How can I import Swift code to Objective-C?

Asked 8/6, 2014 at 1:8 Answered 4/12, 2021 at 18:40

334

I have written a library in Swift and I wasn't able to import it to my current project, written in Objective-C.

Are there any ways to import it?

#import "SCLAlertView.swift" - 'SCLAlertView.swift' file not found

Binghi answered 8/6, 2014 at 1:8 Comment(2)

love this project! – Abstemious 25/4, 2015 at 3:19

Answer to this question can be found in the Apple documentation itself: developer.apple.com/documentation/swift/… I recommend to read the documentation first before reading all the answers. – Milliemillieme 12/2, 2021 at 13:55

525

You need to import ProductName-Swift.h. Note that it's the product name - the other answers make the mistake of using the class name.

This single file is an autogenerated header that defines Objective-C interfaces for all Swift classes in your project that are either annotated with @objc or inherit from NSObject.

Considerations:

If your product name contains spaces, replace them with underscores (e.g. My Project becomes My_Project-Swift.h)
If your target is a framework, you need to import <ProductName/ProductName-Swift.h>
Make sure your Swift file is a member of the target

Billi answered 8/6, 2014 at 4:1 Comment(26)

Note that if you try to use the Swift filename in your import, you will get the error "Expected ';' after top level declarator". in your Swift file after "import Foundation". – Sciomancy 9/6, 2014 at 22:10

Wow, great catch! Small question: Is there anywhere I can see what that project name is? I tried what you suggested and am still getting errors so I'm worried I might have the project name wrong. – Boggers 17/7, 2014 at 15:22

EDIT: Note: for this to work, a project module name MUST be defined. See: https://mcmap.net/q/16306/-swift-to-objective-c-header-not-created-in-xcode-6 – Boggers 17/7, 2014 at 15:34

I just would like to add a note that if your project name has any white space or special character you have to replace them with underscores, like "My App" would be "My_App-Swift.h" – Causality 4/12, 2014 at 4:27

Hi @Billi how do i use swift library through cocoapod in my objective c project...? – Ganiats 7/9, 2015 at 14:50

How does this work in a Framework target, can you just add #import <ProjectName/ProjectName-Swift.h> to the umbrella header? – Fabozzi 14/9, 2015 at 22:42

Why is this so hard and poorly documented? – Treacy 1/11, 2015 at 6:43

@HardikAmal you can still use, for example, #import "SCLAlertView-Swift.h" in Objective-C class, or @import <SCLAlertView>; – Vallation 21/12, 2015 at 9:53

@Treacy it's not that much hard. First time you can feel a bit pain and then later you would be getting mastery on it. – Pronghorn 29/6, 2016 at 7:49

I have used #import "SCLAlertView-Swift.h" in .m and I getting error: SCLAlertView-Swift.h not found, I did something wrong? – Unequaled 22/4, 2017 at 6:41

@Billi now I have used #import "Wow_Dictionary-Swift.h", where Wow Dictionary is my project name. Now I am getting error Wow_Dictionary-Swift.h not found. Still something wrong? – Unequaled 22/4, 2017 at 13:33

@Unequaled Actually, it's the target name, not the project name. Let me update my answer. – Billi 22/4, 2017 at 13:36

@Billi my project name is same as target name. – Unequaled 22/4, 2017 at 13:37

I did this but I get 10 compile errors saying that No type or protocol UIApplicationDelegate and similar – Mascia 1/8, 2017 at 5:26

Do you have to import it in your .m file? – Salmagundi 3/1, 2018 at 20:55

@JohnOttenlips yes – Billi 3/1, 2018 at 21:27

This auto-generated file is now called TargetName-Bridging-Header.h though? – Chanellechaney 29/1, 2018 at 19:31

@Chanellechaney No, that file is the opposite of this one. The bridging header is written by the developer and lets you bring Objective-C and C symbols into your Swift code. The Target-Swift.h file is automatically generated and lets your Objective-C/C code access Swift symbols. – Billi 30/1, 2018 at 0:36

It's not necessarily the Target Name. It is actually Product Module Name which you have defined in Build Settings. You can have a look at the answer by Sumit Singh – Moshe 19/3, 2018 at 5:59

@Billi sorry to bother you but I have been trying to import the Swift header file but couldn't succeed. The issue is that I have 2 targets in my project. One of the Objective-C files requires to access the Swift header files of both the targets. How would I go about that? – Bircher 4/9, 2018 at 11:3

