Question

Hi everyone I have a really strange problem. I create a new subclass of NSObject, but I just cannot use “self.someproperty” in the implementation. Normally when I type the word “self”, Xcode will guess what I’m typing and give me the property name after dot. But in this case, it doesn’t and give me an red error. I have check my code for a night and give up now. So, wish some one give me a advise please let me know this might be a small problem somewhere?

Here’s my code:

#import <Foundation/Foundation.h>

@interface FlickrPhotoCache : NSObject

+(BOOL)isInCache:(NSDictionary *)photo;

@end



#import "FlickrPhotoCache.h"

@interface FlickrPhotoCache()

@property (nonatomic, strong) NSMutableArray *photos;

@end

@implementation FlickrPhotoCache
@synthesize photos = _photos;

+(BOOL)isInCache:(NSDictionary *)photo
{
    self.photos // here I get error
}

@end

Thanks in advance! WHT

Answer 1

You’re using + when declaring the method which is for static (class) methods not instance methods self only exists in the instance methods.

Use

 -(BOOL)isInCache:(NSDictionary *)photo;

When declaring to use the instance variable self for properties.

And then

-(BOOL)isInCache:(NSDictionary *)photo
{
    self.photos;
}

Works just fine.