Question

My json response from a URL is:

[
 {"status":0,
  "id":"26",
   "content":"See info field for info",
   "time":1347565292761,
    "info": {"id":"26",
    "name":"Ruti",
    "twitterPageFollowers":null,
     "facebookPageLikes":null,
     "activeEmailClients":1}
  }
 ]

I need to extract from it the following strings:

twitterPageFollowers
facebookPageLikes
activeEmailClients

How can I do it?

I tried parsing like this

NSData *urlData=[NSURLConnection sendSynchronousRequest:serviceRequest returningResponse:nil error:nil ];
    NSString *returnString=[[NSString alloc]initWithData:urlData encoding:NSUTF8StringEncoding];
    NSData *jsonData = [returnString dataUsingEncoding:NSUTF8StringEncoding];
    NSArray *json = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:nil];
    NSDictionary *response = [json objectAtIndex:0];
    NSString *info = [response objectForKey:@"info"];
    NSData *businessInfoString = [info dataUsingEncoding:NSUTF8StringEncoding];
    NSDictionary *businessInfo =
    [NSJSONSerialization JSONObjectWithData: businessInfoString
                                    options: NSJSONReadingMutableContainers
                                      error: nil];

And the return data is ok, but I get [__NSCFDictionary dataUsingEncoding:unrecognized selector sent to instance for the last NSDictionary creation from info field.
What is wrong or what is the shorter way to retrieve the above fields?

Answer 1

When you retrieve the “info” field using [response objectForKey:@"info"];, you already get an NSDictionary! (and NOT an NSString).

That’s why when you try to call dataUsingEncoding: on this object (that you believed was an NSString but is as NSDictionary) you get the exception.

There is no need to retrieve the value of "info" key then converting it to NSData and converting it back a JSONObject, because it is already a JSONObject, namely an NSDictionary in your case. Why bother trying to convert it back and forth, whereas [response objectForKey:@"info"]; already returns that businessInfo dictionary that you expect at the end of your code?