Can't use Geolocator inside Workmanager's task in Flutter

Question

I am trying to use either Geolocator.getCurrentLocation or Geolocator.checkPermission() inside Workmanager's task. Both of those calls raise the same exception: MissingPluginException(No implementation found for method getCurrentPosition on channel flutter.baseflow.com/geolocator) - for getCurrentLocation.

And MissingPluginException(No implementation found for method checkPermission on channel flutter.baseflow.com/geolocator) for the checkPermission method.

Here is an example of the code

void callbackDispatcher() {
  Workmanager().executeTask((taskName, inputData) async {
    await Geolocator.checkPermission();
    await Geolocator.getCurrentPosition();
  });
}

There are few issues opened in GitHub repo of Geolocator, but there are no answers for them.

• https://github.com/Baseflow/flutter-geolocator/issues/1045
• https://github.com/Baseflow/flutter-geolocator/issues/1041
• https://github.com/Baseflow/flutter-geolocator/issues/1038

Any ideas on how I can solve this?

Answer 1

The problem is that with version 3.1.6 of the geolocator_android the default method channel implementation has been replaced by a platform specific implementation. However since the task is run in a separate isolate which executes without the Flutter engine, the platform specific implementation (in this case geolocator_android) is not registered with the platform interface (geolocator_platform_interface) resulting in the MissingPluginException.

To use version 3.1.6 or later make sure you register the platform specific implementation when the executeTask is run.

void callbackDispatcher() {
  Workmanager().executeTask((task, inputData) async {
   if (defaultTargetPlatform == TargetPlatform.android) {
     GeolocatorAndroid.registerWith();
   } else if (defaultTargetPlatform == TargetPlatform.iOS || defaultTargetPlatform == TargetPlatform.macOS) {
     GeolocatorApple.registerWith();
   } else if (defaultTargetPlatform == TargetPlatform.linux) {
     GeolocatorLinux.registerWith();
   }

    await Geolocator.checkPermission();
    await Geolocator.getCurrentPosition();
  });
}

Alternatively if you are running Flutter 2.11+, you can use the new DartPluginRegistrant.ensureInitialized() method to ensure all packages are registered correctly:

void callbackDispatcher() {
  Workmanager().executeTask((task, inputData) async {
    DartPluginRegistrant.ensureInitialized();

    await Geolocator.checkPermission();
    await Geolocator.getCurrentPosition();
  });
}

More information can be found here and here.

Answer 2

So, I found the solution for current problem. All I had to do is to replace the version of geolocator_android lib from ^3.1.6 with 3.1.5.

For some reason version 3.1.6 doesn't work as excepted.

geolocator: ^8.2.0
geolocator_android: 3.1.5