Is it a way to observe global variable in Swift?

Question

I want to add an observer to check changes of a global variable, but it not seems possible.

var selectedItem: NSManagedObject?

class LCCC: UICollectionViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // need to set up an "observer" that trigger selectedItemDidChange method, if selectedItem changed
    }

    func selectedItemDidChange {
    }
}

Answer 1

I think the most idiomatic way to do this in swift would be using property observers:

var test:NSString = "hi" {
    willSet {

    }
    didSet {

    }
}

(Although you need to provide an initializer)