Pagination in endless recycler view with firebase

Question

I am working on Q/A app . I have successfully loaded questions from firebase . But I am not able to apply pagination from Firebase like database . And how to recognize that we h

Answer 1

To check whether you have reached the bottom of the RecyclerView, you can use the onScrolled listener as below, the if condition here is important and it is defining when a user has reached to the bottom.

mRV.addOnScrollListener(new RecyclerView.OnScrollListener() {

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

                mTotalItemCount = mLayoutManager.getItemCount();
                mLastVisibleItemPosition = mLayoutManager.findLastVisibleItemPosition();

                if (!mIsLoading && mTotalItemCount <= (mLastVisibleItemPosition + mPostsPerPage)) {
                    getUsers(mAdapter.getLastItemId());
                    mIsLoading = true;
                }
            }
        });

Secondly, you can use startAt and limitToFirst methods to get questions in batches as shown below:

query = FirebaseDatabase.getInstance().getReference()
                    .child(Consts.FIREBASE_DATABASE_LOCATION_USERS)
                    .orderByKey()
                    .startAt(nodeId)
                    .limitToFirst(mPostsPerPage);

I have created an open source app that shows exactly how it is done. Please have a look: https://blog.shajeelafzal.com/2017/12/13/firebase-realtime-database-pagination-guide-using-recyclerview/