Pass variable from child view to parent view in Swift

Question

I'm trying to pass a variable from a child view (inputPopUp.swift) to a parent view using setter and getter functions. Here is the code in my child view:

var char: String!
var buttonPressed = String()

@IBAction func addButtonPressed(sender: AnyObject) {
    buttonPressed = "addButton"
    setChar("+")
    getChar()
    self.removeAnimate()
}

@IBAction func minusButtonPressed(sender: AnyObject) {
    buttonPressed = "minusButton"
    setChar("-")
    self.removeAnimate()
}

@IBAction func divideButtonPressed(sender: AnyObject) {
    buttonPressed = "divideButton"
    setChar("/")
    self.removeAnimate()
}

@IBAction func multiplyButtonPressed(sender: AnyObject) {
    buttonPressed = "multiplyButton"
    setChar("*")
    self.removeAnimate()
}

//setter method
func setChar(var thisChar: String){
    char = thisChar
}

//getter method
func getChar()-> String{
    if (buttonPressed == "addButton"){
        char = "+"
    }
    if (buttonPressed == "minusButton"){
        char = "-"
    }
    if (buttonPressed == "divideButton"){
        char = "/"
    }
    if (buttonPressed == "multiplyButton"){
        char = "*"
    }
    return char
}

I am trying to access the 'char' variable in my parent view like so, however it is returning nil - presumably because I am calling a new instance of the function.

@IBAction func runButtonPressed(sender: AnyObject) {
    inputPopUp().getChar()
} 

How can I pass the data from the child to the parent effectively?

I would also like to update a label in my parent view, based on the button click within my child view. I am trying to implement Key-Value Observation. Here's what I've got so far.

class ObserveChar: NSObject {

dynamic var char = String()

func updateChar(){

    char = String()
}

}

private var myContext = 0

class Observer: NSObject {

var objectToObserve = ObserveChar()

override init(){

    super.init()

    objectToObserve.addObserver(self, forKeyPath: "char", options: .New, context: &myContext)
}

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

    if context == &myContext {

        println("Char updated: \(change[NSKeyValueChangeNewKey])")

    } else {
        super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context)
    }
}

deinit {

    objectToObserve.removeObserver(self, forKeyPath: "char", context: &myContext)

}

}

Answer 1

Ok，Maybe you can set the child view as a property of parent view,maybe like this

var inputPopView : inputPopUp       /**<initialize it somewhere */

and then you can use it like this

@IBAction func runButtonPressed(sender: AnyObject) {
self.inputPopView.getChar() 
}