后台推送通知 iOS Firebase

Question

我有一个使用 firebase 的 Flutter iOS 应用，但后台未收到通知。如果在应用处于后台时发送 firebase 通知，则不会收到通知，但在打开应用时会显示（收到）通知。

我在以前的应用上使用了相同的代码并且运行良好，所以我不确定问题是什么。

我在 xcode 中打开了后台模式和推送通知。我已经在 firebase 中提供了 apns。

非常感谢任何帮助。谢谢

这是我的代码

Future<dynamic> myBackgroundMessageHandler(Map<String, dynamic> message){
  print("Background Message Handler");
  print("Background Message: $message");

  return Future<void>.value();
}

class PushMessagingExample extends StatefulWidget {
  @override
  _PushMessagingExampleState createState() => _PushMessagingExampleState();
}
class _PushMessagingExampleState extends State<PushMessagingExample> {
  String _homeScreenText = "Waiting for token...";
  String _messageText = "Waiting for message...";
final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin;
@override
  void initState() {
    super.initState();
    _firebaseMessaging.configure(
      onMessage: (Map<String, dynamic> message) async {
        setState(() {
          _messageText = "Push Messaging message: $message";
        });
        showNotification();
        print("onMessage: $message");
      },

      onBackgroundMessage: myBackgroundMessageHandler,
      onLaunch: (Map<String, dynamic> message) async {
        setState(() {
          _messageText = "Push Messaging message: $message";
        });
        print("onLaunch: $message");
      },
      onResume: (Map<String, dynamic> message) async {
        setState(() {
          _messageText = "Push Messaging message: $message";
        });
        print("onResume: $message");
      },
    );
    _firebaseMessaging.requestNotificationPermissions(
        const IosNotificationSettings(sound: true, badge: true, alert: true));
    _firebaseMessaging.onIosSettingsRegistered
        .listen((IosNotificationSettings settings) {
      print("Settings registered: $settings");
    });
    
    flutterLocalNotificationsPlugin = new FlutterLocalNotificationsPlugin();
    var android = new AndroidInitializationSettings('@mipmap/ic_launcher');
    var iOS = new IOSInitializationSettings();
    var initSetttings = new InitializationSettings(android, iOS);
    flutterLocalNotificationsPlugin.initialize(initSetttings,
        selectNotification: onSelectNotification);
    
    _firebaseMessaging.getToken().then((String token) {
      assert(token != null);
      print("Token:$token");
    });

    _firebaseMessaging.getToken().then((String token) {
      assert(token != null);
      setState(() {
        _homeScreenText = "Push Messaging token: $token";
      });
      print(_homeScreenText);
    });
  }

  Future onSelectNotification(String payload) {
    debugPrint("payload : $payload");
    showDialog(
      context: context,
      builder: (_) => new AlertDialog(
        title: new Text('Notification'),
        content: new Text('$payload'),
      ),
    );
  }


@override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: const Text('Push Messaging Demo'),
        ),
        body: Material(
          child: Column(
            children: <Widget>[
              Center(
                child: Text(_homeScreenText),
              ),
              Row(children: <Widget>[
                Expanded(
                  child: Text(_messageText),
                ),
              ])
            ],
),
        ));
  }

  showNotification() async {
    var android = new AndroidNotificationDetails(
        'channel id', 'channel NAME', 'CHANNEL DESCRIPTION',
        priority: Priority.High, importance: Importance.Max);
    var iOS = new IOSNotificationDetails();
    var platform = new NotificationDetails(android, iOS);
    await flutterLocalNotificationsPlugin.show(
        0, 'New Video is out', 'Hello notif body', platform,
        payload: 'This is the notification body');
  }

}
void main() {
  runApp(
    MaterialApp(
      home: PushMessagingExample(),
    ),
  );
}

<plist version="1.0">
<dict>
    <key>CFBundleDevelopmentRegion</key>
    <string>$(DEVELOPMENT_LANGUAGE)</string>
    <key>CFBundleExecutable</key>
    <string>$(EXECUTABLE_NAME)</string>
    <key>CFBundleIdentifier</key>
    <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
    <key>CFBundleInfoDictionaryVersion</key>
    <string>6.0</string>
    <key>CFBundleName</key>
    <string>code_notif_test</string>
    <key>CFBundlePackageType</key>
    <string>APPL</string>
    <key>CFBundleShortVersionString</key>
    <string>$(FLUTTER_BUILD_NAME)</string>
    <key>CFBundleSignature</key>
    <string>????</string>
    <key>CFBundleVersion</key>
    <string>$(FLUTTER_BUILD_NUMBER)</string>
    <key>LSRequiresIPhoneOS</key>
    <true/>
    <key>UIBackgroundModes</key>
    <array>
        <string>fetch</string>
        <string>processing</string>
        <string>remote-notification</string>
    </array>
    <key>UILaunchStoryboardName</key>
    <string>LaunchScreen</string>
    <key>UIMainStoryboardFile</key>
    <string>Main</string>
    <key>UISupportedInterfaceOrientations</key>
    <array>
        <string>UIInterfaceOrientationPortrait</string>
        <string>UIInterfaceOrientationLandscapeLeft</string>
        <string>UIInterfaceOrientationLandscapeRight</string>
    </array>
    <key>UISupportedInterfaceOrientations~ipad</key>
    <array>
        <string>UIInterfaceOrientationPortrait</string>
        <string>UIInterfaceOrientationPortraitUpsideDown</string>
        <string>UIInterfaceOrientationLandscapeLeft</string>
        <string>UIInterfaceOrientationLandscapeRight</string>
    </array>
    <key>FirebaseAppDelegateProxyEnabled</key>
    <false/>
    <key>UIViewControllerBasedStatusBarAppearance</key>
    <false/>
</dict>
</plist>