一、实现效果

二、功能类结构图解

三、引入依赖

在app的build.gradle在添加以下代码
implementation 'com.github.CymChad:BaseRecyclerViewAdapterHelper:3.0.6'，这个里面带的适配器，直接调用就即可

BaseRecyclerViewAdapterHelper简称BRVAH

Android SDK	是否支持BaseRecyclerViewAdapterHelper:3.0.6
android compileSdkVersion 29	是
android compileSdkVersion 30	是
android compileSdkVersion 31	是
android compileSdkVersion 32	是
android compileSdkVersion 33	是

这依赖包还需要得到要添加，在Project的build.gradle在添加以下代码，不添加就不行

allprojects {
    repositories {
        ...
        maven { url "https://jitpack.io" }//加上
    }
}

四、实现源码

1、分组/可展开收起(类似于ListView/GridView)

1、实体类(item节点和根节点)

根节点RootNode.kt

package com.example.myapplication3.entity.node.section

import com.chad.library.adapter.base.entity.node.BaseExpandNode
import com.chad.library.adapter.base.entity.node.BaseNode

class RootNode(var childNodes: List<BaseNode>, var title: String) : BaseExpandNode(){

    init {
        this.title = title
    }

    override val childNode: MutableList<BaseNode>?
        get() = childNodes as MutableList<BaseNode>

}

item节点ItemNode.kt

package com.example.myapplication3.entity.node.section

import com.chad.library.adapter.base.entity.node.BaseNode

class ItemNode(var img: Int, var name: String) : BaseNode() {

    override val childNode: MutableList<BaseNode>?
        get() = null
}

2、适配器

节点部分适配器NodeSectionAdapter.kt

package com.example.myapplication3.adapter.node.section

import com.chad.library.adapter.base.BaseNodeAdapter
import com.chad.library.adapter.base.entity.node.BaseNode
import com.example.myapplication3.adapter.node.section.provider.RootNodeProvider
import com.example.myapplication3.adapter.node.section.provider.SecondNodeProvider
import com.example.myapplication3.entity.node.section.RootNode

class NodeSectionAdapter(type: Int = 0) : BaseNodeAdapter() {

    init {

        when (type) {
            //list
            1 -> {
                addFullSpanNodeProvider(RootNodeProvider())
                addNodeProvider(SecondNodeProvider(1))//1表示列表下的子菜单类似于ListView
            }

            //grid
            2 -> {
                addFullSpanNodeProvider(RootNodeProvider())
                addNodeProvider(SecondNodeProvider(2))//2表示列表下的子菜单类似于GridView
            }

            //group,分组列表
            3->{
                addFullSpanNodeProvider(RootNodeProvider(3))//3表示分组列表
                addNodeProvider(SecondNodeProvider(1))//1表示列表下的子菜单类似于ListView
            }
        }
    }

    override fun getItemType(data: List<BaseNode>, position: Int): Int {
        val node = data[position]
        return if (node is RootNode) {
            0
        } else {
            1
        }
        return -1
    }
}

节点部分适配器提供了节点和它的item
提供节点类RootNodeProvider.kt

package com.example.myapplication3.adapter.node.section.provider

import android.graphics.Color
import android.view.View
import android.widget.ImageView
import com.chad.library.adapter.base.entity.node.BaseNode
import com.chad.library.adapter.base.provider.BaseNodeProvider
import com.chad.library.adapter.base.viewholder.BaseViewHolder
import com.example.myapplication3.R
import com.example.myapplication3.entity.node.section.RootNode
import com.example.myapplication3.ext.rotation
import kotlinx.android.synthetic.main.def_section_head.view.*

class RootNodeProvider(private val type: Int = 0) : BaseNodeProvider() {

    override val itemViewType: Int
        get() = 0

    override val layoutId: Int
        get() = R.layout.def_section_head

    override fun convert(helper: BaseViewHolder, item: BaseNode) {
        val entity: RootNode = item as RootNode
        helper.setText(R.id.header, entity.title)

