CODEWITHSUNDEEP
iosswiftuilabel
Txo
Txo

Reputation: 37

UILabel not showing if variable has a value

I have a label (in my secondVC) which is displaying a segued Double from the firstVC. In the secondVCs viewDidLoad I am printing the passedDouble and it is printing the correct amount, so I know my Double is being segued correctly. My UILabel is in the secondVC and only shows an amount if the passedDouble = 0.0.

SecondViewController:

@IBOutlet weak var totalLabel: UILabel!

var passedDouble = 0.0

override func viewDidLoad() {
    super.viewDidLoad()

    print("testing for a value \(passedDouble)")
    totalLabel.text = String("\(passedDouble)")
}

If the passed value is 12.2 for example, it prints this

testing for a value 12.2

But the label completely disappears from view.

If the passed value is 0.0 however, it prints

testing for a value 0.0

and the label shows 0.0

In the storyboard I have left the labels standard text as Label. So, I know the label is connected properly as it's text changes IF the value is nil.

EDIT: Code for the firstVC where I am assigning the value

var totalPrice: Double = Double()

@IBAction func basketAction(_ sender: UIButton) {
    for cost in priceDictionaryToBeSent {
        totalPrice += Double(cost)!
    }
    performSegue(withIdentifier: "basket", sender: self)
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "basket" {
        if let basketVC = segue.destination as? BasketViewController {
            basketVC.passedDouble = totalPrice
            //This is sending the correct price
        }
    }
}

Upvotes: 0

Views: 56

Answers (2)

Txo
Txo

Reputation: 37

Thank you to Milan Nosáľ for saying the view could've already loaded, indeed it had, so I moved the code from viewDidLoad in my BasketViewController to viewDidAppear as seen below:

override func viewDidAppear(_ animated: true) {
    super.viewDidAppear(true)
    print("testing for total price £\(passedDouble)")
    totalLabel.text = "Total price £\(passedDouble)"
}

Upvotes: 0

Milan Nosáľ
Milan Nosáľ

Reputation: 19737

My best guess is that in prepare(for:sender:) the basketVC's view is already loaded, so its viewDidLoad got called before you are setting basketVC.passedDouble = totalPrice.

I would rather use setter to update the label everytime the passedDouble gets updated. Change the BasketViewController code to this:

@IBOutlet weak var totalLabel: UILabel!

var passedDouble = 0.0 {
    didSet {
        self.totalLabel?.text = "\(passedDouble)"
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    // no need to set totalLabel.text here
}

Upvotes: 1

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