Flutter Firebase Cloud Messaging - 应用程序在后台时的通知

Question

我目前正在使用 FCM 进行推送通知。当我的应用程序打开时，我会收到通知，但是当应用程序关闭或在后台时 - 在我重新打开应用程序之前我不会收到任何消息。在 XCode 上，我启用了后台提取和远程通知。接下来我应该检查什么？谢谢你。

我在用 firebase_messaging: ^5.1.6

用代码

    _firebaseMessaging.configure(
      onMessage: (Map<String, dynamic> message) async {
        print('message is $message');

        setState(
          () {
            showOverlayNotification((context) {
              return GestureDetector(
                onTap: () {},
                child: Platform.isIOS
                    ? MessageNotification(
                        title: message['notification']['title'],
                        body: message['notification']['body'],
                      )
                    : MessageNotification(
                        title: message['notification']['title'],
                        body: message['notification']['body'],
                      ),
              );
              // }
            }, duration: Duration(milliseconds: 4000));
          },
        );
      },
      onLaunch: (Map<String, dynamic> message) async {
        print('launching');
      },
      onResume: (Map<String, dynamic> message) async {
        print('resuming');
        print("onResume: $message");
      },
    );
    _firebaseMessaging.requestNotificationPermissions(
        const IosNotificationSettings(sound: true, badge: true, alert: true));
    _firebaseMessaging.onIosSettingsRegistered
        .listen((IosNotificationSettings settings) {
      print("Settings registered: $settings");
    });
    _firebaseMessaging.getToken().then((String token) {
      assert(token != null);
      setState(() {
        _firebaseMessaging.subscribeToTopic('all');
        print('subscribed');
        _homeScreenText = "Push Messaging token: $token";
        _saveDeviceToken(token);
      });
      print(_homeScreenText);
    }); ```


My flutter doctor response is:

```[?] Flutter (Channel stable, v1.9.1+hotfix.2, on Mac OS X 10.14.6 18G103, locale en-GB)
    • Flutter version 1.9.1+hotfix.2 at /Users/student/flutter
    • Framework revision 2d2a1ffec9 (3 weeks ago), 2019-09-06 18:39:49 -0700
    • Engine revision b863200c37
    • Dart version 2.5.0


[?] Android toolchain - develop for Android devices (Android SDK version 29.0.0)
    • Android SDK at /Users/student/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-29, build-tools 29.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
    • All Android licenses accepted.

[?] Xcode - develop for iOS and macOS (Xcode 11.0)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.0, Build version 11A420a
    • CocoaPods version 1.7.4

[?] Android Studio (version 3.4)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 38.2.1
    • Dart plugin version 183.6270
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)

[?] VS Code (version 1.38.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.4.1

[?] Connected device (1 available)
    • iPhone • e1100c84b1fc7871a6790337ef23c0fd7af397d5 • ios • iOS 12.4.1