Error Static Injector: StaticInjectorError(AppModule)[GameService -> HttpClient]

Question

I have a problem with a library in Angular. I have done a library where I ask an API with HttpClient but there's a problem, when I try to go on a class from this library, GameService, I receive: "Error Static Injector: StaticInjectorError(AppModule)[GameService -> HttpClient]". When I saw that, I tried to import HttpModule inside my application and add in providers HttpClient but nothing changed. Here's the code of my class library:

import { Injectable } from '@angular/core';
import { HttpHeaders, HttpClient } from '@angular/common/http';
import { Game } from './model/game';
import { Observable } from 'rxjs';
import { EndPointGetterService } from '../utilities/end-point-getter.service';

@Injectable({
  providedIn: 'root'
})
export class GameService {

  private gameUrl = localStorage.getItem('endpoint') + '/Games';
  private headers: HttpHeaders;

  constructor(private http: HttpClient, private EPGetter: EndPointGetterService) {
    this.headers = new HttpHeaders({
      'Access-Control-Allow-Origin': 'http://localhost:4200',
      'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE,OPTIONS',
      'Access-Control-Allow-Headers': '*',
    });
  }
  getStateGame(groupName: string): Observable<number> {
    return this.http.get<number>(this.EPGetter.getEndPointUrl() + '/Games/' + groupName + '/State', { headers: this.headers });
  }

And inside my application I have this inside my app.module.ts:

import { HttpClientModule, HttpClient } from '@angular/common/http';
import { GameService } from '@oneroomic/oneroomlibrary';

@NgModule({
  declarations: [
    AppComponent,
    NavComponent,
    LockscreenComponent,
    SettingsComponent
  ],
  imports: [
    HttpClientModule,
  ],
  providers: [
    HttpClient,
    GameService
  ],

and that's how i inject the GameService:

constructor(
  private snackBar: MatSnackBar,
  private gameService: GameService
  ) {}

Answer 1

Try removing GameService from providers as you have providedIn: 'root'. And HttpClient is not needed there too