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I'm attempting to import my "-Swift.h" file into one of my Objective-C .h files but xcode keeps telling me that the file doesn't exist
#import "Aesculus-Swift.h"
If I command click on the file name it will take me to the generated header file so I know it exists. Why is xcode not able to find it?
This seems like just another issue with Xcode and it's complex tool chain of static analysers and compilers.
Openradar lists radar://21362856 - Swift to Objective-C bridging is unreliable. I am sure there are more but I stopped looking after finding one for this example.
The author imarcelv notes in the description:
I asked a Swift engineer at WWDC in a lab and even he didn't know how to fix this issue.
Steps to Reproduce:
Add a ramdom Swift class to an Objective-C project
Add the #import "ModuleName-Swift.h" file that Xcode generates automatically
Try to use it or just try to compile the project
From time to time it simply doesn't work
It's probably best to file a radar on this issue as it seems that others are already calling it out.
One other thing you could try...
Historically, it was possible for Xcode to completely lose it's syntax highlighting and you could always find out what files the static analyser was giving up on by increasing log level of clang.
I'm not sure if it's still relevant but if I was in your position I'd be trying this command:
defaults write com.apple.dt.Xcode IDEIndexingClangInvocationLogLevel 3
This generates logs you can search with using Console.app for just xcode to highlight the messages. You'll want to trash the derived data of your project to force it to re-compile things.
Although not the same issue as what you're seeing, I have had this post on the syntax highlighting issue bookmarked for years for the above defaults write command to try in times like these.
I solved this recently by adding the following entry to my .xcconfig (you could add it in Xcode's Build Settings > User Header Search Paths if you prefer).
USER_HEADER_SEARCH_PATHS = $(BUILT_PRODUCTS_DIR)/MyFramework.framework/Headers
This tells the compiler to search for headers in the build output directory, which is where Xcode puts the generated header (at least in the case of this framework).
In my case this is a directory like ~/Library/Developer/Xcode/DerivedData/MyProject-LongCode/Build/Products/Debug-iphonesimulator/MyFramework.framework/Headers/MyFramework. You might find your generated header in there too.
Xcode's header and dependency management is a hot mess, and it's not surprising that it doesn't work for you.
I had trouble with this stuff & found that your -Swift file is the Product name of your Target ( not just the name of your Target ) . I found the details here helpful: http://ericasadun.com/2014/08/21/swift-calling-swift-functions-from-objective-c/
When you encounter such situation, just find your kinda "ProductName-Swift.h" file by just cmnd+click on it (even if xcode shows warning about it is not found, the #import "Aesculus-Swift.h" string is still clickable) and then in opened code editor window choose context menu and "Show in Finder" item, then explicitly add it to your project.
I have recently been working to add Swift to an existing project, to get to try it out in a real-world fashion.
Upon adding a Swift source file to the project, I have no problems about getting the "Bridging Header", that is, Objective-C to Swift.
But the *-Swift.h header file that is supposed to expose Swift classes either marked #objc or subclasses of ObjC classes, is nowhere to be found :-(
I don't see any specific instructions on how to accomplish the usage of my new subclass, written in Swift, in my main app code (which is still Objective-C).
The app that I am lead developer of has a fairly large codebase (70.000 lines), so transitioning it in one go is out of the question.
Now it works.
Project must have a Product Module Name that does not include spaces.
Defines Module must be set to Yes in Build Settings, under Packaging.
Finally works. Thanks to everyone for the help :-)
I had a similar problem and found that you can only add
#import "ProductModuleName-Swift.h"
to obj-c .m files, not .h files for the umbrella header to be found
I found that I had to fix all build errors before it would generate the file.
The problem for me was that it was a chicken/egg problem, in that I didn't see any build errors until I'd actually commented out the #import statement:
//#import "ProductModuleName-Swift.h"
which revealed a bunch of other errors in my Swift code.
