How to fix the problem of 'Object of type XXXXX is not registered inside GetIt' in flutter?

Question

I am trying to use get_it in order to create a singleton object to be used. I do not wish to use multiple objects of API which is connecting to Firebase. The singleton object is that of Api call for firebase.

I have used the following code

locator.registerLazySingleton<Api>(() => new Api('teams')) ;

while following code works

locator.registerLazySingleton<TeamViewModel>(() => new TeamViewModel()) ;

The structure of Api class is as follows:

class Api{
  final Firestore _db = Firestore.instance;
  final String path;
  CollectionReference ref;
  
  Api( this.path ) {
    ref = _db.collection(path);
  }

  Future<QuerySnapshot> getDataCollection() {
     return ref.getDocuments() ;
  }
}`

This is how I use the API singleton object:

Api _api = locator<Api>();

while the following code works fine:

Api _api = Api('team');

I get the following error in console:

I/flutter ( 2313): The following _Exception was thrown building MultiProvider:

I/flutter ( 2313): Exception: Object of type Api is not registered inside GetIt

I wish to know if this is even possible of using getit is not the right way to go about this.

Answer 1

Try the following code on your main function.

GetIt locator = GetIt.instance;

void main() {

  locator.registerLazySingleton<Api>(() => new Api('teams')) ;

  runApp(MyApp());
}

Or try to have a separate file for your service locator like:

service_locator.dart

GetIt sl = GetIt.instance;

final httpLink = HttpLink(...);

final GraphQLClient client = GraphQLClient(
  cache: InMemoryCache(),
  link: httpLink,
);

void setUpServiceLocator() {
  // Services
  sl.registerSingleton<LocationsService>(LocationsService(http.Client()));
  ...

  // Managers
  sl.registerSingleton<LocationsManager>(LocationsManager());
  ...
}

main.dart

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  setUpServiceLocator();
  runApp(MyApp());
}

some_file.dart

import 'package:my_awesome_app/service_locator.dart';

...
// call it anywhere you want on your code
sl<LocationsManager>().updateLocationsCommand.execute(query);

// or
sl.get<LocationsManager>().updateLocationsCommand.execute(query);

Answer 2

don't forget to call setupLocator in your main app file before App init

  setupLocator();
  runApp(MyApp());