majdjamaleddine@gmail.com
3 years ago
Hi Brian, can you please explain how index is grabbed through this code line:
let index = self.controllers.firstIndex(where: {$0 == viewController})
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
let index = self.controllers.firstIndex(where: {$0 == viewController}) ?? -1
if index == 0 { return nil }
return controllers[index - 1]
}