        if (type == 3) {
            helper.itemView.run {
                node_ll.setBackgroundColor(Color.GREEN)
                ivIcon.visibility = View.GONE
            }
            return
        }
        // 增量刷新，使用动画变化箭头
        setArrowSpin(helper, item, false)
    }

    override fun onClick(helper: BaseViewHolder, view: View, data: BaseNode, position: Int) {

        if (type == 3) return

        getAdapter()!!.expandOrCollapse(position)
    }

    private fun setArrowSpin(helper: BaseViewHolder, data: BaseNode, isAnimate: Boolean) {
        val entity: RootNode = data as RootNode
        val imageView = helper.getView<ImageView>(R.id.ivIcon)
        if (entity.isExpanded) {
            imageView.rotation(0f, isAnimate)
        } else {
            imageView.rotation(90f, isAnimate)
        }
    }
}

布局def_section_head.xml

<?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="wrap_content"
    android:background="@drawable/ripple_item_select2"
    android:orientation="vertical">

    <LinearLayout
        android:id="@+id/node_ll"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/header"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:gravity="center_vertical"
            android:layout_marginRight="@dimen/dp_5"
            android:textSize="@dimen/sp_15"
            android:padding="@dimen/dp_8"
            android:paddingBottom="@dimen/dp_8"
            android:textColor="@color/black"
            android:layout_weight="1.0"
            android:text="一级标题0"/>

        <ImageView
            android:id="@+id/ivIcon"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            app:srcCompat="@drawable/baseline_keyboard_arrow_right_24"
            tools:ignore="VectorDrawableCompat" />
    </LinearLayout>

    <!--  <color name="veeeeee">#eeeeee</color> -->
    <View
        android:layout_width="match_parent"
        android:layout_height="0.8dp"
        android:background="@color/veeeeee" />
</LinearLayout>

布局Layout的样式ripple_item_select2.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:state_pressed="true">
        <shape android:shape="rectangle">
            <solid android:color="@color/colorRipple" /><!-- colorRipple = E2E2E2 -->
        </shape>
    </item>
    <item>
        <shape android:shape="rectangle">
            <solid android:color="@color/bgColorPrimary" /><!-- bgColorPrimary= FFFFFF -->
        </shape>
    </item>

</selector>

图标样式这是在android studio系统中添加资源图标

箭头动画调用到rotation()方法，ViewExt.kt文件

package com.example.myapplication3.ext

import android.view.View
import android.view.animation.DecelerateInterpolator
import androidx.core.view.ViewCompat

/**
 * 旋转
 * @param value 角度
 * @param isAnimate 动画
 */
fun View.rotation(value:Float, isAnimate: Boolean){
    if (isAnimate) {
        ViewCompat.animate(this).setDuration(200)
            .setInterpolator(DecelerateInterpolator())
            .rotation(value)
            .start()
    } else {
        this.rotation = value
    }
}

提供节点item，SecondNodeProvider.kt

package com.example.myapplication3.adapter.node.section.provider

import android.view.View
import android.widget.Toast
import com.chad.library.adapter.base.entity.node.BaseNode
import com.chad.library.adapter.base.provider.BaseNodeProvider
import com.chad.library.adapter.base.viewholder.BaseViewHolder
import com.example.myapplication3.R
import com.example.myapplication3.entity.node.section.ItemNode
import kotlinx.android.synthetic.main.item_section_grid_content.view.*
import kotlinx.android.synthetic.main.item_section_list_content.view.*

class SecondNodeProvider(private val type: Int = 0) : BaseNodeProvider() {

    override val itemViewType: Int
        get() = 1
    override val layoutId: Int
        get() = when (type) {

            //布局list
            1 -> R.layout.item_section_list_content

            //布局grid
            else -> R.layout.item_section_grid_content
        }

    override fun convert(helper: BaseViewHolder, item: BaseNode) {
        if (item == null) return
        val entity: ItemNode = item as ItemNode

        when(type){

            //布局list
            1->{
                helper.itemView.run {
                    header.text = entity.name
                }
            }

