Xtykutl

I am writing a custom view that has two labels as subviews - titleLabel and subtitleLabel.

I added two @IBInspectable properties called titleText and subtitleText so that I can set the texts of the labels very easily in the storyboard.

class MyView : UIView {

    var titleLabel: UILabel!

    var subtitleLabel: UILabel!



    @IBInspectable

    var titleText: String? {

        get { return titleLabel.text }

        set {

            titleLabel.text = newValue

            let fontSize = // calculates appropriate font size for the text...

            titleLabel.font = font.withSize(fontSize)

        }

    }



    @IBInspectable

    var subtitleText: String? {

        get { return subtitleLabel.text }

        set {

            subtitleLabel.text = newValue

            let fontSize = // calculates appropriate font size for the text...

            subtitleLabel.font = font.withSize(fontSize)

        }

    }



    override func draw(_ rect: CGRect) {

        // here I make the view look prettier, irrelevant to the question

    }

}

Now I need to initialise those two labels and add them as MyView's subviews. I thought I could do this in awakeFromNib:

override func awakeFromNib() {

    titleLabel = UILabel(frame: CGRect(

        x: ...,

        y: ...,

        width: ...,

        height: ...))

    self.addSubview(titleLabel)

    subtitleLabel = UILabel(frame: CGRect(

        x: ...,

        y: ...,

        width: ...,

        height: ...))

    self.addSubview(subtitleLabel)



}

So I added a MyView to the storyboard and set its properties with the properties inspector and I ran the app. It crashed.

Apparently, the IBInspectable properties are set before awakeFromNib so the labels have not been initialised by then.

This means that I need to initialise the labels in a method that is called before the IBInspectable properties are set.

What is a method that is called before IBInspectable properties are set that I can override to initialise the subviews?

This might be obvious but the correct method to put such things into is the initializer.

// called when initialized from code

override init(frame: CGRect) {

    super.init(frame: frame)

    commonInit()

}



// called when initialized from storyboard/xib

required init?(coder: NSCoder) {

    super.init(coder: coder)

    commonInit()

}



private func commonInit() {

   // add subviews

}

Also, there is no real reason for optionals in your specific case:

let titleLabel: UILabel = UILabel()

You can add the labels as subviews and update frames later.