将异步值返回给initState()

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

class MyWidget extends StatefulWidget {
  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  String _data = '';

  @override
  void initState() {
    super.initState();
    _loadData();
  }

  Future<void> _loadData() async {
    // 模拟网络请求
    await Future.delayed(Duration(seconds: 2));
    setState(() {
      _data = 'Hello, World!';
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Async InitState Example'),
      ),
      body: Center(
        child: Text(_data),
      ),
    );
  }
}

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

Future<void> _loadData() async {
  // 模拟网络请求
  await Future.delayed(Duration(seconds: 2));
  setState(() {
    _data = 'Hello, World!';
  });
}