Question

Currently I am using the following method to validate the data for not being Null.

if ([[response objectForKey:@"field"] class] != [NSNull class])
    NSString *temp = [response objectForKey:@"field"];
else
    NSString *temp = @"";

Problem comes when the response Dictionary contains hundreds of attributes (and respective values). I need to add this kind of condition to each and every element for the dictionary.

Any other way around to accomplish?

Any Suggestion for making any change to the web service (except not inserting the null value to database)?

Any Idea, Anyone ??

Answer 1

What I’ve done is put a category on NSDictionary

@interface NSDictionary (CategoryName)

/**
 * Returns the object for the given key, if it is in the dictionary, else nil.
 * This is useful when using SBJSON, as that will return [NSNull null] if the value was 'null' in the parsed JSON.
 * @param The key to use
 * @return The object or, if the object was not set in the dictionary or was NSNull, nil
 */
- (id)objectOrNilForKey:(id)aKey;



@end


@implementation NSDictionary (CategoryName)

- (id)objectOrNilForKey:(id)aKey {
    id object = [self objectForKey:aKey];
    return [object isEqual:[NSNull null]] ? nil : object;
}

@end

Then you can just use

[response objectOrNilForKey:@"field"];

You can modify this to return a blank string if you’d like.