如何在silverlist中对小部件列表进行分组？

import 'package:flutter/material.dart';
import 'package:grouped_list/grouped_list.dart';

class MyWidget extends StatelessWidget {
  final List<Map<String, dynamic>> itemList = [
    {'group': 'Group 1', 'title': 'Item 1'},
    {'group': 'Group 1', 'title': 'Item 2'},
    {'group': 'Group 2', 'title': 'Item 3'},
    {'group': 'Group 2', 'title': 'Item 4'},
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Grouped List Example'),
      ),
      body: GroupedListView<dynamic, String>(
        elements: itemList,
        groupBy: (item) => item['group'],
        groupSeparatorBuilder: (String groupByValue) => Text(groupByValue),
        itemBuilder: (context, item) => ListTile(
          title: Text(item['title']),
        ),
      ),
    );
  }
}