'onRepeatEvent' stops working after several hours in the background.

[thorito]

When I start the application, the ‘onRepeatEvent’ is correctly triggered, updating the push notification every 5 seconds.

However, after the app has been in the background for several hours on Android, if all notifications on the device are cleared, it seems that the event is no longer triggered.

The app is still running, as launching it does not show the Splash screen.

What could be the reason why the ‘onRepeatEvent’ method stops being triggered?

Below is an example implementation following the documentation.

---

flutter doctor -v

 [✓] Flutter (Channel stable, 3.32.5, on macOS 15.5 24F74 darwin-arm64, locale es-ES) [548ms]
    • Flutter version 3.32.5 on channel stable at /Volumes/data/development/flutter/sdk/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision fcf2c11572 (8 days ago), 2025-06-24 11:44:07 -0700
    • Engine revision dd93de6fb1
    • Dart version 3.8.1
    • DevTools version 2.45.1

[✓] Android toolchain - develop for Android devices (Android SDK version 36.0.0) [1.460ms]
    • Android SDK at /Volumes/data/development/android/sdk
    • Platform android-36, build-tools 36.0.0
    • ANDROID_HOME = /Volumes/data/development/android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
      This is the JDK bundled with the latest Android Studio installation on this machine.
      To manually set the JDK path, use: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13391695-b895.109)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 16.3) [967ms]
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 16E140
    • CocoaPods version 1.16.2

[✓] Chrome - develop for the web [10ms]
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2025.1) [9ms]
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13391695-b895.109)

[✓] VS Code (version 1.101.1) [8ms]
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.112.0

[✓] VS Code (version 1.82.2) [8ms]
    • VS Code at /Users/thorito/Documents/Curso Android Lollipop/Visual Studio Code.app/Contents
    • Flutter extension version 3.112.0

[✓] Connected device (3 available) [6,1s]
    • iPhone de Apple Team (wireless) (mobile) • 00008020-00097C623AF3002E • ios            • iOS 18.5 22F76
    • macOS (desktop)                          • macos                     • darwin-arm64   • macOS 15.5 24F74 darwin-arm64
    • Chrome (web)                             • chrome                    • web-javascript • Google Chrome 137.0.7151.122

[✓] Network resources [224ms]
    • All expected network resources are available.

• No issues found!

---

main.dart

 // code ... 
 FlutterForegroundTask.initCommunicationPort();
 runApp(App());

---

background_handler.dart

@pragma('vm:entry-point')
void startCallback() {
  FlutterForegroundTask.setTaskHandler(BackgroundHandler());
}

class BackgroundHandler extends TaskHandler {
  final _translationService = _getTranslations();

  static Map<String, String> _getTranslations() {
    final language = UserPreferences.getDefaultLanguage();
    return getTranslationService(language: language);
  }

@override
  Future<void> onStart(DateTime timestamp, TaskStarter starter) async {
    final time = DateHelper.getTime(timestamp.millisecondsSinceEpoch);
    log('onStart(time: $time, starter: ${starter.name})');

    _updateNotification();
  }

  @override
  void onRepeatEvent(DateTime timestamp) {
    final time = DateHelper.getTime(timestamp.millisecondsSinceEpoch);
    log('onRepeatEvent(time: $time)');
    _updateNotification();
    // code ...
  }

  @override
  Future<void> onDestroy(DateTime timestamp, bool isTimeout) async {
    final time = DateHelper.getTime(timestamp.millisecondsSinceEpoch);
    log('onDestroy(time: $time, isTimeout: $isTimeout)');
  }

  @override
  void onReceiveData(Object data) {
    log('onReceiveData(data: $data)');
  }

  @override
  void onNotificationButtonPressed(String id) {
    log('onNotificationButtonPressed(id: $id)');
  }

  @override
  void onNotificationPressed() {
    log('onNotificationPressed()');
  }

  @override
  void onNotificationDismissed() {
    log('onNotificationDismissed()');
  }

  Future<void> _updateNotification() async {
    await FlutterForegroundTask.updateService(
      notificationTitle: _translationService['service_title'] ?? '',
      notificationText: _translationService['service_description'] ?? '',
    );
  }
}

---

background_service.dart

class BackgroundService {
  static final _translationService = getTranslations();
  static bool _hasLocation = false;

  static Map<String, String> getTranslations() {
    final language = UserPreferences.getDefaultLanguage();

    return getTranslationService(language: language);
  }

  static Future<bool> isRunningBackgroundService() async {
    final isRunning = await FlutterForegroundTask.isRunningService;
    return isRunning;
  }

  static Future<void> requestBackgroundPermissions() async {
    final NotificationPermission notificationPermission =
        await FlutterForegroundTask.checkNotificationPermission();
    if (notificationPermission != NotificationPermission.granted) {
      await FlutterForegroundTask.requestNotificationPermission();
    }

    if (isAndroid) {
      if (!await FlutterForegroundTask.isIgnoringBatteryOptimizations) {
        await FlutterForegroundTask.requestIgnoreBatteryOptimization();
      }

      if (!await FlutterForegroundTask.canScheduleExactAlarms) {
        await FlutterForegroundTask.openAlarmsAndRemindersSettings();
      }
    }
  }

  static Future<void> initService() async {
    FlutterForegroundTask.init(
      androidNotificationOptions: AndroidNotificationOptions(
        channelId: BACKGROUND_SERVICE_CHANNEL_ID,
        channelName: _translationService['service_channel_name'] ?? '',
        channelDescription: _translationService['service_channel_description'],
        onlyAlertOnce: true,
      ),
      iosNotificationOptions: const IOSNotificationOptions(
        showNotification: false,
      ),
      foregroundTaskOptions: ForegroundTaskOptions(
        eventAction: ForegroundTaskEventAction.repeat(5000),
        autoRunOnBoot: true,
        autoRunOnMyPackageReplaced: true,
        allowWifiLock: true,
        allowWakeLock: true,
      ),
    );
  }

  static Future<ServiceRequestResult> startBackgroundService({
    required bool hasLocation,
  }) async {
    _hasLocation = hasLocation;

    if (await FlutterForegroundTask.isRunningService) {
      return FlutterForegroundTask.restartService();
    } else {
      final serviceTypes = [
        ForegroundServiceTypes.dataSync,
        ForegroundServiceTypes.remoteMessaging,
      ];

      if (_hasLocation) {
        serviceTypes.add(ForegroundServiceTypes.location);
      }

      return FlutterForegroundTask.startService(
        serviceId: BACKGROUND_SERVICE_NOTIFICATION_ID,
        notificationTitle: _translationService['service_title'] ?? '',
        notificationText: _translationService['service_description'] ?? '',
        serviceTypes: serviceTypes,
        notificationInitialRoute: '/',
        callback: startCallback,
      );
    }
  }

  static Future<ServiceRequestResult> stopBackgroundService() async {
    // code ...
    return FlutterForegroundTask.stopService();
  }
}

I would appreciate it if you could let me know the reason why it is not doing it.

Thank you very much. 😃