Dagger injected class keeps being null with Dagger

Question

I'm trying to inject an instance of CacheManager into GetTodoRepository which Dagger is probably successfull with doing since I'm not getting any dagger related errors. But when using cacheManager in GetTodoRepository I get a NullPointerException

public class GetTodoRepository {

    @Inject
    public CacheManager cacheManager;

    public RetrofitService retrofitService;
    private ResultListener listener;

    public GetTodoRepository(@NonNull ResultListener listener) {
        this.retrofitService = new RetrofitService();
        this.listener = listener;
    }
}

@Module
public class AppModule {

    private Application application;

    public AppModule(Application application) {
        this.application = application;
    }

    @Provides
    @Singleton
    public Context providesApplicationContext() {
        return application.getApplicationContext();
    }

    @Provides
    @Singleton
    public CacheManager provideCacheManager(Context Context) {
        return new CacheManager(Context);
    }

}



@Singleton
@Component(modules = AppModule.class)
public interface TodoComponents {
    void inject(MainViewModel mainViewModel);
    void inject(CacheManager cacheManager);
    void inject(GetTodoRepository getTodoRepository);
    void inject(PostTodoRepository postTodoRepository);
}

Answer 1

1) Setup Dagger (Component) in Application class

public class TodoApplication extends Application {

private static AppComponent components;

@Override
public void onCreate() {
    super.onCreate();
    components = DaggerAppComponent.builder()
            .appModule(new AppModule(this))
            .build();
}


public static AppComponent getAppComponent() {
    return components;
}

}

2) Call the Component object from Application class in the injection target class

public GetTodoRepository(@NonNull ResultListener listener) {
    this.listener = listener;
    TodoApplication.getAppComponent().inject(this);
}