Sharing code between iOS and Mac

When you develop both an iOS and a Mac app, you want to share as much code as possible. While creating a shared codebase you also have to separate platform specific tasks. We started out with the Mac app and later added iOS. I will talk about how we structured our code to tackle this problem.

Transcript

1. © Tresorit Sharing code between iOS & Mac László Agárdi, 26-04-2018
2. Quick Poll
3. –Overview –Simplest Solution –Organize Files –Go Further –What to Share? –Platform Peculiarities 3 Agenda
4. Overview
5. 5 CORE (C++) iOS Mac Android Windows Linux Native apps
6. 6 CORE (C++) iOS Shared code (Objective-C) Mac
7. 7 iOS (52 KLOC) Shared code (74 KLOC) Mac (49 KLOC) 42% CORE (C++)
8. –Languages (Objective-C, Swift) –Tools (Xcode, Mac) –System frameworks – Foundation, CoreGraphics, CoreData, LocalAuthentication, etc. 8 iOS & Mac development have a lot in common
9. Simplest Solution
10. 10 1. Add target for both platforms in Xcode
11. 11 2. Add shared files to both targets
12. 12 3. Add #if preprocessor directives if needed Objective-C Swift
13. 13 1. Add target for both platforms in Xcode 2. Add shared files to both targets 3. Add #if preprocessor directives 4. Implement UI & platform specific stuff 5. Done (This is OK for small projects.) Simplest Solution
14. Organize Files
15. –Files, resources & information –One or more build targets –Targets “pick” the files they need from the project –Some files are shared, some are not –Include shared files in a framework! 15 Xcode project
16. –A hierarchical directory that encapsulates shared resources –Include code and other resources (assets, localization) –It‘s a bundle, access it using the NSBundle class –Share code and resources! 16 Frameworks
17. 1. Add new target 2. Add a – Cocoa Touch Framework (iOS) – Cocoa Framework (Mac) 3. Add files to the framework 4. Add the framework to your app 17 How to create a framework?
18. –Is it better? –2x targets, more complicated –Shared files but 2 new frameworks 18 We have frameworks
19. –Shared files are added to the frameworks –Shared files are made independent from platform specific files –Improved structure of code 19 We have frameworks
20. –Lots of iOS only files –Lots of Mac only files –Lots of shared files –The project gets cluttered –Files accidentally added to other targets 20 In the Xcode project we have
21. Go Further
22. 22 Split to multiple Xcode projects
23. 23 Split to multiple Xcode projects iOS Mac Shared How to connect these projects?
24. 24 Xcode subproject –Add the shared project to iOS & Mac projects –Xcode cannot open the same project twice
25. –Reference multiple projects –Projects can be interdependent –Add any other files/folders –Cannot be included as resource –File → New → Workspace… 25 Xcode workspace
26. 26 Xcode workspace Add – iOS, Mac and Shared projects to the workspace
27. 27 Xcode projects in a workspace iOS Mac Shared
28. What to Share?
29. 29 What can you share? –Code –Resources –Images, Localizable.strings, etc.
30. 30 What code to share? –Model, Business logic code –Utility classes –Avoid sharing: – Views, ViewControllers – Can be done with tricks, too different on the two platforms –Implement platform specific stuff outside the shared framework
31. 31 Protocols <SharedProtocol> SharedClassA SharedClassB iOSClass MacClass
32. 32 Categories/Extensions SharedClass SharedExtension iOSExtension MacExtension
33. 33 How to share resources? –Add them to your framework like you would add it to your app –Access bundle of the shared framework by getting the framework for a shared class –let sharedBundle = Bundle(for: SharedClass.self)
34. 34 How to share resources? sharedBundle.url – (forResource: String?, withExtension: String?) NSLocalizedString – (_ key: String, tableName: String?, bundle:Bundle, comment: String) UIImage – (named: String, in: Bundle?, compatibleWith: UITraitCollection?)
35. Summary
36. 36 Summary –Add shared files to frameworks –Separate Xcode projects –Use Xcode workspace –Share code & resources too
37. Platform Peculiarities
38. 38 UILabel & UITextField Separate classes – var – text: String? NSTextField –One class (configure) –var stringValue: String –var intValue: Int32 –var floatValue: Float –etc. (NSControl)
39. 39 Setting first responder –iOS –responder.becomeFirstResponder() –Mac –window.makeFirstResponder(responder) –Never invoke becomeFirstResponder() directly
40. 40 View controller lifecycle methods viewDidLoad – () viewWillAppear – () viewDidAppear – () etc. – Only since – macOS 10.10+
41. 41 View controller lifecycle methods –viewDidLoad() –viewWillAppear() –viewDidAppear() –etc. –Only since macOS 10.10+
42. Thank you