iPhone App Dev Help

NSDictionary objectAtKey returns (null)? July 31, 2009

A small work around for problem faced with NSDictionary null return problem.

In cases like

NSString *myImageURL = [user objectForKey:@"imageURL"];

where [user objectForKey:@"imageURL"] may return NSNull object.

This makes myImageURL a NSNull object hence cannot be compared using conventional comparisons. An NSNull is an invalid memory allocation or an error.:)

Two alternative solutions are

if ((NSNull *)[user objectForKey:@"imageURL"] == [NSNull null]) { }

and to convert to string if the above does not works.

NSString *myImageURL = [NSString stringWithFormat:@"%@",[user objectForKey:@"imageURL"]];

this can be compared by

if([imgURL isEqualToString:@""]){
}