Yes, there is opportunity to combine this languages in the same project. It’s great. Apple provides a tutorial how to do this magic. You can find here. But in spite of it I would like to share my experience on real examples, because it’s not as simple as it sounds.

Swift code in Objective C project

Let’s start from Objective C project, and will try to add Swift code to this project. Create the Obj C project. And create new Swift class.

For example, UIViewController:

After that, you will see the following popup message:

Please, choose Yes.

Now, you have ios_objc_mix-Bridging-Header.h file. In this header you can import source files for your Swift class.

After that, you can do the next steps.

• Implement you Swift class with @objc attribute:

  @import UIKit
  
  @objc class SwiftController: UIViewController { }
  

• Defines module set to Yes:

  

• Embedded Content Contains Swift set to Yes:

  

• After that you should found the Product Module Name in your target settings:

  

• And please include header for Swift compatibility for example to pch file.

  #import “Product Module Name-Swift.h”
  
  #ifdef __OBJC__
      #import <UIKit/UIKit.h>
      #import <Foundation/Foundation.h>
  #endif
  
  #import "ios_objc_mix-Swift.h"
  

And now you can use Swift code. Please, see the example on github.

Note: ios_objc_mix-Swift.h file you can’t find in your project browser Xcode automatically generates this header. Magic!

Note: if you have a lot of targets in your project. It really is a pain. You should import magic Product-module-name-Swift.h headers for each target.

Note: if you use Swift classes in the Interface Builder, you should setup the module.

Obj C code in Swift project

It’s similar process. And simpler.

Add Obj C file to project.

And also please choose Yes:

Include our Obj C View Controller to bridging header:

#import "ObjCViewController.h"

And that’s all.

You also you can found example on github.

Hopefully this will save time for someone. Don’t forget star the github repository.