Xamarin iOS中FirebasePushNotificationManager初始化致应用冻结求助

问题描述 #

使用Xamarin（C#）开发应用时，Android端在Application.cs中调用FirebasePushNotificationManager.Initialize(options, true);可正常接收通知，但iOS端在AppDelegate.cs的FinishedLaunching方法中添加该行代码后，应用出现UI冻结（按钮、输入框点击无响应），移除该行代码后iOS应用恢复正常。

用户提供的AppDelegate.cs代码如下：

public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
{
    public override bool FinishedLaunching(UIApplication app, NSDictionary options)
    {
        ServicePointManager
            .ServerCertificateValidationCallback +=
                (sender, cert, chain, sslPolicyErrors) => true;

        global::Xamarin.Forms.Forms.Init();

        var iosClientHandler = new NSUrlSessionHandler();
      
        Services.HttpClientService.HttpClientHandler = iosClientHandler;

        LoadApplication(new App());
        
        //This line is causing the issue
        FirebasePushNotificationManager.Initialize(options, true);

        return base.FinishedLaunching(app, options);
    }

    public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
    {
        FirebasePushNotificationManager.DidRegisterRemoteNotifications(deviceToken);
    }

    public override void FailedToRegisterForRemoteNotifications(UIApplication application, NSError error)
    {
        FirebasePushNotificationManager.RemoteNotificationRegistrationFailed(error);
    }

    // To receive notifications in foreground on iOS 9 and below
    // To receive notifications in background in any iOS version
    public override void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
    {
        // If you are receiving a notification message while your app is in the background,
        // this callback will not be fired 'till the user taps on the notification launching the application.

        // If you disable method swizzling, you'll need to call this method.
        // This lets FCM track message delivery and analytics, which is performed
        // automatically with method swizzling enabled
        FirebasePushNotificationManager.DidReceiveMessage(userInfo);
        // Do your magic to handle the notification data
        System.Console.WriteLine(userInfo);

        completionHandler(UIBackgroundFetchResult.NewData);
    }
}

解决方法 #

1. 调整初始化时机与顺序 #

尝试修改Firebase初始化代码的位置，避免在主线程加载应用后立即执行阻塞操作：

• 方案A：将初始化移至LoadApplication之前

public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
    ServicePointManager
        .ServerCertificateValidationCallback +=
            (sender, cert, chain, sslPolicyErrors) => true;

    global::Xamarin.Forms.Forms.Init();

    var iosClientHandler = new NSUrlSessionHandler();
    Services.HttpClientService.HttpClientHandler = iosClientHandler;

    // 先初始化Firebase，再加载应用
    FirebasePushNotificationManager.Initialize(options, false);

    LoadApplication(new App());

    return base.FinishedLaunching(app, options);
}

• 方案B：将初始化移至base.FinishedLaunching调用之后

public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
    ServicePointManager
        .ServerCertificateValidationCallback +=
            (sender, cert, chain, sslPolicyErrors) => true;

    global::Xamarin.Forms.Forms.Init();

    var iosClientHandler = new NSUrlSessionHandler();
    Services.HttpClientService.HttpClientHandler = iosClientHandler;

    LoadApplication(new App());

    var result = base.FinishedLaunching(app, options);
    
    // 在base方法执行完成后初始化
    FirebasePushNotificationManager.Initialize(options, true);

    return result;
}

2. 禁用延迟注册 #

将初始化的第二个参数enableDelayedRegistration设为false，避免延迟注册逻辑阻塞主线程：

FirebasePushNotificationManager.Initialize(options, false);

确保推送注册的回调方法（RegisteredForRemoteNotifications、FailedToRegisterForRemoteNotifications）已正确实现，保证注册流程正常执行。

3. 后台线程执行初始化 #

如果初始化操作存在同步阻塞，可将其放入后台线程执行，避免占用主线程：

LoadApplication(new App());

// 后台线程执行Firebase初始化
Task.Run(() => 
{
    FirebasePushNotificationManager.Initialize(options, true);
});

return base.FinishedLaunching(app, options);

4. 检查版本兼容性 #

确认Xamarin.Forms版本与Plugin.FirebasePushNotification版本兼容，尝试更新到最新稳定版或回退至已知兼容版本，避免版本冲突导致主线程阻塞。

5. 验证iOS项目配置 #

• 确认GoogleService-Info.plist已添加到iOS项目，且Build Action设置为BundleResource
• 检查Info.plist中是否配置了推送权限：

<key>UIBackgroundModes</key>
<array>
    <string>remote-notification</string>
</array>
<key>NSRemoteNotificationUsageDescription</key>
<string>需要推送通知权限来接收消息</string>

内容的提问来源于stack exchange，提问作者Edward0524