UIPageControl to show current page - ios

Question

I made a PageViewController to switch between different View Controllers, and i'd like to show which page we see. I added a pageControl, and gave it the following code.
pageControl.currentPageIndicatorTintColor = UIColor.blueColor()
pageControl.pageIndicatorTintColor = UIColor.lightGrayColor()
pageControl.numberOfPages = pages.count
The complete code:
import UIKit
class ViewControllerSportinfrastructuur: UIViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
#IBOutlet weak var pageControl: UIPageControl!
var pageViewController: UIPageViewController!
let pages = ["PageOneViewController", "PageTwoViewController"]
//MARK: - page view controller data source
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
if let index = pages.indexOf(viewController.restorationIdentifier!) {
if index > 0 {
return viewControllerAtIndex(index - 1)
}
}
return nil
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
if let index = pages.indexOf(viewController.restorationIdentifier!) {
if index < pages.count - 1 {
return viewControllerAtIndex(index + 1)
}
}
return nil
}
func viewControllerAtIndex(index: Int) -> UIViewController? {
let vc = storyboard?.instantiateViewControllerWithIdentifier(pages[index])
return vc
}
override func viewDidLoad() {
super.viewDidLoad()
if let vc = storyboard?.instantiateViewControllerWithIdentifier("MyPageViewController") {
self.addChildViewController(vc)
self.view.addSubview(vc.view)
pageViewController = vc as! UIPageViewController
pageViewController.dataSource = self
pageViewController.delegate = self
pageViewController.setViewControllers([viewControllerAtIndex(0)!], direction: .Forward, animated: true, completion: nil)
pageViewController.didMoveToParentViewController(self)
pageControl.currentPageIndicatorTintColor = UIColor.blueColor()
pageControl.pageIndicatorTintColor = UIColor.lightGrayColor()
pageControl.numberOfPages = pages.count
}
}
Does anyone know what code i should use to set up the current page? Thanks in advance!

Answer 1

EDIT: found the answer already!
I added pageControl.currentPage = index in following functions:
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
if let index = pages.indexOf(viewController.restorationIdentifier!) {
pageControl.currentPage = index
if index > 0 {
return viewControllerAtIndex(index - 1)
}
}
return nil
}
And did the same for the viewControllerAfterViewController func!

Answer 2

The UIPageViewController provides a default UIPageControl - I would recommend to make use of it if you don't have particular custom requirements.
In order to show it you need to implement the following two optional methods in your UIPageViewControllerDataSource:
func presentationCount(for pageViewController: UIPageViewController) -> Int {
return n //number of view controllers
}
func presentationIndex(for pageViewController: UIPageViewController) -> Int {
return i //index of the visible view controller
}

Answer 3

Set pageViewController.delegate = self, implement protocol UIPageViewControllerDelegate
and use on of these methods to set self.pageControl.currentPage = ...
optional func pageViewController(_ pageViewController: UIPageViewController,
willTransitionToViewControllers pendingViewControllers: [UIViewController])
optional func pageViewController(_ pageViewController: UIPageViewController,
didFinishAnimating finished: Bool,
previousViewControllers previousViewControllers: [UIViewController],
transitionCompleted completed: Bool)