将onChanged函数传递给单选按钮会导致“参数不匹配的闭包调用”

// 导入相关库
import 'package:flutter/material.dart';

// 定义一个变量来存储单选按钮的值
String selectedValue;

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('单选按钮示例'),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              RadioListTile(
                title: Text('选项1'),
                value: '选项1',
                groupValue: selectedValue,
                onChanged: (value) {
                  // 更新选中的值
                  selectedValue = value;
                },
              ),
              RadioListTile(
                title: Text('选项2'),
                value: '选项2',
                groupValue: selectedValue,
                onChanged: (value) {
                  // 更新选中的值
                  selectedValue = value;
                },
              ),
              RadioListTile(
                title: Text('选项3'),
                value: '选项3',
                groupValue: selectedValue,
                onChanged: (value) {
                  // 更新选中的值
                  selectedValue = value;
                },
              ),
            ],
          ),
        ),
      ),
    );
  }
}