Error showing a UIAlertView in swift

Question

Im trying to show a UIAlertView in my swift App

    alert = UIAlertView(title: "",
        message: "bla",
        delegate: self,
        cancelButtonTitle: "OK")
    alert!.show()

=> BAD_ACESS error in: -[_UIAlertViewAlertControllerShim initWithTitle:message:delegate:cancelButtonTitle:otherButtonTitles:] ()

so I suspected self. I set it to nil

    alert = UIAlertView(title: "",
        message: "bla",
        delegate: nil,
        cancelButtonTitle: "OK")
    alert!.show()

=> ARM_DA_ALIGN error in: -[_UIAlertViewAlertControllerShim initWithTitle:message:delegate:cancelButtonTitle:otherButtonTitles:] ()

---

the full code

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UIAlertViewDelegate {

    @lazy var window = UIWindow(frame: UIScreen.mainScreen().bounds)
    @lazy var locationManager = CLLocationManager()
    var alert: UIAlertView? = nil

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {
        //setup dummy window
        self.window.backgroundColor = UIColor.whiteColor()
        self.window.rootViewController = UIViewController()
        self.window.makeKeyAndVisible()

        alert = UIAlertView(title: "",
            message: "bla",
            delegate: nil,
            cancelButtonTitle: "OK")
        alert!.show()

    return true
    }
}

How to do it right? :)

Answer 1

Swift 5

You should do it this way:

let alert = UIAlertController(title: "Title", message: "Message", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Button", style: .default, handler: nil))
self.present(alert, animated: true, completion: nil)