关于recycler两层显示

1.经常会遇到recyclerview嵌套 点击上一层显示内层

考虑到还是优化recyclerview adapter问题

package com.educiot.srcres.view.Expandable;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;
import java.util.List;

/**
 * K 
 * 第一层数据
 * V
 * 第二层数据
 * @author XTER
 * @date 2019/8/9
 */
public abstract class FoldableRecyclerViewAdapter<K, V> extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

   private Context mContext;

   /**
    * 上级布局
    */
   private int mGroupLayoutRes;
   /**
    * 下级布局
    */
   private int mChildLayoutRes;

   /**
    * 数据
    */
   private List<Unit<K, V>> mData;

   /**
    * 点击与长按监听接口
    */
   public interface OnItemClickLitener {
      void onItemClick(View view, int position);

      void onItemLongClick(View view, int position);
   }


   private OnItemClickLitener itemClickLitener;

   public void setOnItemClickLitener(OnItemClickLitener itemClickLitener) {
      this.itemClickLitener = itemClickLitener;
   }

   public FoldableRecyclerViewAdapter(Context mContext, int mGroupLayoutRes, int mChildLayoutRes, List<Unit<K, V>> mData) {
      this.mContext = mContext;
      this.mGroupLayoutRes = mGroupLayoutRes;
      this.mChildLayoutRes = mChildLayoutRes;
      if (mData == null) {
         this.mData = new ArrayList<>();
      } else {
         this.mData = mData;
      }
   }

   @Override
   public int getItemCount() {
      if (mSize == 0) {
         int totalSize = 0;
         for (Unit unit : mData) {
            totalSize += (unit.folded ? 1 : unit.children.size() + 1);
         }
         mSize = totalSize;
      }
//    System.out.println("itemCount="+mSize);
      return mSize;
   }

   private int mSize = 0;

   @Override
   public int getItemViewType(int position) {
      //通过位置判断type，因为数据传入后顺序不变，可通过数据来判断当前位置是哪一类数据
      int currentPosition = -1;
      for (Unit unit : mData) {
         if (unit.folded) {
            currentPosition = currentPosition + 1;
            if (currentPosition == position) {
               return FoldableViewHolder.GROUP;
            }
         } else {
            //算上group
            currentPosition = currentPosition + 1;
            if (currentPosition == position) {
               return FoldableViewHolder.GROUP;
            }
            //算上children，通过比较大小确定是否是当前Unit中的child
            currentPosition = currentPosition + unit.children.size();
            if (position <= currentPosition) {
               return FoldableViewHolder.CHILD;
            }
         }

      }
      return FoldableViewHolder.GROUP;
   }

   /**
    *  根据索引返回Unit中的K或V
    * @param position 索引
    * @return K/V
    */
   public Object getItem(int position) {
      int currentPosition = -1;
      for (Unit unit : mData) {
         if (unit.folded) {
            currentPosition = currentPosition + 1;
            if (currentPosition == position) {
               return unit.group;
            }
         } else {
            //算上group
            currentPosition = currentPosition + 1;
            if (currentPosition == position) {
               return unit.group;
            }
            //算上children，通过计算确定是当前Unit的child的索引
            currentPosition = currentPosition + unit.children.size();
            if (position <= currentPosition) {
               int unitChildIndex = unit.children.size() - 1 - (currentPosition - position);
               return unit.children.get(unitChildIndex);
            }
         }
      }
      return null;
   }

   /**
    * 根据索引确定返回某个数据集
    * @param position 索引
    * @return Unit
    */
   private Unit<K,V> getUnit(int position) {
      int currentPosition = -1;
      for (Unit<K,V> unit : mData) {
         //算上group
         currentPosition += unit.folded ? 1 : unit.children.size() + 1;
         if (position <= currentPosition)
            return unit;
      }
      return null;
   }


   @NonNull
   @Override
   public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
      if (viewType == FoldableViewHolder.CHILD) {
         return new ChildViewHolder(LayoutInflater.from(mContext).inflate(mChildLayoutRes, viewGroup, false));
      }
      return new GroupViewHolder(LayoutInflater.from(mContext).inflate(mGroupLayoutRes, viewGroup, false));
   }

   @Override
   public void onBindViewHolder(@NonNull final RecyclerView.ViewHolder viewHolder, int position) {

      viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
//          System.out.println("click="+viewHolder.getAdapterPosition());
            if (viewHolder instanceof GroupViewHolder) {
               Unit<K,V> unit = getUnit(viewHolder.getAdapterPosition());
               unit.folded = !unit.folded;
               mSize = 0;
//             notifyDataSetChanged();//最准确，但数据多时性能有影响
//             notifyItemRangeChanged(viewHolder.getAdapterPosition()+1,getItemCount());//需要考虑到holder的旧索引问题，暂无太好的办法去规避
               if(unit.folded){
                  notifyItemRangeRemoved(viewHolder.getAdapterPosition()+1,unit.children.size());
               }else{
                  notifyItemRangeInserted(viewHolder.getAdapterPosition()+1,unit.children.size());
               }
            }
            if (itemClickLitener != null)
               itemClickLitener.onItemClick(viewHolder.itemView, viewHolder.getLayoutPosition());
         }
      });
      viewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
         @Override
         public boolean onLongClick(View v) {
            if (itemClickLitener != null)
               itemClickLitener.onItemLongClick(viewHolder.itemView, viewHolder.getLayoutPosition());
            return true;
         }
      });

      onBindView((FoldableViewHolder) viewHolder, position);
   }

   public abstract void onBindView(FoldableViewHolder holder, int position);