Once I fixed these new errors and got the source building successfully, I uncommented out the #import and bingo! The header was created and importing correctly :)
If you're like me you've probably got the header name wrong. After bashing my head for a while I looked for the file in DerivedData and sure enough it's there. On my setup (using the standard derived data folder, I believe):
cd ~/Library/Developer/Xcode/DerivedData
find * -iname '*Swift.h'
Will find it. If nothing in that folder matches then Xcode is not generating it.
I'm using Xcode Version 6.2 (6C86e)
If your project module name has spaces in it, you must replace the spaces with an underscore.
For instance, if your project name is "My Project", you would use:
#import "My_Project-Swift.h"
* The only important thing is: *
to use the defined "Product Module Name" in the target, followed by -Swift.h
#import <Product Module Name>-Swift.h
// in each ObjectiveC .m file having to use swift classes
// no matter in which swift files these classes sit.
No matter if "Defines Module" param is set to Yes or No or if "Product Module Name" Project is not set.
Reminder: Swift classes must deriving from NSObject or been tagged with #objc attribute in order to be exposed to ObjectiveC / Foundation || Cocoa ...
I wanted to add one more reason you might find an issue with this - I was creating a framework that mixed Swift and Objective-C code. I was not able to import the Swift classes outside the framework - I checked for the -Swift.h file and it was being generated but was empty.
The problem turned out to be very, very simple - I had not declared any of my Swift classes public! As soon as I added the public keyword to the classes, I was able to use them from classes inside and outside the framework.
Also of note, inside the framework (inside .m files only as another answer mentions) I had to import the -Swift.h file as:
#import <FrameworkName/FrameworkName-Swift.h>
I had the same problem. Seems like you have to adjust the settings (Defines Module and Product Module Name) before you add your first Swift file.
If you do it afterwards the "*-Swift.h" file will not be generated for this project even if you add further Swift files or delete the Swift file and create a new one.
Allow me to share my experiences trying to use Swift in an old objc project. I did not have to set Defines module to YES.
In my case I needed to manually make sure there was an objc Bridging Header. Only the generated interface header name was present in my build settings.
This lead to a MyApp-Swift.h file to being generated, but without any traces of my Swift classes.
The Apple documentation says that you will be prompted to create a bridging header when adding your first swift file. Well, I wasn't. I manually added a MyApp-Bridging-header.h file and pointed to it in the "Objective-C Bridging Header" field. That made my MyApp-Swift.h file become populated with my Swift classes.
Docs: Importing Swift into Objective-C
Here is another variation of the moduleName-Swift.h not being generated.
I decided to include IOS Charts in my project but did not want to mingle the sources in the same directory, so I placed the Charts Project folder next to my code's project folder. I dragged the Charts project into my Project's Navigator Bar and included the framework in the my project target's Embedded Binaries list in the General project settings and set the Embedded Content Contains Swift Code switch to yes in my project's Build Settings tab in the Build Options section.
My project's moduleName-Swift.h file would never generate no matter what other switches or settings suggested here. Finally, using Lou Z's method of seeking out the -Swift.h files, I saw that a Charts-Swift.h file was being generated deep in my project's xcode Build directory in Charts.framework/Headers/
The solution to using Daniel Gindi's ios-charts Swift package without including the code in my project's source directory was to add:
#import "Charts/Charts-Swift.h"
To the modules charting my project's data.
The file name is always preceded by your Target name. It is referred as Product name but practically it is the target name.
So if you want it to build for a new target be ready to expect that_target-Swift.h file.
One way to handle this is
Add a preprocessor for each of your target that is the name of your target itself (without spaces). Ex. MY_TARGET=1. Add this in Project settings->Build Settings->Preprocessor Macros for each of your targets.
If you are using a PCH file,
Add these lines in the PCH file
#if MY_TARGET==1
#include "My_Target-Swift.h"
#elif THAT_TARGET==1
#include "That_Target-Swift.h"
#endif
Advantage of using PCH file is that you don't have to include the headers everywhere.
