Odtnhj

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.