A RecyclerView.Adapter implementation acts as a wrapper of another RecyclerView.Adapter to support "HeaderView" and "FooterView" in a non-intrusive way.

RecyclerViewAdapterWrapper.java

/**
 * Inspired by Qisen Tang, ref: http://www.woaitqs.cc/android/2017/04/11/new-way-to-add-header-and-footer.html
 *
 * <pre>
 *   <code>
 *     Usage:
 *      
 *     RecyclerViewAdapterWrapper adapterWrapper =
 *       RecyclerViewAdapterWrapper.wrap(new MyRecyclerViewAdapter())
 *         .headerView(headerView)
 *         .footerView(footerView)
 *         .setHeaderViewVisible(false)
 *         .setFooterViewVisible(false);
 *
 *     recyclerView.setAdapter(adapterWrapper);
 *     // at later time, show the header or footer view accordingly
 *     adapterWrapper.setFooterViewVisible(true);
 *   </code>
 * </pre>
 *
 * Author: neevek <i@neevek.net>
 * Date: 2017-05-23
 */
public class RecyclerViewAdapterWrapper extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
  private Handler mMainHandler = new Handler(Looper.getMainLooper());
  private RecyclerView.Adapter<RecyclerView.ViewHolder> mWrappedAdapter;
  private View mHeaderView;
  private View mFooterView;

  private final static int VIEW_TYPE_HEADER = 1;
  private final static int VIEW_TYPE_FOOTER = 2;
  private final static int VIEW_TYPE_OFFSET = 3;

  @SuppressWarnings("unchecked")
  private RecyclerViewAdapterWrapper(RecyclerView.Adapter<?> wrappedAdapter) {
    mWrappedAdapter = (RecyclerView.Adapter<RecyclerView.ViewHolder>)wrappedAdapter;
  }

  public static RecyclerViewAdapterWrapper wrap(RecyclerView.Adapter<?> wrappedAdapter) {
    return new RecyclerViewAdapterWrapper(wrappedAdapter);
  }

  public RecyclerViewAdapterWrapper headerView(View headerView) {
    mHeaderView = headerView;
    return this;
  }
  public RecyclerViewAdapterWrapper footerView(View footerView) {
    mFooterView = footerView;
    return this;
  }

  public RecyclerViewAdapterWrapper setHeaderViewVisible(boolean visible) {
    if (mHeaderView == null ||
        (mHeaderView.getVisibility() == View.VISIBLE) == visible) {
      return this;
    }

    if (visible) {
      mHeaderView.setVisibility(View.VISIBLE);
      mMainHandler.post(this::notifyDataSetChanged);
    } else {
      mHeaderView.setVisibility(View.GONE);
      mMainHandler.post(this::notifyDataSetChanged);
    }
    return this;
  }

  public RecyclerViewAdapterWrapper setFooterViewVisible(boolean visible) {
    if (mFooterView == null ||
        (mFooterView.getVisibility() == View.VISIBLE) == visible) {
      return this;
    }

    if (visible) {
      mFooterView.setVisibility(View.VISIBLE);
      mMainHandler.post(this::notifyDataSetChanged);
    } else {
      mFooterView.setVisibility(View.GONE);
      mMainHandler.post(this::notifyDataSetChanged);
    }
    return this;
  }

  @Override
  public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    switch (viewType) {
      case VIEW_TYPE_HEADER: return new HeaderFooterViewHolder(mHeaderView);
      case VIEW_TYPE_FOOTER: return new HeaderFooterViewHolder(mFooterView);
    }
    return mWrappedAdapter.onCreateViewHolder(parent, viewType);
  }

  @Override
  public void onBindViewHolder(RecyclerView.ViewHolder holder, int position, List<Object> payloads) {
    if (!isHeaderView(position) && !isFooterView(position)) {
      mWrappedAdapter.onBindViewHolder(holder, recalculatePosition(position), payloads);
    }
  }

  @Override
  public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    if (!isHeaderView(position) && !isFooterView(position)) {
      mWrappedAdapter.onBindViewHolder(holder, recalculatePosition(position));
    }
  }

  @Override
  public int getItemViewType(int position) {
    if (isHeaderView(position)) {
      return VIEW_TYPE_HEADER;
    }
    if (isFooterView(position)) {
      return VIEW_TYPE_FOOTER;
    }

    int itemType = mWrappedAdapter.getItemViewType(recalculatePosition(position));
    if (itemType <= 0) {
      // avoid stepping over the header view or footer view
      itemType = (-itemType) + 1;
    }
    return itemType + VIEW_TYPE_OFFSET;
  }

  @Override
  public void setHasStableIds(boolean hasStableIds) {
    super.setHasStableIds(hasStableIds);
    mWrappedAdapter.setHasStableIds(hasStableIds);
  }

  @Override
  public long getItemId(int position) {
    if (isHeaderView(position)) {
      return VIEW_TYPE_HEADER;
    }
    if (isFooterView(position)) {
      return VIEW_TYPE_HEADER;
    }
    return mWrappedAdapter.getItemId(recalculatePosition(position));
  }

  @Override
  public void onViewRecycled(RecyclerView.ViewHolder holder) {
    if (!(holder instanceof HeaderFooterViewHolder)) {
      mWrappedAdapter.onViewRecycled(holder);
    }
  }

  @Override
  public boolean onFailedToRecycleView(RecyclerView.ViewHolder holder) {
    if (!(holder instanceof HeaderFooterViewHolder)) {
      return mWrappedAdapter.onFailedToRecycleView(holder);
    }
    return super.onFailedToRecycleView(holder);
  }

  @Override
  public void onViewAttachedToWindow(RecyclerView.ViewHolder holder) {
    if (!(holder instanceof HeaderFooterViewHolder)) {
      mWrappedAdapter.onViewAttachedToWindow(holder);
    }
  }

  @Override
  public void onViewDetachedFromWindow(RecyclerView.ViewHolder holder) {
    if (!(holder instanceof HeaderFooterViewHolder)) {
      mWrappedAdapter.onViewDetachedFromWindow(holder);
    }
  }

  @Override
  public void onAttachedToRecyclerView(RecyclerView recyclerView) {
    mWrappedAdapter.onAttachedToRecyclerView(recyclerView);
  }

  @Override
  public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
    mWrappedAdapter.onDetachedFromRecyclerView(recyclerView);
  }

  @Override
  public int getItemCount() {
    return mWrappedAdapter.getItemCount() +
        (isHeaderViewVisible() ? 1 : 0) +
        (isFooterViewVisible() ? 1 : 0);
  }

  private int recalculatePosition(int position) {
    return isHeaderViewVisible() ? position - 1 : position;
  }

  private boolean isHeaderView(int position) {
    return position == 0 && isHeaderViewVisible();
  }

  private boolean isFooterView(int position) {
    return position == getItemCount() - 1 && isFooterViewVisible();
  }

  private boolean isHeaderViewVisible() {
    return mHeaderView != null && mHeaderView.getVisibility() == View.VISIBLE;
  }

  private boolean isFooterViewVisible() {
    return mFooterView != null && mFooterView.getVisibility() == View.VISIBLE;
  }

  private static class HeaderFooterViewHolder extends RecyclerView.ViewHolder {
    private HeaderFooterViewHolder(View itemView) {
      super(itemView);
    }
  }
}