MVC for scrollView - ios

Question

Sorry for the extremely basic question, but I'm trying to better understand MVC and how it pertains to more advanced screens.
Say I have a exampleView, that has multiple labels in it and I want to add this view to a ScrollView using addSubview. Should the ScrollView be instantiated in the View Controller and then calling self.view.addSubview(scrollView) and self.scrollView.addSubview(exampleView), or would you turn exampleView into a scrollView and just adding self.view.addSubview(exampleScrollView).
My friend has told me that there should never be programmatic constraints in the view controller if we're following MVC, but I'm not sure if that's true or not.

Answer 1

Constraints have nothing to do with MVC. MVC is a programming architecture or design pattern that attempts to divide the program into three categories: data (model), the visual objects that often represent the data (view), and the objects that bind them together (controller). And constraints are simply a way of positioning visual objects. The way you position visual objects has nothing to do with the architecture you decide for your program; they are completely independent of each other.
And the idea that a view controller should never have programmatic constraints is just ridiculous. Not only do constraints (let alone programmatic constraints) have nothing to do with MVC, forbidding the use of programmatic constraints for any reason is a sign of a very poor developer. You can code an entire application programmatically but you cannot even come close to coding an entire application non-programmatically.
The interface builder, in my opinion, is mostly there for professional programmers who program for a number of clients and find themselves constantly adding view objects (views, labels, buttons, scroll views, table views, etc.) because it's drag and drop. I personally find the whole IB experience very unappealing.
To your question about a scroll view, use this very basic template as a guide. Add the scroll view to the view and add the subviews to the scroll view. To make it work, however, you must anchor the objects in the scroll view to the edges of the scroll view (especially the bottom) so that its content view stretches and it scrolls.
class Slickdaddy: UIViewController {
private let scrollView = UIScrollView()
override func viewDidLoad() {
super.viewDidLoad()
addScrollView()
addAView()
}
private func addScrollView() {
scrollView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(scrollView)
scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
scrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
scrollView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
scrollView.heightAnchor.constraint(equalTo: view.heightAnchor).isActive = true
}
private func addAView() {
let label = UILabel()
label.text = "slick daddy"
label.translatesAutoresizingMaskIntoConstraints = false
scrollView.addSubview(label)
label.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 16).isActive = true
label.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 32).isActive = true
label.sizeToFit()
label.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor, constant: -32).isActive = true
}
}