If you are not using a PCH file, just add these same lines in a single header and include that header wherever you need to use the swift classes.
This should work just fine.
If Xcode is actually generating your -Swift.h header (deep inside DerivedData) but it doesn't refer to your Swift classes, make sure you also have a bridging header defined. The way I read the docs implied I only needed that for calling Objective-C from Swift, but it seems to be necessary for calling Swift from Objective-C too.
See my answer: https://stackoverflow.com/a/27972946/337392
EDIT: It is because of public vs. internal access modifiers, as I eventually found explained in the Apple docs:-
By default, the generated header contains interfaces for Swift
declarations marked with the public modifier. It also contains those
marked with the internal modifier if your app target has an
Objective-C bridging header.
Seconding what a lot of people have here, but adding a pertinent screen shot. Swift and Obj-C code can certainly live together. It's not an all or none game.
To access Swift files in your Objective-C, all you need to do is add this call to your Obj-C file (in the .m / implementation file):
#import "{product_module_name}-Swift.h"
(Where {product_module_name} represents the product module name of your project). Rather than try to guess your product module name or figure out corner cases with spaces and special characters, just go to the build settings tab in the project and type in "product module name" - the inspector will reveal yours to you. Mine was something I did not expect it to be. Check out this screen shot if you're confused.
And to get Obj-c code working in Swift, you just need to add a bridging header file and import the relevant Obj-C headers there.
This answer addresses the use-case where you may already have some Objective-C code that calls Swift classes and then you start receiving this error.
How To Fix Issue
The following steps ultimately resolved all of the issues for me. I read above someone mentioning the "chicken and the egg" and it is exactly that concept which led me to this procedure. This explicit process shows that one has to remove any Objective-C code referencing Swift classes until after the header is generated.
Comment out the #import "ProductModuleName-Swift.h" statement in
your Objective-C implementation file
Comment out any references in the Objective-C implementation file to
Swift Classes
Clean & Build
Resolve all errors/warnings
Remove the comment on the #import "ProductModuleName-Swift.h" statement
Clean & build (successfully or fix any remaining errors, verify that you are not referencing any Swift classes in Objective-C at this point. If so temporarily comment these out)
Verify that "ProductModuleName-Swift.h" is generated by Cmd-Clicking
on the class name of the #import "ProductModuleName-Swift.h" statement
Remove the comment on the code referencing Swift classes in the Objective-C implementation file.
Clean & Build as normal (the "ProductModuleName-Swift.h" should be
generated and your Objective-C code referencing Swift Classes can be
used as normal)
Nota Bene: The answers about changing spaces to underscores and the Defines Module to YES as given above still applies when performing this process, as do the rules specified in the Apple Documentation.
Bridging Header Path
In one error, the file ProductModuleName-Bridging-Header.h was not being found during the build process. This fact generated an error
< unknown>:0: error: bridging header
'/Users/Shared/Working/abc/abc-Bridging-Header.h' does not exist
Closer inspection of the error indicated that the file would never exist at the location described because it was actually located at (a wrong path)
'/Users/Shared/Working/abc/abc/abc-Bridging-Header.h'. a quick search of the target/projects build settings to make the correction manually and the abc-Swift.h file was again auto generated.
Ok, here are all the things you really need!
1.Remove all the swift files you have added, and compile the code, without any errors.
----------
----------
2.Go to the "Projects" build settings, and set the product module name.
Project must have a Product Module Name that does not include spaces.
----------
----------
3.Defines Module must be set to Yes in Build Settings, under Packaging, in your project, and not target!
----------
----------
4.Now create a swift file or a view controller, in file-> newFile->
----------
----------
It will ask to create a bridging-header, allow it to make one.
