Passing Data Between Custom Built UIViewControllers Value Became nil in iOS 9 working in iOS8

Question

I created a custom UIViewController.

@property (weak, nonatomic) NSArray *optionArray;

-(VCSelectionViewController*) getPopoverViewControllerForTextField:(UITextField*)textField {

UIViewController *buttonPopover = [[UIViewController alloc] init];
buttonPopover.optionArray = [OptionArray getLOCQualityArray]

But the optionArray value became nil in viewWillAppear for iOS9. It was working in iOS8. I have spent hours on this with no luck.

This is where I called the getPopoverViewControllerForTextField method listed above.

-(void) displaySelectionPopover:(UITextField *)textField {

VCSelectionViewController *popoverViewController = [self getPopoverViewControllerForTextField:textField];

if(_masterPopoverController == nil && popoverViewController != nil){   //make sure popover isn't displayed more than once in the view
    _masterPopoverController = [[UIPopoverController alloc] initWithContentViewController:popoverViewController];
}

[_masterPopoverController setPopoverContentSize:[popoverViewController getPopoverSize]];
_masterPopoverController.delegate = self;

[_masterPopoverController presentPopoverFromRect:textField.frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
}

After I executed the code above, I can still see the optionArray values. optionArray still exists inside

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

But when it start executing viewWillAppear, optionArray became nil.

-(void) viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];    
    self.view.tintColor = [UIColor blackColor];
    [self layoutButtons];
}

-(void)layoutButtons {

    CGRect buttonRect = CGRectMake(START_POSTITION_X, START_POSTITION_Y, BUTTON_WIDTH, BUTTON_HEIGHT);
    int arrayPosition = 0;

    for (NSString *buttonTitle in _optionArray) {
        UIButton *button = [[UIButton alloc] initWithFrame:buttonRect];
        [button setTitle:buttonTitle forState:UIControlStateNormal];
        }

        [self.view addSubview:button];

        arrayPosition++;
     }
}

Answer 1

I just found the solution.

Changed from weak to strong, and then everything worked again. @property (strong, nonatomic) NSArray *optionArray;

Not sure what changed iOS9 caused this behavior.