我正在开发一个从firebase云消息接收通知的应用程序。收到邮件后，我将其保存在Hive中。我有一个通知屏幕，显示从配置单元读取的通知，当收到通知时会立即更新。这一直运行良好。
现在的问题是，当应用程序在后台运行时收到的通知(不是终止/终止(保存在配置单元中，但当导航到通知屏幕时，屏幕不会更新(配置单元中的更新看不到(，直到应用程序终止并重新运行。
我读到这是因为onBackgroundMessage处理程序在不同的隔离上运行，隔离无法共享存储。我似乎需要一种方法将配置单元通知更新从onBackgroundMessage处理程序传递到主隔离。
这是我迄今为止的实现
push_message.dart实例保存在配置单元中的通知类
import 'dart:convert';
import 'package:dio/dio.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:hive_flutter/hive_flutter.dart';
import 'package:app_name/helpers/helpers.dart';
part 'push_message.g.dart';
@HiveType(typeId: 1)
class PushMessage extends HiveObject {
@HiveField(0)
int id = int.parse(generateRandomNumber(7));
@HiveField(1)
String? messageId;
@HiveField(2)
String title;
@HiveField(3)
String body;
@HiveField(4)
String? bigPicture;
@HiveField(5)
DateTime? sentAt;
@HiveField(6)
DateTime? receivedAt;
@HiveField(7)
String? payload;
@HiveField(8, defaultValue: '')
String channelId = 'channel_id';
@HiveField(9, defaultValue: 'channel name')
String channelName = 'channel name';
@HiveField(10, defaultValue: 'App notification')
String channelDescription = 'App notification';
PushMessage({
this.id = 0,
this.messageId,
required this.title,
required this.body,
this.payload,
this.channelDescription = 'App notification',
this.channelName = 'channel name',
this.channelId = 'channel_id',
this.bigPicture,
this.sentAt,
this.receivedAt,
});
Future<void> display() async {
AndroidNotificationDetails androidPlatformChannelSpecifics =
AndroidNotificationDetails(
channelId,
channelName,
channelDescription: channelDescription,
importance: Importance.max,
priority: Priority.high,
ticker: 'ticker',
icon: "app_logo",
largeIcon: DrawableResourceAndroidBitmap('app_logo'),
);
IOSNotificationDetails iOS = IOSNotificationDetails(
presentAlert: true,
);
NotificationDetails platformChannelSpecifics =
NotificationDetails(android: androidPlatformChannelSpecifics, iOS: iOS);
final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
FlutterLocalNotificationsPlugin();
await flutterLocalNotificationsPlugin
.show(id, title, body, platformChannelSpecifics, payload: payload);
}
Map<String, dynamic> toMap() {
return {
'id': id,
'messageId': messageId,
'title': title,
'body': body,
'bigPicture': bigPicture,
'sentAt': sentAt?.millisecondsSinceEpoch,
'receivedAt': receivedAt?.millisecondsSinceEpoch,
'payload': payload,
};
}
factory PushMessage.fromMap(map) {
return PushMessage(
id: map.hashCode,
messageId: map['messageId'],
title: map['title'],
body: map['body'],
payload: map['payload'],
bigPicture: map['bigPicture'],
sentAt: map['sentAt'] is DateTime
? map['sentAt']
: (map['sentAt'] is int
? DateTime.fromMillisecondsSinceEpoch(map['sentAt'])
: null),
receivedAt: map['receivedAt'] is DateTime
? map['receivedAt']
: (map['receivedAt'] is int
? DateTime.fromMillisecondsSinceEpoch(map['receivedAt'])
: null),
);
}
factory PushMessage.fromFCM(RemoteMessage event) {
RemoteNotification? notification = event.notification;
Map<String, dynamic> data = event.data;
var noti = PushMessage(
id: event.hashCode,
messageId: event.messageId!,
title: notification?.title ?? (data['title'] ?? 'No title found'),
body: notification?.body! ?? (data['body'] ?? 'Can not find content'),
sentAt: event.sentTime,
receivedAt: DateTime.now(),
bigPicture: event.notification?.android?.imageUrl,
);
return noti;
}
Future<void> saveToHive() async {
if (!Hive.isBoxOpen('notifications')) {
await Hive.openBox<PushMessage>('notifications');
}
await Hive.box<PushMessage>('notifications').add(this);
}
String toJson() => json.encode(toMap());
factory PushMessage.fromJson(String source) =>
PushMessage.fromMap(json.decode(source));
Future<void> sendToOne(String receiverToken) async {
try {
await Dio().post(
"https://fcm.googleapis.com/fcm/send",
data: {
"to": receiverToken,
"data": {
"url": bigPicture,
"title": title,
"body": body,
"mutable_content": true,
"sound": "Tri-tone"
}
},
options: Options(
