NSMutableArray and NSDictionary Error - iphone

Question

I have one NSMutableArray called SubList that contains 262 element. Every object is a NSDictionary!
This code works like a charm!
for (NSDictionary *element in listSub){
[cell.textLabel setText:[element objectForKey:#"title"]];
}
But if I try to use use this code I get a SIGBART error!
NSDictionary * element = [listSub objectAtIndex:[indexPath row]];
[cell.textLabel setText:[element objectForKey:#"title"]];
So what's the problem?
*EDit the problem is at this line
NSDictionary * element = [listSub objectAtIndex:[indexPath row]];
and this is the description
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFSet objectAtIndex:]: unrecognized selector sent to instance 0x89a8d90'
Thanks
**Edit
This is the output of listSub!
listSub: {(
{
categories = (
{
id = "user/14761688561595773457/label/Web Programming";
label = "Web Programming";
}
);
firstitemmsec = 1265885595862;
id = "feed/http://feeds.feedburner.com/FamousBloggers";
sortid = A11327DE;
title = "Famous Bloggers";
},
{
categories = (
{
id = "user/14761688561595773457/label/Hacking";
label = Hacking;
}
);
firstitemmsec = 1241258413829;
htmlUrl = "http://backtrack-italia.blogspot.com/";
id = "feed/http://feeds2.feedburner.com/BackTrackItalia";
sortid = E8A04F76;
title = "Back Track Italia";
},
{
categories = (
{
id = "user/14761688561595773457/label/Hacking";
label = Hacking;
}
);
firstitemmsec = 1245376992188;
htmlUrl = "http://www.offensive-security.com";
id = "feed/http://www.offensive-security.com/blog/feed/";
sortid = 92F57555;
title = "BackTrack Information Security Distribution";
},
{
categories = (
{
id = "user/14761688561595773457/label/iOS Developer";
label = "iOS Developer";
}
);
firstitemmsec = 1296830392306;
htmlUrl = "http://amix.dk/Main/";
id = "feed/http://feeds.feedburner.com/amixdk";
sortid = 110C52C3;
title = "amix.dk blog";
},
{
categories = (
{
id = "user/14761688561595773457/label/Apple News";
label = "Apple News";
}
);
firstitemmsec = 1285261350202;
htmlUrl = "http://www.appletvhacks.net";
id = "feed/http://www.appletvhacks.net/feed/";
sortid = 81125D2E;
title = "Apple TV Hacks";
},
{
categories = (
{
id = "user/14761688561595773457/label/Apple News";
label = "Apple News";
}
);
firstitemmsec = 1293230300220;
htmlUrl = "http://www.appletvitalia.it";
id = "feed/http://www.appletvitalia.it/feed/";
sortid = 892FE61C;
title = "Apple Tv Italia";
},
{
categories = (
{
id = "user/14761688561595773457/label/Apple News";
label = "Apple News";
}
);
firstitemmsec = 1270115980935;
htmlUrl = "http://www.appleecious.com";
id = "feed/http://feeds2.feedburner.com/appleecious";
sortid = 00B5AFC2;
title = Appleecious;
},
{
categories = (
{
id = "user/14761688561595773457/label/Hacking";
label = Hacking;
}
);
firstitemmsec = 1258495136927;
htmlUrl = "http://www.rawseo.com/news";
id = "feed/http://www.rawseo.com/news/feed/";
sortid = D6766911;
title = "A blend of programming and seo";
},
{
categories = (
{
id = "user/14761688561595773457/label/Seo e Web Marketing";
label = "Seo e Web Marketing";
}
);
firstitemmsec = 1233684720758;
htmlUrl = "http://it-adsense.blogspot.com/";
id = "feed/http://it-adsense.blogspot.com/atom.xml";
sortid = 9FB570ED;
title = "AdSense Blog-Italiano";
},
{
categories = (
);
firstitemmsec = 1277627346000;
htmlUrl = "http://aext.net";
id = "feed/http://feeds.feedburner.com/aextnet";
sortid = 70800CFE;
title = "AEXT.NET NET MAGAZINE";
},
{
categories = (
);
firstitemmsec = 1217001547735;
htmlUrl = "http://www.alessandroscoscia.it";
id = "feed/http://feeds.feedburner.com/alessandroscoscia";
sortid = 51CB8E6E;
title = "Alessandro Scoscia";
},
{
categories = (
{
id = "user/14761688561595773457/label/iOS Developer";
label = "iOS Developer";
}
);
...
I'm sure that it isn't a NSSet.
Now I post the code that I'm using to populate my array.
NSError *error;
NSURLResponse *response;
NSData *dataReply = [NSURLConnection sendSynchronousRequest:theRequest returningResponse:&response error:&error];
NSString *string = [[NSString alloc] initWithData:dataReply encoding:NSASCIIStringEncoding];
NSLog(#"testing %#",string);
SBJsonParser *vol= [[SBJsonParser alloc]init];
if (string) {
NSArray *feeds = [vol objectWithString:string error:nil];
NSDictionary *results = [string JSONValue];
NSArray *subs = [results valueForKey:#"subscriptions"];
for (NSDictionary *iscrizione in subs){
[subscriptions addObject:iscrizione];
}
This is part of another class and also in this part of my code if i try to do something like this:
NSDictionary * element = [listSub objectAtIndex:0];
NSLog([element objectForKey:#"title"]);
I get the same error while if I try a loop like this
for (NSDictionary *element in listSub){
[cell.textLabel setText:[element objectForKey:#"title"]];
}
Everythings works fine without NSSet errors. This make me crazy!

Answer 1

The problem is probably that listSub was not properly retained and therefore released already. The memory is now re-used and the object at that address is now an __NSCFSet, which does not respond to objectAtIndex:.
Note that autoreleased objects returned by a convenience class method like [NSMutableArray arrayWithXXX] should be retained and only released when not needed anymore. The best way to be sure they are retained is to declare a #property(retain) NSArray *subList, #synthesize it and use self.subList in all cases except perhaps in dealloc.
Addition
It was suggested that the method that created subList returned a set and not an array. If that were the case, the simple loop at the begining of the answer would not function either. That is why I find it very unlikely that subList was originally an NSSet, and much more likely that the array was overreleased and dealloced and the memory re-used for the NSSet.
Please do what people who want to help you ask of you.
Add the line
NSLog(#"listSub: %#", listSub);
at the place where listSub is set and also right before the error line. Then look in the error log what it displays and tell us.

Answer 2

Have you tried:
[cell.textLabel setText:[element objectForKey:#"title"]];
What is that "lol"??

Answer 3

listSub isn't an array, it's an NSSet.

Answer 4

problem is here
[cell.textLabel setText:[NSString stringWithFormat:[element objectForKey:#"title"]]];
when you are call stringWithFormat then you need to give format in string literal form like this
[cell.textLabel setText:[NSString stringWithFormat:#"%#",[element objectForKey:#"title"]]];
or direct set the text with out calling stringWithFormat:
your array got released some where, so for solving the problem you need to call retain on tyour array at right place.

Answer 5

Just try this one.
NSDictionary * element = [listSub objectAtIndex:[indexPath row]];
[cell.textLabel setText:[NSString stringWithFormat:#"%#",[element objectForKey:#"title"]]];
Or try this as you have edit your question, Edit
NSDictionary *element = [[NSDictionary alloc] initWithDictionary:[listSub objectAtIndex:indexPath.row]];
[cell.textLabel setText:[element objectForKey:#"title"]];
[element release];