In this code, I use in some places
required init?(coder: (NSCoder?)) {
// Init some properties
super.init(coder: coder!)
}
And in other places
required init?(coder: NSCoder) {
super.init(coder: coder)
// Init some properties
}
Both seem to work. Is there a preferred one ? In which cases ? Or should I always use the second one ?
And can super be called at anytime ?
Swift’s superclass initialisation rules are complex, so it’s hard to answer questions like this without seeing a concrete example. Anyway, I most commonly see folks hit this when they’re creating a Cocoa view, so let’s look at that:
import AppKit
class MyView: NSView {
var counter: Int
override init(frame: NSRect) {
self.counter = 0
super.init(frame: frame)
}
required init?(coder: NSCoder) {
super.init(coder: coder)
// ^ Property 'self.counter' not initialized at super.init call
self.counter = 0 // A
}
}
This fails because you have to initialise counter before calling super. Moving line A up a line fixes the problem.
If you have an example of the other behaviour, please share it.
Oh, and this was Xcode 26.2 with the macOS 26.2 SDK.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
