I'm following this guide on adding OneSignal to React Native, and there is one section where is says:
Open NotificationService.m or NotificationService.swift and replace the whole file contents with the code below:
<provides code to add>
If you are using Swift, make sure to create a separate Objective-C Bridging Header for your OneSignalNotificationExtensionService and add the following import:
#import "RCTOneSignalExtensionService.h"
Then you need to tell your Xcode project settings what your bridging header is named, like this.
I added the code they provided to NotificationService.swift because that's the only one of the two files that exists in my project. So I assume I'm "using swift" as they put it. The problem is that when they say to create a separate Objective-C Bridging Header, I don't know how to do that. All I've been able to find online is that when you import Objective-C code into your swift project, Xcode should automatically prompt you to create a bridging header. Xcode hasn't done that for me.
Does anyone know how I can create an Objective-C bridging header?
You have to create a new objective c class:
then
then you name it and specify as objective-c class at language
then you select your directory and hit create. At this point xcode is going to ask you whether or not you want to create bridging header. Yep do it.
And at the end it should look more or less like this at your project.
hope that helps you.
In an iOS application I have a subproject (not cocoapods) in which I have included a swift file and ObjC file (that is used by the swift file). XCode automatically created a bridging file but could not build it because apparantly bridging is not allowed in a framework. The workaround that I used was to add the objective-c header to the umbrella file and it worked. Now I need to use a swift class from ObjC. I have define module to set to YES, the generated file Framework-Swift.h . But when I try to import it in objective-c i get
Could not build Objective-C module
The closest I got after some googleing was this answer:
Ah gotcha. It looks like you're building a mixed Swift & Objective-C
pod - if that's the case, Xcode will try to import
within the generated -Swift.h header.
You'll need to create the header manually and add imports for the
Objective-C classes that you want to expose to Swift.
CocoaPods generates an umbrella header automatically and imports it
within the .modulemap, but Xcode doesn't use that when generating the
-Swift.h header
But I am unsure what header needs to be created manually.
Any ideeas or pointer about using swift in an objective-c framework ? In both ways ?
I also had similar issue when using Swift pods in my Swift project containing several targets. No Objective-C code at all. I tried to clear build folder, pods cache, derived data - nothing worked.
Solution:
Open the Build Settings for a target that contains your module code. Set the "Install Objective-C Compatibility Header" to "No"
There's a great and simple article that wraps up this case:
DEFINES_MODULE=YES
To use ObjC classes in Swift, create a bridging header and specify path to it in the build settings
To use Swift classes in ObjC, #import <ModuleName/ModuleName-Swift.h> in your *.m file (use #class SwiftClass; forward declaration in *.h file, if needed)
For swift classes and their members to be visible to objc
inherit your class from NSObject
prepend it with #objcMembers
make both the class and its members public
Spent a lot of time on finding the solution on google and SO but no success. Very hope someone can point out what can be the problem.
So I have objc+swift project. I have a Bridging Header file with imports of Objc header files that I need to use in Swift.
To explain the issue I'll share 2 scenarios. In the 1st scenario, everything works fine. In 2nd it shows an error.
Please note: Both scenarios have the same code base.
Scenario 1. Doesn't work, shows error.
I open the project.
Hard Clean it.
Build
Shows error: 'myProjectName-Swift.h' file not found
It also shows such error:
failed to emit precompiled header
'/Users/tungfam/Library/Developer/Xcode/DerivedData/myProjectName-ctxxkwqtckhvyoawavmuzmdxqaml/Build/Intermediates.noindex/PrecompiledHeaders/myProjectName-Bridging-Header-swift_1UP5PCPCLBPHP-clang_18PVO5108TD8S.pch'
for bridging header
'/Users/tungfam/Developer/myProjectName/myProjectName/App/myProjectName-Bridging-Header.h'
Scenario 2. How to make it work.
I take the same code from Scenario 1.
