"iOS: MVVMC" - Aleksandr Nikolajev from Mooncascade
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This document introduces the MVVMC architecture pattern for iOS apps. MVVMC treats the view controller as a dumb presenter and separates concerns into four main components: model, view, view model, and coordinator. The view model acts as the link between the model and view, updating the view with data from the model and notifying the coordinator of state changes. This improves testability over Apple's MVC pattern by removing tight coupling between views and controllers.
"iOS: MVVMC" - Aleksandr Nikolajev from Mooncascade
- 1. iOS: MVVMC MobileMonday 15 May 2017 Aleksandr Nikolajev iOS developer
- 2. ME • Graduated as material scientist in University of Tartu • Joined Mooncascade in 2015 • FinTech, transportation, multimedia, sports, utilities
- 3. AGENDA • Introduction to MVVMC and it’s pieces • Some examples • Unit testing
- 4. • Tight coupling between View and Controller • Hard to test interactions between View and Controller • Model can be testable THE PROBLEM WITH APPLE’s MVC
- 5. • An architecture pattern • Model - View - ViewModel - Coordinator • MVVMC treats UIViewController as a dumb presenter - just a view WHAT IS MVVMC ?
- 6. HOW IT WORKS ? • Coordinator - owns View and/or another Coordinator(s), notifies Coordinator(s) • View - owns ViewModel, notifies ViewModel (e.g button tap) • ViewModel - owns Model, updates View, notifies Coordinator
- 7. Model • Usually a protocol • C.R.U.D - Create, Read, Update, Delete • Uses functions, NOT properties • Injected into ViewModel
- 9. ViewModel • Usually a class • Independent of UIKit • Injected into View and has no idea what the View is • Business logic • Operate with Model • Provide presentation data to view and notify if that data has changed • Communicate states to Coordinator
- 11. Coordinator • Declared as a protocol • Handle navigation • Create View and inject ViewModel into it
- 13. COMPLEX FLOWS • Many UIViewControllers • Many options to choose where to go • Does the UIViewController has to know what to show next?
- 16. View • UIViewController is also a View !!! • Present human readable data • Do the layout • Inform ViewModel about interactions
- 18. NOT ONLY UIViewController • There is no rule about using ViewModels only with UIViewController • You can use ViewModels on almost on every UI element • UITextField, UIButton, …
- 19. NOT ONLY UIViewController • This will decrease your code lines in ViewModel • Makes code more distributed and increases reusability • Adds more flexibility to write unit tests
- 22. HOW IT COMES TOGETHER? • The GOD — AppCoordinator • Only AppDelegate knows about AppCoordinator • Desides what to show when app is finished launching
- 25. UNIT TESTING • ViewModel gets notified about events happened in the view - we can test what is the result • Test if presentation data is formatted correctly (e.g convert Date object into formatted date string) • Test if correct delegate method is called when it’s needed to move on with the flow • Test if errors are shown to view
- 26. • Well distributed code • Good testability • Easy of use THE PROFIT
- 27. • MVVM-C A simple way to navigate http://tech.trivago.com/2016/08/26/mvvm-c-a- simple-way-to-navigate • iOS Architecture Patterns https://medium.com/ios-os-x-development/ios- architecture-patterns-ecba4c38de52 REFERENCES
- 28. THANK YOU!
- 29. If you wish to play with the code, clone this repo https://github.com/sasnik/MoMoMVVMC