Swift Print Anchor Constant Value - ios

How do you print out the value of an anchor's constant? For example:
let myButton = UIButton()
myButton.topAnchor.constraint(equalTo: view.topAnchor, constant: 5).isActive = true
myButton.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
myButton.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
myButton.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
print(myButton.topAnchor.constant)//this would print 5

The constant is for the constraint that you have laid out for the anchor. Anchors don't have constants. Constraints do. So what you need to do is maintain a reference of the constraint and access the constant.
let myButtonTopAnchorConstraint = myButton.topAnchor.constraint(equalTo: view.topAnchor, constant: 5)
myButtonTopAnchorConstraint.isActive = true
myButton.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
myButton.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
myButton.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
print(myButtonTopAnchorConstraint.constant) //Prints 5
A view will have only one topAnchor, but can have multiple constraints relative to that anchor.

Related

How to set Layout Anchors depending on the length of the inscription?

I want to set UITableViewCell with two UILabels in the same line. For Example:
Tom Ford.
I know how to do it in hardcoded style, but how to do it depending on the length of the first name? I mean first names vary in length and I want to set the last name UILabel in the same length on the right same of the name UILabel. How to do it?
FirstName and LastName:
func setFirstnameLabel() {
firstNameLabel.translatesAutoresizingMaskIntoConstraints = false
firstNameLabel.centerYAnchor.constraint(equalTo: centerYAnchor).isActive = true
firstNameLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 12).isActive = true
firstNameLabel.heightAnchor.constraint(equalToConstant: 30).isActive = true
firstNameLabel.widthAnchor.constraint(equalToConstant: 100).isActive = true
}
func setLastNameLabel() {
lastNameLabel.translatesAutoresizingMaskIntoConstraints = false
lastNameLabel.centerYAnchor.constraint(equalTo: centerYAnchor).isActive = true
lastNameLabel.leadingAnchor.constraint(equalTo: firstNameLabel.trailingAnchor, constant: 20).isActive = true
lastNameLabel.heightAnchor.constraint(equalToConstant: 30).isActive = true
lastNameLabel.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -12).isActive = true
}

Swift Programmatic Constraint not working

I am trying to create a uiview that has a segment control inside. I want to be able to add this uiview to my viewcontroller's view. the segment control should be right on top of my tableview. but everytime i setup the constraints i keep getting this error
"Thread 1: Exception: "Unable to activate constraint with anchors <NSLayoutYAxisAnchor:0x282ee24c0 "UIView:0x119d3a610.bottom"> and <NSLayoutYAxisAnchor:0x282ee2500 "UITableView:0x11a014a00.top"> because they have no common ancestor. Does the constraint or its anchors reference items in different view hierarchies? That's illegal."" I tried working around by adding the subview first and what not but it's not working. here's my code if anyone can help me.
func configureTableView(){
setupSegmentControl()
view.addSubview(tableView)
setTableViewDelegates()
tableView.rowHeight = 50
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
tableView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
tableView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
self.tableView.topAnchor.constraint(equalToSystemSpacingBelow: self.view.topAnchor, multiplier: 20).isActive = true
tableView.register(UINib(nibName: "CustomCellNSB2", bundle: nil), forCellReuseIdentifier: "CustomCellNSB2")
}
func setTableViewDelegates(){
tableView.delegate = self
tableView.dataSource = self
}
func setupSegmentControl(){
var headerView = UIView()
var importanceSegmentControl = CustomSegmentControl()
headerView.addSubview(importanceSegmentControl)
self.view.addSubview(headerView)
importanceSegmentControl.addTarget(self, action: #selector(indexChanged(control:)),for: UIControl.Event.valueChanged)
headerView.translatesAutoresizingMaskIntoConstraints = false
headerView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 20).isActive = true
headerView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: -20).isActive = true
headerView.bottomAnchor.constraint(equalTo: self.tableView.topAnchor, constant: 20).isActive = true
headerView.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 10).isActive = true
importanceSegmentControl.translatesAutoresizingMaskIntoConstraints = false
importanceSegmentControl.leadingAnchor.constraint(equalTo: headerView.leadingAnchor, constant: 20).isActive = true
importanceSegmentControl.trailingAnchor.constraint(equalTo: headerView.trailingAnchor, constant: -20).isActive = true
importanceSegmentControl.bottomAnchor.constraint(equalTo: headerView.topAnchor, constant: 20).isActive = true
importanceSegmentControl.topAnchor.constraint(equalTo: headerView.topAnchor, constant: 10).isActive = true
}
The tableView and importanceSegmentControl doesn't have any common ancestor at the time of adding the constraint to the importanceSegmentControl. So to fix the issue just switch the order of execution:
func configureTableView(){
view.addSubview(tableView)
setupSegmentControl()
//...
}

