Android实现recyclerview列表的展开更多和点击收起功能

1：布局文件使用recyclerview显示四列并加入阴影及点击按钮控件

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/main_bg"
    android:orientation="vertical">
            <FrameLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

                <androidx.recyclerview.widget.RecyclerView
                    android:id="@+id/region_recy"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="12dp"
                    app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
                    app:spanCount="4" />

                <!--                阴影控件设置半透明-->
                <TextView
                    android:id="@+id/txt_yinying"
                    android:layout_width="match_parent"
                    android:layout_height="30dp"
                    android:layout_gravity="bottom"
                    android:background="#b3ffffff" />
            </FrameLayout>

            <!--            //展开更多，点击收起-->
            <RelativeLayout
                android:id="@+id/rl_openall"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:padding="12dp">

                <TextView
                    android:id="@+id/txt_open"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="@color/main_bg"
                    android:gravity="center"
                    android:text="展开更多"
                    android:textColor="@color/txtblue"
                    android:textSize="14sp" />
            </RelativeLayout>

</LinearLayout>

2:代码中设置全部显示数据和收起显示数据

//regionBeans接口list集合数据
 private List<String> mList = new ArrayList<>();
    private List<String> HideList = new ArrayList<>();
            for (int i = 0; i < regionBeans.size(); i++) {
    
    
                     mList.add(regionBeans.get(i).getName());
                    }
                    //收起显示的数据仅显示16条
                    for (int i = 0; i < 16; i++) {
    
    
                            HideList.add(mList.get(i));
                    }
                    //适配器
                    mRegionAdapter = new RegionAdapter(KeywordActivity.this);
                    regionRecy.setAdapter(mRegionAdapter);
                    //默认设置收起时的数据
                    mRegionAdapter.setHideList(HideList);

RegionAdapter适配器中

public class RegionAdapter extends RecyclerView.Adapter<RegionAdapter.ViewHolder> {
    
    
    private Activity activity;
    private List<String> list;

    public RegionAdapter(Activity activity) {
    
    
        this.activity = activity;
    }
    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    
    
        View view = LayoutInflater.from(activity).inflate(R.layout.rmsf_item, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
    
    
        holder.mRmsfname.setText(list.get(position));
    }

    @Override
    public int getItemCount() {
    
    
        return list.size();
    }

//显示收起时数据
    public void setHideList(List<String> newList) {
    
    
        this.list = newList;
        notifyDataSetChanged();
    }

//显示全部数据
    public void setOpenList(List<String> openList) {
    
    
        this.list = openList;
        notifyDataSetChanged();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
    
    

        private final TextView mRmsfname;

        public ViewHolder(@NonNull View itemView) {
    
    
            super(itemView);
            mRmsfname = itemView.findViewById(R.id.rmsf_name);
        }
    }
}

3：点击收起展开按钮执行适配器的两个方法

  case R.id.rl_openall:
                if (txtOpen.getText().toString().equals("展开更多")) {
    
    
                    txtOpen.setText("点击收起");
                    txtYinying.setVisibility(View.GONE);
                    mRegionAdapter.setOpenList(mList);
                } else {
    
    
                    txtOpen.setText("展开更多");
                    txtYinying.setVisibility(View.VISIBLE);
                    mRegionAdapter.setHideList(HideList);
                }

                break;