(Swift) need help swiping between view controllers

Question

These are my view controllers:

I want to make it so that I can swipe between the three of them starting in the middle one. All of the tutorials I've found require you to start from scratch and don't show me how to connect the three I have. Does anyone have a step-by-step instruction of how to do this?

Any help would be greatly appreciated

Answer 1

First Create a class called PageViewController, drag a UIPageViewController in storyboard.For now lets set it as initial view controller from attributes inspector. Also from identity inspector set PageViewController as Class.

Call your three view controller for example StepZero,StepOne,StepTwo Also give them identifier in storyboard.

lets deep into coding now, so in PageViewController should subclass UIPageVIewController:

import UIKit

class PageViewController : UIPageViewController,UIPageViewControllerDataSource {

    var selectedIndex = 1

    override func viewDidLoad() {

        dataSource = self

        view.backgroundColor = UIColor.darkGrayColor()

        // This is the starting point.  Start with step zero.
        setViewControllers([getStepOne()], direction: .Forward, animated: false, completion: nil)
    }

    func getStepZero() -> StepZero {
        return storyboard!.instantiateViewControllerWithIdentifier("StepZero") as! StepZero
    }

    func getStepOne() -> StepOne {
        return storyboard!.instantiateViewControllerWithIdentifier("StepOne") as! StepOne
    }

    func getStepTwo() -> StepTwo {
        return storyboard!.instantiateViewControllerWithIdentifier("StepTwo") as! StepTwo
    }

    func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
        if viewController.isKindOfClass(StepTwo) {
            // 2 -> 1
            return getStepOne()
        } else if viewController.isKindOfClass(StepOne) {
            // 1 -> 0
            return getStepZero()
        } else {
            // 0 -> end of the road
            return nil
        }
    }

    func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
        if viewController.isKindOfClass(StepZero) {
            // 0 -> 1
            return getStepOne()
        } else if viewController.isKindOfClass(StepOne) {
            // 1 -> 2
            return getStepTwo()
        } else {
            // 2 -> end of the road
            return nil
        }
    }

    // Enables pagination dots
    func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
        return 3
    }

    // This only gets called once, when setViewControllers is called
    func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
        return selectedIndex
    }


}

Let's say in Storyboard you have three viewControllers, you should set identifier for them from identity inspector as StepZero StepOne StepTwo for example and when you instantiate them you do :

func getStepZero() -> StepZero {
    return storyboard!.instantiateViewControllerWithIdentifier("StepZero") as! StepZero
}

func getStepOne() -> StepOne {
    return storyboard!.instantiateViewControllerWithIdentifier("StepOne") as! StepOne
}

func getStepTwo() -> StepTwo {
    return storyboard!.instantiateViewControllerWithIdentifier("StepTwo") as! StepTwo
}

The selected index is the index you want to start with which is number 1. And to start with second view controller call getStepOne() in setViewControllers. if you want to start with view controller 3 use selected index 2 and call getStepTwo()...etc

Download Updated Sample : https://mega.nz/#!EQEFhbwS!0yoy5RvAliQNnjRevWo05wPWk7P08e8DVetRZdjg-ro