Implement NSCoding on NSObject

Question

I got these errors on NSObject class only. UIButton and UILabel have no such error.

class Foo: NSObject, NSCoding {
    var title = ""
    var children: [Foo] = []



    // MARK: NSCoding
    override public func encode(with coder: NSCoder) {
        super.encode(with: coder)
        coder.encode(title as Any?, forKey: "title")
        coder.encode(children as Any?, forKey: "children")
    }

    required public init?(coder decoder: NSCoder) {
        super.init(coder: decoder)
        self.title = decoder.decodeObject(forKey: "title") as? String ?? ""
        self.children = decoder.decodeObject(forKey: "children") as? [Foo] ?? []
    }

} 

Any ideas?

Answer 1

NSCoding (and Codable which I think you should be using instead) is a protocol so you are not overriding anything so remove override and any calls to super

public func encode(with coder: NSCoder) {
    coder.encode(title as Any?, forKey: "title")
    coder.encode(children as Any?, forKey: "children")
}

required public init?(coder decoder: NSCoder) {
    self.title = decoder.decodeObject(forKey: "title") as? String ?? ""
    self.children = decoder.decodeObject(forKey: "children") as? [Foo] ?? []
}