            //布局grid
            2->{
                helper.itemView.run {
                    iv.setImageResource(entity.img)
                    tv.text = entity.name
                }
            }
        }
    }

    override fun onClick(helper: BaseViewHolder, view: View, data: BaseNode, position: Int) {
        Toast.makeText(context, "$position", Toast.LENGTH_SHORT).show()
    }
}

list布局item_section_list_content.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/ripple_item_select2"
    android:orientation="vertical">

    <TextView
        android:id="@+id/header"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:gravity="center"
        android:text="二级菜单"
        android:textColor="#FF0000"/>

    <View
        android:layout_width="match_parent"
        android:layout_height="0.8dp"
        android:background="@color/veeeeee" />
</LinearLayout>

grid布局item_section_grid_content.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <RelativeLayout
        android:id="@+id/rl"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/item_bg"
        android:padding="12.0dip">

        <ImageView
            android:id="@+id/iv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:scaleType="fitXY"
            android:layout_centerHorizontal="true"/>

        <TextView
            android:id="@+id/tv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/iv"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="5.0dip"
            android:text="测试"
            android:textSize="@dimen/sp_14" />
    </RelativeLayout>
</RelativeLayout>

item_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true">
        <shape android:shape="rectangle">
            <stroke android:width="1.0px" android:color="@color/line" /><!--<color name="line">#fff5f5f5</color>-->

            <gradient android:angle="270.0" android:endColor="#ffe8ecef" android:startColor="#ffe8ecef" />
        </shape>
    </item>

    <item android:state_focused="true">
        <shape android:shape="rectangle">
            <gradient android:angle="270.0" android:endColor="#ffe8ecef" android:startColor="#ffe8ecef" />

            <stroke android:width="1.0px" android:color="@color/line" />
        </shape>
    </item>

    <item>
        <shape android:shape="rectangle">
            <gradient android:angle="270.0" android:endColor="#ffffffff" android:startColor="#ffffffff" />

            <stroke android:width="1.0px" android:color="@color/line" />
        </shape>
    </item>

</selector>

2、实现视图

分组/吸顶/可展开收起(类似于ListView/GridView)二级列表

MainActivity.kt

package com.example.myapplication3.activity.node

import android.content.Intent
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.example.myapplication3.R
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        //分组列表
        btn_group_list.setOnClickListener {
            val intent = Intent(this@MainActivity, MyGroupActivity::class.java)
            startActivity(intent)
        }

        //吸顶列表
        btn_sticky_list.setOnClickListener {
            val intent = Intent(this@MainActivity, StickyActivity::class.java)
            startActivity(intent)
        }

        //列表下的子菜单类似于ListView
        button1.setOnClickListener {
            val intent = Intent(this@MainActivity, MyListActivity::class.java)
            startActivity(intent)
        }

        //列表下的子菜单类似于GridView
        button2.setOnClickListener {
            val intent = Intent(this@MainActivity, MyGridActivity::class.java)
            startActivity(intent)
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical">

    <Button
        android:id="@+id/btn_group_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="分组列表"/>

    <Button
        android:id="@+id/btn_sticky_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="吸顶列表"/>


    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAllCaps="false"
        android:text="列表下的子菜单类似于ListView"/>

    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAllCaps="false"
        android:text="列表下的子菜单类似于GridView"/>
</LinearLayout>

1、分组列表

分组列表MyGroupActivity.kt

package com.example.myapplication3.activity.node

import android.os.Bundle
import android.view.View
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import com.chad.library.adapter.base.entity.node.BaseNode
import com.example.myapplication3.R
import com.example.myapplication3.adapter.node.section.NodeSectionAdapter
import com.example.myapplication3.entity.node.section.ItemNode
import com.example.myapplication3.entity.node.section.RootNode
import kotlinx.android.synthetic.main.activity_type_list.*

class MyGroupActivity :AppCompatActivity(){

    //listType = 3，3表示分组列表
    private var listType:Int = 3

    private var list = mutableListOf<BaseNode>()

    private val mAdapter by lazy {
        NodeSectionAdapter(listType)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_type_list)
        initView()
        initData()
    }

