当应用程序在 flutter 中关闭时，如何在本地保存 firebase 推送通知设备？

Question

我使用 Hive_flutter 和 flutter_local_notifications：^13.0.0。而且我没有任何关于在应用程序关闭时保存通知设备本地的想法。 你能帮助我吗？谢谢你的关注

Answer 1

我不明白主要问题。您只想在应用程序关闭或在后台时显示通知？或者你真的需要将它们保存到本地数据库？无论如何，尝试使用这个类

import 'dart:async';

import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';

class PushNotificationService {
  static FirebaseMessaging messaging = FirebaseMessaging.instance;
  static final FlutterLocalNotificationsPlugin notificationPlugin =
      FlutterLocalNotificationsPlugin();
  static const AndroidNotificationChannel channel = AndroidNotificationChannel(
    'high_importance_channel', // id
    'High Importance Notifications', // title
    description:
        'This channel is used for important notifications.', // description
    importance: Importance.high,
  );
  static String? idPush;
  static StreamController<RemoteMessage> _messageStream =
      StreamController.broadcast();
  static Stream<RemoteMessage> get messagesStream => _messageStream.stream;

  static Future _backgroundHandler(RemoteMessage message) async {
    _messageStream.add(message);
    // implement your actions here
  }

  static Future _onMessageHandler(RemoteMessage message) async {
    _messageStream.add(message);
    // implement your actions here, if you want to use flutter_local_notifications, use the display() method.
  }

  static Future _onMessageOpenApp(RemoteMessage message) async {
    _messageStream.add(message);
    // implement your actions here
  }

  // iniciar firebase i notificacions locals
  static Future initializeApp() async {
    //Push notifications
    await Firebase.initializeApp();
    idPush = await FirebaseMessaging.instance.getToken();
    print('idPush: $idPush');
    //Handler
    FirebaseMessaging.onBackgroundMessage(_backgroundHandler);
    FirebaseMessaging.onMessage.listen(_onMessageHandler);
    FirebaseMessaging.onMessageOpenedApp.listen(_onMessageOpenApp);

    //local notifications initialization
    const InitializationSettings initializationSettings =
        InitializationSettings(
      iOS: DarwinInitializationSettings(),
      android: AndroidInitializationSettings("@mipmap/ic_notification"),
    );
    notificationPlugin.initialize(initializationSettings);
  }

  // mètode per obrir una notificació local (només amb l'app oberta)
  static void display(RemoteMessage message) async {
    try {
      await notificationPlugin.show(
        message.notification!.hashCode,
        message.notification!.title,
        message.notification!.body,
        NotificationDetails(
          android: AndroidNotificationDetails(
            channel.id,
            channel.name,
            channelDescription: channel.description,
            color: Colors.blue,
            icon: '@mipmap/ic_notification',
          ),
          iOS: const DarwinNotificationDetails(
              presentAlert: true, presentBadge: true, presentSound: true),
        ),
      );
    } on Exception catch (e) {
      print(e);
    }
  }

  // demanar permisos
  Future<void> requestPermission() async {
    NotificationSettings settings = await messaging.requestPermission(
      alert: true,
      announcement: false,
      badge: true,
      carPlay: false,
      criticalAlert: false,
      provisional: false,
      sound: true,
    );

    if (settings.authorizationStatus == AuthorizationStatus.authorized) {
      print('User granted permission');
    } else if (settings.authorizationStatus ==
        AuthorizationStatus.provisional) {
      print('User granted provisional permission');
    } else {
      print('User declined or has not accepted permission');
    }
  }

  static closeStreams() {
    _messageStream.close();
  }
}

当应用程序关闭或在后台时，此类将显示通知。如果您需要在应用程序打开时显示它们，您可以通过显示方法。如果你想将它们保存到配置单元中，只需在处理程序上实现该部分即可。 最后在你的 main 中初始化类：

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await PushNotificationService.initializeApp();
  runApp(const MyApp());
}