Flutter: Using path provider when app is in background - image

Question

I am currently trying to implement FCM and local notifications into my Flutter app. I have successfully configured FCM and the Local notifications for normal notifications, But i also have a different type of notification that I would like to display with an Image, When my app is in the foreground the notification is displayed without error, However when I terminate the app / move it to background I get an exception when trying to save the image using path provider.
The exception:
MissingPluginException(No implementation found for method getApplicationDocumentsDirectory on channel plugins.flutter.io/path_provider)
I'm assuming this error is occurring because the path provider method channel is closed when the app is not in the foreground, Is there something I can do to fix this? Or if not the flutter_local_notifications plugin requires a filepath to a bitmap, Can I achieve saving the image and getting a path in a different way that will work in background (without path provider)?
(What I actually would like to display is an image from a link like this one: https://is1-ssl.mzstatic.com/image/thumb/WNUBiv2P6YSklHn9eA5nlg/1000x1000bb.jpeg)
Saving the image:
static Future<String> saveImage(Image image) {
final completer = Completer<String>();
image.image.resolve(ImageConfiguration()).addListener(ImageStreamListener((imageInfo,_) async {
final byteData = await imageInfo.image.toByteData(format: ImageByteFormat.png);
final pngBytes = byteData.buffer.asUint8List();
final fileName = pngBytes.hashCode;
final directory = await getApplicationDocumentsDirectory();
final filePath = '${directory.path}/$fileName';
final file = File(filePath);
await file.writeAsBytes(pngBytes);
completer.complete(filePath);
}));
return completer.future;
}

Answer 1

you need to register path provider in Application.java as well.
import io.flutter.plugins.pathprovider.PathProviderPlugin;
...
#Override
public void registerWith(PluginRegistry registry) {
PathProviderPlugin.registerWith(registry.registrarFor("io.flutter.plugins.pathprovider.PathProviderPlugin"));
}
Now that flutter uses Kotlin as the default language for android side, here is the Kotlin code:
override fun registerWith(registry: PluginRegistry) {
io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin.registerWith(registry?.registrarFor("io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin"));
PathProviderPlugin.registerWith(registry.registrarFor("io.flutter.plugins.pathprovider.PathProviderPlugin"))
}

Answer 2

This error occured because you did not registered flutter pluging in android MainAcitivity.
Your must change onCreate method of your MainActivity as below:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GeneratedPluginRegistrant.registerWith(this.getFlutterEngine());
}