5+ items UITabBarController

CustomTabBarController.swift

final class CustomTabBarController: UITabBarController {

    private var customMaxItems: CGFloat {
        get {
            self.value(forKey: "_customMaxItems") as! CGFloat
        }

        set {
            self.setValue("_customMaxItems", forKey: key)
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad() 

        self.customMaxItems = 10
    }

}