The latest Cocoapods (0.36) has a nifty feature: it allows you to import pods written in Swift (such as the networking library Alamofire).
It does this by asking you to insert a little line into your Podfile:
use_frameworks!
If you, like me, are new to iOS development it might not be obvious to you what that line does. It converts all of your pods from being static libraries into being frameworks.
I haven’t gotten around to reading the absurdly long and dense Framework Programming Guide but as best I understand, that means that whereas once your pods were snippets of code that were compiled and rolled directly into your project binary, they are now instead separate folders of code that your app is “aware are over there in their own special place, somewhere”.
One consequence of this transformation from libraries into frameworks is that all of your references to Objective-C Cocoapods classes inside of your Swift code will mysteriously stop working. Of course they won’t tell you why they’ve stopped working (that would be silly!). Your Swift files will just suddenly fail to compile, complaining that all your references to these Cocoapod classes are now “unresolved identifiers”.
The solution to this problem isn’t obvious (at least to me), but it is easy. So let me save you the couple of hours it took me to figure it out.
Solution:
Normally when you’re importing Objective-C code into Swift, you do so by including the header of the file containing that code in the “Bridging Header” for your project. And that is indeed how you include code from a static library (which your pods used to be.)
But it is not how your import Objective-C code from a Framework. To do that you simply type…
import Framework
…inside your Swift file that’s using the Objective-C class (where “Framework” is the name of the actual Framework containing the class.)
That’s it. Good luck!