XCFramework with other 3rd party dependencies - ios

Problem
I am developing a Framework (let's name it MyFramework) which I want to use in a host iOS application. MyFramework depends on several other 3rd party libraries (Alamofire, ZIPFoundation, etc.) which I have added as Swift Package Manager dependencies in the MyFramework project.
After creating MyFramework.xcframework and adding it to the host iOS application, I get a compilation error saying No such module 'Alamomfire'. As suggested in this thread I have added Alamofire as SPM dependency in the host iOS Application as well, which resolves the compilation error. But during runtime I get a console message saying Class _TtC9Alamofire21CompositeEventMonitor is implemented in both <HOME>/Library/Developer/Xcode/DerivedData/DevSample-frwzbtlatwjedobzfossixhbtork/Build/Products/Debug-iphonesimulator/MyFramework.framework/MyFramework (0x10346eb98) and <HOME>/Library/Developer/CoreSimulator/Devices/D17DA122-DB76-4447-B8FD-14FC8405A856/data/Containers/Bundle/Application/F68CBE06-CC7F-40AA-ACA8-2210048CA495/DevSample.app/DevSample (0x102ed31f8). One of the two will be used. Which one is undefined.
Questions
Is this expected behavior? As mention in this Apple Doc creating Umbrella Frameworks is discouraged. How to get rid of those runtime warnings/errors then?

#Nominalista I have created a similar app-and-modules setup in this way: I created the app, and the framework within the same directory, and then I dragged this framework's .xcodeproj inside my app. Inside the framework, I have added Swift packages as Alamofire, ZIPFoundation. I can use either of these 2 transitive dependencies both from the framework itself, and the app target as well with a simple ie, "import Alamofire".
I am using Xcode 12.5 and I am explicitly adding Alamofire as Swift package both to the framework and the app, I am not getting "..is implemented in both..." warnings. So can I ask you how your project is being setup?

Related

Xcode "Class ... is implemented in both ... . One of the two will be used"

I have created a custom Framework. The Framework has some SwiftPM dependencies like Alamofire that it makes use of.
If I add the Framework to my app, I can't build the app without adding the dependencies to my app as well. After doing that and running the app, I can even remove the Frameworks from the app's SwiftPM dependencies and it's working fine but only until I clear the build folder.
Having the dependency in both the app and the Framework I get dozens of prints that say
objc[13048]: Class _TtC11CryptoSwift3AES is implemented in both
/Users/Z/Library/Developer/CoreSimulator/Devices/68/data/Containers/Bundle/Application/F0/MyApp.app/Frameworks/MyKit.framework/MyKit (0x106c8e960) and
/Users/Z/Library/Developer/CoreSimulator/Devices/68/data/Containers/Bundle/Application/F0/MyApp.app/MyApp (0x1052ccd20).
One of the two will be used. Which one is undefined.
After cleaning the build folder it again tells me Missing required module 'Alamofire'.
How can I make either the Framework happy with the dependencies from the app or the app happy with the dependencies from the Framework? The app doesn't access Alamofire directly, only the Framework does.
So I'd like to either build the Framework without including the dependencies to it or build the app without including the dependencies to it which will hopefully resolve this warning.

