McarePlus_iPhone/MCPlus/SwiftExtension/ExtensionUIViewController.swift

import Foundation
import UIKit

extension UIViewController{
    
    typealias action = (UIAlertAction)->Void
    func showAlert(_ title:String, _ message:String, _ ok:String? = nil, _ cancel:String? = nil, _ okAction:action? = nil, _ cancelAction:action? = nil, _ style:UIAlertController.Style = .alert){
        let alert = UIAlertController(title: title, message: message, preferredStyle: style)
        if let ok = ok{
            alert.addAction(UIAlertAction(title: ok, style: .default, handler: okAction))
        }
        if let cancel = cancel{
            alert.addAction(UIAlertAction(title: cancel, style: .default, handler: cancelAction))
        }
        // show action sheet
        if let popoverController = alert.popoverPresentationController {
            popoverController.sourceView = self.view
            popoverController.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0)
            popoverController.permittedArrowDirections = []
        }
        self.present(alert, animated: true, completion: nil)
    }
}