ExpandableListView: Estrutura e Funcionamento

public class ExpandableListAdapter extends BaseExpandableListAdapter {
    // ... métodos necessários

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(context).inflate(R.layout.child_item, parent, false);
        }
        TextView childText = convertView.findViewById(R.id.child_text);
        childText.setText("Child Item " + childPosition);
        return convertView;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(context).inflate(R.layout.group_item, parent, false);
        }
        TextView groupText = convertView.findViewById(R.id.group_text);
        groupText.setText("Group Item " + groupPosition);
        return convertView;
    }
}

class ExpandableListAdapter(
    private val context: Context,
    private val groups: List<String>,
    private val children: List<List<String>>
) : BaseExpandableListAdapter() {

    override fun getGroup(groupPosition: Int): Any = groups[groupPosition]

    override fun getChild(groupPosition: Int, childPosition: Int): Any = children[groupPosition][childPosition]

    override fun getGroupId(groupPosition: Int): Long = groupPosition.toLong()

    override fun getChildId(groupPosition: Int, childPosition: Int): Long = childPosition.toLong()

    override fun hasMoreChildren: Boolean = true

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val view = LayoutInflater.from(context).inflate(R.layout.child_item, parent, false)
        return ChildViewHolder(view)
    }
}