If you have declined it once, you will have to manually add a -Bridging-Header.h
5.Add #objc in the controller, to tell the compiler that there is some swift file, which needs to be exposed to ObjectiveC
----------
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6.Build the project and import #import "-Swift.h" in any of the objectiveC controller, and it will work! You can Command-click on it to see the actual file!
----------
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Hope this helps!
The most important thing is that This file is invisible!!! At least it is in Xcode6 beta5. There will be no such file named "YourModule-Swift.h" in your workspace. Just make sure you have module name and defines module set to yes, and use it in your Objective-C class.
You have to import a header in Objective-C classes, which is:
#import “ProductModuleName-Swift.h”
It is automatically generated, on the reference it says "Any Swift files in your target will be visible in Objective-C .m files containing this import statement."
An actual file in the project is not created ([ProductModuleName]-Swift.h). Cmd + Click on the import either generates it on-the-fly (and in-memory) so you can see how the linkage is done, or opens a file somewhere in some Xcode cache dir, but it's not in the project dir.
You need to set Defines Module project prop (in target's Build Settings) to Yes and if your module name has spaces or dashes - use _ in all imports of the [ProductModuleName]-Swift.h file.
You can import it in all .h and .m files where you use swift types or you can import it in the .pch.
So if my Module (project) is named "Test Project", I would import it like this, in the .pch file of my project (just there):
#import "Test_Project-Swift.h"
Just a heads up for anyone who used "." in there project name. Xcode will replace the "." with an underscore "_" for the Swift version of the bridging header file. Oddly enough the Bridging-Header.h that is generated does not replace the periods with underscores.
For example a project with the name My.Project would have the following Bridging Header file names.
Bridging-Header.h (Autogenerated)
My.Project-Bridging-Header.h
Swift.h
My_Project.h
I hope this helps anyone who used a period and was stuck like I was. This file can be found at the following location.
Macintosh HD/Users/user/Library/Developer/Xcode/DerivedData/My.Project-fntdulwpbhbbzdbyrkhanemcrfil/Build/Intermediates/My.Project.build/Debug-iphonesimulator/My.Project.build/DerivedSources
Take care,
Jon
Project must have a Module Name not including spaces.
Defines Module must be set to Yes in Build Settings, under Packaging.
commented out the #import statement:
If still you are having error in importing "ProductModuleName-Swift.h" then
//#import "ProductModuleName-Swift.h"
which revealed a bunch of other errors in my Swift code.
Once I fixed these new errors and got the source building successfully, I uncommented out the #import and bingo! The header was created and importing correctly :)
I found a trick that always works on me.
Create your #import "ProductModuleName-Swift.h" in your appDelegate.h file and in your ProductName-Prefix.pch file. If you don't have it in xcode 6 you can create it with this way Why isn't ProjectName-Prefix.pch created automatically in Xcode 6?
Command+shift+k to clean your code, if you receive an error about your "ProductModuleName-Swift.h" delete it from appDelegate.h file.
Clean your code again. Now everything will work like a charm
If you receive again error about the "ProductModuleName-Swift.h", now create again in appDelegate.h file and clean your code again.
Do this work (delete and create the "ProductModuleName-Swift.h" from appDelegate.h file and clean your code) everytime you receive this error to silent it.
I Found this solution
Create SwiftBridge.h
put #import “ProductModuleName-Swift.h”
Make this .h file public (important) Select the file -> In Show the file Inspector (right bar) -> Make it public
Now you can
#import "SwiftBridge.h"
instead of ProductModuleName-Swift.h
This's a workaround solution, for the next version of Xcode I think this problem will be solved.
Good luck
If you were able to build a project before, with no issues related to “ProductModuleName-Swift.h” not found error, and now you are getting that nasty errors again, the reason might sit in your recent changes.
For me this was by (accidental) incorrect .swift file encoding. Reverting changes and bringing the back manually, does the job.
I was having a hard time determining my module name/objective-c's import of swift's headers. I did read a lot of articles here too.
