question mark in required init?(coder aDecoder: NSCoder)

Asked Dec 05 '18 at 16:43

Active Dec 05 '18 at 16:43

Viewed 92 times

If I'm defining a view I need the following. What does the question mark in init?(coder aDecoder: NSCoder) mean?

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

asked Dec 05 '18 at 16:43

Ted Henry

1

It means it returns an optional. For instance if you have an "important" param in your init, and that param doesn't respects your needs, you might want to return nil instead of an instance that's not correct. – Larme Dec 05 '18 at 16:45
4

See "Failable Initializers" in the Swift Programming Language. https://docs.swift.org/swift-book/LanguageGuide/Initialization.html – Rob Napier Dec 05 '18 at 16:46

0 Answers0