Best Practices for programmatically using autolayout

I am using auto layout throughout my whole app programmatically but I am really struggling to make my App look good on all devices (especially struggling with the iPhone SE). Here is an example of my StartViewController (SE, 8 & 11 Pro Max):
As you can see the view looks pretty good on the iPhone 8 and 11 Pro Max. However on the iPhone SE it's quite bad. I don't quite get why because there would be enough space to layout all the views like in iPhone 8 ?? For some reason I think the buttons and labels are bigger (might just be an illusion).
My question is how I can fix that issue? What are best practices? Shrinking the fontSize? Making the buttons smaller ? What is the best way to get a dynamic layout that works for every iPhone? Apparently I am using Auto-Layout not in the best way...
Here is how I constrain the views from the picture:
//MARK: setupViews
func setUpViews(){
view.addSubview(backgroundImage)
view.addSubview(willkommenLabel)
view.addSubview(textLabel)
view.addSubview(emailButton)
emailButton.addSubview(emailImage)
view.addSubview(oderLabel)
view.addSubview(lineLeft)
view.addSubview(lineRight)
view.addSubview(facebookButton)
facebookButton.addSubview(facebookLogo)
view.addSubview(googleButton)
googleButton.addSubview(googleLogo)
view.addSubview(appleButton)
appleButton.addSubview(appleLogo)
view.addSubview(documentsLabel)
backgroundImage.topAnchor.constraint(equalTo: view.topAnchor, constant: -20).isActive = true
backgroundImage.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 20).isActive = true
backgroundImage.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: -20).isActive = true
backgroundImage.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 20).isActive = true
willkommenLabel.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 80).isActive = true
willkommenLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
willkommenLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
textLabel.topAnchor.constraint(equalTo: willkommenLabel.bottomAnchor, constant: 30).isActive = true
textLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
textLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
emailButton.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
emailButton.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
emailButton.topAnchor.constraint(equalTo: textLabel.topAnchor, constant: 100).isActive = true
emailButton.heightAnchor.constraint(equalToConstant: 50).isActive = true
emailImage.centerYAnchor.constraint(equalTo: emailButton.centerYAnchor).isActive = true
emailImage.leadingAnchor.constraint(equalTo: emailButton.leadingAnchor, constant: 10).isActive = true
emailImage.heightAnchor.constraint(equalToConstant: 25).isActive = true
emailImage.widthAnchor.constraint(equalToConstant: 25).isActive = true
oderLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
oderLabel.bottomAnchor.constraint(equalTo: emailButton.bottomAnchor, constant: 40).isActive = true
oderLabel.widthAnchor.constraint(equalToConstant: 60).isActive = true
lineLeft.centerYAnchor.constraint(equalTo: oderLabel.centerYAnchor).isActive = true
lineLeft.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
lineLeft.trailingAnchor.constraint(equalTo: oderLabel.leadingAnchor).isActive = true
lineRight.centerYAnchor.constraint(equalTo: oderLabel.centerYAnchor).isActive = true
lineRight.leadingAnchor.constraint(equalTo: oderLabel.trailingAnchor).isActive = true
lineRight.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
facebookButton.leadingAnchor.constraint(equalTo: emailButton.leadingAnchor).isActive = true
facebookButton.trailingAnchor.constraint(equalTo: emailButton.trailingAnchor).isActive = true
facebookButton.bottomAnchor.constraint(equalTo: oderLabel.bottomAnchor, constant: 55 + 10).isActive = true
facebookButton.heightAnchor.constraint(equalToConstant: 50).isActive = true
facebookLogo.centerYAnchor.constraint(equalTo: facebookButton.centerYAnchor).isActive = true
facebookLogo.leadingAnchor.constraint(equalTo: facebookButton.leadingAnchor, constant: 10).isActive = true
facebookLogo.heightAnchor.constraint(equalToConstant: 25).isActive = true
facebookLogo.widthAnchor.constraint(equalToConstant: 25).isActive = true
googleButton.leadingAnchor.constraint(equalTo: emailButton.leadingAnchor).isActive = true
