Question

I am working with NSCache in iOS i have following code in .h file for cache:

    NSCache *_cache;

I am adding the image which are downloading from the url to the cache in .m:

-(void)cacheFromURL:(NSURL*)url

{
[_cache setCountLimit:50];

UIImage* newImage = [_cache objectForKey:url.description];
if( !newImage )
{


    NSError *err = nil;

    if(url!=Nil)
    {
        newImage=[UIImage imageWithData:[NSData dataWithContentsOfURL:url options:0 error:&err]];
    }
    if( newImage )
    {

        [_cache setValue:newImage forKey:url.description];

    }
    else
    {
        NSLog( @"UIImageView:LoadImage Failed: %@", err );
    }

    if(_cache==Nil)
    {
        NSLog(@"nil");  
    }

    else 
    {
        NSLog(@"cache is not nil");
    }
}

}

But i am getting the nil cache every time . where i can see the downloading process in log .
why am i getting null cache?

Answer 1

You need to create/initialize the NSCache object before you can add and object to it. Also you need to add object with the setObject:forKey: