How to create an alert box in iphone?

Question

I would like to make an alert type box so that when the user tries to delete something, it says, \"are you sure\" and then has a yes or no for if they are sure. What would b

Answer 1

Everyone's saying UIAlertView. But to confirm deletion, UIActionSheet is likely the better choice. See When to use a UIAlertView vs. UIActionSheet

Answer 2

The post is quite old, but still a good question. With iOS 8 the answer has changed. Today you'd rather use 'UIAlertController' with a 'preferredStyle' of 'UIAlertControllerStyle.ActionSheet'.

A code like this (swift) that is bound to a button:

@IBAction func resetClicked(sender: AnyObject) {
    let alert = UIAlertController(
        title: "Reset GameCenter Achievements",
        message: "Highscores and the Leaderboard are not affected.\nCannot be undone",
        preferredStyle: UIAlertControllerStyle.ActionSheet)
    alert.addAction(
        UIAlertAction(
            title: "Reset Achievements",
            style: UIAlertActionStyle.Destructive,
            handler: {
                (action: UIAlertAction!) -> Void in
                gameCenter.resetAchievements()
            }
        )
    )
    alert.addAction(
        UIAlertAction(
            title: "Show GameCenter",
            style: UIAlertActionStyle.Default,
            handler: {
                (action: UIAlertAction!) -> Void in
                self.gameCenterButtonClicked()
            }
        )
    )
    alert.addAction(
        UIAlertAction(
            title: "Cancel",
            style: UIAlertActionStyle.Cancel,
            handler: nil
        )
    )
    if let popoverController = alert.popoverPresentationController {
        popoverController.sourceView = sender as UIView
        popoverController.sourceRect = sender.bounds
    }
    self.presentViewController(alert, animated: true, completion: nil)
}

would produce this output:

EDIT: The code crashed on iPad, iOS 8+. If added the necessary lines as described here: on another stack overflow answer

Answer 3

UIAlertView seems the obvious choice for confirmation.

Set the delegate to the controller and implement the UIAlertViewDelegate protocol http://developer.apple.com/library/ios/#documentation/uikit/reference/UIAlertViewDelegate_Protocol/UIAlertViewDelegate/UIAlertViewDelegate.html

Answer 4

Here i provided the alert message, which i used in my first app:

@IBAction func showMessage(sender: UIButton) {
    let alertController = UIAlertController(title: "Welcome to My First App",
                              message: "Hello World",
                              preferredStyle: UIAlertControllerStyle.alert)
    alertController.addAction(UIAlertAction(title: "OK",
                                            style: UIAlertActionStyle.default,
                                            handler: nil))
    present(alertController, animated: true, completion: nil)
}

with appropriate handlers for user responses.