Hard Clean it
Comment the imports in Bridging Header file
Comment the Swift code where I used Obc files (that were declared in bridging header that I just commented in previous step)
I build the project. It succeeds.
Since some parts in the app are broken cuz I commented stuff. I uncomment the imports in Bridging Header file and the Swift code where I used Objc classes.
Run again (without hard clean) and everything works.
Will really appreciate any help on this issue. Please share anything you think that may help to fix this issue.
I'm using Xcode 10.0; Swift 4.2
UPDATE1: I think it has to do something with the 2nd error I placed above. Maybe it can't generate that bridging file.
UPDATE2: I read something like: "If you are importing the Objc file named ABC into Bridging Header. And if this ABC imports into himself the file myProjectName-Swift.h. Then this case may have some problems. Do you think it can be true?
You must not use #import "ProjectName-Swift.h" in the header files.
If you need Swift classes or protocols in the Obj-C code, you may forward declare them in the related Obj-C header. Here's more information about that:
When declarations in an Objective-C header file refer to a Swift class or protocol that comes from the same target, importing the generated header creates a cyclical reference. To avoid this, use a forward declaration of the Swift class or protocol to reference it in an Objective-C interface.
// MyObjcClass.h
#class MySwiftClass;
#protocol MySwiftProtocol;
#interface MyObjcClass : NSObject
- (MySwiftClass *)returnSwiftClassInstance;
- (id <MySwiftProtocol>)returnInstanceAdoptingSwiftProtocol;
// ...
#end
Also, please note, you may have issues with importing Swift Enums and Protocols and Classes into ObjC, so you may need to explicitly define items which you want to be available to ObjC code with #objc keyword.
And you won't be able to use Swift structs in Obj-C.
From Swift to Objective C you just have to use #import "ProjectName-Swift.h" on your Objective C classes that needs access to Swift code. There's no need to add on the bridging header file. For the other way Objective C to Swift then you need to declare in the bridging header file.
I have a project that was started in Objective-C, and I am trying to import some Swift code into the same class files that I have previously written Objective-C in.
I have consulted the Apple docs on using Swift and Objective-C in the same project, as well as SO question like this, but still no avail: I continue to get the file not found error after putting in #import "NewTestApp-Swift.h" (NewTestApp is the name of the Product and module).
Here is what I have done so far:
In Define Modules, selected YES for the app.
Ensured that the Product Module name did not have any space in it (see screenshot below question)
I have tried using #import "NewTestApp-Swift.h" inside ViewController.m, ViewController.h and AppDelegate.m but none of them has worked.
What else am I doing incorrectly? Thanks for your help.
Screenshot of settings:
Errors that I am presently encountering:
I was running into the same issue and couldn't get my project to import swift into obj-c classes. Using Xcode 6, (should work for Xcode 6+) and was able to do it in this way....
Any class that you need to access in the .h file needs to be a forward declaration like this
#class MySwiftClass;
In the .m file ONLY, if the code is in the same project (module) then you need to import it with
#import "ProductModuleName-Swift.h"
Link to the apple documentation about it
https://developer.apple.com/documentation/swift/imported_c_and_objective-c_apis/importing_swift_into_objective-c
If the Swift code is inside a Module (like in your case):
#import <ProductName/ProductModuleName-Swift.h>
If the Swift code is inside the project (mixed Swift and ObjC):
#import <ProductModuleName-Swift.h>
In your case, you have to add this line in the *.m file:
#import <NewTestApp/NewTestApp-Swift.h>
IMPORTANT: look at the "<" in the import statement
https://developer.apple.com/library/content/documentation/Swift/Conceptual/BuildingCocoaApps/MixandMatch.html
How I managed to import swift into objective-c:
Defines Module set to YES (on project - not on target)
Product Module Name set (on target - not on project)
In your ViewController.m import the swift code with:
#import "MyProductModuleName-Swift.h"
Add a swift file to your objective-c project (File -> New -> Swift) and Xcode will create the bridging header from objective-c to Swift but this is crucial for making it work the other way around too - apparently.
