class HFAdapter extends HFRecyclerViewAdapter<String, HFAdapter.DataViewHolder>{

        public HFAdapter(Context context) {
            super(context);
        }

        @Override
        public void footerOnVisibleItem() {
            if(!isLoading){
                // loading more data, when load done, should set isLoading to false.
                //...
                isLoading = true;
            }
        }
        @Override
        public DataViewHolder onCreateDataItemViewHolder(ViewGroup parent, int viewType) {
            View v = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.data_item, parent, false);
            return new DataViewHolder(v);
        }

        @Override
        public void onBindDataItemViewHolder(DataViewHolder holder, int position) {
            holder.itemTv.setText(getData().get(position));
        }

        class DataViewHolder extends RecyclerView.ViewHolder{
            TextView itemTv;
            public DataViewHolder(View itemView) {
                super(itemView);
                itemTv = (TextView)itemView.findViewById(R.id.itemTv);
            }
        }
    }

// set Adapter
final HFAdapter hfAdapter = new HFAdapter(this);
recyclerView.setAdapter(hfAdapter);

// add header
View headerView = LayoutInflater.from(this).inflate(R.layout.header, recyclerView, false);
hfAdapter.setHeaderView(headerView);
// add footer
View footerView = LayoutInflater.from(this).inflate(R.layout.footer, recyclerView, false);
hfAdapter.setFooterView(footerView);

// remove header
hfAdapter.removeHeader();
// remove footer
hfAdapter.removeFooter();

// set data
ArrayList<String> data = new ArrayList<>();
for (int i=0; i<8; i++){
    data.add(String.format("Item %d", i));
}
hfAdapter.setData(data);

final GridLayoutManager manager = new GridLayoutManager(this, 3);
recyclerView.setLayoutManager(manager);
//Set header/footer's spanCount to match parent in horizontal.
manager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
    @Override
    public int getSpanSize(int position) {
        if ( (hfAdapter.hasHeader() && hfAdapter.isHeader(position)) ||
                hfAdapter.hasFooter() && hfAdapter.isFooter(position) )
            return manager.getSpanCount();

        return 1;
    }
});