(Dagger 2)为MVP中的不同类型提供相同的实例

// View接口
public interface View {
    // ...
}

// Presenter类
public class Presenter {
    private View view;

    @Inject
    public Presenter(View view) {
        this.view = view;
    }

    // ...
}

// ViewComponent接口
@Component(modules = {ViewModule.class})
public interface ViewComponent {
    void inject(MainActivity activity);
}

// PresenterComponent接口
@Component(modules = {PresenterModule.class})
public interface PresenterComponent {
    void inject(MainActivity activity);
}

// ViewModule类
@Module
public class ViewModule {
    private View view;

    public ViewModule(View view) {
        this.view = view;
    }

    @Provides
    public View provideView() {
        return view;
    }
}

// PresenterModule类
@Module
public class PresenterModule {
    private View view;

    public PresenterModule(View view) {
        this.view = view;
    }

    @Provides
    public View provideView() {
        return view;
    }

    @Provides
    public Presenter providePresenter(View view) {
        return new Presenter(view);
    }
}

// MainActivity类
public class MainActivity extends AppCompatActivity implements View {
    @Inject
    Presenter presenter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // 创建ViewComponent和PresenterComponent
        ViewComponent viewComponent = DaggerViewComponent.builder()
                .viewModule(new ViewModule(this))
                .build();
        PresenterComponent presenterComponent = DaggerPresenterComponent.builder()
                .presenterModule(new PresenterModule(this))
                .build();

        // 注入依赖
        viewComponent.inject(this);
        presenterComponent.inject(this);

        // 使用Presenter
        presenter.doSomething();
    }
}