But the definitive answer for your project name with all its included special characters (be it '.' or a numeric or a space) - you can find the text that will work for you in the "Product Module Name" under the target's Build Settings.
For example my target name started with a numeric - "1mg" and the field mentioned above showed "_mg" as my module name.
so I used #import "_mg-Swift.h" and it worked.
This may be an obvious point (maybe too obvious), but you must have at least one swift file in the project for the header to generate. If you are writing boilerplate or config code with the intention of writing swift later the import won't work.
In my case I had to set the deployment target to at least “OS X 10.9” and the -Swift.h header was automatically generated. Keep in mind that you can get a lot of deprecation warnings when you change the deployment target version, especially when you have an older and very large Objective C code base. In our case we also had a lot of work to do in XIB files & view classes.
I had to delete WatchOS2 swift code from my Objective C project. And only after that XCode offered to generate -Swift.h
I had similar problem but my project was compiling before and suddenly got error after few files code change. It took me while to figure out why I am getting 'File not found' error for myproject-swift.h file. The code changes I had done had some errors. Xcode did not point put those error instead all time showing the 'File not found error'. Then got copy of previous version code and I compared with new code and merged file one by one. After each file merge complied the project to find the error. So bottom line is if you have error in your code Xcode may just display 'file not found error' for myproject-swift.h file. Most likely you have compilation error in your project. Clean those error and it will work.
If you're using something like Cocoapods (and working out of the workspace rather than the project) try opening the project and building it before opening the workspace and building. YMMV.
Sometimes you just need to unset and then set again the target membership on the obj-c .m file.
I'm getting this error while compiling
ld: duplicate symbol _OBJC_METACLASS_$_ScaleTypeDisclosureSection in
.../Build/Intermediates/A.build/Debug-iphonesimulator/A.build/Objects-normal/i386/ScaleEditorViewController-DDFF198930F36D54.o
and
.../Build/Intermediates/A.build/Debug-iphonesimulator/A.build/Objects-normal/i386/ScaleEditorViewController-DDFF198930F36D54.o
for architecture i386
This seems really weird because it appears that the linker is trying to link the file with itself. I have searched my entire computer and there exist only 1 .h and one .m file with that name. I've cleaned my project several times. I've tried ripping the ScaleTypeDisclosureSection class out of my app entirely, and in that case, it just gives me a duplicate symbol error for a different object in the ScaleEditorViewController file! I've checked for double imports also. I'm lost!
To clarify, there are a few classes defined in the ScaleEditorViewController.h and ScaleEditorViewController.m file. One is the view controller, the others are little helpers classes. Even if I take every class out but the main class, I still get an error.
This problem is now fixed. I'm not exactly sure why. I think it might have something to do with me having imported files (into Xcode) and setting their target to my test target instead of my main target. Deleting all file references and then dragging all files back into my project solved the problem.
I am getting this error suddenly when running my app via iPhone simulator:
clang: error: linker command failed with exit code 1 (use -v to see
invocation):
ld: duplicate symbol _OBJC_CLASS_$_Algebra5FirstViewController in
.../Algebra5-anwcuftojtxtgkfootneeeqhwztj/Build/Intermediates/Algebra5.build/Debug-iphonesimulator/Algebra5.build/Objects-normal/i386/ExercisesViewController.o
and
.../Algebra5-anwcuftojtxtgkfootneeeqhwztj/Build/Intermediates/Algebra5.build/Debug-iphonesimulator/PSLE
Algebra5.build/Objects-normal/i386/PSLE_Algebra5FirstViewController.o
for architecture i386
What is it all about?
It look like the class Algebra5FirstViewController is compile multiple time.
Can you make sure that the .m and .mm is only included once in your project sources in Xcode? You can also confirm this by checking in the compile log (last icon at the right, next to the breakpoints icon) and see that confirm that it is only compiled once.
Also, if this class is part of a library that you link against and you have a class with the same name, you could have the same error.
