Basic Mechanics of iOS Frameworks and Xcode (and Swift) - ios

I think I just must be stupid.
I'm having a lot trouble understanding very basic things concerning frameworks in Xcode/iOs/Swift. While I've certainly gotten some things to work, I've gotten more and more confused about what I'm actually doing. And the documentation on the web just confuses me more.
When I see discussions about how to import particular frameworks (e.g. https://github.com/danielgindi/Charts is the library I'm playing with, but I've seen this pattern repeated in other libraries) they seem to always tell me include the Xcode project file as a child project of my project, in addition to linking things as an embedded binary. This confuses me. Is it not possible to link an already compiled framework to my project without including all the source code of the project?
That is, can't I just take a library.framework file, and add it to my embedded libraries list and be done with it?
In the frameworks I've played with (again https://github.com/danielgindi/Charts is my primary example, but this is true in many others I've played with) I can't seem to use the framework without Carthage or CocoaPods. For me at this stage, that is just confusing... I accept that they are useful tools to automate a difficult process, but I'd really like to understand what that process actually is before I let a tool automate it for me. As I search the web I just seem to always be led back to these tools as being the correct way to do things.
So here are my questions.
If I find a framework library on the web... do I need its source code or can I somehow just link to a compiled version of the framework?
In my reading, it seems that libraries made with Swift are somehow second-class citizens because Swift is a newer thing. Is that still the case? (The articles I read about this seems to date from 2014-2015).
Is there are good place to understand how Apple expects me to add a framework to a project, without using CocoaPods or Carthage?

No need to add source code. Just add the framework to Target ->
General -> Linked Framework and Libraries -> Tap on + and select
your framework.
In my opinion, many new libraries are being written is Swift. So you won't be left behind for using swift.
Apple has documentation about adding frameworks to XCode. But I would suggest to use Cocoapods , as its easy to manage libraries.
Cheers :)

Related

How to correctly build a swift framework for iOS

My goal is to build a swift iOS framework which uses two other frameworks (included as separate projects) and which shouldn't reveal the source code after built.
Is there some text/guide/documentation which would explain and navigate me through the process of building such a framework properly and correctly?
I built framework with aggregate target adding and linking frameworks on which my custom framework is dependent using run script as indicated here. I was able to add built of my custom framework to my custom app, together with other two dependencies (again as a separate projects), and run it on the device. However, I am not convinced by the correctness of my custom framework built.
Moreover, I was not able to upload the archive to the Appstore due to the various errors of "Unsupported architectures...", "CFBundleIdentifier Collision...", "Invalid Bundle...", "Invalid Binary" and so on. After sorting these errors out according to the various stackoverflow answers and installing the app from the TestFlight, the app crashed after launch and wasn't working at all.
I was checking various blog posts, stackoverflow questions/answers and Apple Framework Programming Guide but nothing gave me comprehensive understanding on building custom framework under conditions described above.
Everything I did was just following step-by-step tutorials without explanation of the purpose of the steps. I am sure I am missing the basics. Could you please help me and give me some guides?
I can understand you frustration. I, a while ago too searched probably for many documents on how to write a framework correctly but like you I also didn't find anything really that satisfying. From my own experiences I can give a couple of advices.
NO External Libraries
In my opinion DO NOT use external libraries in your own framework. I don't really know what your frameworks purpose is but most of the stuff you want to do can be done without using external libraries. Depending on other libraries is not a good idea especially if its a framework you are working on. Anytime these libraries get updated or even worse if they don't you will have to wait for them to be updated or find another library.So rather than this happening later on I think its better if you do it from the start. So loose the external libraries.
Universal Framework Binary
Second one is pretty easy. Generating a universal framework. I suggest you don't use a script. Most of the scripts I found were either outdated or they didn't work at all. Later on I found out that actually it was pretty easy to generate one on your own. You can do this by building your project once for a real device and one for the simulator.Then you can generate a universal binary by using the command lipo -create "Your simulator executable path" "your iOS device executable path" -output "your framework name". What this does is that it combines your two executable files and generates a universal one. Then you can just go and copy your simulator documents from the modules file and paste them in you iphoneos modules file. I am going to share a link were you can go through the walkthrough yourself. https://medium.com/wireless-registry-engineering/create-a-universal-fat-swift-framework-b7409bbfa18f
Use Objective-C(If you can)
This one is bit of a tricky one unless you know objective-c. What I would recommend is that you implement your framework using Objective-C and writing a swift wrapper around it. I would not have said this if you were creating an iOS app but in case of a framework I still think you should go for objective-c. This is because Objective-c has been around for over 30 years and most of the very old apps are in objective-c. If you want your framework to easily be used by older apps coded in objective-c I recommend you go with it. I have read tons of posts on how people have problems trying to use frameworks written in swift in their objective-c apps. Swift will be the first and probably only choice in the near future but not just yet. On the plus side if you still haven't you will have learnt Objective-C which will give definitely give you a better understanding on how things work. It will be challenging but I promise you it will be worth your while .I have a good read on this which you can checkout yourself. https://academy.realm.io/posts/altconf-conrad-kramer-writing-iOS-sdk/
Naming Conventions
This is a pretty straight forward one. I suggest you stick to apples naming conventions. This is because you will be sharing your code this time and people will look for familiarity when trying to integrate your framework. This will make your code easier to understand. You can check out these two links for more info.https://github.com/raywenderlich/objective-c-style-guide (obj-c) https://github.com/raywenderlich/swift-style-guide (swift)
Access Control
This in my opinion is an important one. When working on you framework think before you implement a class or a function. Consider if you would like someone else to be able to use that part of your code. You may want to limit the user while they use your framework and correct access control is the way to do it. You can easily guide the users so the users do exactly what you want them to do with your framework.
Document Your Code
This is a must if you want your framework be a professional one. You should be documenting every function and variable the user will use. Documenting and explaining what your code does makes a lot of peoples lives easy. You don't one anyone trying to understand what your code does for half an hour while you could have easily written a small explanation for what the parameters do and one that function or variable should be used for.
Test Your Code
Last but not least do write tests for your code. This does take some time but it assures you that your code works the way it should.
Look at other good frameworks
You should definitely checkout other open source libraries and look at what they have done. Usually there is no point in reinventing the wheel unless you are doing something absolutely different but even then there are very familiar ways to do things. I can suggest you check out the mantle sdk(https://github.com/Mantle/Mantle). Another one is the very popular Alamofire sdk(https://github.com/Alamofire/Alamofire) and also the Realm sdk(https://github.com/realm/realm-cocoa). These are good examples of frameworks. Take a look at them. Look how they have done things. It will give you an insight on how your framework should look like.
I know all of these points may also be valid if you were writing an app but what makes these a must is the fact that you will be sharing your code with others. You may manage by not doing some of these while implementing an app but for a framework things do change a little bit. It is always a pleasure to work with easy to use frameworks which make coding a pleasure. These types of small things will make your framework preferable. Happy coding.

