🎯 Dart 기반 Flutter 모바일 앱 개발 시작하기 - 기본부터 고급 개념까지

// 1단계: 프로젝트 생성 후 main.dart 기본 구조
import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MainScreen(), // 기본 화면 설정
    );
  }
}

// 2단계: 화면 전환 구현 (MainScreen.dart)
class MainScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('메인 화면')),
      body: Center(
        child: ElevatedButton(
          onPressed: () => Navigator.push(
            context, 
            MaterialPageRoute(builder: (context) => SecondScreen()),
          ),
          child: Text('다음 화면으로 이동'),
        ),
      ),
    );
  }
}

// 3단계: Provider 상태 관리 구현 (main.dart)
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (_) => AppModel(),
      child: MyApp(),
    ),
  );
}

class AppModel extends ChangeNotifier {
  int _counter = 0;
  get counter => _counter;

  void increment() {
    _counter++;
    notifyListeners();
  }
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: ProviderScreen(),
    );
  }
}

// 4단계: BLoC 패턴 적용 (main.dart)
import 'package:flutter/material.dart';
import 'package:bloc/bloc.dart';

void main() {
  runApp(
    BlocProvider(
      create: (_) => AppBloc(),
      child: MyApp(),
    ),
  );
}

class AppBloc extends Bloc<AppEvent, AppState> {
  @override
  Stream<AppState> mapEventToState(AppEvent event) async* {
    if (event is IncrementEvent) {
      yield AppState(counter: state.counter + 1);
    }
  }
}

class AppEvent {}

class AppState {
  final int counter;
  const AppState({required this.counter});
}