bullseye/lib/main.dart

import 'package:flutter/material.dart';

void main() => runApp(BullsEyeApp());

class BullsEyeApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'BullsEye',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: GamePage(title: 'BullsEye'),
    );
  }
}

class GamePage extends StatefulWidget {
  GamePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _GamePageState createState() => _GamePageState();
}

class _GamePageState extends State<GamePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text("Hello World!",
                style: TextStyle(
                    fontWeight: FontWeight.bold, color: Colors.green)),
            TextButton(child: Text('Hit me!'), onPressed: () {})
          ],
        ),
      ),
    );
  }
}