Flutter-如何在多行文本字段中退出文本字段？

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('TextField Focus Example'),
        ),
        body: MyHomePage(),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final FocusNode _focusNode = FocusNode();

  @override
  void dispose() {
    _focusNode.dispose(); // 释放资源
    super.dispose();
  }

  void _exitTextField() {
    _focusNode.unfocus(); // 失去焦点
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Expanded(
          child: TextField(
            focusNode: _focusNode,
            maxLines: null, // 允许多行输入
            decoration: InputDecoration(
              labelText: 'Enter text here...',
            ),
          ),
        ),
        ElevatedButton(
          onPressed: _exitTextField,
          child: Text('Exit TextField'),
        ),
      ],
    );
  }
}