CODEWITHSUNDEEP
swiftautolayout
Grady
Grady

Reputation: 174

UILabel not showing up in the view

Problem

I'm trying to fully understand building a Swift app entirely programmatically but I'm getting hung up on layout anchors. I have a tableview and if a row is selected it will push a new viewcontroller into the view. 

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let currentCell = tableView.cellForRow(at: indexPath)! as! CoinCell
    if let coin = currentCell.coin {
        let newViewController = CoinViewController(coin)
        self.navigationController?.pushViewController(newViewController, animated: true)
    }
    tableView.deselectRow(at: indexPath, animated: true)
}

Below is my code for the viewcontroller that is being pushed. I'm able to see that the nameLabel has text while debugging but I can't seem to have the labels actually show in the view.

var coin: Coin? {
    didSet {
        nameLabel.text = coin?.name
    }
}

init(_ coin: Coin) {
    super.init(nibName: nil, bundle: nil)
    self.coin = coin
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

override func viewDidLoad() {
    super.viewDidLoad()
    view.backgroundColor = UIColor.white
    view.addSubview(nameLabel)
    view.addSubview(testLabel)
    setupView()
}

let nameLabel: UILabel = {
    let label = UILabel()
    label.translatesAutoresizingMaskIntoConstraints = false
    return label
}()

let testLabel: UILabel = {
    let label = UILabel()
    label.translatesAutoresizingMaskIntoConstraints = false
    label.text = "TEST"
    return label
}()


func setupView() {
    nameLabel.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
    nameLabel.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
    nameLabel.widthAnchor.constraint(equalToConstant: 50).isActive = true
    nameLabel.heightAnchor.constraint(equalToConstant: 50).isActive = true
}

I'm still a beginner with this so I'm not sure of the best way to actually debug an issue like this. Thanks for the help.

Upvotes: 0

Views: 4767

Answers (2)

Andreas Oetjen
Andreas Oetjen

Reputation: 10199

You try to set the text nameLabel in the property observer:

var coin: Coin? {
    didSet {
        nameLabel.text = coin?.name
   }
}

But didSet will not be called from the initializer, therfore the label will remain empty.

In iOS (Cocoa Touch), you should fill your views after/within viewDidLoad (or viewDidAppear) or - in your case - in setupView:

func setupView() {
    nameLabel.text = coin?.name
    // ...
}

Upvotes: 1

Lamour
Lamour

Reputation: 3030

Since you are precisely making sure that your controller receive data (or non optional data) via the initializer, you should replace the property observer (didSet) to just a simple property. 

let coin: Coin 

init(_ coin: Coin) { 
    self.coin = coin 
    super.init(nibName: nil, bundle: nil)
 }
// now in viewDidLoad() you can set the text of your label i.e namelabel.text = self.coin.something

Upvotes: 1

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