Implementing NSValueTransformer for Transformable attributes in Swift

Question

I'm trying to implement a NSValue Transformer, which should help me to save a Double Array into Core Data using a Transformable attribute.

So I tried to implement the transformedValueClass. But NSArray.class() is crossed out. Unfortunately I didn't find a reason for this.

My method looks like this:

class PacePerK:NSValueTransformer{
    class func transformedValueClass() -> AnyClass!
    {
        return NSArray.class()
    }
}

I get the following compiler errors: Expected member name following '.' Expected identifier in class declaration

Unfortunately they don't really help me.

Why is the NSArray.class crossed out? How can I return the class of NSArray without causing a compiler error?

Answer 1

It appears the correct why to reference class objects in Swift is with:

NSArray.self

Also, in your example, you’ll need to mark your transformedValueClass function with “override”. So:

class PacePerK:NSValueTransformer{
    override class func transformedValueClass() -> AnyClass!
    {
        return NSArray.self
    }
}