Hi @Adeel You can create a new header file that #import's Target1-Swift.h and Target2-Swift.h and import that header into your Objective-C files. – Billi 4/9, 2018 at 11:5

In the newly created header file it doesn't let me include either of the two. Moreover, if I exclude the objective-c file from one of the targets then the compiler stops complaining about the header file but starts complaining about one of objc class's subclass because that is included in both the targets. – Bircher 4/9, 2018 at 11:21

I found a new way to find the correct generated header file name: go to your target -> Build Settings -> Search keywords Objective-C Generated Interface Header Name, bingo! – Alastair 21/12, 2018 at 3:36

Important note: You can change the module name for each target to make the name of the swift header the same for each target. Details here -> https://mcmap.net/q/16307/-objective-c-to-swift-header-file-with-multiple-targets – Tannic 11/2, 2019 at 16:2

The key is using the @objc attribute, wish you could make it in bold, because Apple's documentation doesn't state this properly. Or write it as steps. – Trimaran 30/1, 2021 at 4:35

Thanks a lot! This phrase "Make sure your Swift file is member of the target" saved my day! – Raddled 11/8, 2021 at 14:15

179

Here's what to do:

Create a new Project in Objective-C
Create a new .swift file
- A popup window will appear and ask "Would You like to configure an Objective-C bridging Header".
- Choose Yes.
Click on your Xcode Project file
Click on Build Settings
Find the Search bar and search for Defines Module.
Change value to Yes.
Search Product Module Name.
Change the value to the name of your project.
In App delegate, add the following : #import "YourProjectName-Swift.h"

Note: Whenever you want to use your Swift file you must be import following line :

#import "YourProjectName-Swift.h"

Revolute answered 6/7, 2015 at 9:22 Comment(8)

Changing the value of Defines module in Build settings to Yes is what fixed things for me! – Antithesis 31/12, 2015 at 13:35

Embedded Content Contains Swift : YES USE this also – Widow 22/2, 2016 at 11:5

good answer but steps 7-8 are not needed in Xcode 7.3.1 and higher – Orchardman 17/7, 2016 at 23:57

I have skipped step NO. 6 even it is working for me... is this step really needed.??? my define module is set to NO – Tillery 27/7, 2017 at 7:40

Not works for me in xcode 8.3.2. Works in previous versions – Construction 5/9, 2017 at 18:27

@Construction let me know what step you are following because the same steps for same Xcode version is working for me. – Revolute 11/1, 2018 at 6:26

Just want to add that YourProjectName in #import "YourProjectName-Swift.h" will be the name of project from step 8. Useful if your project name contains special characters and you are not sure how exactly you should format it. – Logarithmic 26/4, 2019 at 13:32

This is exactly not answering OPs question. – Cutlery 2/5, 2023 at 15:23

171

Instructions from the Apple website:

To import Swift code into Objective-C from the same framework

Under Build Settings, in Packaging, make sure the Defines Module setting for that framework target is set to Yes. Import the Swift code from that framework target into any Objective-C .m file within that framework target using this syntax and substituting the appropriate names:

#import "ProductName-Swift.h"

Revision:

You can only import "ProductName-Swift.h" in .m files.

The Swift files in your target will be visible in Objective-C .m files containing this import statement.

To avoid cyclical references, don’t import Swift into an Objective-C header file. Instead, you can forward declare a Swift class to use it in an Objective-C header. Note that you cannot subclass a Swift class in Objective-C.

enter image description here

Bullock answered 11/11, 2014 at 20:5 Comment(10)

Only import "ProductName-Swift.h" in .m files helped me. Adding same in .pch file was giving "Cannot find protocol declaration for 'CLLocationManagerDelegate'; did you mean 'NSLayoutManagerDelegate'?" – Orontes 13/8, 2015 at 12:17

@AJit it doesn't directly, the documentation says that. The easiest way is to create an Objective-C class that translates in a format that Objective-C++ understands. developer.apple.com/library/ios/documentation/Swift/Conceptual/… – Phyllis 14/1, 2016 at 17:5

Note that you have to derive from NSObject !!! you can't just straight up declare a class Blah in swift and have it work. it needs to be class Blah : NSObject – Massif 8/12, 2016 at 1:50

Worth reading this answer for some cases: stackoverflow.com/questions/26328034/… Depending on what you are doing: #import <ProductName/ProductModuleName-Swift.h> #import <ProductModuleName-Swift.h> #import <NewTestApp/NewTestApp-Swift.h> – Coleville 3/4, 2017 at 10:19

