iOS主屏幕Widget应用终止时更新内容的可行方案求解

• 正在开发一款显示字符串的简单Widget
• 希望每日从服务器获取数据更新该字符串（仅需用服务器数据更新Widget，无其他偏好）
• 主应用采用Flutter开发，Widget为iOS原生实现
• 核心问题：未找到应用终止（从应用切换器划走）时获取服务器数据并更新Widget的可行方案

本人接受Flutter、iOS原生或混合解决方案。

使用Workmanager包 #

在Flutter中尝试调度周期性任务从Firebase获取数据，Android端运行正常，但根据文档，iOS不支持周期性任务，仅支持单次任务。

通过Firebase Cloud Messaging发送通知或静默通知 #

在Flutter中尝试使用firebaseMessagingBackgroundHandler，但根据文档：

On iOS, if the user swipes away the application from the app switcher, it must be manually reopened for background messages to start working again

实际测试符合该描述：Android端可正确处理并达成预期效果，但iOS端无法实现。

测试结果 #

• 前台状态：Android和iOS均可正确接收并处理通知（推送和静默）
• 后台或终止状态：Android和iOS均可显示推送通知，但无法处理通知内容并更新Widget

Python Google Cloud Function 代码

# Imports
import firebase_admin
from firebase_admin import messaging

# Regular Push Notification
title = 'Title Text'
body = 'Notification Body'

regular_message = messaging.Message(
    notification=messaging.Notification(
        title=title,
        body=body
    ),
    token=token,
)

# Send regular push notification
regular_response = messaging.send(regular_message)


# Silent Push Notification
textA = 'Title Text'
textB = 'Notification Body'

silent_message = messaging.Message(
    data={
        'textA': textA,
        'textB': textB,
        'content_available': '1',
    },
    token=token,
)

# Send silent notification
silent_response = messaging.send(silent_message)

Flutter FirebaseMessaging 代码

Future main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();

  //Setup FCM
  await setupFirebaseCloudMessaging();

  //Set up background message handler
  FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
 
  runApp(MyApp());
}

Future<void> setupFirebaseCloudMessaging() async {
  try {
    // Request FCM permission
    final messaging = FirebaseMessaging.instance;

    final settings = await messaging.requestPermission(provisional: true);

    print('Permission granted: ${settings.authorizationStatus}');

    //Register with FCM
    // It requests a registration token for sending messages to users from your App server or other trusted server environment.
    String? token = await messaging.getToken();
    if (token != null) {
      print('Registration Token=$token');
      await persistToken(token);
    }

    // Set up foreground message handler
    FirebaseMessaging.onMessage.listen((RemoteMessage message) {

      if (message.data.containsKey('content_available') &&
          message.data['content_available'] == '1') {

        // Silent Notification (Data-only)
        print('Handling silent notification');

        // Access data from the data payload
        String textA = message.data['textA'];
        String textB = message.data['textB'];
     

        // Uses HomeWidget package to store in user defaults
        updateWidget(textA, texB);
      } else {
        // Regular Push Notification
        print('Handling regular push notification');

        // Add the message to the stream for normal notification
        _messageStreamController.sink.add(message);

      }
    });

  } catch (e) {
    print('Error setting up FCM: $e');
  }
}


Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
 

  if (message.data.containsKey('content_available') &&
          message.data['content_available'] == '1') {

        // Silent Notification (Data-only)
        print('Handling silent notification');

        // Access data from the data payload
        String textA = message.data['textA'];
        String textB = message.data['textB'];
     

        // Uses HomeWidget package to store in user defaults
        updateWidget(textA, texB);
  } else {
    // Regular Push Notification
    print('Handling regular push notification');
  }
}

了解到iOS对终止或后台状态下的应用有诸多（刻意设置的）限制，但仍有许多应用可在应用终止时用服务器数据更新主屏幕Widget，现求可行方案，不限Flutter或原生实现。

已查阅的资料 #

• Flutter FCM接收相关文档
• Flutter Workmanager iOS配置文档
• FlutterFire项目相关Issue
• Apple官方远程通知后台更新文档
• Stack Overflow：Flutter FCM在iOS应用终止时无法处理消息
• Stack Overflow：Flutter在iOS应用终止时获取数据
• Stack Overflow：iOS推送通知与AppDelegate方法行为
• 其他大量相关内容

内容的提问来源于stack exchange，提问作者Recurring Value