How to encode Int as an optional using NSCoding

Question

I am trying to declare two properties as optionals in a custom class - a String and an Int.

I\'m doing this in MyClass:

var myString: String?
var my         


        

Answer 1

If it can be optional, you will have to use encodeObject for it, too.

You are using an Objective-C framework and Objective-C allows nil only for objects (class/reference types). An integer cannot be nil in Objective-C.

However, if you use encodeObject, Swift will automatically convert your Int to NSNumber, which can be nil.

Another option is to skip the value entirely:

if let myIntValue = myInt {
    aCoder.encodeInteger(myIntValue, forKey: "MyInt")
}

and use containsValueForKey(_:) when decoding.