Access variable in different class - Swift

i got two swift files :

main.swift and view.swift

In main.swift i have a variable (Int) initially set to 0.

With an IBACtion I set that variable to be 10, and everything is ok.

However, if I try access that variable from view.swift, with a simple call like main().getValue(), i get always 0 and not 10 even if the variable has changed it's value in main.swift.

The method getValue() in main.swift looks like this:

func getValue() -> Int {
return variable
}

EDIT

Here is the code (Translated from Italian :D )

import Cocoa

class Main: NSObject {

    var variable: Int = 0

    func getValue() -> Int {
        return variable
    }

    @IBAction func updateVar(sender: AnyObject!) {
        variable = 10
    }
}

class View: NSView {
    override func drawRect(dirtyRect: NSRect) {
       println(Main().getValue()) //Returns always 0
    }
}

Thanks in advance Alberto

I have solved this by creating a generic main class which is accessible to all views. Create an empty swift file, name it 'global.swift' and include it in your project:

global.swift:

class Main {
  var name:String
  init(name:String) {
    self.name = name
  }
}
var mainInstance = Main(name:"My Global Class")

You can now access this mainInstance from all your view controllers and the name will always be "My Global Class". Example from a viewController:

viewController:

override func viewDidLoad() {
        super.viewDidLoad()
        println("global class is " + mainInstance.name)
    }

There is an important distinction to be made between "files" in Swift and "classes". Files do not have anything to do with classes. You can define 1000 classes in one file or 1 class in 1000 files (using extensions). Data is held in instances of classes, not in files themselves.

So now to the problem. By calling Main() you are creating a completely new instance of the Main class that has nothing to do with the instance that you have hooked up to your Xib file. That is why the value comes out as the default.

What you need to do, is find a way to get a reference to the same instance as the one in your Xib. Without knowing more of the architecture of your app, it is hard for me to make a suggestion as to do that.

One thought, is that you can add a reference to your Main instance in your Xib using an IBOutlet in your View. Then you can simply do self.main.getValue() and it will be called on the correct instance.

Access variable in different class - Swift

Related

Recent Posts