3. 기초 프로젝트 생성, AVD(안드로이드) 실행_Flutter와 Bootstrap을 활용한 크로스 플랫폼 웹 개발

Flutter 프로젝트 실습 : Hello World 프로젝트 만들기 

cmd에서 Flutter 프로젝트를 생성해보자 

$ flutter create [프로젝트명]
$ flutter create hello_world

 

※ 프로젝트명은 소문자로만 작성이 가능하다 

숫자가 들어갈 수는 있지만 맨 처음에 들어가는 것은 불가능하다 

원하는 디렉토리로 이동 후 명령어 실행

 

명령어 실행하면 hello_world 자동 생성

 

 

Flutter 프로젝트 파일 구조

 

D:\dev\flutterProject\hello_world

• .dart_tool
  • dartpad
• .idea
  • libraries
  • runConfigurations
• android : Android 애플리케이션을 위한 설정 파일이 포함된 디렉토리 
  • app
  • gradle
• ios : ios 애플리케이션을 위한 설정 파일이 포함된 디렉토리
  • Flutter
  • Runner
  • Runner.xcodeproj
  • Runner.xcworkspace
  • RunnerTests
• lib : 모든 Dart 코드가 포함된 디렉토리로 main.dart 파일이 위치해있다
• linux
  • flutter
• macos
  • Flutter
  • Runner
  • Runner.xcodeproj
  • Runner.xcworkspace
  • RunnerTests
• test : 테스트코드가 포함된 디렉토리 
• web : 웹 애플리케이션을 위한 설정 파일이 포함된 디렉토리
  • icons
• windows
  • flutter
  • runner
• pubspec.yaml : 프로젝트의 의존성을 관리하는 파일 / 패키지, 플러그인, 이미지, 폰트 증의 정보를 정의한다

 

hello_world 실행시켜보기

1)  lib 폴더에 main.dart 파일을 열어 수정합니다 

이 파일에는 모든 Flutter 프로젝트의 시작코드가 포함되어 있다

 

- 생성된 기본코드 -

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // TRY THIS: Try running your application with "flutter run". You'll see
        // the application has a purple toolbar. Then, without quitting the app,
        // try changing the seedColor in the colorScheme below to Colors.green
        // and then invoke "hot reload" (save your changes or press the "hot
        // reload" button in a Flutter-supported IDE, or press "r" if you used
        // the command line to start the app).
        //
        // Notice that the counter didn't reset back to zero; the application
        // state is not lost during the reload. To reset the state, use hot
        // restart instead.
        //
        // This works for code too, not just values: Most code changes can be
        // tested with just a hot reload.
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // TRY THIS: Try changing the color here to a specific color (to
        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
        // change color while the other colors stay the same.
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          //
          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
          // action in the IDE, or press "p" in the console), to see the
          // wireframe for each widget.
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

 

 

- 아래와 같이 변경한다 -

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: Scaffold(
        body: Center(
          child: Text('Hello, World!'),
        ),
      ),
    );
  }
}

> Scaffold, Centre, Text 위젯을 사용해 Hello, World! 메세지를 표시해보는 코드이다

 

 

2) VSCode에서 AVD 실행

AVD를 통해서 실행하면 스마트폰을 연결하지 않고도 Flutter 개발이 가능하다

 

VSCode command palette를 실행(ctrl+shift+p)

Flutter:Select Device 선택

 

실행할 AVD 선택(에뮬레이터)

 

Android Studio - Device Manager에서 해당 에뮬레이터 실행 

에뮬레이터 실행 중인 화면

처음 AVD 실행할 때는 시간이 좀 걸리니 당황하지 말자

 

 

3) VSCode Run and Debug

Run and Debug 버튼을 눌러주자

 

 

안드로이드 에뮬레이터에서 앱이 실행되고 Hello, World가 출력되는 걸 볼 수 있다

Hello, World! 출력

오늘도 찢었다

 

 

 

---

시리즈

1. Flutter와 Bootstrap을 활용한 크로스 플랫폼 웹 개발_1.설정

https://tiny-immj.tistory.com/73

Flutter와 Bootstrap을 활용한 크로스 플랫폼 웹 개발_1. 설정

 

2. Flutter와 Bootstrap을 활용한 크로스 플랫폼 웹 개발_2.Flutter 개발환경 설정

https://tiny-immj.tistory.com/74

Flutter와 Bootstrap을 활용한 크로스 플랫폼 웹 개발_2.Flutter 개발 환경 설정