Question

I made a class that uses the delegate pattern and I put it in a static library. Then, I created a demo app to test the library. The demo just has a single view controller, and in the .h file, I have this:

@interface ViewController : UIViewController <AuthenticationDelegate>

@property (nonatomic, retain) IBOutlet UITextField *usernameTextField;
@property (nonatomic, retain) IBOutlet UITextField *passwordTextField;

@end

When I compile, I get an error right on the first line of the file that says:

Cannot find protocol declaration for ‘AuthenticationDelegate’.

But, in the .m file for the same view controller, I have:

#import "Authentication.h"
#import "ViewController.h"

The file “Authentication.h” is the only header file in my static library, and it does declare the delegate class:

@class AuthenticationProvider;
@protocol AuthenticationDelegate <NSObject>

@optional

- (void)provider:(AuthenticationProvider *)provider didReplyWithResponse:(AuthenticationProviderResponse)response;

@end

Where am I going wrong?

Update:

If I put #import "Authentication.h in ViewController.h, I get this:

Undefined symbols for architecture i386:
  "_OBJC_CLASS_$_AuthenticationProvider", referenced from:
      objc-class-ref in ViewController.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I get that when I remove #import "Authentication.h from ViewController.m also.

Answer 1

Try #import "Authentication.h" in your classes .h file, not your .m file