How to properly advance a PageViewController in Swift - ios

Question

I am trying to develop a tutorial in Swift. I have a page view controller working with the indicators (http://www.appcoda.com/uipageviewcontroller-storyboard-tutorial/) but I want to add a button to go to the next page by clicking it instead of swiping the screen (TODO NextPage).
I've tried:
let startVC = self.viewControllerAtIndex(self.index + 1) as TutorialContentViewController
let viewControllers = NSArray(object: startVC)
self.pageViewController.setViewControllers(viewControllers as! [UIViewController],
direction: UIPageViewControllerNavigationDirection.Forward,
animated: true,
completion: nil)
The problem is that circle page indicator is not being updated and after clicking next, all the pages are the second page.
Source code
import UIKit
class TutorialViewController: UIViewController, UIPageViewControllerDataSource {
var pageViewController: UIPageViewController!
var pageTexts: NSArray!
var pageImages: NSArray!
var index: Int = 0
#IBOutlet var button: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
self.pageTexts = NSArray(objects: "Explore", "Today Widget")
self.pageImages = NSArray(objects: "background1.jpg", "background2.jpg")
self.pageViewController = self.storyboard?.instantiateViewControllerWithIdentifier("PageViewController") as! UIPageViewController
self.pageViewController.dataSource = self
let startVC = self.viewControllerAtIndex(index) as TutorialContentViewController
let viewControllers = NSArray(object: startVC)
self.pageViewController.setViewControllers(viewControllers as! [UIViewController], direction: .Forward, animated: true, completion: nil)
self.pageViewController.view.frame = CGRectMake(0, 0, self.view.frame.width, self.view.frame.size.height - 60)
self.addChildViewController(self.pageViewController)
self.view.addSubview(self.pageViewController.view)
self.pageViewController.didMoveToParentViewController(self)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func viewControllerAtIndex(index: Int) -> TutorialContentViewController {
if (index >= self.pageTexts.count) {
return TutorialContentViewController()
}
let vc: TutorialContentViewController = self.storyboard?.instantiateViewControllerWithIdentifier("TutorialContentViewController") as! TutorialContentViewController
vc.image = self.pageImages[index] as! String
vc.text = self.pageTexts[index] as! String
vc.pageIndex = index
self.index = index
self.button.setTitle(self.index == self.pageTexts.count - 1 ? "Finish" : "Next", forState: .Normal)
return vc
}
// MARK: - Page View Controller Data Source
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
let vc = viewController as! TutorialContentViewController
let index = vc.pageIndex as Int
return self.viewControllerAtIndex(index)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
let vc = viewController as! TutorialContentViewController
var index = vc.pageIndex as Int
if (index == NSNotFound) {
return nil
}
index++
if (index == self.pageTexts.count) {
self.button.setTitle("Finish", forState: .Normal)
return nil
} else {
self.button.setTitle("Next", forState: .Normal)
}
return self.viewControllerAtIndex(index)
}
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
return self.pageTexts.count
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
return 0
}
#IBAction func onButtonClick(sender: AnyObject) {
if (self.index == self.pageTexts.count - 1) {
let vc : UIViewController = self.storyboard!.instantiateViewControllerWithIdentifier("splashViewController")
vc.modalTransitionStyle = UIModalTransitionStyle.CrossDissolve
self.presentViewController(vc, animated: true, completion:nil)
} else {
//TODO NextPage
}
}
}

Answer 1

Here let viewControllers = NSArray(object: startVC) you make an array of UIViewController with only one UIViewController (your second UIViewController).
Instead use the viewControllerAtIndex function from your code.
So now your UIButton action should look like this:
func nextPage(sender: AnyObject) {
self.pageViewController.setViewControllers([self.viewControllerAtIndex(self.index + 1)!], direction: .Forward, animated: true, completion: nil)
}