Understanding UITabBarController subclass initializer code in Obj- C

Question

I found a project on GitHub and am trying to implement it in my Swift project. I am stuck on the syntax of the following line:

YALFoldingTabBarController *tabBarController = (YALFoldingTabBarController *) self.window.rootViewController;

I cannot figure out how to initialize this line in the AppDelegate. Any help and explanation into what this line means would be appreciated. The project can be found here.

Answer 1

That code should translate to something like

let tabBarController: YALFoldingTabBarController = self.window.rootViewController as! YALFoldingTabBarController

Hope that helps :)

Answer 2

if let tabBarController = self.window.rootViewController as? YALFoldingTabBarController {

}

This line doesn't do much though. All it's doing is casting from UIViewController to YALFoldingTabBarController.