Swift 4 Alert Controller Examples

UIAlertController.swift

//Updated for Swift 4

//One Button
class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "My Title", message: "This is my message.", preferredStyle: UIAlertControllerStyle.alert)

        // add an action (button)
        alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}

//Two Buttons
class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "UIAlertController", message: "Would you like to continue learning how to use iOS alerts?", preferredStyle: UIAlertControllerStyle.alert)

        // add the actions (buttons)
        alert.addAction(UIAlertAction(title: "Continue", style: UIAlertActionStyle.default, handler: nil))
        alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}

//Three Buttons
class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "Notice", message: "Lauching this missile will destroy the entire universe. Is this what you intended to do?", preferredStyle: UIAlertControllerStyle.alert)

        // add the actions (buttons)
        alert.addAction(UIAlertAction(title: "Remind Me Tomorrow", style: UIAlertActionStyle.default, handler: nil))
        alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel, handler: nil))
        alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertActionStyle.destructive, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}
//Handling Button Taps

//The handler was nil in the above examples. You can replace nil with a closure to do something when the user taps a button. For example:

alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertActionStyle.destructive, handler: { action in

    // do something like...
    self.launchMissile()

}))

//Notes
    //Multiple buttons do not necessarily need to use different UIAlertActionStyle types. They could all be .default.
    //For more than three buttons consider using an Action Sheet. 

//Alert with Text Box
class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

     print("Add Note!")
        //1. Create the alert controller.
        let alert = UIAlertController(title: "Title", message: "Enter some text", preferredStyle: .alert)
        
        //2. Add the text field. You can configure it however you need.
        alert.addTextField { (textField) in
            textField.text = "Some default text..."
            textField.placeholder = "Enter Text Here"
        }
        
        // 3. Grab the value from the text field, and print it when the user clicks OK.
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { [weak alert] (_) in
            let textField = alert?.textFields![0] // Force unwrapping because we know it exists.
            print("Text field: \(textField?.text ?? "")")
        }))
        
        // 4. Present the alert.
        self.present(alert, animated: true, completion: nil)
}
    
    //4 Buttons
 class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {
        
        let alert = UIAlertController(title: "",
        message: "",
        preferredStyle: .alert)
    
        // Change font of the title and message
       let titleFont:[String : AnyObject] = [ NSFontAttributeName : UIFont(name: "AmericanTypewriter", size: 18)! ]
       let messageFont:[String : AnyObject] = [ NSFontAttributeName : UIFont(name: "HelveticaNeue-Thin", size: 14)! ]
       let attributedTitle = NSMutableAttributedString(string: "Multiple buttons", attributes: titleFont)
       let attributedMessage = NSMutableAttributedString(string: "Select an Action", attributes: messageFont)
       alert.setValue(attributedTitle, forKey: "attributedTitle")
       alert.setValue(attributedMessage, forKey: "attributedMessage")
        
        
        let action1 = UIAlertAction(title: "Action 1", style: .default, handler: { (action) -> Void in
            print("ACTION 1 selected!")
        })

        let action2 = UIAlertAction(title: "Action 2", style: .default, handler: { (action) -> Void in
            print("ACTION 2 selected!")
        })

        let action3 = UIAlertAction(title: "Action 3", style: .default, handler: { (action) -> Void in
            print("ACTION 3 selected!")
        })

        // Cancel button
        let cancel = UIAlertAction(title: "Cancel", style: .destructive, handler: { (action) -> Void in })
        
        // Restyle the view of the Alert
        alert.view.tintColor = UIColor.brown  // change text color of the buttons
        alert.view.backgroundColor = UIColor.cyan  // change background color
        alert.view.layer.cornerRadius = 25   // change corner radius
        
        // Add action buttons and present the Alert
        alert.addAction(action1)
        alert.addAction(action2)
        alert.addAction(action3)
        alert.addAction(cancel)
        present(alert, animated: true, completion: nil)
        
    }
 }
     //Delete with "Yes and No" + Plus Go Back
 class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {
    
         //Delete
        let alert = UIAlertController(title: "Delete Contact", message: "Are you sure you want to delete this contact?", preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "Yes", style: .destructive, handler: { [] (_) in
           print("Deleting...")
            _ = self.navigationController?.popViewController(animated: true)
        }))
        alert.addAction(UIAlertAction(title: "No", style: .cancel, handler: nil))
        self.present(alert, animated: true, completion: nil)
    }
 }