如何在可展开列表视图Kotlin中获取表头中的子数

val expandableListView: ExpandableListView = findViewById(R.id.expandableListView)
val adapter = MyExpandableListAdapter()
expandableListView.setAdapter(adapter)

class MyExpandableListAdapter : BaseExpandableListAdapter() {
    // 实现必要的方法
    // ...
}

override fun getGroupView(groupPosition: Int, isExpanded: Boolean, convertView: View?, parent: ViewGroup?): View {
    var view = convertView
    if (view == null) {
        val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        view = inflater.inflate(R.layout.group_item, null)
    }
    
    // 获取表头中的子数
    val groupItem = getGroup(groupPosition) as GroupItem
    val childCount = groupItem.getChildCount()
    
    // 在视图中显示子数
    val childCountTextView: TextView = view.findViewById(R.id.childCountTextView)
    childCountTextView.text = "子数: $childCount"
    
    return view
}