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iOS Architecture
The document discusses various iOS architecture patterns including MVC, MVP, MVVM, VIPER and Ziggurat. It notes that standard MVC leads to massive view controllers and proposes alternative patterns to better separate concerns and reduce dependencies between layers. The benefits and drawbacks of different patterns are explored, with the key goals being maintainability, reusability and preparing code for future changes.
iOS Architecture
- 1. iOS Architecture Essential Jiakai(Jacky) Lian MobileDeveloper @ GoGet
- 2. About Me ❖ Focuson mobile development since the era of 2G ❖ Master of Applied IT @ Monash ❖ Not a full stack developer ❖ Focus on iOS in recent 2 years ❖ Recently Joined GoGet CarSharing ❖ LinkedIn: https://au.linkedin.com/in/jacky-lian- 06493379 ❖ GitHub: https://github.com/jiakai- lian/
- 3. Purpose of Architecture Design ❖Resolve real business problems ❖ Remove unnecessary dependencies ❖ Reduce maintenance cost ❖ Prepare for changes
- 4. 3 Main Rolesin Architecture ❖ Data Owner ❖ Data Processor ❖ Data Consumer
- 5. Everything starts fromMVC ❖ MVC: Model+View+Controller ❖ MVC in Web programming ❖ View Container: Web Browser ❖ Model: Model Layer
- 6.
- 7. The Reality ❖ MVC= Massive View Controller ❖ View Controllers have too many responsibilities: Networking, Data Access,UI configuration, Data Source, Delegate … ❖ Shared Data causes problems (Mutability Management) ❖ Controllers are the least reusable classes in the project ❖ “Cocoa MVC is the best architectural pattern in terms of the speed of the development.”
- 8. Slim Model V.S.Fat Model ❖ Fat Model ❖ Business Logic in Model ❖ Slim Model ❖ Model + Helpers ❖ MVC-S: MVC+Data Store(Data Access) ❖ MVC-N: MVC+Networking
- 9. The True MVCin Mobile: MVP ❖ MVP: Model+Passive View+Presenter ❖ All UI logic in presenter. ❖ View knows nothing about Model
- 10. MVVM ❖ MVVM =Model+View+ViewModel ❖ ViewModel Definition
- 11. MVVM:View Model ❖ Non-PatternViewModel: ViewData/Transition Data (Immutable) ❖ ViewModel in MVVM: Independent Presentation Logic
- 12. MVVM: Where isthe Controller ❖ MVVM = M-VM-C-V = Model ViewModel Controller View ❖ Controller bind View and ViewModel together
- 13. Benefits of ViewModel ❖No direct dependency between Model & View ❖ UI Independent Presentation Logic
- 14. MVVM With Binding ❖Fine without binding ❖ Even better with binding ❖ Popular Binding Frameworks: ReactiveCocoa(ObjC & Swift), RxSwift ❖ Reactive : Learning Cost ⬆ ❖ Binding: Debugging Difficulty⬆
- 15. VIPER ❖ VIPER =View+Interactor+Presenter+Entity+Router ❖ Interactor: Business Logic, using external data access layer ❖ Presenter: UI related (but UIKit independent) business logic ❖ Entities: Slim Model (Plain Data Objects) ❖ Router: Routing between different modules
- 16. VIPER: Highlights ❖ Evenlydistribute responsibilities ❖ UseCase focused ❖ Able to combine different UI protocols to build up a screen
- 17. VIPER: Problems ❖ Toomany classes: Development/Maintenance Cost ⬆ ❖ Too complex for simple apps: Slow down the development
- 18. VIPER: Suggestions ❖ WorkloadReduce: Use Script/Template to generate all those classes ❖ Not a practical choice for s/m projects ❖ A option for large projects (Team Size ≈ 5/Development Life Cycle ≥ 6 month)
- 19. Ziggurat ❖ Created bySquare ❖ Inspired by React Native & Flux
- 20. Ziggurat ❖ More layersdistribute responsibility evenly ❖ The service layer encapsulates mutability ❖ Presenter & Renders are stateless ❖ One Way Data Flow ❖ Repository = Data Store ❖ View Model = View Data ❖ Drawback: Relatively hard to manage animations
- 21. Rules Of Thumb ❖Dependency is the No.1 concern ❖ More layers = Less coupling = Harder to understand ❖ No right or wrong architecture ❖ Plan well then improve your architecture iteratively
- 22. Massive Class Prevention ❖No more than 300 lines of code
- 23. Future Topics ❖ ArchitectureDesign By Practice ❖ Protocol Oriented Design in Swift ❖ iOS Animation Design By A Live Example/Examples
- 24. References ❖ http://casatwy.com/iosying-yong-jia-gou-tan-viewceng-de-zu-zhi-he-diao-yong-fang- an.html ❖ https://www.objc.io/issues/13-architecture/viper/ ❖https://www.objc.io/issues/13-architecture/mvvm/ ❖ https://medium.com/ios-os-x-development/ios-architecture-patterns- ecba4c38de52#.tlnbspmx8 ❖ https://www.raywenderlich.com/62699/reactivecocoa-tutorial-pt1 ❖ https://www.youtube.com/watch?v=4cP1p5VOrSI ❖ https://corner.squareup.com/2015/12/ziggurat-ios-app-architecture.html ❖ http://khanlou.com/2015/12/mvvm-is-not-very-good/ ❖ http://limboy.me/ios/2015/09/27/ios-mvvm-without-reactivecocoa.html
Editor's Notes
- #4 Today’s topic is more about inner module architecture instead of High Level architecture
- #7 Who is the “View Container” in Apple’s MVC?
- #9 Model = Model Class Fat Slim: Both in Modal Layers
- #10 Storyboard inits controllers: Make implementation harder Dependency Injection Presenter controls everything
- #11 What is View Model?