What if you want import a Swift extension? – Kafka 30/8, 2017 at 23:0

In my case "ProductName-Swift.h" works perfect in xcode 7.3 but now works in xcode 8.3.2 – Construction 5/9, 2017 at 18:25

@AlejandroIván I have UIView swift class will it work ? I am not able to import swift into objective c – Alexander 5/1, 2018 at 22:47

The missing module was my issue for a test project. Furthermore, if your project name starts with a numerical, (eg, 1234.xcodeproj), it too will replace the first offending character with _, thus your module name will default to "_234" and thus your include will look like "_234-Swift.h". – Davisdavison 13/3, 2018 at 20:40

"Note that you cannot subclass a Swift class in Objective-C." Thank you for including this, it saved me from going crazy. – Decibel 8/11, 2018 at 14:39

will this work for structs. I dont believe that they can be derived from NSObject so I am guessing not. I am trying to do this with a constants class – Stogner 16/5, 2020 at 0:35

If you're using Cocoapods and trying to use a Swift pod in an ObjC project you can simply do the following:

@import <FrameworkName>;

Cotter answered 29/9, 2015 at 20:18 Comment(2)

Thanks a lot! you saved my day. – Kist 15/11, 2017 at 11:12

This works like a charm if we installed swift-made library through Cocoapods. Upvoted !!! – Mephitic 17/11, 2018 at 10:52

Go to build settings in your project file and search for "Objective-C Generated Interface Header Name. The value of that property is the name that you should include.

If your "Product Module Name" property (the one that the above property depends on by default) varies depending on whether you compile for test/debug/release/etc (like it does in my case), then make this property independent of that variation by setting a custom name.

Furthermost answered 22/4, 2016 at 11:46 Comment(0)

Importing Swift file inside Objective-c can cause this error, if it doesn't import properly.

NOTE: You don't have to import Swift files externally, you just have to import one file which takes care of swift files.

When you Created/Copied Swift file inside Objective-C project. It would've created a bridging header automatically.

Check Objective-C Generated Interface Header Name at Targets -> Build Settings.

Based on above, I will import KJExpandable-Swift.h as it is.

Your's will be TargetName-Swift.h, Where TargetName differs based on your project name or another target your might have added and running on it.

As below my target is KJExpandable, so it's KJExpandable-Swift.h

Kop answered 4/7, 2017 at 10:59 Comment(0)

First Step:-

Select Project Target -> Build Setting -> Search('Define') -> Define Module update value No to Yes

"Defines Module": YES.

"Always Embed Swift Standard Libraries" : YES.

"Install Objective-C Compatibility Header" : YES.

Second Step:-

Add Swift file Class in Objective C ".h" File as below

#import <UIKit/UIKit.h>

@class TestViewController(Swift File);

@interface TestViewController(Objective C File) : UIViewController

@end

Import 'ProjectName(Your Project Name)-Swift.h' in Objective C ".m" file

//TestViewController.m 
#import "TestViewController.h"

/*import ProjectName-Swift.h file to access Swift file here*/

#import "ProjectName-Swift.h"

Fyn answered 17/5, 2017 at 9:26 Comment(1)

The forward declaration (@class) of the class is a very good point! Thanks! – Alicea 20/6, 2017 at 7:43

If you have a project created in Swift 4 and then added Objective-C files, do it like this:

@objcMembers
public class MyModel: NSObject {
    var someFlag = false         
    func doSomething() {         
        print("doing something")
    }
}

Reference: https://useyourloaf.com/blog/objc-warnings-upgrading-to-swift-4/

Verger answered 31/8, 2018 at 15:40 Comment(3)

In my code, after I updated it to Swift 4.2 from swift 3. It's not working – Fjord 3/3, 2019 at 15:51

what error are you getting? I have used above code in Swift4.2 and its working fine. – Verger 10/3, 2019 at 16:23

Ok that’s great. – Verger 21/5, 2020 at 15:49

There's one caveat if you're importing Swift code into your Objective-C files within the same framework. You have to do it with specifying the framework name and angle brackets:

#import <MyFramework/MyFramework-Swift.h>

MyFramework here is the "Product Module Name" build setting (PRODUCT_NAME = MyFramework).

