当继承StatelessWidget组件时，在组件中更新数据时页面不会立即刷新。

如果继承StatefulWidget时，只要在setState方法中更新数据后页面会实时更新数据。

完整代码：

import 'package:flutter/material.dart';void main() {runApp(const MyApp());
}class MyApp extends StatelessWidget {const MyApp({super.key});@overrideWidget build(BuildContext context) {return MaterialApp(theme: ThemeData(primarySwatch: Colors.blue),home: Scaffold(appBar: AppBar(title: const Text("Flutter"),),body: const MyHomePage(),),);}
}class MyHomePage extends StatelessWidget {const MyHomePage({Key? key}) : super(key: key);@overrideWidget build(BuildContext context) {return const _HomePageState();}
}///StatefulWidget:状态组件，改变页面数据状态
class _HomePageState extends StatefulWidget {const _HomePageState();@overrideState<_HomePageState> createState() => _HomePageStateState();
}class _HomePageStateState extends State<_HomePageState> {final List<String> _list = ["数据一", "数据二", "数据三"];@overrideWidget build(BuildContext context) {return Scaffold(body: ListView(children: _list.map((v) {return ListTile(title: Text(v));}).toList(),),floatingActionButton: FloatingActionButton(onPressed: () {setState(() {_list.add("新增数据");});},child: const Icon(Icons.add),),);}
}