Question

I have this int I am declaring in my .h file like this:

@interface searchResultsViewController : UIViewController {
  int selectedEvent;
}

@property (nonatomic) int selectedEvent;

It holds the selected row in a table. When a user taps the row, the int is set here:

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    self.selectedEvent = [indexPath row];
}

And then passed onto this method here:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    if ([segue.identifier isEqualToString:@"detailView"]) {
        NSLog(@"%@", self.selectedEvent);
    }
}

However, in that method, the NSLog returns null. I am not editing the int in any other part of the file and I am @synthesizeing it at the top of the file. I’m not exactly sure what is going on, could someone please explain?

Thanks

Answer 1

An int is not an object, so you when you use %@, the computer looks for something at the memory address of whatever the int is set to, and when it finds nothing, returns null. To log an int use %d. Like this:

NSLog(@"%d", self.selectedEvent);

Other valid types are %@ for an object (NSString, NSDictionary, NSArray, etc.), %f for double, %u for unsigned int, etc.

More info here.