UIScrollView with NSLayoutConstraint - swift

Question

UIScrollView is not scrolling the subviews but it does show a scroll-bar.
Here is what I am trying to do
class SetupViewController: UIViewController {
let scrollView = UIScrollView()
let pageLabel = UILabel()
override func viewDidLoad() {
super.viewDidLoad()
self.setupViews()
self.setupConstraints()
self.setText()
}
func setupViews() {
self.scrollView.backgroundColor = .red
self.scrollView.translatesAutoresizingMaskIntoConstraints = false
// Page Label
self.pageLabel.font = UIFontLocalized(englishFontSize: 22, arabicFontSize: 22)
self.pageLabel.textAlignment = .center
self.pageLabel.translatesAutoresizingMaskIntoConstraints = false
}
func setupConstraints() {
// Add To Sub Views
self.view.addSubview(self.pageLabel)
self.view.addSubview(self.scrollView)
// Page Label
NSLayoutConstraint(item: self.pageLabel, attribute: .top, relatedBy: .equal, toItem: self.topLayoutGuide, attribute: .bottom, multiplier: 1.0, constant: 30.0).isActive = true
NSLayoutConstraint(item: self.pageLabel, attribute: .leading, relatedBy: .equal, toItem: self.view, attribute: .leading, multiplier: 1.0, constant: 20.0).isActive = true
NSLayoutConstraint(item: self.pageLabel, attribute: .width, relatedBy: .equal, toItem: self.view, attribute: .width, multiplier: 1.0, constant: -40.0).isActive = true
NSLayoutConstraint(item: self.pageLabel, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 36.0).isActive = true
// Scroll View
NSLayoutConstraint(item: self.scrollView, attribute: .top, relatedBy: .equal, toItem: self.line1, attribute: .bottom, multiplier: 1.0, constant: 0.0).isActive = true
NSLayoutConstraint(item: self.scrollView, attribute: .leading, relatedBy: .equal, toItem: self.view, attribute: .leading, multiplier: 1.0, constant: 0.0).isActive = true
NSLayoutConstraint(item: self.scrollView, attribute: .width, relatedBy: .equal, toItem: self.view, attribute: .width, multiplier: 1.0, constant: 0.0).isActive = true
NSLayoutConstraint(item: self.scrollView, attribute: .height, relatedBy: .equal, toItem: self.view, attribute: .height, multiplier: 1.0, constant: -100.0).isActive = true
self.scrollView.contentSize.height = 2000
// NSLayoutConstraint for rest of elements are removed in this example code.
}
}
I can confirm UIScrollView is added in the view because I checked by giving background red color to scrollview and it does show the background red color in correct position. My issue is the subviews does not move only the scroll bar is moving.
What could be the possible issue here?
Note: NSLayoutConstraint exist for all UIKit elements, I have not added it in the code.

Answer 1

I got this issue sorted our. As pointed out in the comment, the issue was related to superview in constraint which was set to self.view changing it to self.scrollView solved the issue.