MovieActivityPresenter.java

public class MovieActivityPresenter extends Presenter<MovieActivityView>

Subscription sub;

public void getSimilarMovies() {
        sub = apiInterface.getSimilarMovies(Integer.valueOf(movieID),ApiInterface.KEY)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(
                        moviesResponse -> similarMovies = moviesResponse.getResults(),
                        throwable -> {},
                        () -> {
                            for (Movie m:similarMovies) {
                                m.setPosterPath(posterURL + m.getPosterPath());
                                m.setBackdropPath(backdropURL + m.getBackdropPath());
                            }
                            view.setMovieDetails();
                            view.setCastAdapter();
                            view.setSimilarMoviesAdapter();
                        }
                );
    }
    
    @Override
    public void onViewDetached() {
        super.onViewDetached();
        if (sub != null && !sub.isUnsubscribed()) {
                sub.unsubscribe();        
        }
    }
}

Presenter.java

public abstract class Presenter<V> {

    protected V view;

    public void onViewAttached(V view) {
        this.view = view;
    }

    public void onViewDetached() {
        this.view = null;
    }
}