Если вы хотите отобразить всплывающее окно в приложении, вам не нужно onBackgroundMessage - это только для обработки данных, когда сообщение принимается в фоновом режиме.Нет возможности запустить приложение в момент получения сообщения.
Однако, если пользователь нажмет на уведомление, приложение запустится, и будут вызваны обратные вызовы onResume или onLaunch.
Вы можете уведомить соответствующий экран, чтобы отобразить всплывающее окно, когдаэто происходит.
Вот простая реализация:
В firebase_notification_receiver.dart:
import 'dart:async';
import 'package:firebase_messaging/firebase_messaging.dart';
class NotificationEvent {
final Map<String, dynamic> content;
/// whether the notification was delivered while the app was in the foreground
final bool inApp;
NotificationEvent({this.content, this.inApp = false});
}
class FirebaseNotificationReceiver extends NotificationReceiver {
final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
StreamController<NotificationEvent> _controller = StreamController<NotificationEvent>.broadcast();
StreamSubscription _streamSubscription;
Function(NotificationEvent) _listener;
init{
// add the rest of the code to initialise firebase here
_firebaseMessaging.configure(
/// Fires when App was in foreground when receiving the notification
onMessage: (Map<String, dynamic> message) async {
print("onMessage: $message");
_controller.sink.add(NotificationEvent(content: message, inApp: true));
},
/// Fires when App was in background when receiving the notification and user has tapped on it
onResume: (Map<String, dynamic> message) async {
print("onResume: $message");
_controller.sink.add(NotificationEvent(content: message));
}
/// Fires when App was closed when receiving the notification and user has tapped on it
onLaunch: (Map<String, dynamic> message) async {
print("onLaunch: $message");
_controller.sink.add(NotificationEvent(content: message));
},
);
_streamSubscription =
_controller.stream.listen(_onStreamEvent, onError: (e) {
print("Notification Stream error $e");
});
}
setListener(Function(NotificationEvent) onData) {
this._listener = onData;
}
}
В main.dart:
// imports go here
void main(){
final notificationReceiver = NotificationReceiver.firebase();
runApp(
MultiProvider(
providers: [
Provider<NotificationReceiver>(
builder: (_) => notificationReceiver),
// more providers go here
],
child: App(), // Your custom app class
),
);
}
В notification_listenable.dart:
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
class NotificationListenable extends StatefulWidget {
final Widget child;
final Function(NotificationEvent) onData;
const NotificationListenable({@required this.child, this.onData});
@override
_NotificationListenableState createState() => _NotificationListenableState();
}
class _NotificationListenableState extends State<NotificationListenable> {
@override
Widget build(BuildContext context) {
Provider.of<NotificationReceiver>(context).setListener(widget.onData);
return widget.child;
}
}
В my_screen.dart:
/// add your imports here
class MyScreen extends StatefulWidget {
@override
HomePageState createState() => HomePageState();
}
class MyScreenState extends State<MyScreen> {
final _scaffoldKey = GlobalKey<ScaffoldState>();
void _onNotification(NotificationEvent n) {
(_scaffoldKey.currentState)?.showSnackBar(
SnackBar(
duration: Duration(seconds: 2),
content: Text("I am a pop up"),
),
),
}
@override
Widget build(BuildContext context) {
return NotificationListenable(
child: YourCustomScreenContent(),
onData: _onNotification,
);
}