olxios

import UIKit

class PageItemController: UIViewController {
    
    // MARK: - Variables
    // ***
    var itemIndex: Int = 0
    
    // ***
    var imageName: String = "" {

olxios

#import "ViewController.h"

@interface ViewController () <UIPageViewControllerDataSource>

@property (nonatomic, strong) NSArray *contentImages;
@property (nonatomic, strong) UIPageViewController *pageViewController;

@end

olxios

import UIKit

class ViewController: UIViewController, UIPageViewControllerDataSource {
    
    // MARK: - Variables
    private var pageViewController: UIPageViewController?
    
    // Initialize it right away here
    private let contentImages = ["nature_pic_1",
                                 "nature_pic_2",

olxios

@implementation ViewController

#pragma mark View Lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self createPageViewController];
    [self setupPageControl];
}

olxios

// MARK: - View Lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()
        createPageViewController()
        setupPageControl()
    }
    
    private func createPageViewController() {
        
        let pageController = self.storyboard!.instantiateViewControllerWithIdentifier("PageController") as! UIPageViewController

olxios

#pragma mark UIPageViewControllerDataSource

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
    PageItemController *itemController = (PageItemController *)viewController;
    
    if (itemController.itemIndex > 0)
    {
        return [self itemControllerForIndex:itemController.itemIndex-1];
    }

olxios

// MARK: - UIPageViewControllerDataSource
    
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
        
    let itemController = viewController as! PageItemController
        
    if itemController.itemIndex > 0 {
       return getItemController(itemController.itemIndex-1)
    }
        

olxios

#pragma mark Page Indicator

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController
{
    return [_contentImages count];
}

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController
{
    return 0;

olxios

// MARK: - Page Indicator
    
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
    return contentImages.count
}
    
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
    return 0
}

olxios

- (UIViewController *)currentController
{
    if ([self.pageViewController.viewControllers count])
    {
        return self.pageViewController.viewControllers[0];
    }
    
    return nil;
}