수 없게 되었다. 
공식문서

Cloud Messaging | FlutterFire

예제

FirebaseExtended/flutterfire

main.dart 일부분

Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  // If you're going to use other Firebase services in the background, such as Firestore,
  // make sure you call `initializeApp` before using other Firebase services.
  await Firebase.initializeApp();

  print("Handling a background message: ${message.messageId}");
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  await Firebase.initializeApp();
  // Set the background messaging handler early on, as a named top-level function
  FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);

  runApp(MyApp());
}

 

IOS 권한 설정

final FirebaseMessaging _firebaseMessaging = FirebaseMessaging.instance;


Future.microtask(() async {
  await _firebaseMessaging
      .requestPermission(
    alert: true,
    announcement: false,
    badge: true,
    carPlay: false,
    criticalAlert: false,
    provisional: false,
    sound: true,
  )
      .then((settings) {
    print('User granted permission: ${settings.authorizationStatus}');
  });

  await FirebaseMessaging.instance
      .setForegroundNotificationPresentationOptions(
    alert: true,
    badge: true,
    sound: true,
  );
});

 

핸들링 메시지

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

  // Firebase

  FirebaseMessaging.instance
      .getInitialMessage()
      .then((RemoteMessage? initialMessage) {
    print('initialMessage data: ${initialMessage?.data}');
  });

  FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) {
    print('onMessageOpenedApp data: ${message.data}');
  });

  FirebaseMessaging.onMessage.listen((RemoteMessage message) {
    print('Got a message whilst in the foreground!');
    print('onMessage data: ${message.data}');

    if (message.notification != null) {
      print('Message also contained a notification: ${message.notification}');
    }
  });

  // Firebase
}