How to create sticky headers in FirebaseRecyclerAdapter

Question

I have a main recyclerview that I want to add headers to. This would have been an easy task if I created my own adapter, but I'm using FirebaseRecyclerAdapter from the firebase Ui library because of the advantages it has. My json data in firebase contains 2 types of "objects" in the same main list, one type is the movie release and the other type is the header object. So this means I can check what data we're talking about, if it's a header object the movie id will be null (not existent). I want sticky headers which means that I want the month header to always be on top. I want the 'May' header to stick to the top until the user scrolls downwards to 'June' movie releases in which case the next item to stick to the top would be 'June'. How do i do this?

My code as of know:

        FirebaseRecyclerOptions<_Release> options =
            new FirebaseRecyclerOptions.Builder<_Release>()
                    .setQuery(mReleasesRef, _Release.class)
                    .build();

    adapter = new FirebaseRecyclerAdapter<_Release, RecyclerView.ViewHolder>(options) {
        public final static int TYPE_HEADER = 0;
        public final static int TYPE_ITEM = 1;

        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            // Create a new instance of the ViewHolder, in this case we are using a custom
            // layout called R.layout.message for each item
            if (viewType == TYPE_ITEM) {
                View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.movie_release_item, parent, false);
                return new ReleaseHolder(view);
            } else {
                View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.header, parent, false);
                return new HeaderHolder(view);
            }
        }

        @Override
        public int getItemViewType(int position) {
            if (getItem(position).getGame() == null) {
                return TYPE_HEADER;
            }
            return TYPE_ITEM;
        }

        @Override
        protected void onBindViewHolder(RecyclerView.ViewHolder holder, int position, _Release release) {
            // Bind the Release object to the ReleaseHolder
            if (holder instanceof  HeaderHolder) {
                HeaderHolder headerHolder = (HeaderHolder) holder;
                headerHolder.setHeaderText(release.getName());
            } else if (holder instanceof ReleaseHolder) {
                ReleaseHolder releaseHolder = (ReleaseHolder) holder;
                releaseHolder.setName("");

            }
        }
    };

My database structure:

"data" : [ {
    "m" : 5,
    "name" : "May 2018",
    "y" : 2018
  }, {
    "category" : 0,
    "created_at" : 1525589123745,
    "date" : 1525564800000,
    "movie" : 121,
    "human" : "2018-May-06",
    "id" : 152209,
    "m" : 5,
    "platform" : [ 3, 14, 6 ],
    "region" : 8,
    "updated_at" : 1525594750205,
    "y" : 2018
  }]

A library that works with FirebaseRecyclerAdapter would be fine too, thank you! — , May 18 '18 at 23:54
please update question to clarify what do you mean by "sticky headers" — Mladen, May 19 '18 at 00:54

score 1 · Answer 1 · answered May 19 '18 at 00:53

You can add any custom object to FirebaseRecyclerAdapter (without the need of loading it from Firebase Database) by overriding getItemCount and getItem methods.

Example (java) - custom item on position 0. the rest of the list loaded from db):

@Override
public int getItemCount() {
    if (super.getItemCount() == 0)
      return 0;    // use this perk to prevent showing heder element before 
                   // database query is fully-loaded

      return super.getItemCount() + 1;
}

@Override
public _Release getItem(int position) {
    if (position == (getItemCount() - 1)) {
        _Release asdf = new _Release();
        // init data of object
        return asdf;
    } else {
        return super.getItem(position);
    }
}

How to create sticky headers in FirebaseRecyclerAdapter

1 Answers1