Why class isn't injected to module?

Question

I have some Group module with MVP pattern.I just started to learn Dagger2 and I expect GroupComponent to inject repository into presenter, and provide presenter for GroupFragment.

There is my Repository:

    public class GroupServerRepository {
        @Inject
        public GroupServerRepository(){}

my Presenter:

    public class GroupPresenter implements LifecycleObserver {
        private GroupServerRepository repository;
        @Inject
        public GroupPresenter(GroupServerRepository repository){
            this.repository = repository;
        }

Component:

    @Component
    interface GroupComponent{
        GroupPresenter getPresenter();
        GroupServerRepository getRepository();
    }

Fragment:

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.fragment_group, container, false);

        GroupContracts.GroupComponent component = 
        DaggerGroupContracts_GroupComponent.create();
        presenter = component.getPresenter();

So i expect to have next code in generated component class:

    @Override
    public GroupPresenter getPresenter() {
        return new GroupPresenter(getRepository());
    }

    @Override
    public GroupServerRepository getRepository() {
        return new GroupServerRepository();
    }

But instead of this, i have next one:

    @Override
    public GroupPresenter getPresenter() {
        return new GroupPresenter(new GroupServerRepository());
    }

    @Override
    public GroupServerRepository getRepository() {
        return new GroupServerRepository();
    }

I tried to rebuild the project but i didn't help.

Answer 1

Like Jannik noted there is a scoping problem. Every time when you just use @Inject or @Provides a new instance will be created. You need to have some Scope. There is scope out of the box for you which is @Singleton, but it is not what you need. You need custom scopes like:

@ActivityScope

@FragmentScope

and etc.

Here is an example:

https://github.com/google/iosched/blob/master/shared/src/main/java/com/google/samples/apps/iosched/shared/di/ActivityScoped.java

You can check the project itself which is a great example for right usage of Dagger2.

https://github.com/google/iosched

Here is an article about the app:

https://medium.com/@JoseAlcerreca

But read something how scopes work.

https://proandroiddev.com/dagger-2-component-relationships-custom-scopes-8d7e05e70a37