Rx pagination

Presenter

	public void bindListener() {
		Observable<Integer> scrollObs = view().getScrollObs(LIMIT);
		subscribe = scrollObs.subscribe(new MyTripsViewListViewSubscriber(view()));
	}

	private void clearObs() {
		if (subscribe != null && !subscribe.isUnsubscribed()) {
			subscribe.unsubscribe();
		}
	}

	public void refresh() {
		clearObs();
		tripsUseCase.setOffset(0,LIMIT).execute(new MyLoadSubscriber(view(),true));
	}

	private class MyTripsViewListViewSubscriber extends ViewSubscriber<MyTripsView, Integer> {
		public MyTripsViewListViewSubscriber(MyTripsView view) {
			super(view);
		}

		@Override
		public void onNext(Integer integer) {
		  // Загрузка новой порции данных
			tripsUseCase.setOffset(integer,LIMIT).execute(new MyLoadSubscriber(view(),false));
		}
	}

	private class MyLoadSubscriber extends LoadSubscriber<MyTripsView, List<TripsModel>> {
		private final boolean isNew;

		public MyLoadSubscriber(MyTripsView view, boolean isNew) {
			super(view);
			this.isNew = isNew;
		}

		@Override
		public void onNext(List<TripsModel> item) {
			view().bind(item,isNew);
			if (isNew) {
				bindListener();
			}
		}
	}

View

@Override
	public Observable<Integer> getScrollObs(int limit) {
		int itemCount = adapter.getItemCount();
		return ViewUtils.getScrollObservable(recyclerView, limit, itemCount < limit ? itemCount : 0);
	}
	
	

ViewUtils.java

public class ViewUtils {

	public static Observable<Integer> getScrollObservable(RecyclerView recyclerView, int limit, int emptyListCount) {
		Observable<Integer> integerObservable = Observable.create(subscriber -> {
			final RecyclerView.OnScrollListener sl = new RecyclerView.OnScrollListener() {
				@Override
				public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
					if (!subscriber.isUnsubscribed()) {
						int position = getLastVisibleItemPosition(recyclerView);
						int updatePosition = recyclerView.getAdapter()
								.getItemCount() - 1 - (limit / 2);
						if (position >= updatePosition) {
							subscriber.onNext(recyclerView.getAdapter()
									.getItemCount());
						}
					}
				}
			};
			recyclerView.addOnScrollListener(sl);
			subscriber.add(Subscriptions.create(() -> recyclerView.removeOnScrollListener(sl)));
			if (recyclerView.getAdapter()
					.getItemCount() == emptyListCount) {
				subscriber.onNext(recyclerView.getAdapter()
						.getItemCount());
			}
		});
		return integerObservable.distinctUntilChanged();
	}

	private static int getLastVisibleItemPosition(RecyclerView recyclerView) {
		RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
		Class recyclerViewLMClass = layoutManager.getClass();
		if (recyclerViewLMClass == LinearLayoutManager.class || LinearLayoutManager.class.isAssignableFrom(recyclerViewLMClass)) {
			LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;
			return linearLayoutManager.findLastVisibleItemPosition();
		} else if (recyclerViewLMClass == StaggeredGridLayoutManager.class || StaggeredGridLayoutManager.class.isAssignableFrom(recyclerViewLMClass)) {
			StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
			int[] into = staggeredGridLayoutManager.findLastVisibleItemPositions(null);
			List<Integer> intoList = new ArrayList<>();
			for (int i : into) {
				intoList.add(i);
			}
			return Collections.max(intoList);
		}
		throw Exceptions.propagate(new Throwable("Unknown LayoutManager class: " + recyclerViewLMClass.toString()));
	}
}