main.dartimport 'package:flutter/material.dart';​void main() {runApp(new Center(child: new Text('Hello, world!'),),);}
import 'package:flutter/material.dart';​void main() {runApp(new MaterialApp(title: 'Hello World App',home: new myApp(),));}​class myApp extends StatelessWidget {Widget build(BuildContext context) {return new Scaffold(appBar: new AppBar(title: new Text('Hello World App'),),body: new Center(child: new Text('Hello, world!'),),);}}