# Flutter Design Patterns (Flutter) > Singleton, Factory, Repository, Dependency Injection, Service Locator, SOLID 원칙 - 24 면접 질문 - Senior - [면접 질문: Flutter](https://sharpskill.dev/ko/technologies/flutter/interview-questions.md) ## 1. Dart/Flutter에서 Singleton 패턴이란 무엇입니까? **답변** Singleton은 클래스에 인스턴스가 하나만 존재하도록 보장하고 그 인스턴스에 대한 전역 접근점을 제공합니다. Dart에서는 일반적으로 factory 생성자와 private 정적 인스턴스로 구현합니다. 이 패턴은 설정이나 API 클라이언트 같은 공유 서비스에 유용합니다. ## 2. factory 생성자를 사용하여 Dart에서 Singleton을 올바르게 구현하는 방법은 무엇입니까? **답변** 표준 구현은 private 정적 _instance, private _internal() 생성자, 그리고 항상 _instance를 반환하는 factory 생성자를 사용합니다. 이 방식은 인스턴스가 하나만 존재하도록 보장하며, 단일 스레드 이벤트 루프 덕분에 Dart에서 thread-safe합니다. ## 3. Flutter 애플리케이션에서 Singleton 패턴의 주요 단점은 무엇입니까? **답변** Singleton은 전역 상태를 만들어 인스턴스를 모킹하거나 교체하기 어렵게 만들어 단위 테스트를 어렵게 합니다. 또한 클래스 간 강한 결합을 도입하고 실제 의존성을 숨길 수 있어 코드의 유지보수성을 떨어뜨리고 리팩터링을 어렵게 만듭니다. ## 21개 추가 질문 이용 가능 - 객체 지향 프로그래밍에서 Factory 패턴이란 무엇입니까? - Flutter에서 Factory Method와 Abstract Factory의 차이점은 무엇입니까? 무료로 가입하기: https://sharpskill.dev/ko/login ## 기타 Flutter 면접 주제 - [Dart 기초](https://sharpskill.dev/ko/technologies/flutter/interview-questions/dart-basics.md): 25개 질문, Junior - [Dart 언어 핵심](https://sharpskill.dev/ko/technologies/flutter/interview-questions/dart-language-essentials.md): 15개 질문, Junior - [Flutter 기초](https://sharpskill.dev/ko/technologies/flutter/interview-questions/flutter-fundamentals.md): 18개 질문, Junior - [위젯 생명주기](https://sharpskill.dev/ko/technologies/flutter/interview-questions/widget-lifecycle.md): 20개 질문, Junior - [로컬 스토리지](https://sharpskill.dev/ko/technologies/flutter/interview-questions/local-storage.md): 20개 질문, Junior - [애플리케이션 생명주기](https://sharpskill.dev/ko/technologies/flutter/interview-questions/app-lifecycle.md): 20개 질문, Junior - [Layouts & Constraints](https://sharpskill.dev/ko/technologies/flutter/interview-questions/layouts-constraints.md): 24개 질문, Mid-Level - [ListView & GridView](https://sharpskill.dev/ko/technologies/flutter/interview-questions/listview-gridview.md): 25개 질문, Mid-Level - [내비게이션 및 라우팅](https://sharpskill.dev/ko/technologies/flutter/interview-questions/navigation-routing.md): 22개 질문, Mid-Level - [기본 상태 관리](https://sharpskill.dev/ko/technologies/flutter/interview-questions/state-management-basics.md): 22개 질문, Mid-Level - [Provider 패턴](https://sharpskill.dev/ko/technologies/flutter/interview-questions/provider-pattern.md): 18개 질문, Mid-Level - [Networking & HTTP](https://sharpskill.dev/ko/technologies/flutter/interview-questions/networking-http.md): 20개 질문, Mid-Level - [JSON 직렬화](https://sharpskill.dev/ko/technologies/flutter/interview-questions/json-serialization.md): 20개 질문, Mid-Level - [로컬 데이터베이스](https://sharpskill.dev/ko/technologies/flutter/interview-questions/local-database.md): 22개 질문, Mid-Level - [폼과 유효성 검사](https://sharpskill.dev/ko/technologies/flutter/interview-questions/forms-validation.md): 20개 질문, Mid-Level - [애니메이션](https://sharpskill.dev/ko/technologies/flutter/interview-questions/animations.md): 20개 질문, Mid-Level - [Firebase 통합](https://sharpskill.dev/ko/technologies/flutter/interview-questions/firebase-integration.md): 18개 질문, Mid-Level - [유닛 테스트](https://sharpskill.dev/ko/technologies/flutter/interview-questions/unit-testing.md): 20개 질문, Mid-Level - [위젯 테스트](https://sharpskill.dev/ko/technologies/flutter/interview-questions/widget-testing.md): 18개 질문, Mid-Level - [빌드 및 배포](https://sharpskill.dev/ko/technologies/flutter/interview-questions/build-deployment.md): 16개 질문, Mid-Level - [패키지 관리](https://sharpskill.dev/ko/technologies/flutter/interview-questions/package-management.md): 16개 질문, Mid-Level - [메모리 및 성능](https://sharpskill.dev/ko/technologies/flutter/interview-questions/memory-performance.md): 22개 질문, Senior - [Streams & RxDart](https://sharpskill.dev/ko/technologies/flutter/interview-questions/streams-rxdart.md): 24개 질문, Senior - [고급 State Management](https://sharpskill.dev/ko/technologies/flutter/interview-questions/advanced-state-management.md): 26개 질문, Senior - [성능 최적화](https://sharpskill.dev/ko/technologies/flutter/interview-questions/performance-optimization.md): 26개 질문, Senior - [Platform Channels](https://sharpskill.dev/ko/technologies/flutter/interview-questions/platform-channels.md): 20개 질문, Senior - [Custom Painting](https://sharpskill.dev/ko/technologies/flutter/interview-questions/custom-painting.md): 22개 질문, Senior - [Flutter 애플리케이션 아키텍처](https://sharpskill.dev/ko/technologies/flutter/interview-questions/flutter-app-architecture.md): 22개 질문, Senior --- Source: SharpSkill (https://sharpskill.dev), tech interview preparation for your real stack. HTML version of this page: https://sharpskill.dev/ko/technologies/flutter/interview-questions/flutter-design-patterns