googleButton.trailingAnchor.constraint(equalTo: emailButton.trailingAnchor).isActive = true
googleButton.bottomAnchor.constraint(equalTo: facebookButton.bottomAnchor, constant: 55 + 10).isActive = true
googleButton.heightAnchor.constraint(equalToConstant: 50).isActive = true
googleLogo.centerYAnchor.constraint(equalTo: googleButton.centerYAnchor).isActive = true
googleLogo.leadingAnchor.constraint(equalTo: googleButton.leadingAnchor, constant: 10).isActive = true
googleLogo.heightAnchor.constraint(equalToConstant: 25).isActive = true
googleLogo.widthAnchor.constraint(equalToConstant: 25).isActive = true
appleButton.leadingAnchor.constraint(equalTo: emailButton.leadingAnchor).isActive = true
appleButton.trailingAnchor.constraint(equalTo: emailButton.trailingAnchor).isActive = true
appleButton.bottomAnchor.constraint(equalTo: googleButton.bottomAnchor, constant: 55 + 10).isActive = true
appleButton.heightAnchor.constraint(equalToConstant: 50).isActive = true
appleLogo.centerYAnchor.constraint(equalTo: appleButton.centerYAnchor).isActive = true
appleLogo.leadingAnchor.constraint(equalTo: appleButton.leadingAnchor, constant: 10).isActive = true
appleLogo.heightAnchor.constraint(equalToConstant: 25).isActive = true
appleLogo.widthAnchor.constraint(equalToConstant: 25).isActive = true
documentsLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 10).isActive = true
documentsLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -10).isActive = true
documentsLabel.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -5).isActive = true
}
Give this a try.
It uses a few percentage heights (based on your original layout on an iPhone 8 screen).
I didn't change any of your existing code. Just add the following func and change your call from:
setupViews()
to
setupViewsDon()
Should be clear from the comments where you might want to make any adjustments... but hopefully this will get you close to your goal - and maybe you'll find a few tips for future use:
func setupViewsDon(){
// setting these properties here, so I don't have to change your original initialization
willkommenLabel.numberOfLines = 1
willkommenLabel.adjustsFontSizeToFitWidth = true
willkommenLabel.minimumScaleFactor = 0.5
textLabel.numberOfLines = 2
textLabel.adjustsFontSizeToFitWidth = true
textLabel.minimumScaleFactor = 0.5
// prevent willkommenLabel from being compressed or streched
willkommenLabel.setContentHuggingPriority(.required, for: .vertical)
willkommenLabel.setContentCompressionResistancePriority(.required, for: .vertical)
// prevent oderLabel from being compressed or streched
oderLabel.setContentHuggingPriority(.required, for: .vertical)
oderLabel.setContentCompressionResistancePriority(.required, for: .vertical)
// prevent documentsLabel from being compressed or streched
documentsLabel.setContentHuggingPriority(.required, for: .vertical)
documentsLabel.setContentCompressionResistancePriority(.required, for: .vertical)
view.addSubview(backgroundImage)
view.addSubview(willkommenLabel)
view.addSubview(textLabel)
view.addSubview(emailButton)
emailButton.addSubview(emailImage)
view.addSubview(oderLabel)
view.addSubview(lineLeft)
view.addSubview(lineRight)
view.addSubview(facebookButton)
facebookButton.addSubview(facebookLogo)
view.addSubview(googleButton)
googleButton.addSubview(googleLogo)
view.addSubview(appleButton)
appleButton.addSubview(appleLogo)
view.addSubview(documentsLabel)
backgroundImage.topAnchor.constraint(equalTo: view.topAnchor, constant: -20).isActive = true
backgroundImage.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 20).isActive = true
backgroundImage.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: -20).isActive = true
backgroundImage.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 20).isActive = true
// add a layout guide for percentage top spacing
let topSpaceGuide = UILayoutGuide()
view.addLayoutGuide(topSpaceGuide)
// based on iPhone 8 ... 80-pts from top
// will be shorter on smaller devices, taller on larger devices
topSpaceGuide.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
topSpaceGuide.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 80.0 / 667.0).isActive = true
willkommenLabel.topAnchor.constraint(equalTo: topSpaceGuide.bottomAnchor).isActive = true
willkommenLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
willkommenLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
// textLabel top constrained to willkommenLabel bottom
