Page View controller content not displaying its widgets - ios

Question

the page view controller is not displaying its content view controller,
please can anyone help to figure the error and help with a solution
thanks
import UIKit
class ViewController: UIViewController, UIPageViewControllerDataSource {
var pageViewController: UIPageViewController!
var hymnTitles: [String]!
var hymnContents: [String]!
let hymn1 = "this is my story , this is my song"
let hymn2 = "Amazing grace how sweet thou art"
let hymn3 = "God moves in a mysterious way"
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.hymnTitles = ["Hymn 1", "Hymn 2", "Hymn 3"]
self.hymnContents = [hymn1, hymn2, hymn3]
self.pageViewController = self.storyboard?.instantiateViewControllerWithIdentifier("PageViewController") as! UIPageViewController
self.pageViewController.dataSource = self
let startVC = self.viewControllerAtIndex(0) as ContentViewController
let viewControllers = NSArray(object: startVC)
self.pageViewController.setViewControllers(viewControllers as? [UIViewController], direction: UIPageViewControllerNavigationDirection.Forward, animated: true, completion: nil)
self.pageViewController.view.frame = CGRectMake(0, 30, self.view.frame.width, self.view.frame.height - 60)
self.addChildViewController(self.pageViewController)
self.view.addSubview(self.pageViewController.view)
self.pageViewController.didMoveToParentViewController(self)
}
func viewControllerAtIndex(index: Int) -> ContentViewController
{
if ((self.hymnTitles.count == 0) || (index >= self.hymnTitles.count)) {
return ContentViewController()
}
let vc: ContentViewController = self.storyboard?.instantiateViewControllerWithIdentifier("ContentViewController") as! ContentViewController
vc.hymnContent = self.hymnContents[index]
vc.titleText = self.hymnTitles[index]
vc.pageIndex = index
return vc
}
// MARK: - Page View Controller Data Source
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController?
{
let vc = viewController as! ContentViewController
var index = vc.pageIndex as Int
if (index == 0 || index == NSNotFound)
{
return nil
}
index--
return self.viewControllerAtIndex(index)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
let vc = viewController as! ContentViewController
var index = vc.pageIndex as Int
if (index == NSNotFound)
{
return nil
}
index++
if (index == self.hymnTitles.count)
{
return nil
}
return self.viewControllerAtIndex(index)
}
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int
{
return self.hymnTitles.count
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int
{
return 0
}
}
}
the page view controller is not displaying its content view controller,
please can anyone help to figure the error and help with a solution
thanks

Answer 1

You need to add all the required functions of a page view controller.
Try adding the following code:
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController?
{
var index = (viewController as! ContentViewController).pageIndex
if (index == 0) || (index == NSNotFound) {
return nil
}
index--
return viewControllerAtIndex(index)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController?
{
var index = (viewController as! ContentViewController).pageIndex
if index == NSNotFound {
return nil
}
index++
if (index == self.pageTitles.count) {
return nil
}
return viewControllerAtIndex(index)
}
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int
{
return self.pageTitles.count
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int
{
return 0
}