ListView with Nested childrens

PListView.dart

import 'package:flutter/material.dart';
import 'package:store/model/Entry.dart';
 
class PListView extends StatelessWidget {

  final List<Entry> dataEntry;
  final ValueChanged<String> onSelect;

  PListView({
    Key key,
    @required this.dataEntry,
    @required this.onSelect,
  }) : super(key: key);
  
  @override
  Widget build(BuildContext context) {
    return Scrollbar(
      child: ListView.builder(
        itemCount: dataEntry.length,
        itemBuilder: (BuildContext context, int index) => EntryItem(dataEntry[index],onSelect),
      ),
    );
  }
}
 
class EntryItem extends StatefulWidget {
  final Entry entry;
  final ValueChanged<String> onItemClicked;
  const EntryItem(this.entry, this.onItemClicked);
  @override
  EntryItemState createState() => EntryItemState();
}

class EntryItemState extends State<EntryItem> {

  Widget buildTiles(Entry root, double depth) {
    if (root.children.isEmpty) {
      double mPadding = depth == 0 ? 0 : depth;
      return ListTile(
        title: Padding(padding: EdgeInsets.only(left: mPadding.toDouble()),child: Text('${root.title}')),
        onTap: () => widget.onItemClicked(root.getKey()),
        trailing: root.amount == 0 ? Text('') : Text('${root.getAmount()}'),
      );
    }else{
      ExpansionTile elementList =  ExpansionTile(
        key: PageStorageKey<Entry>(root),
        title: Padding(padding: EdgeInsets.only(left: depth.toDouble()),child: Text('${root.title}')),
        children: root.children.map((entry) => buildTiles(entry, depth + 18.toDouble())).toList(),
      );
      return elementList;
    }
  }
 
  @override
  Widget build(BuildContext context) {
    return buildTiles(widget.entry, 0);
  }

}