Can't use Swift classes inside Objective-C

dnnagy picture dnnagy · Jun 13, 2014 · Viewed 158.2k times · Source

I try to integrate Swift code in my app.My app is written in Objective-C and I added a Swift class. I've done everything described here. But my problem is that Xcode haven't created the -Swift.h file, only the bridging headers. So I created it, but it's actually empty. I can use all my ObjC classes in Swift, but I can't do it vice versa. I marked my swift class with @objc but it didn't help. What can I do now?

EDIT: Apple says:" When you import Swift code into Objective-C, you rely on an Xcode-generated header file to expose those files to Objective-C. [...] The name of this header is your product module name followed by adding “-Swift.h”. "

Now when I want to import that File, it gives an error:

    //MainMenu.m

    #import "myProjectModule-Swift.h" //Error: 'myProjectModule-Swift.h' file not found

    @implementation MainMenu

Here is my FBManager.swift file:

@objc class FBManager: NSObject {

    var descr = "FBManager class"

    init() {
        super.init()
    }

    func desc(){
        println(descr)
    }

    func getSharedGameState() -> GameState{
        return GameState.sharedGameState() //OK! GameState is written in Objective-C and no error here
    }
}

Answer

sig picture sig · Dec 2, 2014

I spent about 4 hours trying to enable Swift in my Xcode Objective-C based project. My myproject-Swift.h file was created successfully, but my Xcode didn't see my Swift-classes. So, I decided to create a new Xcode Objc-based project and finally, I found the right answer! Hope this post will help someone :-)

Step by step Swift integration for Xcode Objc-based project:

  1. Create new *.swift file (in Xcode) or add it by using Finder.
  2. Create an Objective-C bridging header when Xcode asks you about that.
  3. Implement your Swift class:

    import Foundation
    
    // use @objc or @objcMembers annotation if necessary
    class Foo {
        //..
    }
    
  4. Open Build Settings and check these parameters:

    • Defines Module : YES

      Copy & Paste parameter name in a search bar

    • Product Module Name : myproject

      Make sure that your Product Module Name doesn't contain any special characters

    • Install Objective-C Compatibility Header : YES

      Once you've added *.swift file to the project this property will appear in Build Settings

    • Objective-C Generated Interface Header : myproject-Swift.h

      This header is auto-generated by Xcode

    • Objective-C Bridging Header : $(SRCROOT)/myproject-Bridging-Header.h
  5. Import Swift interface header in your *.m file.

    #import "myproject-Swift.h"
    

    Don't pay attention to errors and warnings.

  6. Clean and rebuild your Xcode project.
  7. Profit!