Why my viewcontrollers are not being shown on scrollview controller? - ios

Question

I have three step view controllers. I'm trying to display those three steps on a single viewcontroller (RegisterViewController) using a scroll view so that users can swipe through the steps.
I saw some other posts and got this far. When I run the app I'm getting a blank screen with the background color of the RegisterViewController. I wrote some println statements in the step view controllers to check whether they are being instantiated or not and I could see those statements' output on console. Please if anybody can help?
class RegisterViewController: UIViewController {
#IBOutlet weak var scrollView: UIScrollView!
#IBOutlet weak var registerStepsPageControl: UIPageControl!
override func viewDidLoad() {
super.viewDidLoad()
setupScrollView()
}
func setupScrollView() {
let storyboard = UIStoryboard(name: "Login", bundle: nil)
let stepOneViewController = storyboard.instantiateViewControllerWithIdentifier("RegisterStepOne") as! RegisterStepOneViewController
let stepTwoViewController = storyboard.instantiateViewControllerWithIdentifier("RegisterStepTwo") as! RegisterStepTwoViewController
let stepThreeViewController = storyboard.instantiateViewControllerWithIdentifier("RegisterStepThree") as! RegisterStepThreeViewController
var stepViewControllers = [stepOneViewController, stepTwoViewController, stepThreeViewController]
for index in 0..<stepViewControllers.count {
self.addChildViewController(stepViewControllers[index])
let originX: CGFloat = CGFloat(index) * CGRectGetWidth(self.scrollView.frame);
stepViewControllers[index].view.frame = CGRectMake(originX, 0, self.view.frame.size.width, self.view.frame.size.height);
stepViewControllers[index].view.frame.size = self.view.frame.size
self.scrollView.addSubview(stepViewControllers[index].view)
stepViewControllers[index].didMoveToParentViewController(self)
}
self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * CGFloat(stepViewControllers.count), self.view.frame.height)
self.scrollView.delegate = self
self.registerStepsPageControl.numberOfPages = stepViewControllers.count
}
}
EDIT01:
This code below works. It loads the images and they are being displayed as they are supposed to. But I don't know what might be the problem while loading views from other viewcontrollers.
#IBOutlet weak var tutorialStepsPageControl: UIPageControl!
#IBOutlet weak var scrollView: UIScrollView!
var stepImages: [UIImage] = [UIImage(named: "tutorial_image_step1")!, UIImage(named: "tutorial_image_step2")!, UIImage(named: "tutorial_image_step3")!]
override func viewDidLoad() {
super.viewDidLoad()
self.tutorialStepsPageControl.numberOfPages = stepImages.count
setupScrollView()
}
func setupScrollView() {
var imageFrame: CGRect = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)
var imageView: UIImageView!
for index in 0..<stepImages.count {
imageFrame.origin.x = self.view.frame.size.width * CGFloat(index)
imageFrame.size = self.view.frame.size
imageView = UIImageView(frame: imageFrame)
imageView.image = stepImages[index]
imageView.contentMode = .ScaleAspectFit
self.scrollView.addSubview(imageView)
}
self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * CGFloat(stepImages.count), self.view.frame.size.height)
self.scrollView.delegate = self
}

Answer 1

Try moving the line:
self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * CGFloat(stepViewControllers.count), self.view.frame.height)
Above this line:
for index in 0..<stepViewControllers.count {
This issue might be coming from the fact that you're adding the subviews before you sent the contentSize.

Answer 2

Okay I deleted the step controllers and added them again from scratch. Did a clean build and now it's working. Don't know what was I doing wrong. :/