compile 'com.drawthink:expandable-recyclerview:0.0.3'

public int getGroupViewResId()

public int getChildViewResId()

public class ImageViewHolder extends BaseViewHolder {

  public ImageView image;
  public TextView tvTitle;

  /**
   * 初始化你的View(这里包括GroupView,和childView)
   */
  public ImageViewHolder(Context ctx, View itemView, int viewType) {
    super(ctx,itemView, viewType);
    image = (ImageView) itemView.findViewById(R.id.iv_image);
    tvTitle = (TextView)itemView.findViewById(R.id.tv_title);
  }

  /**
   * @return 返回你的GroupView 布局文件中根节点的ID
   */
  @Override
  public int getGroupViewResId() {
    return R.id.group;
  }

  /**
   * @return 返回你的ChildView 布局文件中根节点的ID
   */
  @Override
  public int getChildViewResId() {
    return R.id.child;
  }

}

/**
 * author：Drawthink
 * describe:
 * date: 2017/5/22
 * T :group data
 * S :child data
 * VH :ViewHolder
 */

public abstract class BaseRecyclerViewAdapter<T,S,VH extends BaseViewHolder> extends RecyclerView.Adapter<VH>

public class ImageAdapter extends BaseRecyclerViewAdapter<String,ImageBean,ImageViewHolder> {

  private Context ctx;
  private List datas;
  private LayoutInflater mInflater;

  public ImageAdapter(Context ctx, List<RecyclerViewData> datas) {
    super(ctx, datas);
    mInflater = LayoutInflater.from(ctx);
    this.ctx = ctx;
    this.datas = datas;
  }

  @Override
  public void onBindGroupHolder(ImageViewHolder holder, int groupPos,int position, String groupData) {
    holder.tvTitle.setText(groupData);
  }

  @Override
  public void onBindChildpHolder(ImageViewHolder holder, int groupPos,int childPos,int position, ImageBean childData) {
    holder.image.setBackgroundResource(childData.getResId());
  }

  @Override
  public View getGroupView(ViewGroup parent) {
    return mInflater.inflate(R.layout.title_item_layout,parent,false);
  }

  @Override
  public View getChildView(ViewGroup parent) {
    return mInflater.inflate(R.layout.item_image_layout,parent,false);
  }

  @Override
  public ImageViewHolder createRealViewHolder(Context ctx, View view, int viewType) {
    return new ImageViewHolder(ctx,view,viewType);
  }
}

/**
   * @param groupData
   * @param childDatas
   * @param isExpand  初始化展示数据时，该组数据是否展开
   */
public RecyclerViewData(T groupData, List<S> childDatas,boolean isExpand)

    mDatas = new ArrayList<>();
    List<ImageBean> bean1 = new ArrayList<>();
    List<ImageBean> bean2 = new ArrayList<>();
    List<ImageBean> bean3 = new ArrayList<>();
    // 每个子列表长度可以不相同
    bean1.add(new ImageBean("Dog", R.mipmap.dog));
    bean1.add(new ImageBean("Dog", R.mipmap.dog));
    bean2.add(new ImageBean("Cat", R.mipmap.cat));
    bean3.add(new ImageBean("Bird", R.mipmap.bird));

    mDatas.add(new RecyclerViewData("Dog", bean1, true));
    mDatas.add(new RecyclerViewData("Cat", bean2, true));
    mDatas.add(new RecyclerViewData("Bird", bean3, true));