我的Expandablelistview代码可以在Activity中使用，但是当我想在Fragment中使用它时，代码无法使用。我正在分享我的Fragment和Adapter代码。如果你能帮助我，我将非常高兴。我不太擅长编写代码，如果你能简单地解释一下，那就太好了。
片段：

@Suppress("UNREACHABLE_CODE")
class AnaSayfaFragment : Fragment() {

    private lateinit var listViewAdapter: ExpandableListViewAdapter
    private lateinit var chapterList : List<String>
    private lateinit var topicList : HashMap<String,List<String>>
    private var _binding: FragmentAnaSayfaBinding? = null
    private val binding get() = _binding!!

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        //return inflater.inflate(R.layout.fragment_chat, container, false)
        _binding = FragmentAnaSayfaBinding.inflate(inflater, container, false)
        val view = binding.root
        return view
        showList()

        listViewAdapter= ExpandableListViewAdapter(this,chapterList,topicList)
        binding.eListView.setAdapter(listViewAdapter)

    }


    private fun showList() {

        chapterList = ArrayList()
        topicList = HashMap()
        (chapterList as ArrayList<String>).add("Sayı Alıştırmaları")
        (chapterList as ArrayList<String>).add("Toplama İşlemi")
        (chapterList as ArrayList<String>).add("Çıkarma İşlemi")
        (chapterList as ArrayList<String>).add("Ölçme")

        val topic1: MutableList<String> = ArrayList()
        topic1.add("Ritmik Saymalar")
        topic1.add("Önceki Sonraki Sayılar")
        topic1.add("Aradaki Sayılar")
        topic1.add("Sayı Kadar Şekil")
        topic1.add("Sayı Karşılaştırma")
        topic1.add("Bul Boya")
        topic1.add("Sayı Okuma")
        topic1.add("Sayı Yazma")

        val topic2: MutableList<String> = ArrayList()
        topic2.add("Toplama İşlemi (Rakamlarla)")
        topic2.add("Toplama İşlemi (10'a Kadar)")
        topic2.add("Toplama İşlemi (2 Basamak - 1 Basamak)")
        topic2.add("Toplama İşlemi (20 İçinde)")
        topic2.add("Toplamı 10 Olan Sayılar")
        topic2.add("10 ile Toplama")
        topic2.add("Verilmeyenli Toplama")

        val topic3: MutableList<String> = ArrayList()
        topic3.add("Çıkarma İşlemi (Rakamlarla)")
        topic3.add("Çıkarma İşlemi (Seviye 2)")
        topic3.add("Çıkarma İşlemi (Seviye 3)")

        val topic4: MutableList<String> = ArrayList()
        topic4.add("Saat Okuma")
        topic4.add("Saat Çizme")

        topicList[chapterList[0]] = topic1
        topicList[chapterList[1]] = topic2
        topicList[chapterList[2]] = topic3
        topicList[chapterList[3]] = topic4


    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }

}

可扩展适配器：

class ExpandableListViewAdapter internal constructor(private val context: Context, private val chapterList: List<String>, private val topicList: HashMap<String,List<String>>) :
    BaseExpandableListAdapter() {
    override fun getGroupCount(): Int {
        return chapterList.size
    }

    override fun getChildrenCount(p0: Int): Int {
        return this.topicList[this.chapterList[p0]]!!.size
    }

    override fun getGroup(p0: Int): Any {
        return chapterList[p0]
    }

    override fun getChild(p0: Int, p1: Int): Any {
        return this.topicList[this.chapterList[p0]]!![p1]
    }

    override fun getGroupId(p0: Int): Long {
        return p0.toLong()
    }

    override fun getChildId(p0: Int, p1: Int): Long {
        return p1.toLong()
    }

    override fun hasStableIds(): Boolean {
        return false
    }

    override fun getGroupView(p0: Int, p1: Boolean, convertView: View?, p3: ViewGroup?): View {
        var convertView = convertView
        val chapterTitle= getGroup(p0) as String

        if (convertView == null){

            val inflater =  context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
            convertView = inflater.inflate(R.layout.chapter_list, null)
        }
        val chapterTv = convertView!!.findViewById<TextView>(R.id.chapter_tv)
        chapterTv.setText(chapterTitle)

        return convertView
    }

    override fun getChildView(p0: Int, p1: Int, p2: Boolean, convertView: View?, p4: ViewGroup?): View {
        var convertView = convertView
        val topicTitle= getChild(p0, p1) as String

        if (convertView == null){
            val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
            convertView = inflater.inflate(R.layout.topics_list, null)
        }
        val topicTv = convertView!!.findViewById<TextView>(R.id.topics_tv)
        topicTv.setText(topicTitle)

        convertView.setOnClickListener {
            val chapterTv = convertView.findViewById<TextView>(R.id.chapter_tv)
            // if (getChild(p0, p1) =="Ritmik Saymalar"){ }

            when(getChild(p0,p1)){

                "Ritmik Saymalar" -> {
                    val intent = Intent(context, AnaSayfaFragment::class.java)
                    context.startActivity(intent)
                }



            }


        }

        return convertView
    }

    override fun isChildSelectable(p0: Int, p1: Int): Boolean {
        return true
    }
}

我猜问题出在listViewAdapter上，但我找不到解决方法。