How to add a local framework to a Flutter plugin for iOS

So, I've been struggling for some time with embedding a third party framework into a Flutter plugin I'm writing for iOS.
The plugin is fairly straightforward, mostly just forwarding calls and events to/from the third party framework.
The third party framework in questions is for controlling a Sphero robot (RobotKit.framework).
This particular framework is an umbrella framework, with several sub frameworks within.
To include this .framework in my plugin, I've tried a lot of combinations between
preserve_paths
vendored_frameworks
resource
xcconfig
in the .podspec file to link to the RobotKit.framework package (inspired by blog), but without luck.
I can use
vendored_frameworks = 'Frameworks/RobotKit.framework'
to get Xcode to detect the package and import the headers, but when building I get an error linking to a header in one of the sub frameworks (RobotKitClassic is a sub framework):
fatal error: 'RobotKitClassic/RobotKitClassic.h' file not found #import <RobotKitClassic/RobotKitClassic.h>
Am i approaching this the wrong way, or is there a trick that I'm missing?
I ended up working around this by implementing the plugin functionality directly in my main app project instead of in a separate Flutter plugin.
Doing this, i can add the RobotKit framework to the Runner project and it links, builds and runs just fine.
IF your case is nested frameworks to use the result in app then nesting frameworks isn't allowed in IOS , here from apple forums , I faced error like can't load frameWork #rpath to do this all code in dynamic framework must be pure code not pods or plugins

Embedding frameworks inside closed-source Swift framework

Our company wants to distribute a closed-source SDK for iOS to our clients. I've been using Cocoapods to build the framework and built an example app making use of it. Previously the app worked fine on the simulator as well as when deployed on the device. However, I was also embedding the Pods.framework file in the app itself. One other piece of information that may be of interest is that the framework is written in Swift, the included cocoapods dependencies are both Swift and Objective-C.
I wanted to make the pods requirements easier to manage so the user doesn't need to be concerned with them and tried to embed the Pods.framework file inside of the SDK we're building - so I removed the steps to Embed Pods Frameworks and Copy Pods Resources from the example app, leaving them only in the framework, I also removed Pods.framework as a dependency of the example app, leaving it only in the SDK. This seemed to work in the simulator, but the app now crashes on mobile device with dyld: Library not loaded error.
Upon researching it, I stumbled into a few related discussions:
https://github.com/CocoaPods/CocoaPods/issues/344 https://objectpartners.com/2014/06/25/developing-private-in-house-libraries-with-cocoapods/
However, the suggested solution of using private pods does not look like it would work for us, it's my understanding that the source code in the private pod would still be open, and we can't share it with our clients.
Could someone advise on a solution that would work in this case?
OK, I finally have a more durable solution. It's a modified, cleaner version of my old one now that I understand how Xcode links in my Swift sub-frameworks better
Problem that makes distribution/compilation a bit ugly:
Since Swift standard libraries aren't bundled on the device like Obj-C, nor are they guaranteed to be stable between versions yet (stable binary interface promised in Swift 3: https://github.com/apple/swift-evolution#development-major-version--swift-30) we have to make sure the entire project is compiled against the same version of Swift. That means the guy using your closed-source framework has to be using the same version of Swift in their Xcode for their project as you did for compiling the library, even if he's not using Swift in his code because ultimately it's his version of Swift that gets bundled into the app and your SDK runs against. This is only an issue for closed-source frameworks because open-source ones will always be compiled against the same version as final project. Possible workaround is to restrict clients to same version you use or distribute multiple compilations (i.e. Swift 2.1 and Swift 2.0). To remedy this, you could provide users with copies of binaries compiled against multiple versions of Swift.
Aside from that, here is what I had to do during compilation/distribution to make a binary framework that works in Swift:
When building the framework:
In project target, make sure to add Pods.framework to Linked Frameworks and Libraries (make sure this is a pre-compiled RED version of Pods.framework, I had a black compiled Pods.framework in the same directory which built fine but then resulted in a framework that would cause the project to complain about missing armv7 architecture during linker phase in later project)
In Build Settings, under User-Defined section, add a field called BITCODE_GENERATION_MODE and set it to bitcode
DO NOT #import any frameworks in your bridging header, all instructions telling you to do that are leftover from Swift 1.0-1.2 days, you don't need it anymore and it does more harm than good (the later project will complain that it can't find these headers that aren't even exposed to it)
Change build target to Generic iOS Device, Archive and Export the framework
When building the project using the framework:
Drag and drop the framework into the project, in General tab add it to Embedded Binaries and Linked Frameworks and Libraries (you only need to add the framework itself, not the sub-frameworks or the pods file)
In Build Settings tab, add a new path to Framework Search Paths: $(PROJECT_DIR)/MyFramework.framework/Frameworks
Build the project

