Android中RecyclerView实现多级折叠列表效果(TreeRecyclerView)

/**
 * Created by Jlanglang on 2016/12/7.
*
 */
public abstract class TreeAdapterItem {
 /**
 * 当前item的数据
 */
 protected D data;
 /**
 * 持有的子数据
 */
 protected List childs;
 /**
 * 是否展开
 */
 protected boolean isExpand;
 /**
 * 布局资源id
 */
 protected int layoutId;
 /**
 * 在每行中所占的比例
 */
 protected int spanSize;

 ····
 get/set方法省略。。。。
 ····
 public TreeAdapterItem(D data) {
 this.data = data;
 childs = initChildsList(data);
 layoutId = initLayoutId();
 spanSize = initSpansize();
 }
 /**
 * 展开
 */
 public void onExpand() {
 isExpand = true;
 }

 /**
 * 折叠
 */
 public void onCollapse() {
 isExpand = false;
 }

 /**
 * 递归遍历所有的子数据，包括子数据的子数据
 *
 * @return List
 */
 public List getAllChilds() {

  ArrayList treeAdapterItems = new ArrayList<>();

  for (int i = 0; i < childs.size(); i++) {

  TreeAdapterItem treeAdapterItem = childs.get(i);

  treeAdapterItems.add(treeAdapterItem);

  if (treeAdapterItem.isParent()) {

   List list = treeAdapterItem.getAllChilds();

   if (list != null && list.size() > 0) {

   treeAdapterItems.addAll(list);
   }
  }
  }
  return treeAdapterItems;
 }

 /**
 * 是否持有子数据
 *
 * @return
 */
 public boolean isParent() {
  return childs != null && childs.size() > 0;
 }
 /**
 * item在每行中的spansize
 * 默认为0,如果为0则占满一行
 * 不建议连续的两级,都设置该数值
 *
 * @return 所占值
 */
 public int initSpansize() {
  return spanSize;
 }
 /**
 * 初始化子数据
 *
 * @param data
 * @return
 */
 protected abstract List initChildsList(D data);
 /**
 * 该条目的布局id
 *
 * @return 布局id
 */
 protected abstract int initLayoutId();

 /**
 * 抽象holder的绑定
 *
 * @param holder ViewHolder
 */
 public abstract void onBindViewHolder(ViewHolder holder);
}

public class TreeRecyclerViewAdapter extends RecyclerView.Adapter {

 protected Context mContext;
 /**
 * 存储所有可见的Node
 */
 protected List mDatas;//处理后的展示数据

 /**
 * 点击item的回调接口
 */
 private OnTreeItemClickListener onTreeItemClickListener;

 public void setOnTreeItemClickListener(OnTreeItemClickListener onTreeItemClickListener) {
 this.onTreeItemClickListener = onTreeItemClickListener;
 }

 /**
 *
 * @param context 上下文
 * @param datas 条目数据
 */
 public TreeRecyclerViewAdapter(Context context, List datas) {
 mContext = context;
 mDatas = datas;
 }

 /**
 * 相应RecyclerView的点击事件 展开或关闭
 * 重要
 * @param position 触发的条目
 */
 public void expandOrCollapse(int position) {
 //获取当前点击的条目
 TreeAdapterItem treeAdapterItem = mDatas.get(position);
 //判断点击的条目有没有下一级
 if (!treeAdapterItem.isParent()) {
  return;
 }
 //判断是否展开
 boolean expand = treeAdapterItem.isExpand();
 if (expand) {
  //获取所有的子数据.
  List allChilds = treeAdapterItem.getAllChilds();
  mDatas.removeAll(allChilds);
  //告诉item,折叠
  treeAdapterItem.onCollapse();
 } else {
  //获取下一级的数据
  mDatas.addAll(position + 1, treeAdapterItem.getChilds());
  //告诉item,展开
  treeAdapterItem.onExpand();
 }
 notifyDataSetChanged();
 }
 //adapter绑定Recycleview后.
 @Override
 public void onAttachedToRecyclerView(RecyclerView recyclerView) {
 super.onAttachedToRecyclerView(recyclerView);
 //拿到布局管理器
 RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
 //判断是否是GridLayoutManager,因为GridLayoutManager才能设置每个条目的行占比.
 if (layoutManager instanceof GridLayoutManager) {
  final GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
  gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
  @Override
  public int getSpanSize(int position) {

