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<D> { /** * 当前item的数据 */ protected D data; /** * 持有的子数据 */ protected List<TreeAdapterItem> 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<TreeAdapterItem> */ public List<TreeAdapterItem> getAllChilds() {  ArrayList<TreeAdapterItem> 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<TreeAdapterItem> 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<T extends TreeAdapterItem> extends RecyclerView.Adapter<ViewHolder> { protected Context mContext; /** * 存储所有可见的Node */ protected List<T> 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<T> 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<CityBean> { 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<TreeAdapterItem> initChildsList(CityBean data) {//这个CityBean 是一级数据 ArrayList<TreeAdapterItem> oneChilds= new ArrayList<>(); List<CityBean.CitysBean> 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<String> {.... @Override protected List<TreeAdapterItem> initChildsList(String data) { ArrayList<TreeAdapterItem> 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<String> { .......//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"); } }}