我建议您使用
FutureBuilder：
import 'package:flutter/material.dart';class MyApp extends StatefulWidget { @override _MyAppState createState() => _MyAppState();}class _MyAppState extends State<MyApp> { // save in the state for caching! DeviceInfoPlugin _deviceInfoPlugin; @override void initState() { super.initState(); _deviceInfoPlugin = DeviceInfoPlugin(); } @override Widget build(BuildContext context) { return MaterialApp( title: 'My Device Info', home: Scaffold( appBar: AppBar( title: Text('My Device Info'), ), body: FutureBuilder<AndroidDeviceInfo>( future: _deviceInfoPlugin.androidInfo, builder: (BuildContext context, AsyncSnapshot<AndroidDeviceInfo> snapshot) { if (!snapshot.hasData) { // while data is loading: return Center( child: CircularProgressIndicator(), ); } else { // data loaded: final androidDeviceInfo = snapshot.data; return Center( child: Text('Android version: ${androidDeviceInfo.version}'), ); } }, ), ), ); }}通常，在使用
FutureBuilder或
Futures时，必须记住可以随时重新构建封闭的小部件（例如，因为设备已旋转或显示了键盘）。这意味着将
build再次调用该方法。
在这种特殊情况下，这不是问题，因为该插件会缓存该值并立即返回它，但通常来说，您永远不要创建或获取
Future该
build方法的内部内容。相反，您可以通过
initState点击事件处理程序或点击事件处理程序执行此操作：
import 'package:flutter/material.dart';class FooWidget extends StatefulWidget { @override _FooWidgetState createState() => _FooWidgetState();}class _FooWidgetState extends State<FooWidget> { Future<int> _bar; @override void initState() { super.initState(); _bar = doSomeLongRunningCalculation(); } void _retry() { setState(() { _bar = doSomeLongRunningCalculation(); }); } @override Widget build(BuildContext context) { return Column( children: <Widget>[ FutureBuilder<int>( future: _bar, builder: (BuildContext context, AsyncSnapshot<int> snapshot) { if (snapshot.hasData) { return Text('The answer to everything is ${snapshot.data}'); } else { return Text('Calculating answer...'); } }, ), RaisedButton( onPressed: _retry, child: Text('Retry'), ) ], ); }}Future<int> doSomeLongRunningCalculation() async { await Future.delayed(Duration(seconds: 5)); // wait 5 sec return 42;}
