flutter:如何在ListWheelChildLoopingListDelegate中获取所选项目的索引？

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('ListWheelScrollView Example'),
        ),
        body: Center(
          child: ListWheelScrollView(
            itemExtent: 50,
            diameterRatio: 2.0,
            physics: FixedExtentScrollPhysics(),
            childrenDelegate: ListWheelChildLoopingListDelegate(
              children: List<Widget>.generate(10, (index) {
                return ListTile(
                  title: Text('Item $index'),
                );
              }),
            ),
            onSelectedItemChanged: (index) {
              print('Selected item index: $index');
            },
          ),
        ),
      ),
    );
  }
}