func pageViewController()

in sampleapp-ios-swift/RootViewController.swift [56:64]


    func pageViewController(_: UIPageViewController,
                            viewControllerAfter viewController: UIViewController) -> UIViewController? {
        let index = services.firstIndex(of: viewController.restorationIdentifier!)!
        if index < services.count - 1 {
            return storyboard?.instantiateViewController(withIdentifier: services[index + 1])
        } else {
            return nil
        }
    }