Flutter集成FCM与flutter_local_notifications时Android 12+崩溃求助

1. 修复'Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified'崩溃 #

• 打开安卓项目android/app/build.gradle，若compileSdkVersion和targetSdkVersion为31及以上，添加WorkManager兼容依赖：

  dependencies {
      // 其他依赖保留
      implementation "androidx.work:work-runtime:2.8.1" // 版本需≥2.7.0
  }
  

• 或升级FCM相关依赖到最新稳定版：
  在android/build.gradle更新Google服务插件：

  dependencies {
      classpath 'com.google.gms:google-services:4.4.0' // 最新稳定版
  }
  

  在android/app/build.gradle更新firebase-messaging：

  implementation 'com.google.firebase:firebase-messaging:23.3.1' // 最新稳定版
  

2. 解决'com.example.blog_app.java.MyFirebaseMessagingService'类未找到错误 #

• 检查android/app/src/main/AndroidManifest.xml中服务注册路径：若用Kotlin实现服务，路径需去掉.java后缀；若用Java，确认文件在java/com/example/blog_app/目录下，类名与注册名称完全一致。
• 正确的服务注册示例：

  <service
      android:name=".MyFirebaseMessagingService"
      android:exported="false">
      <intent-filter>
          <action android:name="com.google.firebase.MESSAGING_EVENT" />
      </intent-filter>
  </service>
  

• 执行flutter clean→flutter pub get，重新编译项目。

3. 修复前台不显示通知问题 #

• 确保正确初始化flutter_local_notifications：

  final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();
  
  Future<void> _initializeNotifications() async {
    const AndroidInitializationSettings initializationSettingsAndroid =
        AndroidInitializationSettings('@mipmap/ic_launcher');
    const InitializationSettings initializationSettings =
        InitializationSettings(android: initializationSettingsAndroid);
    await flutterLocalNotificationsPlugin.initialize(initializationSettings);
    await _createNotificationChannel(); // 调用渠道创建方法
  }
  

• 配置前台消息监听并显示通知：

  void main() async {
    WidgetsFlutterBinding.ensureInitialized();
    await Firebase.initializeApp();
    await _initializeNotifications();
    
    FirebaseMessaging.onMessage.listen((RemoteMessage message) {
      RemoteNotification? notification = message.notification;
      AndroidNotification? android = message.notification?.android;
      if (notification != null && android != null) {
        flutterLocalNotificationsPlugin.show(
          notification.hashCode,
          notification.title,
          notification.body,
          NotificationDetails(
            android: AndroidNotificationDetails(
              'blog_app_channel',
              'Blog App Notifications',
              channelDescription: 'Notifications for blog updates',
              icon: android.smallIcon,
            ),
          ),
        );
      }
    });
  
    FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
    runApp(const MyApp());
  }
  

• 补充创建Android通知渠道（Android 8.0+强制要求）：

  Future<void> _createNotificationChannel() async {
    const AndroidNotificationChannel channel = AndroidNotificationChannel(
      'blog_app_channel',
      'Blog App Notifications',
      description: 'Notifications for blog updates',
      importance: Importance.max,
    );
    await flutterLocalNotificationsPlugin
        .resolvePlatformSpecificImplementation<AndroidFlutterLocalNotificationsPlugin>()
        ?.createNotificationChannel(channel);
  }
  

内容的提问来源于stack exchange，提问作者ayush