    private fun initView() {
        val layoutManager = LinearLayoutManager(this@MyGroupActivity)
        layoutManager.orientation = LinearLayoutManager.VERTICAL
        rv_list.layoutManager = layoutManager
        rv_list.adapter = mAdapter
    }

    private fun initData() {
        setResources()
        mAdapter.setList(list)
    }

    private fun setResources() {
        disableGroup()
    }

    private fun disableGroup() {
        for (i in 0 until 8){

            //Item Node
            val itemEntity1 = ItemNode(0, "二级菜单1")
            val itemEntity2 = ItemNode(0, "二级菜单2")
            val itemEntity3 = ItemNode(0, "二级菜单3")
            val itemEntity4 = ItemNode(0, "二级菜单4")
            val itemEntity5 = ItemNode(0, "二级菜单5")
            val itemEntity6 = ItemNode(0, "二级菜单6")
            val itemEntity7 = ItemNode(0, "二级菜单7")
            val itemEntity8 = ItemNode(0, "二级菜单8")

            val items = mutableListOf<BaseNode>()
            items.add(itemEntity1)
            items.add(itemEntity2)
            items.add(itemEntity3)
            items.add(itemEntity4)
            items.add(itemEntity5)
            items.add(itemEntity6)
            items.add(itemEntity7)
            items.add(itemEntity8)

            // Root Node
            val entity = RootNode(items,"一级标题$i")

            //数据都展开
            entity.isExpanded = true

            list.add(entity)
        }
    }

    fun goBack(v: View){
        finish()
    }
}

activity_type_list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:background="@color/bg"
    android:orientation="vertical">
    
    <!-- <color name="bg">#F0F0F0</color>-->

    <!--  标题栏左边返回箭头图标，你自己写-->
    <include layout="@layout/toolbar"/>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"/>
</LinearLayout>

2、吸顶列表

1、实体类

TestModel.java

package com.example.myapplication3.entity;

public class TestModel {

    private String info = "";
    private boolean isTitle = false;

    public String getInfo() {
        return info;
    }

    public void setInfo(String info) {
        this.info = info;
    }

    public boolean isTitle() {
        return isTitle;
    }

    public void setTitle(boolean isTitle) {
        this.isTitle = isTitle;
    }
}

2、适配器

适配器RvAdapter.kt

package com.example.myapplication3.adapter

import android.graphics.Color
import android.view.Gravity
import com.chad.library.adapter.base.BaseQuickAdapter
import com.chad.library.adapter.base.viewholder.BaseViewHolder
import com.example.myapplication3.R
import com.example.myapplication3.entity.TestModel
import kotlinx.android.synthetic.main.item_text_view.view.*

class RvAdapter(layoutResId: Int = R.layout.item_text_view) :
    BaseQuickAdapter<TestModel, BaseViewHolder>(layoutResId) {
    override fun convert(helper: BaseViewHolder, item: TestModel) {
        helper.itemView.run {
            item_info.text = item.info
            if (item.isTitle){
                item_info.setBackgroundResource(R.color.red)
                item_info.setTextColor(Color.BLACK)
                item_info.gravity = Gravity.CENTER
                item_info.setPadding(0,item_info.paddingTop,0,item_info.paddingBottom)
            }else{
                item_info.setBackgroundColor(Color.WHITE)
                item_info.setTextColor(Color.BLACK)
                item_info.gravity = Gravity.LEFT
                item_info.setPadding(40,item_info.paddingTop,0,item_info.paddingBottom)
            }
        }
    }
}

item_text_view.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/item_info"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="10dp"
    android:paddingTop="10dp"
    android:textSize="18sp" />

