在TabBarController中覆盖ViewControllers的类型？

Question

I'm trying to override type for viewControllers manner.

override var viewControllers : [BaseViewController]? {
    get {
        return self.viewControllers
    }
}

But I get this error.

Property 'viewControllers' with type '[BaseViewController]?' cannot override a property with type '[UIViewController]?'

Can this even be done?

Answer 1

You can workaround it by creating new property. Like this for instance.

var baseViewControllers: [BaseViewController]? {
      return self.viewControllers as? [BaseViewController] 
}

Answer 2

You cannot override properties type which is already of type UIViewController. What you can do is to cast the property viewControllers to [BaseViewController]?.

class base: UIViewController {

}

class tab: UITabBarController {
  override func viewDidLoad() {
    super.viewDidLoad()
    let bases = viewControllers as? [base]
  }
  override var viewControllers: [UIViewController]? {
    get {
        return [base()]
    }
    set {

    }
  }
}