Finally, you can try a clean and rebuild, just in case the old object files are still present and there is some junk in the compiled files. Just in case...
EDIT
I also note that the second reference is made in the file for ExercisesViewController. Maybe there is something in this file. Either you #imported the Algebra5FirstViewController file instead of the .h, or the ExercisesViewController has #implementation (Algebra5FirstViewController) instead of #implementation (ExercisesViewController), or there was some junk with this file that will cleaned with a Clean an Rebuild.
That can happen if the same .m file is referenced multiple times in your target's "Compile Sources" section in "Build Phases". Remove duplicate entries and you should be fine.
also had this problem by declaring a const * NSString in the header file (incorrectly) instead of the implementation file (correctly)
I got this issue because I accidentally imported the .m instead of the .h. Hope reading this saves someone with same problem some time.
I had same problem. Got it solved!
If you have imported any files into project then check .m (main) file for same does exists in Targets (Project Name) -> Build Phases -> Compile Sources.
If file does not exists then include it using (+) Add button shown.
Also, if duplicate files exists (if any) then delete it.
Now press cmd+shift+k to clean the project. New Build should not display this error.
I got a similar error when adding files from another project, like #paiego explained. My error was that I didn't check "Add to targets". As explained above, I deleted the references and added the files again but this time checking "Add to targets".
I was getting similar error and I got it resolved this way.
Try to set Build Active Architecture Only to NO for 'Pods' project and
your app's target
In one case, I saw this error when dragging a new class' .h and .m into the project. The only solution I found was to remove the references to these files and then add them back via the project menu.
I met it when import a ViewController.m in TableViewController. Try to delete '#import "ViewController.m"' if it exited. Hope this help!
'linker command failed with exit code 1 (use -v to see invocation)'- I got this error when running a phonegap application on iPhone. I changed Build Active Architecture Only to Yes and it worked fine.
It seems that for m, I dragged the files into the project and after that didn't work, clicked file "add files to project". Both were the incorrect approach. just drag it into the projects folder (in finder) that houses the other .h and .m files.
once i got
18 duplicate symbols for architecture i386
clang: error: linker command failed with exit code 1
For me this was due to that i have used "const NSInteger" in my switch case.
What i did is change the const NSInteger to enum, and replace the reference with enum values.
This fixed the error for me.
This happens either, some files are missing in the "Compile Sources" section, or duplicate entries are found for some file(s). In my case, I had duplicate entries for two files, I deleted one entry for each of the files, that solved my problem. Hope this helps.
I found this article that provided a solution for me. It pertains to Xcode 7 where the default for No Common Blocks is Yes rather than No in previous versions.
This is a quote from the article:
The problem seems to be that the "No common blocks" in the "Apple LLVM
6.1 - Code Generation" section in the Build settings pane is set to Yes, in the latest version of Xcode.
This caused what I will describe as circular references where a class that was included in my Compile Sources was referenced via a #import in another source file (appDelegate.m). This caused duplicate blocks for variables that were declared in the original base class.
Changing the value to No immediately enabled my app to compile and resolved my problem.
I'm posting a new answer to this because I ran into this error and had to use a different solution that I think is specific to iOS 9.
I had to explicitly disable the Enable Bitcode in Build Settings, which is automatically turned on in the update.
Referenced answer: New warnings in iOS 9
[XCODE 7.1 UPDATE]
First Option That Worked:
I changed the Deployment Target from 7.1 to 8.1 and the error went away.
Hope that helps someone.
UPDATE (day 2): Second time I'm back here in 2 days.
On day 2 I started to get more errors in addition to this annoying error. The problem was a conflicting file that Xcode didn't recognize. I used the links below as help:
"_OBJC_CLASS_$_viewsampleViewController", referenced from:
‘ld: warning: directory not found for option’
And ultimately:
"_OBJC_CLASS_$_viewsampleViewController", referenced from:
I was deleting everything from the FrameWork Search Paths + Compile Resources + Run Script Phases + the pods and then re-installing them again to ultimately find success.
