输入命令后如何删除消息？

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: CommandInputScreen(),
    );
  }
}

class CommandInputScreen extends StatefulWidget {
  @override
  _CommandInputScreenState createState() => _CommandInputScreenState();
}

class _CommandInputScreenState extends State<CommandInputScreen> {
  final TextEditingController _controller = TextEditingController();
  final List<String> _messages = [];

  void _handleCommand() {
    final String command = _controller.text.trim();
    if (command.isNotEmpty) {
      setState(() {
        _messages.add(command);
        _controller.clear(); // 清空输入框
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Command Input Example'),
      ),
      body: Column(
        children: [
          Expanded(
            child: ListView.builder(
              itemCount: _messages.length,
              itemBuilder: (context, index) {
                return ListTile(
                  title: Text(_messages[index]),
                );
              },
            ),
          ),
          Padding(
            padding: const EdgeInsets.all(8.0),
            child: Row(
              children: [
                Expanded(
                  child: TextField(
                    controller: _controller,
                    decoration: InputDecoration(
                      labelText: 'Enter command',
                    ),
                    onSubmitted: (value) => _handleCommand(),
                  ),
                ),
                IconButton(
                  icon: Icon(Icons.send),
                  onPressed: _handleCommand,
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}