Question

Why is it that in the DetailViewController the NSLogs in viewDidLoad return Label and (null) respectively but in IBAction they return their expected values from the selected row? How can I get the proper values in viewDidLoad as well?

TableViewController

- (void)tableView:(UITableView *) tableView didSelectRowAtIndexPath:(NSIndexPath *__strong)indexPath {
    DetailViewController *detail = [self.storyboard instantiateViewControllerWithIdentifier:@"Detail"];
    [self.navigationController pushViewController:detail animated:YES];
    NSUInteger row = [indexPath row];
    detail.selected1.text = [array1 objectAtIndex:row];
    detail.selected2 = [array2 objectAtIndex:row];    }

DetailViewController

-(void) viewDidLoad
{
    NSLog(@"Log: %@", selected1.text);
    NSLog(@"Log: %@", selected2);

}

- (IBAction) test:(id)sender
{
NSLog(@"Log: %@", selected1.text);
    NSLog(@"Log: %@", selected2);
}

Answer 1

viewDidLoad gets called as a result of loading the view controller (i.e.instantiateViewControllerWithIdentifier:). So by the time you set your labels, viewDidLoad has already been run and has returned. Try putting your logging statements in viewDidAppear instead.