在flutter中使用文本字段“取消选择”按钮

import 'package:flutter/material.dart';

class MyTextField extends StatefulWidget {
  @override
  _MyTextFieldState createState() => _MyTextFieldState();
}

class _MyTextFieldState extends State<MyTextField> {
  TextEditingController _controller = TextEditingController();

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  void _clearText() {
    setState(() {
      _controller.clear();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('TextField示例'),
      ),
      body: Padding(
        padding: EdgeInsets.all(16.0),
        child: Column(
          children: [
            TextField(
              controller: _controller,
              decoration: InputDecoration(
                labelText: '文本字段',
              ),
            ),
            SizedBox(height: 16.0),
            RaisedButton(
              onPressed: _clearText,
              child: Text('取消选择'),
            ),
          ],
        ),
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: MyTextField(),
  ));
}