Simply adding #import "MyFramework-Swift.h" won't work. If you check the built products directory (before such an #import is added, so you've had at least one successful build with some Swift code in the target), then you should still see the file MyFramework-Swift.h in the Headers directory.

Scupper answered 27/10, 2017 at 10:7 Comment(0)

Be careful with dashes and underscores, they can be mixed up and your Project Name and Target name won't be the same as SWIFT_MODULE_NAME.

Locomobile answered 5/6, 2019 at 5:26 Comment(0)

Checkout the pre-release notes about Swift and Objective C in the same project

https://developer.apple.com/library/prerelease/ios/documentation/Swift/Conceptual/BuildingCocoaApps/MixandMatch.html#//apple_ref/doc/uid/TP40014216-CH10-XID_75

You should be importing

#import "SCLAlertView-Swift.h"

Skeie answered 8/6, 2014 at 1:15 Comment(4)

Showed me this error: 'SCLAlertView-Swift.h' file not found. – Binghi 8/6, 2014 at 1:32

Needs to be the project name, not the filename - see my answer. – Billi 8/6, 2014 at 4:2

Thanks for the documentation link. That was useful for reference. – Sciomancy 9/6, 2014 at 22:9

To quote from the provided link: The name of this header is your product module name followed by adding "-Swift.h". So it's not the class name as you wrote, but the name of your product module and that takes care of importing all swift files, not just a specific one – Ravenna 24/5, 2015 at 13:41

Search for "Objective-C Generated Interface Header Name" in the Build Settings of the target you're trying to build (let's say it's MyApp-Swift.h), and import the value of this setting (#import "MyApp-Swift.h") in the source file where you're trying to access your Swift APIs.

The default value for this field is $(SWIFT_MODULE_NAME)-Swift.h. You can see it if you double-click in the value field of the "Objective-C Generated Interface Header Name" setting.

Also, if you have dashes in your module name (let's say it's My-App), then in the $(SWIFT_MODULE_NAME) all dashes will be replaced with underscores. So then you'll have to add #import "My_App-Swift.h".

Scupper answered 8/9, 2017 at 8:12 Comment(1)

Better than the approved. The dashes wasted 20 min I'll never get back haha. – Telemotor 3/10, 2017 at 13:27

If you want to use Swift file into Objective-C class, so from Xcode 8 onwards you can follow below steps:

If you have created the project in Objective-C:

Create new Swift file
Xcode will automatically prompt for Bridge-Header file
Generate it
Import "ProjectName-Swift.h" in your Objective-C controller (import in implementation not in interface) (if your project has space in between name so use underscore "Project_Name-Swift.h")
You will be able to access your Objective-C class in Swift.

Compile it and if it will generate linker error like: compiled with newer version of Swift language (3.0) than previous files (2.0) for architecture x86_64 or armv 7

Make one more change in your

Xcode -> Project -> Target -> Build Settings -> Use Legacy Swift Language Version -> Yes

Build and Run.

Clasping answered 7/12, 2016 at 6:32 Comment(1)

i am not getting this option of use legacy swift language version – Millwork 9/9, 2017 at 7:10

#import <TargetName-Swift.h>

you will see when you enter from keyboard #import < and after automaticly Xcode will advice to you.

Premeditation answered 8/8, 2019 at 13:15 Comment(0)

only some tips about syntax, about Xcode everything has been said

you cannot import 'pure" functions, only classes, even if marked "public", so:

public func f1(){ print("f1"); }

will NOT be called in ANY way.

If You write classes., add inheritance from NSObject, other will NOT be usable.
if it inherits from NSObject, as below:

class Utils : NSObject{

static func aaa()->String{ return "AAA" }

@objc static func bbb()->String{ return "BBB" }

@objc private static func ccc()->String{ return "CCC" }

}

in OBJC:

aaa() NOT called: "No known class method for selector 'aaa'"

bbb() ok

ccc() NOT called: "No known class method for selector 'aaa'"

Buckles answered 4/12, 2021 at 18:40 Comment(0)

-2

Find the .PCH file inside the project. and then add #import "YourProjectName-Swift.h" This will import the class headers. So that you don't have to import into specific file.

#ifndef __IPHONE_3_0
#warning "This project uses features only available in iPhone SDK 3.0 and later."
#endif


#ifdef __OBJC__
    #import <Foundation/Foundation.h>
    #import <UIKit/UIKit.h>
    #import "YourProjectName-Swift.h"
#endif

Greaser answered 18/6, 2018 at 20:31 Comment(0)

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