Trying to make sense of UILabel behavior. - swift

Question

I am trying to replicate Apple's calculator UI layout.
Here is a gif of what I have so far.
The problems that I am encountering mostly have to do with the UILables.
As seen in the gif above, I am experiencing the following problems:
On device rotation, the labels "L1" and "L2" pop, instead of transitioning smoothly.
The labels on the brown colored buttons disappear when transitioning back to portrait.
For the labels "L1" and "L2" I have tried experimenting with the content mode and constraints, however, I still get clunky transitions.
As for the disappearing labels, instead of hiding/unhiding the stack view to make the layout appear and disappear via it's is hidden property, I instead tried using constraints on the stack view to handle the transition, however, the results remain the same.
I have also looked online and tried some suggestions, however, most answers were outdated or simply did not work.
The code is very straight forward, it primarily consists of setting up the views and its constraints.
extension UIStackView {
convenience init(axis: UILayoutConstraintAxis, distribution: UIStackViewDistribution = .fill) {
self.init()
self.axis = axis
self.distribution = distribution
self.translatesAutoresizingMaskIntoConstraints = false
}
}
class Example: UIView {
let mainStackView = UIStackView(axis: .vertical, distribution: .fill)
let subStackView = UIStackView(axis: .horizontal, distribution: .fillProportionally)
let portraitStackView = UIStackView(axis: .vertical, distribution: .fillEqually)
let landscapeStackView = UIStackView(axis: .vertical, distribution: .fillEqually)
var containerView: UIView = {
$0.backgroundColor = .darkGray
$0.translatesAutoresizingMaskIntoConstraints = false
return $0
}(UIView(frame: .zero))
let mainView: UIView = {
$0.backgroundColor = .blue
$0.translatesAutoresizingMaskIntoConstraints = false
return $0
}(UIView(frame: .zero))
let labelView: UIView = {
$0.backgroundColor = .red
$0.translatesAutoresizingMaskIntoConstraints = false
return $0
}(UIView(frame: .zero))
var labelOne: UILabel!
var labelTwo: UILabel!
override init(frame: CGRect) {
super.init(frame: frame)
backgroundColor = .red
autoresizingMask = [.flexibleWidth, .flexibleHeight]
labelOne = createLabel(text: "L1")
labelOne.translatesAutoresizingMaskIntoConstraints = false
labelOne.backgroundColor = .darkGray
labelTwo = createLabel(text: "L2")
labelTwo.translatesAutoresizingMaskIntoConstraints = false
labelTwo.backgroundColor = .black
landscapeStackView.isHidden = true
mainView.addSubview(labelView)
labelView.addSubview(labelOne)
labelView.addSubview(labelTwo)
addSubview(mainStackView)
mainStackView.addArrangedSubview(mainView)
setButtonStackView()
setStackViewConstriants()
setDisplayViewConstriants()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func setStackViewConstriants() {
mainStackView.translatesAutoresizingMaskIntoConstraints = false
mainStackView.topAnchor.constraint(equalTo: topAnchor).isActive = true
mainStackView.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true
mainStackView.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true
mainStackView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
}
func setDisplayViewConstriants() {
mainView.heightAnchor.constraint(equalTo: heightAnchor, multiplier: 288/667).isActive = true
labelView.heightAnchor.constraint(equalTo: mainView.heightAnchor, multiplier: 128/288).isActive = true
labelView.centerYAnchor.constraint(equalTo: mainView.centerYAnchor).isActive = true
labelView.leadingAnchor.constraint(equalTo: mainView.leadingAnchor, constant: 24).isActive = true
labelView.trailingAnchor.constraint(equalTo: mainView.trailingAnchor, constant: -24).isActive = true
labelOne.heightAnchor.constraint(equalTo: labelTwo.heightAnchor, multiplier: 88/32).isActive = true
labelOne.trailingAnchor.constraint(equalTo: labelView.trailingAnchor).isActive = true
labelOne.leadingAnchor.constraint(equalTo: labelView.leadingAnchor).isActive = true
