Question

Im trying to add an init method in a category like this:

@interface NSError (message)

+(id)errorWithCode:(NSInteger)code message:(NSString*)message;
-(id)initWithCode:(NSInteger)code message:(NSString*)message;

@end

–
@implementation NSError (message)

+(id)errorWithCode:(NSInteger)code message:(NSString*)message;
{
    return [[[[self class] alloc] initWithCode:code message:message] autorelease];
}

-(id)initWithCode:(NSInteger)code message:(NSString*)message;
{
    NSMutableDictionary * userInfo = [NSMutableDictionary dictionary];
    [userInfo setValue:message forKey:NSLocalizedDescriptionKey];

    self = [super initWithDomain:@"some.domain" code:code userInfo:userInfo]; // problem line

    return self;
}

@end

But it complais about “super” beeing of class NSObject and not responding to initWithDomain…
I tried casting super to NSError but compiler says it is not allowed.

If I run it, I get “unrecognized selector sent to…” so it’s not just a casting error.

Answer 1

You didn’t inherit from NSError, you added new code to the same class. So instead of super you should probably be calling self.