吸顶列表StickyActivity.kt

package com.example.myapplication3.activity.node

import android.os.Bundle
import android.view.View
import android.widget.RelativeLayout
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.example.myapplication3.R
import com.example.myapplication3.adapter.RvAdapter
import com.example.myapplication3.entity.TestModel
import kotlinx.android.synthetic.main.activity_sticky_list.*
import java.util.*

class StickyActivity : AppCompatActivity() {

    private var list = ArrayList<TestModel>()
    private var mAdapter: RvAdapter? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_sticky_list)

        for (i in 0..7) {
            val model = TestModel()
            model.info = "一级菜单$i"
            model.isTitle = true
            list.add(model)
            for (j in 0..2) {
                val model = TestModel()
                model.info = "二级菜单$j"
                list.add(model)
            }
        }
        mAdapter = RvAdapter()

        val layoutManager = LinearLayoutManager(this@StickyActivity)
        layoutManager.orientation = LinearLayoutManager.VERTICAL
        listview.layoutManager = layoutManager

        listview.adapter = mAdapter
        title_text.text = list[0].info

        mAdapter!!.setList(list)

//        listview.setOnItemClickListener { parent, view, position, l ->
//            Toast.makeText(this@StickyActivity2, list[position].info, Toast.LENGTH_SHORT).show()
//        }

        listview.addOnScrollListener(object : RecyclerView.OnScrollListener() {
//            override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
//                super.onScrollStateChanged(recyclerView, newState)
//            }

            override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
                super.onScrolled(recyclerView, dx, dy)
//                val topPosition = layoutManager.findLastCompletelyVisibleItemPosition()

                val MylayoutManager = recyclerView.layoutManager as LinearLayoutManager


                val firstVisibleItem = MylayoutManager.findFirstVisibleItemPosition()
//                val lastVisible = MylayoutManager.findLastVisibleItemPosition()
//                val visibleItemCount = lastVisible - firstVisibleItem

                val visibleItemCount = recyclerView.childCount

                if (firstVisibleItem < list.size && visibleItemCount > 0) {

                    val params = title_text.layoutParams as RelativeLayout.LayoutParams

                    val itemView: View = recyclerView.getChildAt(1)

                    var top = 0

                    if (list[firstVisibleItem + 1].isTitle) {
                        top = itemView.top - itemView.height
                    }
//                    title_text.text = list[firstVisibleItem].info.substring(0, 1).toUpperCase()

                    if (list[firstVisibleItem].info.subSequence(0, 1) == "一") {
                        title_text.text = list[firstVisibleItem].info
                    }

                    params.setMargins(0, top, 0, 0)
                    title_text.layoutParams = params
                }
            }
        })
    }

    fun goBack(v: View) {
        finish()
    }
}

activity_sticky_list.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/xxx"/>

    <TextView
        android:id="@+id/title_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/red"
        android:gravity="center"
        android:paddingTop="10dp"
        android:paddingBottom="10dp"
        android:textColor="@android:color/black"
        android:textSize="18sp"
        android:layout_below="@id/xxx"/>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_below="@id/title_text"
        android:background="@android:color/white"/>

    <include
        android:id="@+id/xxx"
        layout="@layout/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</RelativeLayout>

3、列表下的子菜单类似于ListView

列表下的子菜单类似于ListView，MyListActivity.kt

package com.example.myapplication3.activity.node

import android.os.Bundle
import android.view.View
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import com.chad.library.adapter.base.entity.node.BaseNode
import com.example.myapplication3.R
import com.example.myapplication3.adapter.node.section.NodeSectionAdapter
import com.example.myapplication3.entity.node.section.ItemNode
import com.example.myapplication3.entity.node.section.RootNode
import kotlinx.android.synthetic.main.activity_type_list.*

class MyListActivity :AppCompatActivity(){

    //listType = 1，1表示item子菜单类似于ListView
    private var listType:Int = 1

    private var list = mutableListOf<BaseNode>()

    private val mAdapter by lazy {
        NodeSectionAdapter(listType)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_type_list)
        initView()
        initData()
    }

    private fun initView() {
        val layoutManager = LinearLayoutManager(this@MyListActivity)
        layoutManager.orientation = LinearLayoutManager.VERTICAL
        rv_list.layoutManager = layoutManager
        rv_list.adapter = mAdapter
    }

    private fun initData() {
        setResources()
        mAdapter.setList(list)
    }

