MissingPluginException when using in isolate with Android Alarm Service

Describe the bug I’m trying to get device location in a callback of android_alarm_service. So I create a new alarm:

AndroidAlarmManager.periodic(
              Duration(minutes: 1),
              1,
              updateDeviceLocation,
              wakeup: true,
            );

Then updateDeviceLocation is called in a separate isolate in this case. Here is the function:

static void updateDeviceLocation() {
    print("Starting device location update...");
    SharedPreferences.getInstance().then((prefs){
      print("... loading settings");
      String url = prefs.getString('app-webhook-url');
      if (url != null && url.isNotEmpty) {
        print("... done. Getting device location...");
        try {
          var location = new Location();
          location.getLocation().then((currentLocation){
            print("... done. Sending data home...");
            Map<String, String> headers = {};
            headers["Content-Type"] = "application/json";
            var data = {
              "type": "update_location",
              "data": {
                "gps": [currentLocation.latitude, currentLocation.longitude],
                "gps_accuracy": currentLocation.accuracy,
                "battery": 45
              }
            };
            http.post(
                url,
                headers: headers,
                body: json.encode(data)
            );
          });
        } on PlatformException catch (e) {
          if (e.code == 'PERMISSION_DENIED') {
            print("... no location permission. Aborting");
          }
        }
      } else {
        print("... no webhook. Aborting");
      }
    });
  }

If I call updateDeviceLocation directly in main isolate all works fine. But when updateDeviceLocation called by Alarm Manager in a separate isolate I’m getting:

Unhandled Exception: MissingPluginException(No implementation found for method getLocation on channel lyokone/location)

I tried flutter clean, restarting and rebuilding everything, but no luck.

Expected behavior I hope this plugin can work fine in a separate isolate.

Tested on:

• Android 9, API Level 28, real device

Additional logs

I/flutter (14499): Starting device location update...
I/flutter (14499): ... loading settings
I/flutter (14499): ... checking settings
I/flutter (14499): ... done. Getting device location...
E/flutter (14499): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: MissingPluginException(No implementation found for method getLocation on channel lyokone/location)
E/flutter (14499): #0      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:314:7)
E/flutter (14499): <asynchronous suspension>
E/flutter (14499): #1      Location.getLocation (package:location/location.dart:61:8)
E/flutter (14499): #2      PremiumFeaturesManager.updateDeviceLocation.<anonymous closure> (package:hass_client/premium_features_manager.class.dart:22:20)
E/flutter (14499): #3      _rootRunUnary (dart:async/zone.dart:1132:38)
E/flutter (14499): #4      _CustomZone.runUnary (dart:async/zone.dart:1029:19)
E/flutter (14499): #5      _FutureListener.handleValue (dart:async/future_impl.dart:126:18)
E/flutter (14499): #6      Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:639:45)
E/flutter (14499): #7      Future._propagateToListeners (dart:async/future_impl.dart:668:32)
E/flutter (14499): #8      Future._complete (dart:async/future_impl.dart:473:7)
E/flutter (14499): #9      _SyncCompleter.complete (dart:async/future_impl.dart:51:12)
E/flutter (14499): #10     _AsyncAwaitCompleter.complete.<anonymous closure> (dart:async-patch/async_patch.dart:33:20)
E/flutter (14499): #11     _rootRun (dart:async/zone.dart:1120:38)
E/flutter (14499): #12     _CustomZone.run (dart:async/zone.dart:1021:19)
E/flutter (14499): #13     _CustomZone.runGuarded (dart:async/zone.dart:923:7)
E/flutter (14499): #14     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:963:23)
E/flutter (14499): #15     _rootRun (dart:async/zone.dart:1124:13)
E/flutter (14499): #16     _CustomZone.run (dart:async/zone.dart:1021:19)
E/flutter (14499): #17     _CustomZone.runGuarded (dart:async/zone.dart:923:7)
E/flutter (14499): #18     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:963:23)
E/flutter (14499): #19     _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
E/flutter (14499): #20     _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)

[Lyokone]

Hey ! Sorry for the huge delay in response, I was mostly away from my computer this last months. I’ll look into that as soon as possible !