contentType: 'application/json; charset=UTF-8',
headers: {
"Authorization":
"Bearer xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
},
),
);
} catch (e) {
debugPrint("Error sending notification");
debugPrint(e.toString());
}
}
}
notifications.dart通知屏幕
import 'package:flutter/material.dart';
import 'package:hive_flutter/hive_flutter.dart';
import 'package:app_name/custom_widgets/drawer_sheet.dart';
import 'package:app_name/custom_widgets/notification_expandable.dart';
import 'package:app_name/models/config.dart';
import 'package:app_name/models/push_message.dart';
class Notifications extends StatelessWidget {
const Notifications({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
if (!Hive.isBoxOpen('notifications')) {
Hive.openBox<PushMessage>('notifications');
}
return Scaffold(
appBar: AppBar(
title: const Text("Notifications"),
centerTitle: true,
),
body: ValueListenableBuilder<Box<PushMessage>>(
valueListenable: Hive.box<PushMessage>('notifications').listenable(),
builder: (context, Box<PushMessage> box, widget) {
return box.isEmpty
? const Center(child: Text('Empty'))
: ListView.builder(
itemCount: box.length,
itemBuilder: (BuildContext context, int i) {
int reversedIndex = box.length - i - 1;
return NotificationExpandable((box.getAt(reversedIndex))!);
},
);
},
),
drawer: !useDrawer
? null
: const DrawerSheet(
currentPage: "notifications",
),
floatingActionButton: FloatingActionButton(
onPressed: () {
Hive.box<PushMessage>('notifications').clear();
},
child: const Text('Clear'),
),
);
}
}
后台消息处理程序
Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
if (!Hive.isAdapterRegistered(1)) {
Hive.registerAdapter(PushMessageAdapter());
}
await Hive.initFlutter();
if (!Hive.isBoxOpen('notifications')) {
await Hive.openBox<PushMessage>('notifications');
}
await Firebase.initializeApp();
print('Handling a background message ${message.messageId}');
PushMessage msg = PushMessage.fromFCM(message);
await msg.saveToHive();
msg.display();
Hive.close();
}
我找到了绕过它的方法。
从firebase云消息的onBackgroundMessage处理程序到主隔离程序是不可能通信的，因为该函数在不同的隔离程序上运行，我不知道它是在哪里触发的。FCM文档还说，任何影响UI的逻辑都不能在这个处理程序中完成，但像将消息存储在设备存储中这样的io过程是可能的。
我将后台消息保存在与保存前台消息不同的配置单元框中。因此，在通知屏幕的initstate中，我首先从后台框中获取消息，将其附加到前台框中清除，然后启动一个在隔离中运行的函数，该函数每1秒检查一次后台消息。当函数获得后台消息时，它会将主隔离作为映射发送给它，在那里它被转换为前台消息的实例并附加到前台消息框中。每当前台通知框的值发生变化时，小部件就会得到更新，因为我使用了一个ValueListenableBuilder来监听前台通知的配置单元框。然后在屏幕的处置方法中终止隔离。这是代码。
import 'dart:async';
import 'dart:isolate';
import 'package:flutter/material.dart';
import 'package:hive_flutter/hive_flutter.dart';
import 'package:path_provider/path_provider.dart';
import 'package:app_name/custom_widgets/drawer_sheet.dart';
import 'package:app_name/custom_widgets/notification_expandable.dart';
import 'package:app_name/models/background_push_message.dart';
import 'package:app_name/models/config.dart';
import 'package:app_name/models/push_message.dart';
class Notifications extends StatefulWidget {
const Notifications({Key? key}) : super(key: key);
@override
State<Notifications> createState() => _NotificationsState();
}
class _NotificationsState extends State<Notifications> {
bool loading = true;
late Box<PushMessage> notifications;
@override
void dispose() {
stopRunningIsolate();
super.dispose();
}
@override
void initState() {
super.initState();
startIsolate().then((value) {
setState(() {
loading = false;
});
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("Notifications"),
centerTitle: true,
),
body: ValueListenableBuilder<Box<PushMessage>>(
valueListenable: Hive.box<PushMessage>('notifications').listenable(),
builder: (context, Box<PushMessage> box, widget) {
return box.isEmpty
? const Center(child: Text('Empty'))
: ListView.builder(
itemCount: box.length,
itemBuilder: (BuildContext context, int i) {
int reversedIndex = box.length - i - 1;
return NotificationExpandable((box.getAt(reversedIndex))!);
},
);
},
),
drawer: fromSchool
? null
: const DrawerSheet(
