Exception throw flutter

Question

am learning api integration with bloc, these exception is been thrown when data is trying to fetch, for loadingstate i assigned a progressindicator then after that state when trying to get data,these exeption is been thrown ,pls helpenter image description here

as per the console i tried to change the data type to from double to num, still same exception

 try {
            _emitters.add(emitter);
            await handler(event as E, emitter);
          } catch (error, stackTrace) {
            onError(error, stackTrace);
            rethrow;
          } finally {
            onDone();
          }

networkfile.dart

class Repository {
  List<FakeStore> collections = [];
  Future<List<FakeStore>?> getdata() async {
    String url = 'https://fakestoreapi.com/products';
    final data = await http.Client().get(Uri.parse(url));

    if (data.statusCode != 200) {
      return null;
    } else {
      Iterable values = jsonDecode(data.body);
      for (var value in values) {
        FakeStore fakeStore = FakeStore.fromJson(value);

        collections.add(fakeStore);
      }
      return collections;
    }
  }
}

bloc.dart

class FakestoreBloc extends Bloc<FakestoreEvent, FakestoreState> {
  final Repository repository;

  FakestoreBloc({required this.repository}) : super(FakestoreInitialstate()) {
    on<FakestoreEvent>((event, emit) async {
      if (event is StorelaodEvent) {
        emit(Fakestorelaodingstate());
        List<FakeStore>? apiresult = await repository.getdata();

        if (apiresult == null) {
          emit(FAkestoreErrorstate());
        } else {
          emit(Fakestoreloadedstate(apiresult: apiresult));
        }
      }
    });
  }
}