How to fix UITableView not displaying in UIStackView - swift

Question

I followed a tutorial to build a weather app programmatically (without a storyboard) that displays the current city and temperature. I am modifying it to display a 5 day forecast instead of just the current temperature by adding a UITableView, but it is not showing up.
Here is my WeatherView code:
class WeatherView: UIView, UITableViewDelegate, UITableViewDataSource {
override init(frame: CGRect) {
super.init(frame: frame)
setup()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
private func setup() {
setupViews()
setupConstraints()
}
private func setupViews() {
self.addSubview(mainStack)
conditionsImageStack.addArrangedSubview(conditionsImageView)
mainStack.addArrangedSubview(conditionsImageStack)
// forecastTable.register(UITableView.self, forCellReuseIdentifier: "forecast")
forecastTable.register(UITableViewCell.self, forCellReuseIdentifier: "forecast")
forecastTable.delegate = self
forecastTable.dataSource = self
mainStack.addArrangedSubview(centerContentStack)
// centerContentStack.addArrangedSubview(temperatureLabel)
centerContentStack.addArrangedSubview(forecastTable)
centerContentStack.addArrangedSubview(cityAndConditionsStack)
cityAndConditionsStack.addArrangedSubview(cityLabel)
cityAndConditionsStack.addArrangedSubview(conditionsLabel)
mainStack.addArrangedSubview(buttonsStack)
buttonsStack.addArrangedSubview(celsiusButton)
buttonsStack.addArrangedSubview(fahrenheitButton)
buttonsStack.addArrangedSubview(UIView(frame: .zero))
}
private func setupConstraints() {
mainStack.pinEdges(to: self)
}
let mainStack: UIStackView = {
let stackView = UIStackView(frame: .zero)
stackView.axis = .vertical
stackView.distribution = .equalSpacing
stackView.spacing = 10
stackView.isLayoutMarginsRelativeArrangement = true
stackView.layoutMargins = UIEdgeInsets(top: 10, left: 30, bottom: 30, right: 30)
return stackView
}()
let conditionsImageStack: UIStackView = {
let stackView = UIStackView(frame: .zero)
stackView.axis = .vertical
stackView.distribution = .equalSpacing
stackView.alignment = .trailing
stackView.spacing = 10
return stackView
}()
let cityAndConditionsStack: UIStackView = {
let stackView = UIStackView(frame: .zero)
stackView.axis = .vertical
stackView.distribution = .fillProportionally
stackView.spacing = 10
return stackView
}()
let centerContentStack: UIStackView = {
let stackView = UIStackView(frame: .zero)
stackView.axis = .vertical
stackView.distribution = .fillProportionally
stackView.alignment = .center
stackView.spacing = 60
return stackView
}()
// TABLE CODE HERE
var animalArray : [String] = ["elephant", "pig", "goat"]
var forecastTable: UITableView = {
let tableView = UITableView()
let estimatedHeight = tableView.numberOfRows(inSection: 3) //You may need to modify as necessary
// let width = parentView.frame.size.width
let width = estimatedHeight
tableView.frame = CGRect(x: 0, y: 0, width: width, height: estimatedHeight)
return tableView
}()
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 3
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = forecastTable.dequeueReusableCell(withIdentifier: "forecast")
cell?.textLabel!.text = "Success"
return cell!
}
let temperatureLabel: UILabel = {
let label = UILabel(frame: .zero)
label.font = UIFont.systemFont(ofSize: 144)
label.textColor = .white
label.textAlignment = .center
label.text = "18°"
return label
}()
let cityLabel: UILabel = {
let label = UILabel(frame: .zero)
label.font = UIFont.systemFont(ofSize: 36)
label.textColor = .white
label.textAlignment = .center
label.text = "Atlanta"
return label
}()
let conditionsLabel: UILabel = {
let label = UILabel(frame: .zero)
label.font = UIFont.systemFont(ofSize: 20)
label.textColor = .white
label.textAlignment = .center
label.text = "Sunny"
return label
}()
let conditionsImageView: UIImageView = {
let image = UIImage(named: "sun")
let imageView = UIImageView(image: image)
imageView.contentMode = .scaleAspectFit
imageView.widthAnchor.constraint(equalToConstant: image!.size.width).isActive = true
imageView.heightAnchor.constraint(equalToConstant: image!.size.height).isActive = true
return imageView
}()
let celsiusButton: UIButton = {
let button = UIButton(type: .system)
button.setTitle("°C", for: .normal)
button.titleLabel?.font = UIFont.systemFont(ofSize: 73)
button.setTitleColor(.white, for: .normal)
return button
}()
let fahrenheitButton: UIButton = {
let button = UIButton(type: .system)
button.setTitle("°F", for: .normal)
button.titleLabel?.font = UIFont.systemFont(ofSize: 73)
button.setTitleColor(.white, for: .normal)
return button
}()
let buttonsStack: UIStackView = {
let stackView = UIStackView(frame: .zero)
stackView.axis = .horizontal
stackView.distribution = .equalCentering
stackView.spacing = 10
return stackView
}()
}
Here is my ViewController code:
class WeatherViewController: UIViewController {
var mainView: WeatherView! { return self.view as! WeatherView }
let presenter: WeatherPresenter!
init(with presenter: WeatherPresenter){
self.presenter = presenter
super.init(nibName: nil, bundle: nil)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init coder not implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
updateBackground()
}
func updateBackground() {
self.mainView.updateGradient(presenter.backgroundColor)
}
override func loadView() {
self.view = WeatherView(frame: UIScreen.main.bounds)
}
}
Here is my UIView + Constraints code:
extension UIView {
func pinEdges(to view: UIView){
self.translatesAutoresizingMaskIntoConstraints = false
self.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true
self.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
self.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
self.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
}
}
I have tried forcing it to display by setting the dimensions with tableView.frame = CGRect(x: 0, y: 0, width: width, height: estimatedHeight) but that did not work.
I am registering the table in the view class instead of of the view controller class, but I am not sure if this is the problem or how to modify it correctly.

Answer 1

You're doing a couple things wrong...
First, in your var forecastTable: UITableView = {...} declaration, you have a line:
let estimatedHeight = tableView.numberOfRows(inSection: 3)
But, at that point, the table view has no dataSource -- even if it did, your dataSource has only section. So the value returned is undefined. If Iprint(esttmatedHeight)I get9223372036854775807. So you are trying to set the frame of your table view to9223372036854775807 x 9223372036854775807`
Next, when you add a table view to a stack view, the stack view will try to arrange it based on the stack view's properties and the table view's intrinsic size. However, the table view has no intrinsic size at that point - you must use auto-layout properties.
So, remove the frame setting for your table view, and after you've added it to the stack view, use:
// I'm guessing you want a height based on number of rows * row height?
// so, something like:
let estimatedHeight = CGFloat(3 * 44)
forecastTable.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
forecastTable.widthAnchor.constraint(equalTo: centerContentStack.widthAnchor),
forecastTable.heightAnchor.constraint(equalToConstant: estimatedHeight),
])
That will make the table view the same width as the centerContentStack that holds it, and give it a height.
At this point, you should see your table.

Answer 2

You are adding mainStack to the superView but not specifying it's dimensions. You need to set constrains to mainStack similar this,
mainStack.translatesAutoresizingMaskIntoConstraints = false
mainStack.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
mainStack.trailingAnchor.constraint(equalTo: self.trailingAnchor).isActive = true
mainStack.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
mainStack.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
Above code fills the entire super view with mainStack. You can modify this code according to your requirement.