The class 'FirebaseMessaging' doesn't have a default constructor Flutter 2 - flutter

Question

Before switching to Flutter 2, I was using an old version of firebaseMessaging without problems, and now I have the latest version.After upgrading I get the following error:
The class 'FirebaseMessaging' doesn't have a default constructor.
And:
The method 'configure' isn't defined for the type 'FirebaseMessaging'.
Full class:
class ShowNotifications {
static final FirebaseMessaging firebaseMessaging = FirebaseMessaging();
static FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
new FlutterLocalNotificationsPlugin();
static void initialization(){
var initializationSettingsAndroid =
new AndroidInitializationSettings('#mipmap/ic_launcher');
var initializationSettingsIOS = new IOSInitializationSettings();
var initializationSettings = new InitializationSettings(
android: initializationSettingsAndroid, iOS: initializationSettingsIOS);
flutterLocalNotificationsPlugin = new FlutterLocalNotificationsPlugin();
flutterLocalNotificationsPlugin.initialize(initializationSettings,
onSelectNotification: onSelectNotification);
}
static void showNotification(String title, String body) async {
await _demoNotification(title, body);
}
static Future<void> _demoNotification(String title, String body) async {
var androidPlatformChannelSpecifics = AndroidNotificationDetails(
'channel_ID', 'channel name', 'channel description',
importance: Importance.max,
playSound: true,
// sound: 'sound',
// sound: true,
showProgress: true,
priority: Priority.high,
ticker: 'test ticker');
var iOSChannelSpecifics = IOSNotificationDetails();
var platformChannelSpecifics = NotificationDetails(
android: androidPlatformChannelSpecifics, iOS: iOSChannelSpecifics);
await flutterLocalNotificationsPlugin
.show(0, title, body, platformChannelSpecifics, payload: 'test');
}
static Future onSelectNotification(String payload) async {
showDialog(
// context: context,
builder: (_) {
return new AlertDialog(
title: Text("PayLoad"),
content: Text("Payload : $payload"),
);
},
);
}
static notification(){
firebaseMessaging.configure(
onMessage: (Map<String, dynamic> message) async {
showNotification(message['notification']['title'], message['notification']['body']);
// print("onMessage: $message");
},
onLaunch: (Map<String, dynamic> message) async {
print("onLaunch: $message");
},
onResume: (Map<String, dynamic> message) async {
print("onResume: $message");
},
);
}
}
I was able to control this class from all the application pages.
What do I need to change with the new version. So that I can use the class as it was in the past.

Answer 1

Try to update your firebase_messaging package and also take care to use compatile packages for the other Firebase SDKs. I would recommend to copy the ones from the official documentation for each one you use.
Here is a full example how the new Firebase Messaging SDK would work with the new API:
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:fluttertoast/fluttertoast.dart';
import '../constants.dart';
FirebaseMessaging messaging = FirebaseMessaging.instance;
final _database = FirebaseDatabase.instance;
final _firestore = FirebaseFirestore.instance;
final _auth = FirebaseAuth.instance;
class MessagingService {
static bool showToast = true;
static String currentToken;
static void initialize() async {
await messaging.requestPermission(
alert: true,
announcement: false,
badge: true,
carPlay: false,
criticalAlert: false,
provisional: false,
sound: true,
);
FirebaseMessaging.onMessage.listen((RemoteMessage message) {
if (message.notification != null) {
print('Message also contained a notification: ${message.notification}');
}
if (showToast && message.notification != null) {
Fluttertoast.showToast(
msg: "${message.notification.title}: ${message.notification.body} ",
toastLength: Toast.LENGTH_SHORT,
gravity: ToastGravity.BOTTOM,
timeInSecForIosWeb: 1,
//backgroundColor: Colors.red,
//textColor: Colors.white,
fontSize: 16.0,
);
}
});
messaging.onTokenRefresh.listen((String token) async {
await syncToken();
});
await syncToken();
}
static Future<String> getToken() async {
String token = await messaging.getToken();
return token;
}
static Future syncToken() async {
try {
String token = await messaging.getToken();
if (token != currentToken) {
if (syncDatabase == databases.RealtimeDatabase) {
await _database
.reference()
.child(
'$kNotificationTokensSyncBasePath${_auth.currentUser.uid}/$token')
.set(true);
} else {
await _firestore
.doc('$kNotificationTokensSyncBasePath${_auth.currentUser.uid}')
.set({'$token': true}, SetOptions(merge: true));
}
currentToken = token;
}
} catch (e) {
print(e);
}
return;
}
static Future unsyncToken(User user) async {
try {
String token = await messaging.getToken();
if (syncDatabase == databases.RealtimeDatabase) {
await _database
.reference()
.child('$kNotificationTokensSyncBasePath${user.uid}/$token')
.set(null);
} else {
await _firestore
.doc('$kNotificationTokensSyncBasePath${_auth.currentUser.uid}')
.set({'$token': FieldValue.delete()}, SetOptions(merge: true));
}
currentToken = null;
} catch (e) {
print(e);
}
return;
}
}