CODEWITHSUNDEEP
iosswiftappdelegateuialertcontroller
TFLOW9Z1
TFLOW9Z1

Reputation: 63

iOS popup message in app delegate?

I tried to create a pop-up alert message in my app delegate but it's not showing up at all. The program is written is Swift 4.

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    let alert = UIAlertController(title: "title", message: "message", preferredStyle: UIAlertControllerStyle.alert)
    alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))
    self.window?.rootViewController?.present(alert, animated: true, completion: nil)
}

Upvotes: 1

Views: 1098

Answers (2)

trungduc
trungduc

Reputation: 12154

According to the documentation for didFinishLaunching:

Tells the delegate that the launch process is almost done and the app is almost ready to run.

So I don't think you can show an alert in didFinishLaunchingWithOptions.

Try to move your code to applicationDidBecomeActive.

Upvotes: 5

MrWaqasAhmed
MrWaqasAhmed

Reputation: 1489

If there’s one rule to remember in iOS native programming, it is this: UI components can only be properly manipulated on main thread. Keep this in mind and I’m sure it will spare you from headaches in the future.

 let alert = UIAlertController(title: "Title", message: "Message", preferredStyle: .alert)

    let actionYes = UIAlertAction(title: "Yes", style: .default, handler: { action in
        print("Handler YES")
    })

    let actionCancel = UIAlertAction(title: "Cancel", style: .destructive, handler: { action in
        print("Handler CANCEL")
    })

    alert.addAction(actionYes)
    alert.addAction(actionCancel)

    DispatchQueue.main.async {
        self.window?.rootViewController?.present(alert, animated: true, completion: nil)
    }

Upvotes: -1

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