Flutter iOS端前台无法接收OneSignal静默通知问题排查

核心问题排查 #

1. OneSignal SDK未初始化：你的AppDelegate里完全没初始化OneSignal，这直接导致SDK无法接管通知处理逻辑，静默通知自然没法触发原生回调。
2. 前台通知回调未配置：没有设置UNUserNotificationCenter的delegate，前台收到通知时不会走原生方法，全被OneSignal Flutter插件拦截了。
3. 静默通知Payload可能不符合要求：APN发送的静默通知必须严格符合格式，否则iOS不会识别为静默通知。

具体修复步骤 #

1. 补全OneSignal初始化与Delegate配置 #

修改AppDelegate.swift，添加OneSignal初始化代码，同时设置通知中心delegate，确保前台通知能触发原生回调：

import Flutter
import UIKit
import OneSignal // 别忘了导入OneSignal

@main
@objc class AppDelegate: FlutterAppDelegate {
    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
        print("**** didFinishLaunchingWithOptions ****");
        
        // 初始化OneSignal，替换成你的App ID
        OneSignal.initialize("YOUR_ONESIGNAL_APP_ID", withLaunchOptions: launchOptions)
        
        let center = UNUserNotificationCenter.current()
        center.requestAuthorization(options: [.alert, .badge, .sound]) { (granted, error) in
            if granted {
                DispatchQueue.main.async {
                    UIApplication.shared.registerForRemoteNotifications()
                }
            }
        }
        // 设置delegate，确保前台通知能触发原生方法
        center.delegate = self
        
        GeneratedPluginRegistrant.register(with: self)
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }

    // 处理前台收到的所有通知（包括非静默和静默）
    override func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        print("**** 前台收到通知 ****")
        let userInfo = notification.request.content.userInfo
        
        // 检查是否为静默通知
        if let aps = userInfo["aps"] as? [String: Any], aps["content-available"] as? Int == 1 {
            // 传递给Flutter
            if let flutterVC = window?.rootViewController as? FlutterViewController {
                let channel = FlutterMethodChannel(name: "com.shachardev.vivencia/notifications", binaryMessenger: flutterVC.binaryMessenger)
                channel.invokeMethod("notificationReceived", arguments: userInfo)
            }
            // 静默通知不需要展示，直接传空选项
            completionHandler([])
        } else {
            // 非静默通知交给OneSignal处理，同时展示通知
            OneSignal.didReceiveNotificationExtensionRequest(notification.request, with: notification.request.content.mutableCopy() as! UNMutableNotificationContent, withContentHandler: { content in
                completionHandler([.alert, .sound, .badge])
            })
        }
    }

    override func application(
        _ application: UIApplication,
        didReceiveRemoteNotification userInfo: [AnyHashable: Any],
        fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void
    ) {
        print("**** didReceiveRemoteNotification ****");
               
        DispatchQueue.main.async {
                print("收到通知内容: \(userInfo)")
        }        
        // 处理静默通知
        if let aps = userInfo["aps"] as? [String: Any],
           aps["content-available"] as? Int == 1 {
            if let flutterVC = window?.rootViewController as? FlutterViewController {
                let channel = FlutterMethodChannel(name: "com.shachardev.vivencia/notifications", binaryMessenger: flutterVC.binaryMessenger)
                channel.invokeMethod("notificationReceived", arguments: userInfo)
            }
            completionHandler(.newData)
            return
        }

        // 非静默通知交给OneSignal处理
        OneSignal.didReceiveRemoteNotification(userInfo, fetchCompletionHandler: completionHandler)
    }
}

2. 确保静默通知Payload格式正确 #

通过APN控制台发送的静默通知必须满足：

• aps字典必须包含"content-available": 1
• 不能有alert、badge、sound这些会触发通知展示的字段
• 示例Payload：

{
  "aps": {
    "content-available": 1
  },
  "custom_data": "你的自定义数据"
}

3. 验证后台权限配置 #

• 在Xcode的Signing & Capabilities中，添加Background Modes，勾选Remote notifications
• 确认Info.plist中UIBackgroundModes数组包含remote-notification

4. 关于NotificationServiceExtension #

这个扩展只处理带有mutable-content: 1的通知（比如需要修改通知内容、加附件），静默通知不需要这个扩展，所以它不会触发，属于正常情况。如果不需要修改通知内容，可以直接移除这个扩展。

测试注意事项 #

• 必须用真机测试，模拟器收不到APN通知
• 设备要登录Apple ID，并且开启了应用的通知权限
• 测试前台静默通知时，确保应用处于完全活跃的前台状态（没被挂起）

内容的提问来源于stack exchange，提问作者Shachar