RecyclerView添加头部尾部

public class LRecyclerView extends RecyclerView
{
      private Adapter mAdapter;
      //定义数据
      public class FixedViewInfo
      {
          public View view;
          public Object data;
          public boolean isSelectable;
      }

      private ArrayList mHeaderViewInfos = new ArrayList<>();
      private ArrayList mFooterViewInfos = new ArrayList<>();

      public LRecyclerView(Context context)
      {
          this(context, null);
      }

      public LRecyclerView(Context context, @Nullable AttributeSet attrs)
      {
          super(context, attrs);
      }
      //添加头部
      public void addHeaderView(View v, Object data, boolean isSelectable)
      {
          final FixedViewInfo info = new FixedViewInfo();
          info.view = v;
          info.data = data;
          info.isSelectable = isSelectable;
          mHeaderViewInfos.add(info);
      }

      public void addHeaderView(View v)
      {
          addHeaderView(v, null, true);
      }
      //获取头部数量
      public int getHeaderViewCount()
      {
          return mHeaderViewInfos.size();
      }
      //移除头部
      public boolean removeHeaderView(View v)
      {
          if (mHeaderViewInfos.size() > 0)
          {
              boolean result = false;
              if (mAdapter != null && ((WrapAdapter) mAdapter).removeHeaderView(v))
              {
                  result = true;
              }
              //从mHeaderViewInfos移除数据
              removeFixedViewInfo(v, mHeaderViewInfos);
              return result;
          }
          return false;
      }
      //移除list中的数据
      private void removeFixedViewInfo(View v, ArrayList where)
      {
          int len = where.size();
          for (int i = 0; i < len; ++i)
          {
              FixedViewInfo info = where.get(i);
              if (info.view == v)
              {
                  where.remove(i);
                  break;
              }
          }
      }
      //添加尾部
      public void addFooterView(View v, Object data, boolean isSelectable)
      {
          final FixedViewInfo info = new FixedViewInfo();
          info.view = v;
          info.data = data;
          info.isSelectable = isSelectable;
          mFooterViewInfos.add(info);
      }

      public void addFooterView(View v)
      {
          addFooterView(v, null, true);
      }
      //移除尾部
      public boolean removeFooterView(View v)
      {
          //判断有尾部，则移除
          if (mFooterViewInfos.size() > 0)
          {
              boolean result = false;
              if (mAdapter != null && ((WrapAdapter) mAdapter).removeFooterView(v))
              {
                  result = true;
              }
              //从mFooterViewInfos移除数据
              removeFixedViewInfo(v, mFooterViewInfos);
              return result;
          }
          return false;
     }

      @Override
      public void setAdapter(Adapter adapter)
      {
          //判断有头部或尾部，mAdapter为WrapAdapter，否则为adapter
          if (mHeaderViewInfos.size() > 0 || mFooterViewInfos.size() > 0)
          {
              mAdapter = new WrapAdapter(mHeaderViewInfos, mFooterViewInfos, adapter);
          } else
          {
              mAdapter = adapter;
          }
          super.setAdapter(mAdapter);
      }
}

自定义的WrapAdapter，参照ListView的WrapAdapter

public class WrapAdapter extends RecyclerView.Adapter {

public static final int ITEM_VIEW_TYPE_HEADER = -2;
public static final int ITEM_VIEW_TYPE_FOOTER = -3;

private int headerPosition = 0;
private int footerPosition = 0;

private final RecyclerView.Adapter mAdapter;

ArrayList mHeaderViewInfos;
ArrayList mFooterViewInfos;

static final ArrayList EMPTY_INFO_LIST = new ArrayList<>();

public WrapAdapter(ArrayList headerViewInfos,
                   ArrayList footerViewInfos,
                   RecyclerView.Adapter adapter) {
    mAdapter = adapter;

    if (headerViewInfos == null) {
        mHeaderViewInfos = EMPTY_INFO_LIST;
    } else {
        mHeaderViewInfos = headerViewInfos;
    }

    if (footerViewInfos == null) {
        mFooterViewInfos = EMPTY_INFO_LIST;
    } else {
        mFooterViewInfos = footerViewInfos;
    }
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    if (viewType == ITEM_VIEW_TYPE_HEADER) {
        return new ViewHolder(mHeaderViewInfos.get(headerPosition++).view);
    } else if (viewType == ITEM_VIEW_TYPE_FOOTER) {
        return new ViewHolder(mFooterViewInfos.get(footerPosition++).view);
    } else {
        return mAdapter.onCreateViewHolder(parent, viewType);
    }
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    int numHeaders = getHeaderViewCount();

    if (position < numHeaders) {
        return;
    }

    final int adjPosition = position - numHeaders;
    int adapterCount = 0;
    if (mAdapter != null) {
        adapterCount = mAdapter.getItemCount();
        if (adjPosition < adapterCount) {
            mAdapter.onBindViewHolder(holder, position-numHeaders);
        }
    }

