Unknown type name while known?

Question

Xcode has showed out of the blue this error: "Unknown type name"

I'll explain: My StoriesViewController.h:

#import <UIKit/UIKit.h>
#import "Stories.h"

@interface StoriesViewController : UIViewController <UITextViewDelegate>

@property (strong) Stories *story; //Here it goes- "Unknown type name `Stories`"
@property (weak) IBOutlet UITextView *storyView;
@end

In my Stories.h:

#import <UIKit/UIKit.h>
#import "ViewController.h"

@interface Stories : UIDocument


@property (strong) NSString * storyContent;

@end

Again, out of the blue.

Thanks in advance.

EDIT:

In my ViewController.h:

#import <UIKit/UIKit.h>
#import "Stories.h"
#import "StoriesViewController.h"
#import "StoriesPickerViewController.h"
#import <QuartzCore/QuartzCore.h>

@interface ViewController : UIViewController <UITextFieldDelegate,  UIAlertViewDelegate> {

}


@end

NB @class throws loads of ARC issues.

I have removed useless references to ViewController.h, worked. SOLVED!

score 13 · Answer 1 · edited May 23 '17 at 12:10

13

You have a circular reference problem.

What's happening is that when you load your ViewController it goes through it's imports, it loads Stories.h, it goes to load it's imports and it goes back to ViewController.h, so you are stuck in an infinite loop there.

Either remove one of the conflicting imports, or use forward class declaration (that example is for C++, see here for an example with Objective-C)

edited May 23 '17 at 12:10

Community

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answered Sep 05 '12 at 14:47

jere

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Again, @class throws lots of errors when using properties. Is there a way to solve it using #import? – Lior Pollak Sep 05 '12 at 14:57
can't you remove the `#import "ViewController.h"` in `Stories`? what are you using it for? what errors does it throw when using `@class`? – jere Sep 05 '12 at 15:02
You are awesome..I was frustrated with this error.. Thanks a lot – Saheb Singh Aug 30 '16 at 12:35

score 0 · Answer 2 · answered Mar 01 '23 at 12:29

After so many hours spending I found that, I have imported a some files in .h header file which was causing the import recursion.

How I fixed - I moved the same import in .m file and the build is successful.

Suggestion - Avoid class implementation imports in .h file.

Hope this helps!

Unknown type name while known?

2 Answers2

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