textLabel.topAnchor.constraint(equalTo: willkommenLabel.bottomAnchor, constant: 0).isActive = true
textLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
textLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
// textLabel height = a percentage of view height using 100-pts based on an iPhone 8
// priority = .defaultHigh so it can be compressed if needed (on smaller devices)
let c = textLabel.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 100.0 / 667.0)
c.priority = .defaultHigh
c.isActive = true
// set email button height
emailButton.heightAnchor.constraint(equalToConstant: 50).isActive = true
// set other button heights equal to emailButton
facebookButton.heightAnchor.constraint(equalTo: emailButton.heightAnchor).isActive = true
googleButton.heightAnchor.constraint(equalTo: emailButton.heightAnchor).isActive = true
appleButton.heightAnchor.constraint(equalTo: emailButton.heightAnchor).isActive = true
// add the logo images to the buttons, and make their heights relative to button heights
// in case you want to change the button heights
for (btn, img) in [(emailButton, emailImage), (facebookButton, facebookLogo), (googleButton, googleLogo), (appleButton, appleLogo)] {
btn.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
btn.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
btn.addSubview(img)
img.centerYAnchor.constraint(equalTo: btn.centerYAnchor).isActive = true
img.leadingAnchor.constraint(equalTo: btn.leadingAnchor, constant: 10).isActive = true
img.heightAnchor.constraint(equalTo: btn.heightAnchor, multiplier: 0.5).isActive = true
img.widthAnchor.constraint(equalTo: img.heightAnchor).isActive = true
}
emailButton.topAnchor.constraint(equalTo: textLabel.bottomAnchor, constant: 20).isActive = true
oderLabel.topAnchor.constraint(equalTo: emailButton.bottomAnchor, constant: 15).isActive = true
facebookButton.topAnchor.constraint(equalTo: oderLabel.bottomAnchor, constant: 15).isActive = true
googleButton.topAnchor.constraint(equalTo: facebookButton.bottomAnchor, constant: 10).isActive = true
appleButton.topAnchor.constraint(equalTo: googleButton.bottomAnchor, constant: 10).isActive = true
// make sure appleButton stays above documentsLabel
appleButton.bottomAnchor.constraint(lessThanOrEqualTo: documentsLabel.topAnchor, constant: -20.0).isActive = true
// horizontal arrangement of oderLabel and left/right lines
oderLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
oderLabel.widthAnchor.constraint(equalToConstant: 60).isActive = true
lineLeft.centerYAnchor.constraint(equalTo: oderLabel.centerYAnchor).isActive = true
lineLeft.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
lineLeft.trailingAnchor.constraint(equalTo: oderLabel.leadingAnchor).isActive = true
lineRight.centerYAnchor.constraint(equalTo: oderLabel.centerYAnchor).isActive = true
lineRight.leadingAnchor.constraint(equalTo: oderLabel.trailingAnchor).isActive = true
lineRight.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
// documentsLabel stay at bottom
documentsLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 10).isActive = true
documentsLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -10).isActive = true
documentsLabel.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -5).isActive = true
}
Actually this depnds on how you wan the layout to look in every device , so if you want fixed height for all elements then you should wrap all elements inside a scrollview that will scroll for small devices and act if not exists in large devices , or if you need to make elements fit in screen in all devices then you should make height constraints proportional to screen height
If you want your design to work perfect in all devices then you have to avoid setting constant values as much as you can unless it's necessary, here you are setting heights and paddings fixed numbers, trying to set them related to screen size, for example you can here set all buttons in a view and set it's height to half of screen would be :
Let height = view.frame.size.height / 2
buttonView.heightAnchor.constrains(equalTo: height).isActive = true
And also insert the buttons inside a stackView covers the buttonsview and set it to fill equally for buttons. So you would have all buttons equally and not hard coded, as well as dynamic view of the buttons related ro screen size of whichever device runs the app

