HideOnScrollExample - RecyclerAdapter class

RecyclerAdapter.java

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
  //added view types
  private static final int TYPE_HEADER = 2;
  private static final int TYPE_ITEM = 1;
  
  private List<String> mItemList;
  
  public RecyclerAdapter(List<String> itemList) {
    mItemList = itemList;
  }
  
  //modified creating viewholder, so it creates appropriate holder for a given viewType
  @Override
  public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    Context context = parent.getContext();
    if (viewType == TYPE_ITEM) {
      final View view = LayoutInflater.from(context).inflate(R.layout.recycler_item, parent, false);
      return RecyclerItemViewHolder.newInstance(view);
    } else if (viewType == TYPE_HEADER) {
      final View view = LayoutInflater.from(context).inflate(R.layout.recycler_header, parent, false);
      return new RecyclerHeaderViewHolder(view);
    }
    throw new RuntimeException("There is no type that matches the type " + viewType + " + make sure your using types    correctly");
  }
  
  //modifed ViewHolder binding so it binds a correct View for the Adapter
  @Override
  public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
    if (!isPositionHeader(position)) {
      RecyclerItemViewHolder holder = (RecyclerItemViewHolder) viewHolder;
      String itemText = mItemList.get(position - 1); // we are taking header in to account so all of our items are correctly positioned
      holder.setItemText(itemText);
    }
  }
  
  //our old getItemCount()
  public int getBasicItemCount() {
    return mItemList == null ? 0 : mItemList.size();
  }
  
  //our new getItemCount() that includes header View
  @Override
  public int getItemCount() {
    return getBasicItemCount() + 1; // header
  }
  
  //added a method that returns viewType for a given position
  @Override
  public int getItemViewType(int position) {
    if (isPositionHeader(position)) {
    return TYPE_HEADER;
    }
    return TYPE_ITEM;
  }
  
  //added a method to check if given position is a header
  private boolean isPositionHeader(int position) {
    return position == 0;
  }

}