For the last piece in this puzzle thanks to Swiftoverload for making me aware of actually adding a Swift file via Xcode GUI and not just dragging and dropping existing swift-files into my project for making it work:
http://nikolakirev.com/blog/using-swift-in-objective-c-project
Using Xcode 8.2.1 and if you look at Project > Build Settings > Objective-C Generated Interface Header Name, there it shows only one header file named like Product-Swift.h
This means that instead of importing each modules separately from Objective-C .m file, using individual -Swift.h file, you just import one Product-Swift.h which aggregated all Swift modules.
I encountered the same problem by looking for traditional way of importing modules separately, but the current version of Xcode and Swift 3 changed it to use only one header for all module importing.
Spent an hour on this issue, following these steps will help you to understand what's missing:
Open Xcode preference and navigate to DerivedData folder
Search for "swift.h" in finder
If you can not find any project-swift.h file, this file haven't been generated. You usually need to add #objc to one of your swift class and successfully build the app, only then will Xcode generate this file
If you found "xxx-swift.h" file, make sure your import statement contains the correct name.
I was having problems importing Swift into an Objective-C project. In the end I looked into the Derivied Data folder to check what Xcode 7 was generating. The filename was completely different to the one I was expecting.
Once I had the actual filename I imported that and the project could build.
iOS - Swift.h file not found
[Mixing Objective-C and Swift]
<name>-Swift.h should be created by Xcode automatically if Swift code expose an API via #objc or #objcMembers[About]
Usually a location looks like
~/Library/Developer/Xcode/DerivedData/
ProductModuleName-foo/
Build/
Intermediates.noindex/
ProductModuleName.build/
Debug-iphoneos/
ProductModuleName.build/
DerivedSources/
ProductModuleName-Swift.h
It can be changed by
Project editor -> select a target -> Build Settings -> Per-configuration Intermediate Build Files Path
By default the value is $(PROJECT_TEMP_DIR)/$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)
Importing the header file, i.e.
#import "<ProjectName>-Swift.h"
within the .h file generated an error, stating:
-Swift.h' file not found
and the build failed.
Instead use:
#import "<ProjectName>-Swift.h"
within the .m file, and even though the same error appears, running the project anyway suppresses the error.
The swift classes are then available within the .m file.
If Your App name have any special character then use _ for special character.
For Example if your App name is Name "Test App®"
Then you can import swift file by "Test_App_-Swift.h".
Space and ® is replace by _ while you are import.
Make sure your swift class has the public declaration, and extends NSObject:
public class MySwiftClass: NSObject {
//...
}
The import should work with quotes, not brackets, if the swift class is in the same project.
if you add a Swift File first, rememeber to add swift file to your target..., in the left column
Had faced the same problem with my team when was working on project using git. One developer hasn't updated Xcode to the last version (7.3) which was required for latest Swift 2.2 version. So, compiler hasn't recognized new Swift syntax and couldn't generate interface for Swift library (projectname-swift.h).
Check if Xcode version is the latest one!
DEFINE MODULES: YES
and import "ProjectName-Swift.h" in .m file of Obj-C class
This worked for me to access Swift classes in Obj-c.
I had the same problem with #import "myProj-Swift.h" not found, Xcode 12.3, the year is 2021.
It appears that unless a bridging header has been generated, it is not possible to import myProj-Swift.h.
My (reproducible) solution, when needing to add Swift to objective-C projects is to create (File - New File - Swift file) a dummy empty Swift file in my project. Xcode then asks whether to create a bridging header, to which I answer yes. This causes a "myProj-Bridging-Header.h" file to be added to my project, which is visible in the Project Navigator.
Once this is done, the error on #import "myProj-Swift.h" disappears.
After that I can delete the dummy file, and insert the needed Swift classes into the project.
The logic of generating a visible bridging header, but leaving the -Swift.h entirely invisible escapes me entirely. Never mind the challenge of trying to find out about this in the official documentation Importing Swift into Objective-C, which (to me inaccurately) states "You don’t need to do anything special to create the generated header".