labelOne.topAnchor.constraint(equalTo: labelView.topAnchor).isActive = true
labelTwo.topAnchor.constraint(equalTo: labelOne.bottomAnchor).isActive = true
labelTwo.trailingAnchor.constraint(equalTo: labelView.trailingAnchor).isActive = true
labelTwo.leadingAnchor.constraint(equalTo: labelOne.leadingAnchor).isActive = true
labelTwo.bottomAnchor.constraint(equalTo: labelView.bottomAnchor).isActive = true
}
func createLabel(text: String) -> UILabel {
let label = UILabel(frame: .zero)
label.text = text
label.font = UIFont.init(name: "Arial-BoldMT", size: 60)
label.textColor = .white
label.textAlignment = .right
label.contentMode = .right
label.minimumScaleFactor = 0.1
label.adjustsFontSizeToFitWidth = true
label.numberOfLines = 0
label.translatesAutoresizingMaskIntoConstraints = false
return label
}
func createButton(text: String) -> UIButton {
let button = UIButton(type: .custom)
button.setTitle(text, for: .normal)
button.setTitleColor(.white, for: .normal)
button.layer.borderColor = UIColor.white.cgColor
button.layer.borderWidth = 1
button.titleLabel?.font = UIFont.init(name: "Arial-BoldMT", size: 60)
button.titleLabel?.minimumScaleFactor = 0.1
button.titleLabel?.adjustsFontSizeToFitWidth = true
button.titleLabel?.translatesAutoresizingMaskIntoConstraints = false
button.titleLabel?.leadingAnchor.constraint(equalTo: button.leadingAnchor).isActive = true
button.titleLabel?.trailingAnchor.constraint(equalTo: button.trailingAnchor).isActive = true
button.titleLabel?.topAnchor.constraint(equalTo: button.topAnchor).isActive = true
button.titleLabel?.bottomAnchor.constraint(equalTo: button.bottomAnchor).isActive = true
button.titleLabel?.textAlignment = .center
button.titleLabel?.contentMode = .scaleAspectFill
button.titleLabel?.numberOfLines = 0
return button
}
func setButtonStackView() {
for _ in 1...5 {
let stackView = UIStackView(axis: .horizontal, distribution: .fillEqually)
for _ in 1...4 {
let button = createButton(text: "0")
button.backgroundColor = .brown
stackView.addArrangedSubview(button)
}
landscapeStackView.addArrangedSubview(stackView)
}
for _ in 1...5 {
let stackView = UIStackView(axis: .horizontal, distribution: .fillEqually)
for _ in 1...4 {
let button = createButton(text: "0")
button.backgroundColor = .purple
stackView.addArrangedSubview(button)
}
portraitStackView.addArrangedSubview(stackView)
}
subStackView.addArrangedSubview(landscapeStackView)
subStackView.addArrangedSubview(portraitStackView)
mainStackView.addArrangedSubview(subStackView)
}
override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
if UIDevice.current.orientation.isLandscape && landscapeStackView.isHidden == true {
self.landscapeStackView.isHidden = false
}
if UIDevice.current.orientation.isPortrait && landscapeStackView.isHidden == false {
self.landscapeStackView.isHidden = true
}
self.layoutIfNeeded()
}
}

Answer 1

Overview:
Do things incrementally with separate components / view controllers (easier to debug)
The below solution is only for labels L1 and L2.
For the calculator buttons, it would be best to use a UICollectionViewController. (I haven't implemented it, add as a child view controller)
Code:
private func setupLabels() {
view.backgroundColor = .red
let stackView = UIStackView()
stackView.axis = .vertical
stackView.alignment = .fill
stackView.distribution = .fill
stackView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(stackView)
stackView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
stackView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
stackView.topAnchor.constraint(equalTo: view.topAnchor, constant: 20).isActive = true
let label1 = UILabel()
label1.text = "L1"
label1.textColor = .white
label1.backgroundColor = .darkGray
label1.textAlignment = .right
label1.font = UIFont.preferredFont(forTextStyle: .title1)
let label2 = UILabel()
label2.text = "L2"
label2.textColor = .white
label2.backgroundColor = .black
label2.textAlignment = .right
label2.font = UIFont.preferredFont(forTextStyle: .caption1)
stackView.addArrangedSubview(label1)
stackView.addArrangedSubview(label2)
}