how can i auto update value of bool variable

Question

i have one bool variable isValidSession i want to observer this variable in whole application whenever it becomes false it will automatically call method and renew the session.

override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {

        if let newValue = change?[NSKeyValueChangeNewKey] {

        }
    }

Answer 1

Try this:

var isValidSession: Bool = true {
        didSet {
            if isValidSession == false  {
                //do something (renew session here)
            }
        }
    }