It is probably a good idea to also mind the answer from #Sandeep Bhandari to this question - who says the -Swift.h file will only be generated if the project compiles successfully.
More info also in this and this question.
I ran into this problem after duplicating an existing target. When I tried to build with the duplicated target, the "ProductName-Swift.h file not found" error appears.
After going through the build settings in the new target, I found the value of the setting "Product Name" somehow is set as the same as the target name. After setting it with the correct one the error disappeared.
If your product name is TestApp-Dev then filename will TestApp_Dev-Swift.h
You can verify by going to the following location
~/Library/Developer/Xcode/DerivedData//Build/Intermediates.noindex/yourProjectbuild/Debug-iphonesimulator/MashreqMobileApp.build/DerivedSources
If you want same file name for each build schemes then go to
Build Settings to be the same across your modules/schemes. (set it to $(PROJECT_NAME)-Swift.h).
If project name is TestApp, then the file generated will TestApp-Swift.h and it will remain same across the schemes
During development, there might be a possibility that you would have any swift class that is not completely implemented due to which there might be some syntax errors.
The swift header file will be available for use only if all the swift files are error free.
Make sure there are no syntax errors in the swift files and then try to import the swift header in the objective - c file
I faced the problem with the name of project (target). It included symbol "-". So the decision was next: if name of project is "Test-App", then name of imported class is "Test_App-Swift.h"
If you have multiple target make sure that you have build all frameworks
Xcode 11
I ran into this problem when building on Xcode 11. Took me a bit to figure out what was wrong, but essentially, I had changed the "Display Name" setting on the Target's "General" tab instead of changing directly in the Info.plist file through the "Info" tab on the Target.
This resulted in Xcode 11.5 going through an rewriting/creating a bunch of brand new custom build settings and modifying the name of the app module and the built .app product. In this case the new display name also had a forward slash (/) character in it which may ultimately be why it wasn't building (see #Silversky Technology's answer).
Regardless, I resolved this by undoing all of Xcode 11.5's automatic changes to the project file and manually making the same change to the bundle display name in the Info.plist file and everything works perfectly.
I wish it would tell you that it was doing stuff like this before it just up and does it without your consent.
Target executable was missing a dependency on my (or any other in fact) framework.
Build Phases -> Dependencies must list the dependencies of a target to avoid intermittent errors: in my case debug
build was fine and automated Jenkins CI builds were failing.
A nightmare to debug considering Jenkins output produces
voluminous garbage that's a huge time pit to get through.
I'm working on an iOS project that contains Swift and Objective-C Classes.
To instantiate an object described in Objective-C, I've understand that I needed to have a Bridging-Header file that contains all the imports of the headers I will have to use on my Swift classes. And it works great on my project.
I made all classes I needed, I subclassed Objective-C classes in Swift, everything is OK.
My problem is when it comes to do the opposite: instantiate a swift object in an Objective-C file. So I read that I need to have those options:
Define Modules as Yes
add the line #import "<#YourProjectName#>-Swift.h" on the *.m file I'm working on.
And that is what I did:
I changed all the values on the Build Settings that needed to be changed. I added the import line, I even tried to create the header file, but I still have the "<#YourProjectName#>-Swift.h" file not found error.
Of course, I replaced the YourProjectName by the actual module name, the one I found under Product Module Name in Packaging section on Build Settings. Also, there is no spaces in the Project Name.
Did I forgot a step?
Make sure you are importing the -Swift.h file from a .m Objective-C file and not a .h header file. The docs only talk about importing from .m:
... import the Xcode-generated header file for your Swift code into any Objective-C .m file you want to use your Swift code from.
The -Swift.h file is generated during the build and I've found that importing it from a .h file always fails, even when I know the file exists. Since it's generated by the build, I'm guessing it's cleaned out when the compiler is sifting through the headers and regenerated once the .swift files are compiled.