   TreeAdapterItem treeAdapterItem = mDatas.get(position);
   if (treeAdapterItem.getSpanSize() == 0) {
   //如果是默认的大小,则占一行
   return gridLayoutManager.getSpanCount();
   }
   //根据item的SpanSize来决定所占大小
   return treeAdapterItem.getSpanSize();
  }
  });
 }
 }


 @Override
 public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
 //这里,直接通过item设置的id来创建Viewholder
 return ViewHolder.createViewHolder(mContext, parent, viewType);
 }

 @Override
 public void onBindViewHolder(ViewHolder holder, final int position) {
 final TreeAdapterItem treeAdapterItem = mDatas.get(position);
 holder.itemView.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
  //折叠或展开
  expandOrCollapse(position);
  if (onTreeItemClickListener != null) {
   //点击监听的回调.一般不是最后一级,不需要处理吧.
   onTreeItemClickListener.onClick(treeAdapterItem, position);
  }
  }
 });
 treeAdapterItem.onBindViewHolder(holder);
 }

 @Override
 public int getItemViewType(int position) {
 //返回item的layoutId
 return mDatas.get(position).getLayoutId();
 }

 @Override
 public int getItemCount() {
 return mDatas == null ? 0 : mDatas.size();
 }

 public interface OnTreeItemClickListener {
 void onClick(TreeAdapterItem node, int position);
 }
}

/**
 * Created by baozi on 2016/12/8.
 */
public class OneItem extends TreeAdapterItem {

 public OneItem(CityBean data) {
 super(data);
 }
 //这里数据用的是,一个三级城市列表数据。
 @Override
 protected List initChildsList(CityBean data) {//这个CityBean 是一级数据
 ArrayList oneChilds= new ArrayList<>();
 List citys = data.getCitys();
 if (citys == null) {//如果没有二级数据就直接返回.
  return null;
 }
 for (int i = 0; i < citys.size(); i++) {//遍历二级数据.
  TwoItem twoItem = new TwoItem(citys.get(i));//创建二级条目。
  oneChilds.add(twoItem);
 }
 return oneChilds;
 }

 @Override
 protected int initLayoutId() {//当前级数的布局
 return R.layout.itme_one;
 }

 @Override
 public void onExpand() {
 super.onExpand();

 }


 @Override
 public void onBindViewHolder(ViewHolder holder) {
 //设置当前级数的viewhodler.
 //如果需要某个view展开关闭时的动画，可以在这里保存view到成员变量。
 //然后在onExpand()方法里面操作。
 holder.setText(R.id.tv_content, data.getProvinceName());
 }
}

/**
 * Created by baozi on 2016/12/8.
 */
public class FourItem extends TreeAdapterItem {
....

 @Override
 protected List initChildsList(String data) {
 ArrayList treeAdapterItems = new ArrayList<>();
 for (int i = 0; i < 10; i++) {
  FiveItem threeItem = new FiveItem("我是五级");
  //在遍历的时候,通过条件,重设孩子的布局id.和所占比
  if (i % 4 == 0) {//偷个懒,不多写布局了.
  threeItem.setLayoutId(R.layout.itme_one);
  threeItem.setSpanSize(0);
  } else if (i % 3 == 0) {
  threeItem.setLayoutId(R.layout.item_two);
  threeItem.setSpanSize(2);
  }
  treeAdapterItems.add(threeItem);
 }
 return treeAdapterItems;
 }
....
}

/**
 * Created by baozi on 2016/12/8.
 */
public class FiveItem extends TreeAdapterItem {
 .......
//设置默认的布局
 @Override
 protected int initLayoutId() {
 return R.layout.item_five;
 }
//设置默认的占比
 @Override
 public int initSpansize() {
 return 2;
 }
 //根据layoutId来判断viewhodler并设置
 @Override
 public void onBindViewHolder(ViewHolder holder) {
 if (layoutId == R.layout.itme_one) {
  holder.setText(R.id.tv_content, "我是第一种五级");
 } else if (layoutId == R.layout.item_five) {
  holder.setText(R.id.tv_content, "我是第二种五级");
 }else if (layoutId == R.layout.item_two) {
  holder.setText(R.id.tv_content, "我是第三种五级");
 }
 }
}