Can not save NSDictionary with NSUserDefaults!!

One of the reason is one of which is of type NSNull which is not a property list value. iterate over the keys of the dictionary I just produced so conveniently with dictionaryWithValuesForKeys and remove those of type NSNull




NSMutableDictionary* dict = [NSMutableDictionary dictionaryWithDictionary:currentNullValueDic];

 for( id key in [dict allKeys] )

  {

       if( [[dict valueForKey:key] isKindOfClass:[NSNull class]] )

          {

                          [dict setObject:@"" forKey:key];

          }

}