The issue on my size (on day 2) was more of a problem with conflicting files or files that Xcode didn't recognize.
But ultimately, removing everything (mentioned above and in the links), cleaning a lot of times and reinstalling the pods/frameworks/run script phases helped.
Really hope this helps someone.
Running Xcode 4.6.3 on OSX 10.7.5 was able to fix this error by changing Architectures to Native Architecture of Build Machine from $(NATIVE_ARCH_ACTUAL).
I received this once by (accidentally) importing both the .h and .m files into the same class.
I got this error while implementing a subclass without the necessary framework added (MPMoviePlayerController without the MediaPlayer framework, in this example)
I got this same issue when working with Bolts.framework. It turns out that when Bolts gets corrupted, no amount of re-importing will fix the issue. I had to go back to the original download file and reimport it completely from scratch. This fixed it right away. It was such a weird issue that it took me forever to figure it out... hopefully this tip will spare some of you from the same frustrations :)
This occurred for me when I named a UILabel reference and an int the same thing, I didn't get an error when I typed it only when I tried to run it so I didn't realize that that was the problem, but if you have something like a label which is the "score" and you call it score, and name an int which is the score also score then this problem occurs.
Variations on this issue can occur if you have a missing library or file. Check there aren't any missing files in your Project Explorer: they'll be written in red if Xcode can't find them.
"Link Binary With Libraries" had old project name pod library. Fixed after removal.
List item
Project
Build Phases
Link Binary With Libraries
Remove deprecated library.
I had this same issue with a library, and I tried all of the answers listed here and nothing helped.
I ended up simply removing the library from Link Binary With Libraries and then re-adding it and it worked fine.
The only (and unfailing) way to resolve this issue is building test from command line:
xcodebuild -workspace MyProject.xcworkspace/ -scheme MyScheme -sdk iphonesimulator -destination 'platform=iOS Simulator,name=iPhone 7,OS=10.3.1' test
So, at this point, your compilation will surely fail but you'll see all linking problem. In my case, I had several problem such as:
ld: framework 'Foo' not found
To resolve this, you need to on your target, BuildSettings->Linking->OtherLinkerFlags and remove 'Foo' framework .
Use of unresolved identifier 'ClassName' .
To resolve this, I need to add/check file's target membership to UITest target too.
Other possible problems will be raised by xcodebuild and you can easily fix it.
Simply cleaning CMD + SHIFT + K, then building CMD + B worked for me.
In my case I had a reference to a library in Other Linker Flags. Removing it got rid of the error.
I had the same error.
I had imported a audio frame work that i was no longer using. I removed it (DO NOT DELETE IT!) and it built successfully.
I am trying to run my cocos2d application and facing this error, as I have recently upgraded my sdk to 4.2 and my cocos2d to 0.99.5.
I tried to clean my project even change the Target ios Deployment but error remains the same. Also rename the className aswell in order to avoid duplication from Library classes names of cocos2d.
ld: duplicate symbol _OBJC_METACLASS_$_MenuSceneNew in
/Users/umaidsaleem/Desktop/functionalityTest/build/Debug-iphonesimulator/libcocos2d
libraries.a(MenuScene.o) and
/Users/umaidsaleem/Desktop/functionalityTest/build/functionalityTest.build/Debug-iphonesimulator/functionalityTest.build/Objects-normal/i386/MenuScene.o
Another rather simple thing to check is that you did not accidentally #import a .m file instead of a .h header file.
Happened to me.
You are linking the file MenuScene.m twice. You apparently have it in a static library and also in your main application.
Another reason for this, for those out there who did the same as I just did, might be that you re-created a managed object class. By doing that and choosing another group in the project structure, you accidentally create another reference to the same files.
I ended up with two references for header and implementation in both the root of the project and in my model group. Removing the topmost references to .h and .m files got rid of the linking failure.
