Xamarin.Forms iOS端Firebase推送收不到通知，OnNotificationReceived未触发

一、配置细节再核对 #

• 确认GoogleService-Info.plist的Build Action是BundleResource，文件不要嵌套在子文件夹里，避免读取失败
• 检查Entitlements.plist：除了开启推送通知，还要确认APS Environment配置和测试环境匹配——开发环境选development，生产环境选production；如果用到App Groups也要确保配置正确
• Info.plist里设了FirebaseAppDelegateProxyEnabled为false后，必须手动处理APNs回调，不能依赖Firebase自动代理
• 后台模式除了勾选「远程通知」，如果需要静默推送，还要勾选「后台获取」

二、AppDelegate代码逻辑检查 #

禁用Firebase代理后，必须手动实现APNs回调并转发给插件，关键代码要覆盖这些场景：

public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
    // 初始化Firebase和推送插件
    Firebase.Core.App.Configure();
    CrossFirebasePushNotification.Current.Initialize();

    // 请求推送权限
    UNUserNotificationCenter.Current.RequestAuthorization(UNAuthorizationOptions.Alert | UNAuthorizationOptions.Badge | UNAuthorizationOptions.Sound, (granted, error) =>
    {
        if (granted)
        {
            UIApplication.SharedApplication.RegisterForRemoteNotifications();
        }
    });

    // 其他初始化代码...
    return base.FinishedLaunching(app, options);
}

// 注册APNs成功后转发Token给插件
public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
{
    CrossFirebasePushNotification.Current.RegisterDeviceToken(deviceToken);
}

// iOS 9及以下后台/前台接收通知
public override void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
{
    CrossFirebasePushNotification.Current.OnNotificationReceived(userInfo);
    completionHandler(UIBackgroundFetchResult.NewData);
}

// iOS 10+ 前台显示通知回调
[Export("userNotificationCenter:willPresentNotification:withCompletionHandler:")]
public void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)
{
    CrossFirebasePushNotification.Current.OnNotificationReceived(notification.Request.Content.UserInfo);
    // 前台要显示通知必须设置这个选项
    completionHandler(UNNotificationPresentationOptions.Alert | UNNotificationPresentationOptions.Sound);
}

// iOS 10+ 用户点击通知回调
[Export("userNotificationCenter:didReceiveNotificationResponse:withCompletionHandler:")]
public void DidReceiveNotificationResponse(UNUserNotificationCenter center, UNNotificationResponse response, Action completionHandler)
{
    CrossFirebasePushNotification.Current.OnNotificationReceived(response.Notification.Request.Content.UserInfo);
    completionHandler();
}

• 检查是否漏写了上述任意回调方法，尤其是iOS 10+的两个UNUserNotificationCenter相关方法

三、推送测试方式验证 #

• 推送消息格式必须符合APNs+Firebase要求，示例JSON（可通过Firebase API发送）：

{
  "to": "你的iOS设备Token",
  "notification": {
    "title": "测试标题",
    "body": "测试内容"
  },
  "data": {
    "custom_key": "custom_value"
  },
  "apns": {
    "payload": {
      "aps": {
        "alert": {
          "title": "测试标题",
          "body": "测试内容"
        },
        "sound": "default"
      }
    }
  }
}

• 区分前台/后台场景：APP在前台时，必须在WillPresentNotification中设置显示选项，否则通知不会弹窗；后台推送如果需要静默处理，要在aps里加"content-available": 1
• 确认Firebase控制台的iOS应用配置中，上传的APNs证书和测试环境匹配——开发环境用开发证书，生产环境用生产证书

四、日志深度排查 #

• 在AppDelegate的所有推送相关回调里加日志输出，比如：

public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
{
    Console.WriteLine($"APNs Token获取成功: {deviceToken}");
    CrossFirebasePushNotification.Current.RegisterDeviceToken(deviceToken);
}

public override void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
{
    Console.WriteLine($"收到APNs原始消息: {userInfo}");
    CrossFirebasePushNotification.Current.OnNotificationReceived(userInfo);
    completionHandler(UIBackgroundFetchResult.NewData);
}

• 打开Xcode的设备日志（Window > Devices and Simulators > 选中设备 > View Device Logs），搜索APNs、Firebase关键词，找隐藏的错误（比如证书不匹配、消息格式错误）
• 查看Firebase控制台「Cloud Messaging」>「Reports」，看推送的送达状态，如果显示「已发送但未送达」，大概率是APNs证书问题

五、版本兼容性检查 #

• 确认Plugin.FirebasePushNotification 3.4.35和Xamarin.Forms 5.0.0.2515的兼容性，尝试更新插件到最新稳定版，或者回退到已知兼容的版本
• 检查Firebase相关NuGet包（如Xamarin.Firebase.iOS.CloudMessaging、Xamarin.Firebase.iOS.Core）的版本，必须和插件版本匹配，避免版本冲突

内容的提问来源于stack exchange，提问作者raito tec