How to create framework with other frameworks and library dependency?

I know, there are so many same questions but I didn't get answer for my requirement.
First time I am creating framework. I have created test framework using Raywenderlich example. But my requirement is little bit different. I used so many different frameworks and also used SQLCipher in my project. Now, I want to convert this project into framework. I followed all the steps but the problem is occur when I am trying to build. Getting an error for SQLCypher because I didn’t add to my framework to avoid conflicts. Finally, I have added SQLCypher library to create build without error and it worked but now I am getting linker error when I am using that framework to test in testProject. I didn’t find any example with third parties. Please help me to solve this issue.
I had the same issue.
One solution is to change all method names of other frameworks or libs, but some lib is not open source.
Another solution is work for me which is to use cocoapods. But the user
who wants to use your framework will be forced using cocoapods, depending iOS 8.0 or above, depending the same version of 3rd libs. I have nothing to do with this restriction.
Seems the best way is do not depend 3rd libs in a framework.

Can't Use Swift-Generated Shared Framework in Objective-C

This is a variant of the old "dyld: Library not loaded: #rpath/libswiftCore.dylib" problem. I'm pretty sure I know what the issue is, but I don't have any ideas on how to fix it.
I'll reference the project I'm working on, so I don't clutter the question with huge blocks of code.
The project generates a dylib that can be thrown into another project, and abstract a huge block of coding for developers (a communication layer of a client/server system).
I want the framework to be as simple as possible to to use; even if that means making it a big fat pig. I just want people to be able to toss it into their project (Swift or ObjC), and not have to worry about playing around with different variants for things like simulators and devices.
I use a variant of the old Wenderlich script to lipo the executables for x86 and ARM together.
Note the commented-out section. There be draggones.
Works great. In Swift.
Objective-C, not so great. That's because of the various Swift frameworks that need to be carried into the Objective-C program.
I switched on the embed frameworks setting, and the target dutifully gives me all my frameworks.
The problem is that each architecture has frameworks for ONLY that architecture. They aren't "fat" frameworks, so my hand-built "fat" framework really is kinda skinny, because it will only work on certain architectures.
My question is whether or not there's a way to ensure that the Swift frameworks I embed can be made "fat," or if I just have to give up, and package different variants of the framework for Objective-C programmers.
Any ideas?
I'm giving up on this sucker.
You cain't git thar f'm here.
This library will be Swift-only.

