Scroll View not working iOS Swift - ios

Question

Below is the code where I am trying to set scroll view to my view controller. Could someone please suggest why I am unable to scroll down the view.
I have a most part of my day trying to resolve this. Any help would be greatly appreciated.
import UIKit
class ScrollViewTestVC: UIViewController {
// FOR SCREEN DIMENSIONS
let screenSize : CGRect = UIScreen.main.bounds
var screenWidth : CGFloat
var screenHeight : CGFloat
var scrollView = UIScrollView()
var contentView = UIView()
required init?(coder aDecoder: NSCoder) {
screenHeight = screenSize.height
screenWidth = screenSize.width
super.init(coder: aDecoder)
}
override func viewDidLoad() {
super.viewDidLoad()
// Setting scroll view size
scrollView = UIScrollView(frame: view.bounds)
scrollView.isScrollEnabled = true
let firstName : UILabel = {
let label = UILabel()
label.text = "First Name"
return label
}()
let lastName : UILabel = {
let label = UILabel()
label.text = "Last Name"
return label
}()
let age : UILabel = {
let label = UILabel()
label.text = "Age"
return label
}()
let weight : UILabel = {
let label = UILabel()
label.text = "Weight"
return label
}()
let gender : UILabel = {
let label = UILabel()
label.text = "Gender"
return label
}()
// TEXT FIELDS
let firstNameText : UITextField = {
let tf = UITextField()
tf.placeholder = "Enter first name"
return tf
}()
let lastNameText : UITextField = {
let tf = UITextField()
tf.placeholder = "Enter last name"
return tf
}()
let ageText : UITextField = {
let tf = UITextField()
tf.placeholder = "Enter Age"
return tf
}()
let weightText : UITextField = {
let tf = UITextField()
tf.placeholder = "Enter weight"
return tf
}()
let genderText : UITextField = {
let tf = UITextField()
tf.placeholder = "Enter Gender"
return tf
}()
// ADDING SUB VIEWS
contentView.addSubview(firstName)
contentView.addSubview(lastName)
contentView.addSubview(age)
contentView.addSubview(weight)
contentView.addSubview(gender)
contentView.addSubview(firstNameText)
contentView.addSubview(lastNameText)
contentView.addSubview(ageText)
contentView.addSubview(weightText)
contentView.addSubview(genderText)
// Adding the content view to the scroll view
scrollView.addSubview(contentView)
//self.view.addSubview(contentView)
// Pinning the contentView to the scrollView
pinView(contentView, to: scrollView)
// Adding scroll view to the main view
self.view.addSubview(scrollView)
// Removing default constraints
firstName.translatesAutoresizingMaskIntoConstraints = false
lastName.translatesAutoresizingMaskIntoConstraints = false
age.translatesAutoresizingMaskIntoConstraints = false
weight.translatesAutoresizingMaskIntoConstraints = false
gender.translatesAutoresizingMaskIntoConstraints = false
firstNameText.translatesAutoresizingMaskIntoConstraints = false
lastNameText.translatesAutoresizingMaskIntoConstraints = false
ageText.translatesAutoresizingMaskIntoConstraints = false
weightText.translatesAutoresizingMaskIntoConstraints = false
genderText.translatesAutoresizingMaskIntoConstraints = false
// Views Dict
var viewsDict = [
"firstName" : firstName,
"lastName" : lastName,
"age" : age,
"weight" : weight,
"gender" : gender,
"firstNameText" : firstNameText,
"lastNameText" : lastNameText,
"ageText" : ageText,
"weightText" : weightText,
"genderText" : genderText
]
// Do any additional setup after loading the view.
// SETTING CONSTRAINTS
var space = 100
var edgeSpace = 10
// First Name
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-10-[firstName]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[firstName]", options: [], metrics: nil, views: viewsDict))
// First Name Text
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[firstName]-5-[firstNameText]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[firstNameText]|", options: [], metrics: nil, views: viewsDict))
// Last Name
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[firstNameText]-\(space)-[lastName]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[lastName]", options: [], metrics: nil, views: viewsDict))
// Last Name Text
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[lastName]-5-[lastNameText]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[lastNameText]|", options: [], metrics: nil, views: viewsDict))
// Age
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[lastNameText]-\(space)-[age]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[age]", options: [], metrics: nil, views: viewsDict))
// Age Text
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[age]-5-[ageText]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[ageText]|", options: [], metrics: nil, views: viewsDict))
// Weight
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[ageText]-\(space)-[weight]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[weight]", options: [], metrics: nil, views: viewsDict))
// Weight Text
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[weight]-5-[weightText]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[weightText]|", options: [], metrics: nil, views: viewsDict))
// Gender
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[weightText]-\(space)-[gender]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[gender]", options: [], metrics: nil, views: viewsDict))
// Gender Text
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[gender]-5-[genderText]", options: [], metrics: nil, views: viewsDict))
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(edgeSpace)-[genderText]|", options: [], metrics: nil, views: viewsDict))
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
}
// The below function is used to pin one view to another view
public func pinView(_ view: UIView, to scrollView: UIScrollView) {
view.translatesAutoresizingMaskIntoConstraints = false
view.pin(to: scrollView)
}
public func pin(to view: UIView) {
NSLayoutConstraint.activate([
leadingAnchor.constraint(equalTo: view.leadingAnchor),
trailingAnchor.constraint(equalTo: view.trailingAnchor),
topAnchor.constraint(equalTo: view.topAnchor),
bottomAnchor.constraint(equalTo: view.bottomAnchor)
])
}
}

Answer 1

Your bottommost item needs to be connected to the superview so that the scrollview can compute its height. Add "|":
self.view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[gender]-5-[genderText]|", options: [], metrics: nil, views: viewsDict))

Answer 2

You have to set the content size of scrollview.
See documentation