如何在flutter文本字段上添加复制操作

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Copy Text Field'),
        ),
        body: Center(
          child: CopyTextField(),
        ),
      ),
    );
  }
}

class CopyTextField extends StatelessWidget {
  final TextEditingController _controller = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onLongPress: () {
        final String textValue = _controller.text;
        Clipboard.setData(ClipboardData(text: textValue));
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Copied to clipboard')),
        );
      },
      child: TextField(
        controller: _controller,
        decoration: InputDecoration(
          hintText: 'Enter text',
        ),
      ),
    );
  }
}