Alertbox function for common utils iOS swift || Alertbox custom function in common

 Solution:

You can use the below function to show alert as a single function you can call wherever you want.

Also must to be implement the extension of the application.

    func showAlert(msg:NSString,controller:UIViewController) {

        if let topController = UIApplication.topViewController() {

            if !(topController is UIAlertController) {

                let alert = UIAlertController(title:"Apptitle" as String , message: msg as String, preferredStyle: .alert)

                alert.addAction(UIAlertAction(title: "OK", style: .default, handler:nil))

                topController.present(alert, animated: true, completion: nil)

            }

        }

    }

Use the extension of the application as like function below

extension UIApplication {

    class func topViewController(base: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {

        if let nav = base as? UINavigationController {

            return topViewController(base: nav.visibleViewController)

        }

        if let tab = base as? UITabBarController {

            if let selected = tab.selectedViewController {

                return topViewController(base: selected)

            }

        }

        if let presented = base?.presentedViewController {

            return topViewController(base: presented)

        }

        return base

    }

}