Swift - auto constrain items in ScrollView

I am having problems to constrain my items inside my UIScrollView, to be more specific trailing - anchors are behaving weird:
As you can see trailing-anchors are not the same as leading-anchors..
These are my constrains:
scrollView.topAnchor.constraint(equalTo: view.topAnchor, constant: 130).isActive = true
scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -30).isActive = true
scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
emailTextField.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
emailTextField.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
emailTextField.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
emailTextField.heightAnchor.constraint(equalToConstant: 50).isActive = true
anzeigeNameTextField.topAnchor.constraint(equalTo: emailTextField.topAnchor, constant: 80).isActive = true
anzeigeNameTextField.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
anzeigeNameTextField.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
anzeigeNameTextField.heightAnchor.constraint(equalToConstant: 50).isActive = true
wishlistHandleTextField.topAnchor.constraint(equalTo: anzeigeNameTextField.topAnchor, constant: 80).isActive = true
wishlistHandleTextField.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
wishlistHandleTextField.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
wishlistHandleTextField.heightAnchor.constraint(equalToConstant: 50).isActive = true
passwordTextField.topAnchor.constraint(equalTo: wishlistHandleTextField.topAnchor, constant: 80).isActive = true
passwordTextField.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
passwordTextField.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
passwordTextField.heightAnchor.constraint(equalToConstant: 50).isActive = true
eyeButtonOne.centerYAnchor.constraint(equalTo: passwordTextField.centerYAnchor, constant: 10).isActive = true
eyeButtonOne.trailingAnchor.constraint(equalTo: passwordTextField.trailingAnchor).isActive = true
passwordWiederholenTextField.topAnchor.constraint(equalTo: passwordTextField.topAnchor, constant: 80).isActive = true
passwordWiederholenTextField.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
passwordWiederholenTextField.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
passwordWiederholenTextField.heightAnchor.constraint(equalToConstant: 50).isActive = true
eyeButtonTwo.centerYAnchor.constraint(equalTo: passwordWiederholenTextField.centerYAnchor, constant: 10).isActive = true
eyeButtonTwo.trailingAnchor.constraint(equalTo: passwordWiederholenTextField.trailingAnchor).isActive = true
documentsLabel.topAnchor.constraint(equalTo: passwordWiederholenTextField.topAnchor, constant: 80).isActive = true
documentsLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
documentsLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
documentsLabel.heightAnchor.constraint(equalToConstant: 50).isActive = true
signUpButton.topAnchor.constraint(equalTo: documentsLabel.topAnchor, constant: 80).isActive = true
signUpButton.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
signUpButton.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
signUpButton.heightAnchor.constraint(equalToConstant: 50).isActive = true
What am I doing wrong? Do I have to constraint differently inside a UIScrollView? And if so, how and why?
create sample code for you. Hope it will be useful
and read this link for better sene below code: scrollView with auto layout
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.view.backgroundColor = UIColor.red.withAlphaComponent(0.5)
// create scrollView
let scrollView = UIScrollView.init()
scrollView.translatesAutoresizingMaskIntoConstraints = false
scrollView.backgroundColor = UIColor.blue.withAlphaComponent(0.5)
self.view.addSubview(scrollView)
scrollView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true
scrollView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
scrollView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
scrollView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
// create tempView inside scrollView for use autolayout with scrollView
let tempView = UIView.init()
tempView.translatesAutoresizingMaskIntoConstraints = false
scrollView.addSubview(tempView)
tempView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
tempView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
tempView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
tempView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
// is important, just for use autolayout inside scrollView with scroll if content large screen
tempView.widthAnchor.constraint(equalTo: self.view.widthAnchor).isActive = true
let heightConstraint = tempView.heightAnchor.constraint(equalTo: self.view.heightAnchor)
heightConstraint.priority = .init(250)
heightConstraint.isActive = true
// create sample UI inside tempView
let emailTextField = UITextField.init()
emailTextField.translatesAutoresizingMaskIntoConstraints = false
emailTextField.backgroundColor = .white
tempView.addSubview(emailTextField)
emailTextField.topAnchor.constraint(equalTo: tempView.topAnchor, constant: 200).isActive = true
emailTextField.leadingAnchor.constraint(equalTo: tempView.leadingAnchor, constant: 50).isActive = true
emailTextField.trailingAnchor.constraint(equalTo: tempView.trailingAnchor, constant: -50).isActive = true
emailTextField.heightAnchor.constraint(equalToConstant: 100).isActive = true
}
screenShot
uiview needed to be subview of scrollview, after that you can embed you're elements into uiview

Centered UITextField text moving unexpectedly on edit

I have a centered UITextField inside a UICollectionView Cell, but the text moves weirdly to the right when editing. What is causing the problem?
let textLabel: UITextField = {
let label = UITextField()
label.textAlignment = .center
label.adjustsFontSizeToFitWidth = true
label.minimumFontSize = 12
return label
}()
addSubview(textLabel)
textLabel.leadingAnchor.constraint(equalTo: self.leadingAnchor, constant: 15).isActive = true
textLabel.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
textLabel.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
textLabel.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -15).isActive = true
Here is a screen capture of the problem:
Update: Turns out the UITextfield's height is too large, I reduced its height and everything works perfectly now. Thanks for your kind help!
textLabel.leadingAnchor.constraint(equalTo: self.leadingAnchor, constant: 15).isActive = true
textLabel.heightAnchor.constraint(equalToConstant: 50).isActive = true
textLabel.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
textLabel.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -15).isActive = true

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