how to delete the Superfluous Escape-character in a NSString object - ios

Question

I'm a newbie about development of iOS.
And when I deal a json with NSJSONSerialization , I find something really a problem to me.
NSLog(#"response: %#", responseString);
NSData *jsonData = [responseString dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
NSLog(#"dict: %#", dict);
and the output is:
2013-03-18 20:13:56.228 XXXX[3550:5003] response: {"status":"success","data":"{\"title\":\"\",\"sessionName\":\"sid\",\"sessionID\":\"9217e5df3db6b4b4aa3eed800890069f\",\"rand\":5360}","md5":"292ee1e78628fc6360c647e938c4f1ea"}
2013-03-18 20:13:56.229 XXXX[3550:5003] dict: {
data = "{\"title\":\"\",\"sessionName\":\"sid\",\"sessionID\":\"9217e5df3db6b4b4aa3eed800890069f\",\"rand\":5360}";
md5 = 292ee1e78628fc6360c647e938c4f1ea;
status = success;
with the "\" the data section cannot be a NSDictionary object
So what should I do to make it right?
Sorry for my poor English.

Answer 1

For whatever reason, the value of "data" is not a JSON dictionary, but a string containing JSON data. You can fix this by applying JSONObjectWithData to this string again and replacing the value in the dictionary:
NSData *jsonData = [responseString dataUsingEncoding:NSUTF8StringEncoding];
NSMutableDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
NSData *nestedJsonData = [[dict objectForKey:#"data"] dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *nestedDict = [NSJSONSerialization JSONObjectWithData:nestedJsonData options:NSJSONReadingMutableContainers error:nil];
[dict setObject:nestedDict forKey:#"data"];
NSLog(#"dict: %#", dict);
Output:
dict: {
data = {
rand = 5360;
sessionID = 9217e5df3db6b4b4aa3eed800890069f;
sessionName = sid;
title = "";
};
md5 = 292ee1e78628fc6360c647e938c4f1ea;
status = success;
}