NotificationBloc.dart

const notificationChannel = "Notification channel";
const notificationChannelId = "Channel_id_1";
const notificationChannelDescription =
    "Notification channel description";

class NotificationService extends Bloc<NotificationEvent, NotificationState> {
	
  FirebaseMessaging _firebaseMessaging;
  FlutterLocalNotificationsPlugin _localNotifications;

  String _fcmToken;
  
	static int _notificationId = 1; //Id for every notification

  bool _hasLaunched = false;
  
	String _payLoad;

  NotificationService() {
    _localNotifications = FlutterLocalNotificationsPlugin();
    _firebaseMessaging = new FirebaseMessaging();
  }

  initialize() async {
    NotificationAppLaunchDetails _appLaunchDetails =
        await _localNotifications.getNotificationAppLaunchDetails();

    var initializationSettings = _getPlatformSettings();
    await _localNotifications.initialize(initializationSettings,
        onSelectNotification: _handleNotificationTap);

    _createNotificationChannel();
    if (Platform.isIOS) {
      var hasPermission = await _requestIOSPermissions();
      if (hasPermission) {
        await _fcmInitialization();
      } else {
        add(NotificationErrorEvent(
            "You can provide permission by going into Settings later."));
      }
    } else {
      await _fcmInitialization();
    }

    _hasLaunched = _appLaunchDetails.didNotificationLaunchApp;
    if (_hasLaunched) {
      if (_appLaunchDetails.payload != null) {
        _payLoad = _appLaunchDetails.payload;
      }
    }
  }

  Future<bool> _requestIOSPermissions() async {
    var platformImplementation =
        _localNotifications.resolvePlatformSpecificImplementation<
            IOSFlutterLocalNotificationsPlugin>();
    bool permission = false;
    if (platformImplementation != null) {
      permission = await platformImplementation.requestPermissions(
        alert: true,
        badge: true,
        sound: true,
      );
    }
    return permission;
  }

  @override
  NotificationState get initialState => StartUpNotificationState();

  @override
  Stream<NotificationState> mapEventToState(NotificationEvent event) async* {
    switch (event.runtimeType) {
      case NotificationEvent:
        Notification notification = Notification.fromJson(event.payload);
        if (notification.notificationType == BindAppConstants.dayReminderType) {
          yield IndexedNotification(1);
        }
        break;
      case NotificationErrorEvent:
        yield NotificationErrorState((event as NotificationErrorEvent).error);
        break;
    }
  }

Future<void> _showNotification(Notification payload) async {
    var vibrationPattern = Int64List(4);
    vibrationPattern[0] = 0;
    vibrationPattern[1] = 200;
    vibrationPattern[2] = 200;
    vibrationPattern[3] = 200;

    var bigTextStyleInformation = BigTextStyleInformation(
        payload.notificationBody,
        contentTitle: payload.notificationTitle);

    var androidPlatformChannelSpecifics = AndroidNotificationDetails(
        _notificationId.toString(),
        notificationChannel,
        notificationChannelDescription,
        icon: 'app_icon',
        color: BindColors.primaryColor,
        vibrationPattern: vibrationPattern,
        importance: Importance.Max,
        priority: Priority.Max,
        styleInformation: bigTextStyleInformation);
    var iOSPlatformChannelSpecifics = IOSNotificationDetails();
    var platformChannelSpecifics = NotificationDetails(
        androidPlatformChannelSpecifics, iOSPlatformChannelSpecifics);
    await _localNotifications.show(
        payload.notificationId,
        payload.notificationTitle,
        payload.notificationBody,
        platformChannelSpecifics,
        payload: payload.toJson());
  }

  Notification convertToNotification(
      int notificationId, Map<String, dynamic> message) {
    Notification notification;
    if (Platform.isAndroid) {
      notification = new Notification((object) => object
        ..notificationId = notificationId
        ..notificationTitle = message['notification']['title']
        ..notificationBody = message['notification']['body']
        ..notificationType = message['data']['notification_type']);
    } else {
      notification = new Notification((object) => object
        ..notificationId = notificationId
        ..notificationTitle = message['aps']['alert']['title']
        ..notificationBody = message['aps']['alert']['body']
        ..notificationType = message['notification_type']);
      print(notification.toJson());
    }
    return notification;
  }

  void _createNotificationChannel() async {
    var androidNotificationChannel = AndroidNotificationChannel(
      notificationChannelId,
      notificationChannel,
      notificationChannelDescription,
    );
    await _localNotifications
        .resolvePlatformSpecificImplementation<
            AndroidFlutterLocalNotificationsPlugin>()
        ?.createNotificationChannel(androidNotificationChannel);
  }

  _getPlatformSettings() {
    var initializationSettingsAndroid =
        AndroidInitializationSettings('app_icon');
    var initializationSettingsIOS = IOSInitializationSettings(
        requestAlertPermission: true,
        requestBadgePermission: true,
        requestSoundPermission: true);
    return InitializationSettings(
        initializationSettingsAndroid, initializationSettingsIOS);
  }

  Future _handleNotificationTap(String payload) async {
    if (payload != null) {
      add(NotificationEvent(payload));
    }
  }

  Future _fcmInitialization() async {
    try {
      _fcmToken = await _firebaseMessaging.getToken();
     
      _firebaseMessaging.onTokenRefresh.listen((event) {
				//API call can be done here to update token in back-end
        _fcmToken = event;
      });

      _firebaseMessaging.configure(
        onMessage: (Map<String, dynamic> message) async {
          Notification notification =
              convertToNotification(_notificationId++, message);
          await _showNotification(notification);
        },
        onLaunch: (Map<String, dynamic> message) async {
          print("onLaunch: $message");
          Notification notification =
              convertToNotification(_notificationId++, message);
          _hasLaunched = true;
          _payLoad = notification.toJson();
        },
        onResume: (Map<String, dynamic> message) async {
          print("onResume: $message");
          Notification notification =
              convertToNotification(_notificationId++, message);
          add(NotificationEvent(notification.toJson()));
        },
      );
    } catch (e) {
      add(NotificationErrorEvent(e.toString()));
    }
  }

  void checkForLaunchedNotifications() {
    if (_hasLaunched && _payLoad != null) add(NotificationEvent(_payLoad));
  }

  String getFcmToken() => _fcmToken;
}

Hello.

getFcmToken() Doesn't work (return null), returns null when I call it this way:

BlocProvider.of<NotificationBloc>(context).getFcmToken()

Hi,
Can you check following things?

1. Check whether you've called initialize() method before you access getFcmToken() method?
2. If yes, please check whether your FCM initialisation works or not? (By adding debugger over there)

It works, I just took out inizialize() from main.dart and put it in the bloc constructor

Hello,
How do u call u bloc from onBackgroundMessage ie the new messaging methods
regard