Question

I was wondering how it can be that iterating through an NSMutableArray works, but when I call objectAtIndex it fails with “*** -[NSCFSet objectAtIndex:]: unrecognized selector sent to instance 0x…”

Here is some sample code, the program is too big to share in whole so I hope it’s enough. The code is executed in the latest iPhone Simulator from XCode.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
 RDLogString(@"Creating cell @ row no. %d", indexPath.row);
 CPPlayerAppDelegate * appDelegate = [[UIApplication sharedApplication] delegate];
 RDLogString(@"Conversations: %p. Item count: %d", appDelegate.distribution.conversations, appDelegate.distribution.conversations.count);  
 //This works  
 for(CPConversation * x in appDelegate.distribution.conversations){
  RDLogString(@"Pointer: %p with name %@", x, x.name);
 }  
 //This fails with aforementioned error  
 CPConversation * conversationAtCurrentIndex = [appDelegate.distribution.conversations objectAtIndex: indexPath.row];

Sorry for the bad formatting, still figuring it out. 🙂

Thanks in advance,
Nick

Answer 1

objectAtIndex: is part of NSArray, not NSSet. This means your appDelegate.distribution.conversations is returning an NSSet and you need an NSArray.