在buildMethod中分配TextEditingController的值

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('TextEditingController Example')),
        body: MyForm(),
      ),
    );
  }
}

class MyForm extends StatefulWidget {
  @override
  _MyFormState createState() => _MyFormState();
}

class _MyFormState extends State<MyForm> {
  final TextEditingController _controller = TextEditingController();

  @override
  void dispose() {
    // 重要：记得在dispose方法中释放控制器资源
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        TextField(
          controller: _controller,
          decoration: InputDecoration(labelText: 'Enter your name'),
        ),
        SizedBox(height: 20),
        ElevatedButton(
          onPressed: () {
            // 获取文本框的值
            String name = _controller.text;
            print('Name: $name');
          },
          child: Text('Submit'),
        ),
      ],
    );
  }
}

class _MyFormState extends State<MyForm> {
  late final TextEditingController _controller;

  @override
  void initState() {
    super.initState();
    _controller = TextEditingController();
  }

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

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        TextField(
          controller: _controller,
          decoration: InputDecoration(labelText: 'Enter your name'),
        ),
        SizedBox(height: 20),
        ElevatedButton(
          onPressed: () {
            String name = _controller.text;
            print('Name: $name');
          },
          child: Text('Submit'),
        ),
      ],
    );
  }
}