这是我的代码:import'package:flutter/material.dart';import'package:flutter/services.dart';voidmain()=>runApp(App());classAppextendsStatelessWidget{@overrideWidgetbuild(BuildContextcontext){returnMaterialApp(title:"test",theme:ThemeData(primarySwatch:Colors.blueGrey),home:Scaffold(body:MyWidget()),);}}c