在来自DropdownButton的正确类别上显示文本字段

import 'package:flutter/material.dart';

class MyDropdownButton extends StatefulWidget {
  @override
  _MyDropdownButtonState createState() => _MyDropdownButtonState();
}

class _MyDropdownButtonState extends State<MyDropdownButton> {
  String _selectedOption;

  @override
  Widget build(BuildContext context) {
    return DropdownButton<String>(
      value: _selectedOption,
      onChanged: (String newValue) {
        setState(() {
          _selectedOption = newValue;
        });
      },
      items: <DropdownMenuItem<String>>[
        DropdownMenuItem<String>(
          value: 'option1',
          child: ListTile(
            title: Text('Option 1'),
            subtitle: Text('This is the first option'),
          ),
        ),
        DropdownMenuItem<String>(
          value: 'option2',
          child: ListTile(
            title: Text('Option 2'),
            subtitle: Text('This is the second option'),
          ),
        ),
      ],
    );
  }
}