Question

I am trying to implement a protocol in Objective C.

@implementation UsingViewsViewController : UIViewController<UIAlertViewDelegate>

- (void)viewDidLoad
    ...

However, XCode issues an error: “Unexpected identifier or ‘(‘”.

The code compiles, however, if I take out <UIAlertViewDelegate>.

Why is it erring with the protocol notice?

Answer 1

You have your @interface and @implementation mixed up. Try:

@interface MyClass : UIViewController <UIViewAlertDelegate>
...
@end

@implementation MyClass
...
@end

Note that the @interface belongs in the header file, and the @implementation belongs in the .m file.