How to create a framework for a swift project with iOS 7+ support?

Question

I have a requirement to create a framework for a shared set of common utilities that we plan to use in multiple iOS projects in our organization. The utility classes are written in swift and the framework needs to support projects in iOS 7 and above. I'm using Xcode 6.1.1.

I tried creating both a 'Cocoa Touch Framework' and a 'Cocoa Touch Static Library' and can't seem to get it working for iOS 7 builds.

With 'Cocoa Touch Framework', I get a warning that 'Embedded dylibs/frameworks only run on iOS 8 or later' and though I can get it to run, it fails during the iTunesconnect step with an error that the project's deployment target must not be less than 8.0 (mine is 7.0).

I tried with 'Cocoa Touch Static Library' as well using the steps given in http://www.raywenderlich.com/65964/create-a-framework-for-ios, but it just does not build with swift files. When I remove all swift files and add Obj-C files, it works properly.

Any help is greatly appreciated. How do I create a framework for a swift project with iOS 7+ support?

Thanks

Answer 1

Unfortunately, you cannot. It's one of the more disappointing factors about Swift.

As shown in the documentation, you cannot make a static framework/library with swift and dynamic libraries are only supported in iOS 8+.

The only option I recommend is that you develop an Objective-C static framework for iOS 7 and then begin to use swift when you wish to drop iOS 7 support. It's not the most ideal situation, but because you are able to have mixed languages in a dynamic framework, it means you won't have to waste time rewriting code (unless, of course, you want to).

Answer 2

Apple not supporting pure Swift frameworks before iOS 8 is somewhat hurting Swift adoption rate.

I'm not advocating the following solution as best practice. Honestly, it's a very flawed hack. We have a large pure Swift framework that does most of the heavy lifting for things here at work. And, we needed that framework in a product that ran on iOS 7.1+.

Here is the hack - Directory hierarchy is important. In an ideal situation, the project and the framework are siblings in the directory tree. Create a group in the project. In Finder, shift/command select all of the source files from the framework, and drop them into the newly created group. Make sure not to copy the files. Your telling Xcode to simply add the files to the project file, creating relative path links to them.

The framework should now compile directly into your project. I can't emphasize enough how fragile this solution is. As files are added to your framework, they also have to be added/linked into any project that you've "link embedded" the framework.

This "solution" should only be used as a last resort. Having to repeat framework parity across multiple projects is dumb. If time goes by with the project staying static, and the framework evolves, dump the framework in the project, and re-add it. It takes less than a minute to dump/re-add the framework, and reduces the chance of error.

Apple, please help us, so we can maintain best practices. I'm embarrassed to share this solution, as it's just a horrible way to get around something Apple is not supporting.