[flutter] HelloWorld 만들기

1)

import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      home: Scaffold(
        backgroundColor: Colors.black,
        body: Center(
          child: Text('Hello World',
          style: TextStyle(
            color: Colors.white,
            fontSize: 20.0,
          )),
        ),
      ),
    ),
  );
}