Sharing code between original iOS App and App Extension

Question

Sharing class between iOS app and extension app

I want to use a custom class in both my app and the extension app. If I just have the class in the main app folder, the extension doesn't pick up on it. I tried making a copy of it and putting it into the extension folder, but I of course get a invalid redeclaration of [my class] error. What's the best solution for this? It's just one class, not multiple resources.

Answer 1

Nothing should be copied. Just add required files to compile sources for your extension:

Answer 2

Just make sure that the files you want to share gets a tick in the section Target Membership .

Select your file, open the utility panel on the right and tick the appropriate target under Target Membership .

Answer 3

Embedded frameworks are a great way to reuse code between your application and your extension. Having moved some of the code to embedded frameworks will provide us with a great opportunity to write some unit tests around it.

See section Using an Embedded Framework to Share Code https://developer.apple.com/library/ios/documentation/General/Conceptual/ExtensibilityPG/ExtensionScenarios.html#//apple_ref/doc/uid/TP40014214-CH21-SW1

Answer 4

App Extension(Widget, Today)

App Extension - from iOS v8 - is a packaged bundle which uses different process than Containing App and can communicate with Host App . It has .appex file extension and is located in PlugIns folder. Something similar to CXTests ^[About]

Application packaged bundle

SpeedWidgetExtension.appex - Application Extension packaged bundle

• Share data - use App Group ^[About]
• Share code

  • Target Membership - the simplest way or for pre iOS v8 which allows you to add files into every target. It increases a footprint of package because this file will be duplicated for every target

  • Framework - module for grouping/reusing code

    • Embedded framework aka Dynamic framework - the most appropriate way to share common code base. Please note that for using Embedded framework you should embed it only in Containing App (and don't add this framework in App Extension . If you include framework and for App Extension it will have the same framework in App Extension bundle - framework will be duplicated). It is possible because of @prath ^[About]

     //App Extension LD_RUNPATH_SEARCH_PATHS = @executable_path/../../Frameworks //It means that App Extension can uses Dynamic framework from Containing app

    • Static Framework - link the code to executable binary. You can link library only for Containing App

[iOS extensions]
[Vocabulary]