}

@Override
public void onViewAttachedToWindow(RecyclerView.ViewHolder holder) {
    super.onViewAttachedToWindow(holder);
    ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();
    if (lp != null && lp instanceof StaggeredGridLayoutManager.LayoutParams) {
        int numHeaders = getHeaderViewCount();
        if (holder.getLayoutPosition() < numHeaders) {
            StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
            p.setFullSpan(true);
        }
        final int adjPosition = holder.getLayoutPosition() - numHeaders;
        int adapterCount = 0;
        adapterCount = mAdapter.getItemCount();
        if (adjPosition < adapterCount) {
            return;
        }
        StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
        p.setFullSpan(true);
    }
}

@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
    super.onAttachedToRecyclerView(recyclerView);
    RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
    if(manager instanceof GridLayoutManager) {
        final GridLayoutManager gridManager = ((GridLayoutManager) manager);
        gridManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
            @Override
            public int getSpanSize(int position) {
                int numHeaders = getHeaderViewCount();
                if (position < numHeaders) {
                    return gridManager.getSpanCount();
                }
                final int adjPosition = position - numHeaders;
                int adapterCount = 0;
                adapterCount = mAdapter.getItemCount();
                if (adjPosition < adapterCount) {
                    return 1;
                }
                return gridManager.getSpanCount();
            }
        });
    }
}

@Override
public void registerAdapterDataObserver(RecyclerView.AdapterDataObserver observer) {
    if (mAdapter != null)
        mAdapter.registerAdapterDataObserver(observer);
}

@Override
public void unregisterAdapterDataObserver(RecyclerView.AdapterDataObserver observer) {
    if (mAdapter != null)
        mAdapter.unregisterAdapterDataObserver(observer);
}

@Override
public int getItemCount() {
    if (mAdapter != null) {
        return mAdapter.getItemCount() + getHeaderViewCount() + getFooterViewCount();
    }
    return getHeaderViewCount() + getFooterViewCount();
}

public int getHeaderViewCount() {
    return mHeaderViewInfos.size();
}

public int getFooterViewCount() {
    return mFooterViewInfos.size();
}

@Override
public int getItemViewType(int position) {
    int numHeaders = getHeaderViewCount();
    if (position < numHeaders) {
        return ITEM_VIEW_TYPE_HEADER;
    }
    if (mAdapter != null && position >= numHeaders) {
        int adjPosition = position - numHeaders;
        int adapterCount = mAdapter.getItemCount();
        if (adjPosition < adapterCount) {
            return mAdapter.getItemViewType(adjPosition);
        }
    }
    return ITEM_VIEW_TYPE_FOOTER;
}

@Override
public long getItemId(int position) {
    int numHeaders = getHeaderViewCount();
    if (mAdapter != null && position >= numHeaders) {
        int adjPosition = position - numHeaders;
        int adapterCount = mAdapter.getItemCount();
        if (adjPosition < adapterCount) {
            return mAdapter.getItemId(adjPosition);
        }
    }
    return -1;
}

public boolean removeHeaderView(View v) {
    for (int i = 0; i < mHeaderViewInfos.size(); i++) {
        LRecyclerView.FixedViewInfo info = mHeaderViewInfos.get(i);
        if (info.view == v) {
            mHeaderViewInfos.remove(i);
            return true;
        }
    }
    return false;
}

public boolean removeFooterView(View v) {
    for (int i = 0; i < mFooterViewInfos.size(); i++) {
        LRecyclerView.FixedViewInfo info = mFooterViewInfos.get(i);
        if (info.view == v) {
            mFooterViewInfos.remove(i);
            return true;
        }
    }
    return false;
}

private static class ViewHolder extends RecyclerView.ViewHolder {

    public ViewHolder(View itemView) {
        super(itemView);
    }
}
}