Creating framework that requires (depends on) another framework

I'd like to create a framework using Cocoa Touch Framework Project in Swift. However, I'm building this framework on top of another framework called RNCryptor, which is Objective-C based. I've seen various tutorials on how to create a framework in Xcode but none has covered a framework with its own dependency.
I tried to create a framework project and then using CocoaPods to manage its dependencies. However, there are errors appeared: 'Check Dependencies' Unable to run command...'
So the question is: is it possible to create a framework on top of another framework in Xcode. And if so, how?
Frameworks should never embed other frameworks directly. This leads to collisions if the importing project or any other framework also includes that framework. Instead, you need to tell your consumer that they also need to include your dependency. CocoaPods will do this for you automatically, so you should let it. (If you're having trouble with CocoaPods dependencies, you should ask a question about that and get it cleared up. The whole point of CocoaPods is to manage these kinds of things.)
Note that I will be releasing the Swift version of RNCryptor into beta today (or tomorrow, but I really hope today). This version bridges to ObjC and will be the preferred version going forward. (The ObjC version will continue to be available of course for projects that cannot or don't want to include Swift.)

How to build iOS framework with XCode 6

I know of familiar tutorials on this, but introduction of framework XCode 6 template has changed the game.
I already watched WWDC 2014 video about building modern frameworks but it talks more about building extensions, framework & app all inside single project. It does not specify if the framework I make with it is truly reusable across any project.
I am building framework the XCode 6 way (File->New Project->Framework and Library->Cocoa Touch Framework), but when I import it inside my test app project (separate from framework project) - I keep getting various errors.
Example: Include of non-modular header inside framework, and so on.
I know this is not what it says, and there are quite some missing steps in whatever I am doing. The older tricks may have worked for everyone, but I simply don't find which way to follow after XCode 6.
For example, there is some folder structure that a framework needs, but XCode 6 doesn't comply to it while building it. Is it right? If not, how can I change the way the XCode builds framework folder hierarchy?
Do I go back to old school or am I screwing some tiny thing in XCode 6 that I am unable to create a reusable framework?
I am not sure if you are trying to build a framework with Objective-C or Swift as your question doesn't state it. I've encountered errors you are mentioning with Swift so I'll give you my method to build Swift frameworks.
I found the process for Objective-C to be very straightforward and well documented, so I'll skip this.
As for Swift, there are a few things to consider. First, Swift static libraries are not supported, so you must exclusively use a framework (aka dynamic library) when linking an app to a library.
Here are the steps:
Create the Framework using New > Project under IOS > Framework & Library, select Cocoa Touch Framework
To avoid the "ld: warning: directory not found for option..." goto Library Search Paths in Build Settings for your target and delete the paths.
You can't mix Objective-C with Swift so don't even consider adding the Swift-Header bridge file in your code.
There are some cases in swift where you need to import code from unexposed Frameworks. I've successfully used the module-map inside the framework to deal with these case.
I also select CLANG_ALLOW_NON_MODULAR_INCLUDES_IN_FRAMEWORK_MODULES = YES in the Build Settings to solve 'include of non-modular header inside framework module'. That seems to work
I make sure that the header file that gets generated is marked as Public (not Project). Click on the file and you'll see the selection in the inspector under 'Target Membership'
You may run into some bizarre error messages when building. Xcode has a tendency to report linker errors when your code can't compile correctly resulting in missing files the linker needs to output its binaries. Sometimes XCode won't show the errors in the files you are compiling and you need to go manually on the build output and go back to the files. Some other time, you'll get a problem where you need to delete the cache. Those issues I call XCode blues and deal with it constantly. I found this type of problems happens more often when building libraries. The rest should work as expected.

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