Sometimes Core Data inserts AnyProjectNameModel.xcdatamodeld to the Compile Sources of the Build Phases. Check it and delete it and everything is run again...
The error message just indicates the generated ManagedObjects...
The correct place for the AnyProjectNameModel.xcdatamodeld is the Copy Bundle resources in the Build Phases.
Check the Compile Sources of your target and see if a class.m file is included twice
A stupid mistake that I made was that I named my #implementation the same as my superclass.
In the .h
#interface Subclass : Superclass
#end
In the .m
#import "Subclass.h"
#implementation Superclass
#end
None of the regular suggestions from google seemed to help, so if someone is as crazy or tired as I am (maybe a healthy mix of both), make sure you haven't duplicated an #implementation!
In my case this was happening because of Xcode automatically generating my NSManagedObject class, which then clashed with my manually created NSManagedObject class. In this case you can set "Codegen" to "Manual/None" in the Data Model Inspector for your newly created Entity.
Another thing to check for the double linking - its possible to have the same file in two different places in the file list on the left. Then the compiler compiles and links it twice.
This happens when playing with organizing your file hierarchy, for example.
You don't have to be making a library or anything fancy - just drag a .m in to two different locations in the project tree.
Remember to only remove the reference to one of them, no file trashing is needed.
To me, removing -all_load from 'Other Linker Flags' fixed the problem.
I have also had this particular error occur when a file that has not been added to the project, is referenced somewhere in the project. The two cases where I have experienced this are where I have deleted/removed files from the project without removing references to them, and when working cooperatively on a project where a teammate added the reference but I have not added the file to my version of the project.
I know the OP has resolved their problem, but I felt this might help someone else who reads this question while looking for help.
I have figured out the solution myself, sorry for posting little delayed. All assistance are much appreciated the but problem arises when I add new CCLayer derived class and checkmark cocos2d 0.99.5 static library which was wrong. Then I re-Ad my class without checking and clean my targets and then build and go. Problem solved now.
I had a project with 2 targets. A target named Component and the second named Sample. Sample was using component as a link library.
Then Component was using a pod named MyPod (installed with cocoapod).
The Podfile was written like this :
def shared_pods
pod 'MyPod'
end
target 'Component' do
shared_pods
end
target 'Sample' do
shared_pods
end
Both targets was referencing the shared pod list. When building Component target, no problem appears, but when building sample i get a duplicate symbol _OBJC_METACLASS_$_ClassName.
I have changed the Podfile to :
def shared_pods
# empty
end
target 'Component' do
pod 'MyPod'
shared_pods
end
target 'Sample' do
shared_pods
end
And that solve the problem.
3 hours spent, hope to save somebody time.
XCode Beta crashed for me while deleting a reference to a class. This caused the problem described in the answer, the fix was different again.
In my Target's Build Phase, under "Compile Sources", the item giving me grief was red. I couldn't remove it with the minus button, but typing "skip" in the compiler flags caused the red class to disappear after reloading the project. I'm assuming you could type anything in there.
It took me two hours to find the solution to my prob, I put it in here for another option to those having this problem, although it is probably not going to be a common one.
None of the Answers worked for me, so what I did was remove the files from the project and choose only Remove References.
Then I added back the same files and it worked.
That fixed my error. Maybe XCode got lost references stored somewhere since the project is multi-collaboration.
Hope that helps someone.
Another possibility for error like this is when there is a class name collision. Either 2 classes with the same name within your project, or class from your project clashing with one defined in some of dependency libraries.
Remove target from right panel and again add target. This will remove any duplicate references.
It may happen if 2 programmer add the same target and commit the project file.
In my case I was using a binary library includes the same class name I was using outside,
So I changed my class name and It's working fine :)
In my case, I had added the libxxxx.a to Link Binary with Libraries section in the subProjects as well as in the mainProject. Hence there were duplicate symbols. Removing from subProjects fixed it.