Overridden properties issue in Swift - swift

Question

I have a subclass of UIButton as follows:
class VectorizedButton: UIButton {
override var highlighted: Bool {
didSet {
setNeedsDisplay()
}
}
}
Everything works great, until I added this line in my root controller:
var twitterButton: TwitterButton?
TwitterButton extends VectorizedButton.
Here is the error I get:
...UIView+Vectorized.swift:42:7: Class 'VectorizedButton' has no initializers
...UIView+Vectorized.swift:44:18: Stored property 'highlighted' without initial value prevents synthesized initializers
Easy, let's set a default value:
override var highlighted: Bool = false
Tougher error:
<unknown>:0: error: super.init called multiple times in initializer
<unknown>:0: error: super.init called multiple times in initializer
<unknown>:0: error: super.init called multiple times in initializer
Try overriding init?
required init(coder aDecoder: NSCoder) {
highlighted = false
super.init(coder: aDecoder)
}
Even more errors:
error: 'self' used before super.init call
highlighted = false
^
error: 'self' used before super.init call
highlighted = false
^
Anyone cares to explain what's going on here?

Answer 1

You just had to add the required init
Here is what I did :
class VectorizedButton: UIButton {
override var highlighted: Bool {
didSet {
setNeedsDisplay()
}
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
}
class TwitterButton: VectorizedButton {
}
And in a ViewController :
var twitterButton: TwitterButton?
Works fine like this.
You wanted to override the highlighted property and create the twitterButton as Optional, so you need to implement an init in your class.
You cannot set the highlighted property with this :
override var highlighted: Bool = false
You need to set it in the init, or like this :
override var highlighted: Bool {
get { return false }
set { super.highlighted = newValue }
}
And for this :
required init(coder aDecoder: NSCoder) {
highlighted = false
super.init(coder: aDecoder)
}
You need to set your property after the call to super.init.