Question

In my application I catch the response from server in json format, something like this:

{"hotels":
  {"data":
    [{"id":"id1",
    "country":"counry1",
    "state":"state1",
    "city":"city1",
    }
    {"id":"id2",
     "country":"counry2",
     "state":"state2",
     "city":"city2",
    }]
  }
}

If I try to access to element by this code

ID = [[[ParsedResponse objectForKey:@"hotels"] objectForKey:@"data"] valueForKey:@"id"];

everything is ok. But if I do

NSMutableDictionary *ItemsFromParsedResponse = [[NSMutableDictionary alloc] init];
ItemsFromParsedResponse = [ParsedResponse valueForKeyPath:@"hotels.data"];
while (ItemsFromParsedResponse = (NSMutableDictionary*)[ParsedResponseEnumerator nextObject]) {
    ID = [ItemsFromParsedResponse valueForKey:@"id"];
}

ID is [null]. And I don’t understand, why.
Thanks for any advice.

Answer 1

You’re either doing something strange here, or we don’t have all your code. I would write your failing piece of code as follows:

 itemsFromParsedResponse = [parsedResponse valueForKeyPath:@"hotels.data"];

 for (NSDictionary *jsonFragment in itemsFromParsedResponse) {
     jsonID = [jsonFragment valueForKey:@"id"];
 } 

I’ve followed the convention of variable names beginning with a lowercase character (starting with an uppercase character should be reserved for class names), and I’m using fast enumeration, bearing in mind that the information at hotels.data is an NSArray. I’ve also renamed ID to jsonID to avoid confusion with the id pointer.