[jafar96]

Hey guys. I finally fixed this problem. I used background_fetch package into android_alarm_manager and worked for me. you can do following steps :

Note : since I need to get Location every 1 minute and minimum period of background_fetch is 15 minutes , I do this. in other words I start and stop background_fetch every 1 minute by android_alarm_manager.

in main.dart :

main.dart

void getLocation() async{
  Location location = Location();
  LocationData locationData = await location.getLocation();
  print(locationData.latitude);
  // do something else
}

void myAlarmManager()async {
        BackgroundFetch.scheduleTask(TaskConfig(
          taskId: 'getLocation',
          delay: 1000,
          enableHeadless: true,
          stopOnTerminate: false,
          forceAlarmManager: true,
          startOnBoot: true,
        ));
}

void backgroundFetchHeadlessTask(String taskId) async {
  print("[BackgroundFetch] Headless event received: $taskId");
  getLocation();
  BackgroundFetch.finish(taskId);
  BackgroundFetch.stop();
}

void main() async{
  final backgroundLocationID = 0;
  WidgetsFlutterBinding.ensureInitialized();
  await AndroidAlarmManager.initialize();
  runApp(InspectorApp());
  BackgroundFetch.registerHeadlessTask(backgroundFetchHeadlessTask);
  await AndroidAlarmManager.periodic(
    const Duration(minutes: 1),
    backgroundLocationID,
    myAlarmManager,
    rescheduleOnReboot: true,
  );
}

.......
class MyAppState extends State<MyApp>{
 
 ......
  @override
  void initState() {
    initPlatformState();
    super.initState();
  }
  

  void initPlatformState() async {
    // Configure BackgroundFetch.
    BackgroundFetch.configure(BackgroundFetchConfig(
      minimumFetchInterval: 15,
      forceAlarmManager: false,
      stopOnTerminate: false,
      startOnBoot: true,
      enableHeadless: true,
      requiresBatteryNotLow: false,
      requiresCharging: false,
      requiresStorageNotLow: false,
      requiresDeviceIdle: false,
      requiredNetworkType: NetworkType.ANY,
    ), _onBackgroundFetch).then((int status) {
      print('[BackgroundFetch] configure success: $status');
    }).catchError((e) {
      print('[BackgroundFetch] configure ERROR: $e');
    });
    if (!mounted) return;
  }

  void _onBackgroundFetch(String taskId) async {
    print("[BackgroundFetch] Event received: $taskId");
    getLocation();
    BackgroundFetch.finish(taskId);
    BackgroundFetch.stop();
  }

}

create a new class and named it MyApplication.java.

MyApplication.java

package yourPackageName;

import io.flutter.app.FlutterApplication;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback;
import io.flutter.plugins.sharedpreferences.SharedPreferencesPlugin;
import io.flutter.plugins.androidalarmmanager.AlarmService;
import io.flutter.plugins.androidalarmmanager.AndroidAlarmManagerPlugin;
import com.lyokone.location.LocationPlugin;
import com.transistorsoft.flutter.backgroundfetch.BackgroundFetchPlugin;

public class MyApplication extends FlutterApplication implements PluginRegistrantCallback {
    @Override
    public void onCreate() {
        super.onCreate();
        AlarmService.setPluginRegistrant(this);
    }

    @Override
    public void registerWith(PluginRegistry registry) {
        AndroidAlarmManagerPlugin.registerWith(registry.registrarFor("io.flutter.plugins.androidalarmmanager.AndroidAlarmManagerPlugin"));
        SharedPreferencesPlugin.registerWith(registry.registrarFor("io.flutter.plugins.sharedpreferences.SharedPreferencesPlugin"));
        LocationPlugin.registerWith(registry.registrarFor("com.lyokone.location.LocationPlugin"));
        BackgroundFetchPlugin.registerWith(registry.registrarFor("com.transistorsoft.flutter.backgroundfetch.BackgroundFetchPlugin"));
    }
}

and set name attribute in application tag to “.MyApplication”

I hope to work for you