Why we have to use dependency manager?

I am developing an app for IOS,and I have to use some framework.
as you know Cocoa pods and Carthage are dependancy manager for iOS and mac OS
my question is "why we have to use dependancy manager?, instead of using dependancy manager just clone that project[was written by other programmer and can be used as framework] and drag and drop to your project ??"
Thanks for your answers
Few things that you need to think about is:
Updating your dependencies when new versions came out.
Updating dependencies for multiple platforms.
Interdependent frameworks and different framework versions for dependant frameworks.
Basically, time that you will spend on maintaining dependancies for your project will grow as your project grows. Dependancy managers allow you to avoid all this unnecessary and boring work.
There are a lot of other reasons to use DM instead of just importing frameworks. More about you can find here. And here.
At some point you might want to use 3rd party code to get extra features or something, you can copy the source code but how you will update it in the future? keep coping it again!!
Also some of your 3rd party code might depend on other 3rd part code, and if you copied it twice, you will get duplicate symbols.
Dependency managers handle all this for you.
My advice is to use Carthage or submodules, but do not use CocoPods, anything that touches the project file is not a good practice with Apple.
Why Libraries are Your Friend
While you aren’t strictly required to use third-party libraries or
frameworks, they can definitely save you a lot of time and let you
focus on polishing your app instead of typing out countless lines of
code that you simply don’t need to write.
You can use third-party frameworks and libraries without a dependency
manager too, and you can get hands-on tutorials about them right here
on this site. For example, there’s our Alamofire tutorial, and our
SwiftyJSON tutorial.
Without a dependency manager, you simply add each library’s code to
your project manually. However, this approach has several
disadvantages:
Updating a library to a new version can be difficult, especially if several libraries must be updated together because one depends on
another.
Including a library in your project makes it tempting to make local changes to the code, making it harder to update to a newer version
later.
Determining the current versions of libraries used in your app can be hard to do, especially if you don’t proactively keep track of them.
Finding new libraries can be difficult without a central location to see all the available libraries.
CocoaPods helps you overcome all of these issues and more. It fetches library code, resolves dependencies between libraries, helps
you search for and discover new libraries, and even sets up the right
environment to build your project with minimum hassle.
Courtesy
https://www.raywenderlich.com/97014/use-cocoapods-with-swift

How can frameworks used by a static library be automatically imported on iOS?

My company makes a static library for iOS apps. One annoying step for developers is that they have to manually link against all the required frameworks that the library uses, and failing to do so leads to somewhat confusing compiler errors.
I would have previously thought this wasn't possible, but the company Chartboost claims to automatically link against non-default frameworks like AdSupport and StoreKit. Based on my testing in their sample app (available from the linked page), so far this appears to be the case (Even when disabling "Enable Modules" and "Link Frameworks Automatically" in the app that links against the static library).
Is there some way to enable this feature when creating a static library? I've tried enabling modules and the "Link Frameworks Automatically" LLVM options in Xcode, but so far haven't been able to get it working.
There's a piece of code called CBDynamicallyLoadedDependencies that calls dlopen() on the appropriate system library before making the function or method call.
My original answer wasn't correct. the dlopen() call is just in the x86 code. On the device, it's something different, but my ARM assembly isn't strong enough to figure it out. All I can say is that there's a piece of code that's acting as a trampoline to the desired functions and that references the system library files (like /System/Library/Frameworks/AdSupport.framework/AdSupport).
But the point is that it's not a simple project trick that makes it work normally. There's internal code involved.
They might use modules you mentioned and #import instead of #import, which should make the libraries link automatically.
For reference, check this question.
This might not be what you're looking for, but if you don't yet support Cocoapods, I would strongly advise taking a look:
http://cocoapods.org/
(Edit: Cocoapods is essentially linked to Xcode. Other IDEs will need another solution.)
You can advertise Cocoapods to developers as the "easy" way to work with your library, and the manual method as...well, the manual method. ;)
I'm not aware of any industry resistance to Cocoapods, so I don't see a downside to supporting it, and it does solve the problem you're talking about (albeit in a roundabout sort of way).
Also I've found Chartboost VERY developer-friendly. You might even reach out to them and ask.

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