importing Pure Swift Framework in Objective-C Project

Question

I want to import a Swift framework called "Beethoven" into Objective-C project. I import this framework via cocoapods. The problem is that framework is written in pure swift. Since the classes are not subclass of NSObject they can't be used directly in my objC classes.

I am newbie in Swift and intermediate in objC, but I think there may be 2 solutions for that:

1-Modifying the whole library: which is probably not an optimal solution. 2-Using a new class which behaves as an interface between swift framework and my objC code. I think second solution will be a better alternative in terms of time and effort needed.

Actually below given post explains modifying the pure swift classes but I don't know how to apply this in my case. How to use Swift non-NSObject subclass in Objective-C

As I mentioned I am not a very capable programmer and there may be better solutions for that problem. I would be grateful if someone can help me and suggest the best solution for integrating pure Swift framework into my objC project.

Answer 1

NSObject is usually not the only problem. Swift has many features that are not supported by Objective-C. To name a few: swift value types (struct's), swift enums with attached values. If a library uses any of those, it will not be possible to auto-generate an Objective-C header (.h) for it.

Adapting the code of the library on the spot might work, but it is likely more work long term in case if you ever need to update that library again.

Your 2nd approach sounds better: create a layer that is compatible with Objective-C on top of the library which exports methods that need to be exported with @objc and adapts the types. If you go that way consider making a PR contribution to the original library so that everyone could use it in Objective-C projects, and you share responsibility of updating it when the swift code changes.

The 3rd approach would be actually to rewrite some parts of you app to Swift. That might or might not be easier depending on the size of the part of the app that is using the library and how well it is isolated from the rest of the app.