UIPageViewController deallocating first view controller after moving to the third?

Question

I'm using UIPageViewController to display 3 viewcontrollers. If I move to the third and then go back to the first view controller, the first view controller is deallocated from memory. How can I fix this while still using UIPageViewController or is it just not the intended use of UIPageViewController?

Answer 1

Keep a strong reference to the UIViewController's either with an array, or individually in your UIPageViewController. Note that when the device runs low on memory, the controllers will unload their views.

Swift:

class PageViewController: UIPageViewController {
    var viewControllers: [UIViewController]?
    // or
    var viewControllerA: UIViewController?
    var viewControllerB: UIViewController?
    var viewControllerC: UIViewController?
}

Objective-C:

@interface PageViewController: UIPageViewController

@property (nonatomic, strong) NSMutableArray* viewControllers;
// or
@property (nonatomic, strong) UIViewController* viewControllerA;
@property (nonatomic, strong) UIViewController* viewControllerB;
@property (nonatomic, strong) UIViewController* viewControllerC;

@end