Only iOS 7 crash [NSNull intValue]: unrecognized selector sent to instance

Question

I want to get data from JSON service. Only iOS 7 version crash when get data from JSON value. It returns from JSON service below that:

{
    voteAverageRating =         


        

Answer 1

As the others have said, JSON null will be deserialized to NSNull. Unlike nil, You cannot send (most) messages to NSNull.

One solution is to add an implementation of -intValue on NSNull via category:

@implementation NSNull (IntValue)
-(int)intValue { return 0 ; }
@end

Now your code will work since sending -intValue to NSNull will now return 0

Another option: You could also add an "IfNullThenNil" category to NSObject...

@implementation NSObject (IfNullThenNil)
-(id)ifNullThenNil { return self ; }
@end

@implementation NSNull (IfNullThenNil)
-(id)ifNullThenNil { return nil ; }
@end

Now, your code becomes:

int voteCount = [[[listDic objectForKey:@"voteCount"] ifNullThenNil] intValue] ;

Just add a call to -ifNullThenNil wherever you access values from a JSON object.