   /*------------------ 关于数据的增删改  ------------------*/


   public void add(Unit<K,V> element) {
      mData.add(element);
      mSize = 0;
      notifyDataSetChanged();
   }

   public void add(List<Unit<K,V>> elemList) {
      mData.addAll(elemList);
      mSize = 0;
      notifyDataSetChanged();
   }

   public void remove(Unit<K,V> elem) {
      mData.remove(elem);
      mSize = 0;
      notifyDataSetChanged();
   }

   public void replace(List<Unit<K,V>> elemList) {
      mData.clear();
      mData.addAll(elemList);
      mSize = 0;
      notifyDataSetChanged();
   }

   public void setData(List<Unit<K,V>> elemList) {
      mData=elemList;
      mSize = 0;
      notifyDataSetChanged();
   }

   /*------------------ 一些准备工作，定义数据或Holder之类  ------------------*/

   protected static abstract class FoldableViewHolder extends RecyclerView.ViewHolder {

      static final int GROUP = 0;
      static final int CHILD = 1;

      private SparseArray<View> views = new SparseArray<>();
      private View convertView;

      public FoldableViewHolder(@NonNull View itemView) {
         super(itemView);
         this.convertView = itemView;
      }

      @SuppressWarnings("unchecked")
      public <T extends View> T getView(int resId) {
         View v = views.get(resId);
         if (null == v) {
            v = convertView.findViewById(resId);
            views.put(resId, v);
         }
         return (T) v;
      }
   }

   protected static class GroupViewHolder extends FoldableViewHolder {

      public GroupViewHolder(@NonNull View itemView) {
         super(itemView);
      }

   }

   protected static class ChildViewHolder extends FoldableViewHolder {

      public ChildViewHolder(@NonNull View itemView) {
         super(itemView);
      }
   }

   /**
    * 数据实体，一对多
    *
    * @param <K>
    * @param <V>
    */
   public static class Unit<K, V> {
      public K group;
      public List<V> children;
      public boolean folded = true;

      public Unit(K group, List<V> children) {
         this.group = group;
         if (children == null) {
            this.children = new ArrayList<>();
         } else {
            this.children = children;
         }
      }

      public Unit(K group, List<V> children, boolean folded) {
         this(group, children);
         this.folded = folded;
      }
   }
}
activity 用法

recyclerView.setLayoutManager(new Linearlayout(this))
继承的adapter = new 继承的adapter (conetxt, 一层布局,
        二层布局, 总数据源);
recyclerView.setAdapter(dormBuildAdapter);

继承的adapter.setOnItemClickLitener(new FoldableRecyclerViewAdapter.OnItemClickLitener() {
            @Override
            public void onItemClick(View view, int position) {
                switch (dormBuildAdapter.getItemViewType(position)) {
                    case 0:
                        数据源= (数据源) 继承的adapter.getItem(position);
                        ImageView img = view.findViewById(R.id.img);
                       // 点击事件收起还是隐藏
                        if (!groundItem.isExpand()) {
                            img.setImageResource(R.mipmap.icon_open_2);
                            groundItem.setExpand(true);
                        } else {
                            img.setImageResource(R.mipmap.icon_open_2);
                            groundItem.setExpand(false);
                        }
                        break;
                    case 1: //子节点
                        // 子节点事件1
//                        }
                        break;
                }
            }

            @Override
            public void onItemLongClick(View view, int position) {

            }
        });

/

public class 继承的adapter extends FoldableRecyclerViewAdapter<一层数据源, 二层数据源> {

    public 继承的adapter(Context mContext, int mGroupLayoutRes, int mChildLayoutRes, List<Unit<一层数据源,  二层数据源>> mData) {
        super(mContext, mGroupLayoutRes, mChildLayoutRes, mData);
    }

    @Override
    public void onBindView(FoldableViewHolder holder, int position) {
        if (holder instanceof GroupViewHolder) {
            // 一层holder view 设置数据
            TextView tvbuildname = holder.getView(R.id.自己view);
          一层数据源 childitem = (一层数据源) getItem(position);

        if (holder instanceof ChildViewHolder) {
        // 二层holder view 设置数据
            二层数据源 childitem = (二层数据源) getItem(position);
            TextView tvtier = holder.getView(R.id.text_tier);
        

        }
    }