如何将RefreshIndicator添加到列表的子部分？

import 'package:flutter/material.dart';

class MyListPage extends StatefulWidget {
  @override
  _MyListPageState createState() => _MyListPageState();
}

class _MyListPageState extends State<MyListPage> {
  List<String> _items = List.generate(20, (index) => 'Item ${index + 1}');

  Future<void> _refreshList() async {
    // 模拟刷新操作
    await Future.delayed(Duration(seconds: 2));

    // 更新列表数据
    setState(() {
      _items = List.generate(20, (index) => 'Refreshed Item ${index + 1}');
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('My List'),
      ),
      body: RefreshIndicator(
        onRefresh: _refreshList,
        child: ListView.builder(
          physics: const AlwaysScrollableScrollPhysics(),
          itemCount: _items.length,
          itemBuilder: (context, index) {
            return ListTile(
              title: Text(_items[index]),
            );
          },
        ),
      ),
    );
  }
}