Flutter -如何从FutureBuilder中提供TextField的初始值和动态值？

import 'package:flutter/material.dart';

class MyWidget extends StatelessWidget {
  Future<String> fetchData() async {
    // 异步操作，例如从数据库或网络获取数据
    await Future.delayed(Duration(seconds: 2));
    return '初始值';
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<String>(
      future: fetchData(),
      builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
        if (snapshot.connectionState == ConnectionState.waiting) {
          // 异步操作正在进行中，显示加载中的UI
          return CircularProgressIndicator();
        } else if (snapshot.hasError) {
          // 异步操作发生错误，显示错误信息
          return Text('Error: ${snapshot.error}');
        } else {
          // 异步操作已完成，显示TextField和按钮
          TextEditingController controller = TextEditingController(text: snapshot.data);
          return Column(
            children: [
              TextField(
                controller: controller,
                onChanged: (value) {
                  // 获取用户输入的动态值
                  print('动态值：$value');
                  // 更新TextEditingController的text属性
                  controller.text = value;
                },
              ),
              RaisedButton(
                child: Text('提交'),
                onPressed: () {
                  // 提交操作
                },
              ),
            ],
          );
        }
      },
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: Scaffold(
      body: MyWidget(),
    ),
  ));
}