How to add view controller objects to a mutable array?

Question

I want to add some view controller objects to a mutable array. Below is my code.

- (void) viewDidLoad
{
    [super viewDidLoad];

    [_vc addObject:[self viewControllerAtIndex:0]];
    NSLog(@"VC Count is %lu",(unsigned long)[_vc count]));
}

- (UIViewController *)viewControllerAtIndex:(NSUInteger)index
{

    if (index == 0){
        QSG0Controller *QSG0Controller = [self.storyboard instantiateViewControllerWithIdentifier:@"QSG0Controller"];
        return QSG0Controller;
    }
    else {
        return nil
    }
}

And in the output window, it shows that VC count is 0.

Can anyone tell me why??? Thanks a lot!!!

Answer 1

You need create _vc first. Try _vc = [NSMutableArray new] before [_vc addObject:[self viewControllerAtIndex:0]];