导入'package:flutter / material.dart'; 导入'package:flutter_app_guilherme / second.dart'; void main(){ runApp(MyApp()); } 类MyApp扩展了StatelessWidget {//此小部件是应用程序的根。 @override Widget build(BuildContext context){ return MaterialApp( debugShowCheckedModeBanner: false, title: 'Flutter Demo', theme: ThemeData( primarySwatch: Colors.blueGrey, ), home: MyHomePage(title: 'Visualizador de Image