Firebase динамически загружает данные при прокрутке

Это прекрасно работает. Infinite-Scroll-Endless-Scrolling-Tutorial

    private RecyclerView recyclerView;
    boolean userScrolled=false;

    private boolean loading = true;
    int pastVisiblesItems, visibleItemCount, totalItemCount;

    LinearLayoutManager mLayoutManager;



        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);


        mLayoutManager = new LinearLayoutManager(MainActivity.this);
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(mAdapter);


// Implement scroll listener
public void implementScrollListener() {

    recyclerView
        .addOnScrollListener(new RecyclerView.OnScrollListener() {

            @Override
            public void onScrollStateChanged(RecyclerView recyclerView,
                                             int newState) {

                super.onScrollStateChanged(recyclerView, newState);

                // If scroll state is touch scroll then set userScrolled
                // true
                if (newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
                    userScrolled = true;

                }

            }

            @Override
            public void onScrolled(RecyclerView recyclerView, int dx,
                                   int dy) {
                super.onScrolled(recyclerView, dx, dy);

                // Here get the child count, item count and visibleitems
                // from layout manager

                visibleItemCount = mLayoutManager.getChildCount();
                totalItemCount = mLayoutManager.getItemCount();
                pastVisiblesItems = mLayoutManager
                        .findFirstVisibleItemPosition();

                // Now check if userScrolled is true and also check if
                // the item is end then update recycler view and set
                // userScrolled to false
                if (userScrolled
                        && (visibleItemCount + pastVisiblesItems) == totalItemCount) {
                    userScrolled = false;

                    RefreshData(oldestPostId);
                }
            }
        });
}

В Firebase есть FirebaseRecyclerAdapter для подключения RecyclerView напрямую к базе данных firebase. Подробнее см. пример приложения FriendlyChat от Google: https://github.com/firebase/friendlychat

вы можете использовать методы startAt(), endAt() и equalTo(), официальная ссылка введите здесь описание ссылки

// Find all dinosaurs that are at least three meters tall.
var ref = firebase.database().ref("dinosaurs");
ref.orderByChild("height").startAt(3).on("child_added", function(snapshot) {
console.log(snapshot.key)
});

ответил: https://stackoverflow.com/a/41583467/1429832