currentPage: "notifications",
),
floatingActionButton: FloatingActionButton(
onPressed: () {
Hive.box<PushMessage>('notifications').clear();
},
child: const Text('Clear'),
),
);
}
}
Isolate? isolate;
Future<bool> startIsolate() async {
if (!Hive.isAdapterRegistered(2)) {
Hive.registerAdapter(BackgroundPushMessageAdapter());
}
Hive.initFlutter();
if (!Hive.isBoxOpen('notifications')) {
await Hive.openBox<PushMessage>('notifications');
}
if (Hive.isBoxOpen('background_notifications')) {
await Hive.box<BackgroundPushMessage>('background_notifications').close();
}
await Hive.openBox<BackgroundPushMessage>('background_notifications');
Iterable<BackgroundPushMessage> bgNotifications =
Hive.box<BackgroundPushMessage>('background_notifications').values;
List<PushMessage> bgMsgs =
bgNotifications.map((e) => PushMessage.fromMap(e.toMap())).toList();
Hive.box<PushMessage>('notifications').addAll(bgMsgs);
await Hive.box<BackgroundPushMessage>('background_notifications').clear();
await Hive.box<BackgroundPushMessage>('background_notifications').close();
ReceivePort receivePort = ReceivePort();
String path = (await getApplicationDocumentsDirectory()).path;
isolate = await Isolate.spawn(
backgroundNotificationCheck, [receivePort.sendPort, path]);
receivePort.listen((msg) {
List<Map> data = msg as List<Map>;
List<PushMessage> notis =
data.map((noti) => PushMessage.fromMap(noti)).toList();
Hive.box<PushMessage>('notifications').addAll(notis);
});
return true;
}
void stopRunningIsolate() {
isolate?.kill(priority: Isolate.immediate);
isolate = null;
}
Future<void> backgroundNotificationCheck(List args) async {
SendPort sendPort = args[0];
String path = args[1];
if (!Hive.isAdapterRegistered(1)) {
Hive.registerAdapter(PushMessageAdapter());
}
Hive.init(path);
Timer.periodic(const Duration(seconds: 1), (Timer t) async {
if (!Hive.isAdapterRegistered(2)) {
Hive.registerAdapter(BackgroundPushMessageAdapter());
}
if (Hive.isBoxOpen('background_notifications')) {
await Hive.box<BackgroundPushMessage>('background_notifications').close();
}
await Hive.openBox<BackgroundPushMessage>('background_notifications');
if (Hive.box<BackgroundPushMessage>('background_notifications')
.isNotEmpty) {
List<Map> notifications =
Hive.box<BackgroundPushMessage>('background_notifications')
.values
.map((noti) => noti.toMap())
.toList();
sendPort.send(notifications);
await Hive.box<BackgroundPushMessage>('background_notifications').clear();
}
await Hive.box<BackgroundPushMessage>('background_notifications').close();
});
}
onBackgroundNotification处理程序
if (!Hive.isAdapterRegistered(2)) {
Hive.registerAdapter(BackgroundPushMessageAdapter());
}
final documentDirectory = await getApplicationDocumentsDirectory();
Hive.init(documentDirectory.path);
if (Hive.isBoxOpen('background_notifications')) {
await Hive.box<BackgroundPushMessage>('background_notifications').close();
}
await Hive.openBox<BackgroundPushMessage>('background_notifications');
await Firebase.initializeApp();
print('Handling a background message ${message.messageId}');
BackgroundPushMessage msg = BackgroundPushMessage.fromFCM(message);
msg.display();
Hive.box<BackgroundPushMessage>('background_notifications').add(msg);
print("Notification shown for $msg");
print(
"Notification length ${Hive.box<BackgroundPushMessage>('background_notifications').length}");
if (Hive.isBoxOpen('background_notifications')) {
Hive.box<BackgroundPushMessage>('background_notifications').close();
}
注意，我对后台通知对象和前台通知对象都有不同的类，因为hive不能在不同的框中注册同一类的两个实例。因此，我必须为每个类注册适配器。不过，我让一个类扩展另一个类以避免重复代码。
我正在使用Firestore更新应用程序。
在onBackgroundMessage中，我正在执行以下
await Firebase.initializeApp().then((value) async {
FirebaseFirestore.instance.collection('background').doc(dt1).set({
"date": dt1,
// add fields to the Doc
}).then((value) async {
FirebaseService.localNotificationsPlugin.show(
0,
"$title",
"$body",
FirebaseService.platformChannelSpecifics,
payload: "$payload",
)
});