    private fun setResources() {
        disableGroup()
    }

    private fun disableGroup() {
        for (i in 0 until 8){

            //Item Node
            val itemEntity1 = ItemNode(0, "二级菜单1")
            val itemEntity2 = ItemNode(0, "二级菜单2")
            val itemEntity3 = ItemNode(0, "二级菜单3")
            val itemEntity4 = ItemNode(0, "二级菜单4")
            val itemEntity5 = ItemNode(0, "二级菜单5")
            val itemEntity6 = ItemNode(0, "二级菜单6")
            val itemEntity7 = ItemNode(0, "二级菜单7")
            val itemEntity8 = ItemNode(0, "二级菜单8")

            val items = mutableListOf<BaseNode>()
            items.add(itemEntity1)
            items.add(itemEntity2)
            items.add(itemEntity3)
            items.add(itemEntity4)
            items.add(itemEntity5)
            items.add(itemEntity6)
            items.add(itemEntity7)
            items.add(itemEntity8)

            // Root Node
            val entity = RootNode(items,"一级标题$i")
            if (i == 0){

                // 第1号数据默认不展开
                entity.isExpanded = true
            }else{
                entity.isExpanded = false
            }
            list.add(entity)
        }
    }

    fun goBack(v: View){
        finish()
    }
}

4、列表下的子菜单类似于GridView

列表下的子菜单类似于GridView，MyGridActivity.kt

package com.example.myapplication3.activity.node

import android.os.Bundle
import android.view.View
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.GridLayoutManager
import com.chad.library.adapter.base.entity.node.BaseNode
import com.example.myapplication3.R
import com.example.myapplication3.adapter.node.section.NodeSectionAdapter
import com.example.myapplication3.entity.node.section.ItemNode
import com.example.myapplication3.entity.node.section.RootNode
import kotlinx.android.synthetic.main.activity_type_list.*

class MyGridActivity : AppCompatActivity()
{

    //listType = 2，2表示item子菜单类似于GridView，
    private var gridType:Int = 2

    private var list = mutableListOf<BaseNode>()

    private val mAdapter by lazy {
        NodeSectionAdapter(gridType)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_type_list)
        initView()
        initData()
    }

    private fun initView() {
        rv_list.layoutManager = GridLayoutManager(this@MyGridActivity,5)
        rv_list.adapter = mAdapter
    }

    private fun initData() {
        setResources()
        mAdapter.setList(list)
    }

    private fun setResources() {
        disableGroup()
    }

    private fun disableGroup() {
        for (i in 0 until 8){

            //Item Node
            val itemEntity1 = ItemNode(R.mipmap.ic_c, getString(R.string.test1))//<string name="test1">测试1</string>
            val itemEntity2 = ItemNode(R.mipmap.ic_c, getString(R.string.test2))//<string name="test2">测试2</string>
            val itemEntity3 = ItemNode(R.mipmap.ic_c, getString(R.string.test3))//<string name="test3">测试3</string>
            val itemEntity4 = ItemNode(R.mipmap.ic_c, getString(R.string.test4))//<string name="test4">测试4</string>
            val itemEntity5 = ItemNode(R.mipmap.ic_c, getString(R.string.test5))//<string name="test5">测试5</string>
            val itemEntity6 = ItemNode(R.mipmap.ic_c, getString(R.string.test6))//<string name="test6">测试6</string>
            val itemEntity7 = ItemNode(R.mipmap.ic_c, getString(R.string.test7))//<string name="test7">测试7</string>
            val itemEntity8 = ItemNode(R.mipmap.ic_c, getString(R.string.test8))//<string name="test8">测试8</string>

            val items = mutableListOf<BaseNode>()
            items.add(itemEntity1)
            items.add(itemEntity2)
            items.add(itemEntity3)
            items.add(itemEntity4)
            items.add(itemEntity5)
            items.add(itemEntity6)
            items.add(itemEntity7)
            items.add(itemEntity8)

            // Root Node
            val entity = RootNode(items,"一级标题$i")
            if (i == 0){
                // 第1号数据默认不展开
                entity.isExpanded = true
            }else{
                entity.isExpanded = false
            }
            list.add(entity)
        }
    }

    fun goBack(v: View){
        finish()
    }
}

图标样式这是在android studio系统中添加资源图标