How to use a variable in other class that is defined in AppDelegate

Question

I have a variable var window: UIWindow? in AppDelegate.swift file inside class AppDelegate that I want to use in other class xyz.swift file inside class xyz as explained in here Get current view controller from the app delegate (modal is possible) but I am getting error at the first line any help will be appreciated. here is the code from xyz.swift

func CurrentView() -> UIView
  {
     let navigationController = window?.rootViewController as? UINavigationController // Use of Unresolved identifier 'window'
     if let activeController = navigationController!.visibleViewController {
     if activeController.isKindOfClass( MyViewController )  {
       println("I have found my controller!")
          }
      }
  }

Even if I use let navigationController = AppDelegate.window?.rootViewController as? UINavigationController error is 'AppDelegate.Type' does not have member named 'window'

Where have you defined var windows? Is it in AppDelegate class or just inside the file? Also where is CurrentView() method is defined? Please post code with context. — Abdullah, May 12 '15 at 02:41
`var window: UIWindow?` is in AppDelegate class and `CurrentView()` function is another class named `class ServiceManager: NSObject {` what else code you want ? — Varun Naharia, May 12 '15 at 02:46

score 1 · Answer 1 · edited May 23 '17 at 12:15

This line of code is in xyz.swift

  let navigationController = window?.rootViewController as? UINavigationController // Use of Unresolved identifier 'window'

You don't provide any context for window so it's expected to be in this class or a global variable.

This is closer:

navigationController = AppDelegate.window?.rootViewController as? UINavigationController

and you seem to realise that you need to reference the window variable within your AppDelegate instance however the syntax you are using references a static variable and window is a member variable.

I suggest you read through the swift manual and gain a better understanding of variable scopes and check this:

How do I get a reference to the app delegate in Swift?

score 1 · Accepted Answer · answered May 12 '15 at 02:52

You may have to do as follows:

    var appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
    let navigationController = appDelegate.window?....

As @Dave Durbin has pointed out you are trying to use a variable defined in one class into another class without the reference of the defining class.

How to use a variable in other class that is defined in AppDelegate

2 Answers2