在 iOS 框架内嵌入 a.dylib

Question

I've been trying to submit a Swift app with an Obj-C Dynamic Library (.dylib) which keeps getting rejected by the iOS App Store with error messages such as

Invalid Swift Support - The files libswiftDarwin.dylib, libswiftDispatch.dylib, libswiftCoreGraphics.dylib, libswiftUIKit.dylib, libswiftCore.dylib, libswiftFoundation.dylib, libswiftQuartzCore.dylib, libswiftObjectiveC.dylib, libswiftCoreImage.dylib aren't at the expected location /Payload//Frameworks. Move the file to the expected location, rebuild your app using the current public (GM) version of Xcode, and resubmit it

From the Apple docs at https://developer.apple.com/library/archive/technotes/tn2435/_index.html#//apple_ref/doc/uid/DTS40017543-CH1-PROJ_CONFIG-APPS_WITH_DEPENDENCIES_BETWEEN_FRAMEWORKS the error " may indicate your app is embedding a dynamic library that is not packaged as a framework. Dynamic libraries outside of a framework bundle, which typically have the file extension.dylib, are not supported on iOS, watchOS, or tvOS, except for the system Swift libraries provided by Xcode. "

So the next step was to embed the Dynamic Library (as a subproject) within a Cocoa Touch Framework project. Once that was set up, although the framework built fine, I got stuck on "symbol not found" errors for the imported dylib classes.

I would like to know the steps required to achieve this project structure, or if its even possible on iOS.

Answer 1

I was able to submit an app with a.dylib by creating a framework first. I first tried the method described in the apple documentation, but got errors when submitting to the store ( "invalid bundle. the bundle at xyz.framework contains disallowed file 'Frameworks' )

What i did was use lipo to manually package my.dylib into a framework.

$ lipo -create mylib.dylib -output mylib

Now you get a binary file called 'mylib' Create a folder called mylib.framework and put the binary file in it. Then add an Info.plist ( you can just copy and modify one from an existing framework. ) In the Info.plist, fill out the fields for your framework. The main one to update or add is "Executable" which should be the name of that binary file.

I had another issue where another framework I was using was referencing my original.dylib, which is gone and now inside the framework. To fix this I used the "install_name_tool" to modify the other framework to look for my new framework.

$ cd OtherLib.framework 
$ install_name_tool -change @rpath/mylib.dylib @rpath/mylib.framework/mylib OtherLib

You can read more about that tool in this good blog post: https://medium.com/@donblas/fun-with-rpath-otool-and-install-name-tool-e3e41ae86172