Get input value from TextField in iOS alert in Swift

I'm trying to make an alert message with input, and then get the value from the input. I've found many good tutorials how to make the input text field. but I can't get the value from the alert.

Updated for Swift 3 and above:

//1. Create the alert controller.
let alert = UIAlertController(title: "Some Title", message: "Enter a text", preferredStyle: .alert)

//2. Add the text field. You can configure it however you need.
alert.addTextField { (textField) in
    textField.text = "Some default text"
}

// 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)

Swift 2.x

Assuming you want an action alert on iOS:

//1. Create the alert controller.            
var alert = UIAlertController(title: "Some Title", message: "Enter a text", preferredStyle: .Alert)

//2. Add the text field. You can configure it however you need.
alert.addTextFieldWithConfigurationHandler({ (textField) -> Void in
    textField.text = "Some default text."
})

//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] (action) -> Void in
    let textField = alert.textFields![0] as UITextField
    println("Text field: \(textField.text)")
}))

// 4. Present the alert.
self.presentViewController(alert, animated: true, completion: nil)

Swift 5

You can use the below extension for your convenience.

Usage inside a ViewController:

showInputDialog(title: "Add number",
                subtitle: "Please enter the new number below.",
                actionTitle: "Add",
                cancelTitle: "Cancel",
                inputPlaceholder: "New number",
                inputKeyboardType: .numberPad, actionHandler:
                        { (input:String?) in
                            print("The new number is \(input ?? "")")
                        })

The extension code:

extension UIViewController {
    func showInputDialog(title:String? = nil,
                         subtitle:String? = nil,
                         actionTitle:String? = "Add",
                         cancelTitle:String? = "Cancel",
                         inputPlaceholder:String? = nil,
                         inputKeyboardType:UIKeyboardType = UIKeyboardType.default,
                         cancelHandler: ((UIAlertAction) -> Swift.Void)? = nil,
                         actionHandler: ((_ text: String?) -> Void)? = nil) {
        
        let alert = UIAlertController(title: title, message: subtitle, preferredStyle: .alert)
        alert.addTextField { (textField:UITextField) in
            textField.placeholder = inputPlaceholder
            textField.keyboardType = inputKeyboardType
        }
        alert.addAction(UIAlertAction(title: actionTitle, style: .default, handler: { (action:UIAlertAction) in
            guard let textField =  alert.textFields?.first else {
                actionHandler?(nil)
                return
            }
            actionHandler?(textField.text)
        }))
        alert.addAction(UIAlertAction(title: cancelTitle, style: .cancel, handler: cancelHandler))
        
        self.present(alert, animated: true, completion: nil)
    }
}

In Swift5 ans Xcode 10

Add two textfields with Save and Cancel actions and read TextFields text data

func alertWithTF() {
    //Step : 1
    let alert = UIAlertController(title: "Great Title", message: "Please input something", preferredStyle: UIAlertController.Style.alert )
    //Step : 2
    let save = UIAlertAction(title: "Save", style: .default) { (alertAction) in
        let textField = alert.textFields![0] as UITextField
        let textField2 = alert.textFields![1] as UITextField
        if textField.text != "" {
            //Read TextFields text data
            print(textField.text!)
            print("TF 1 : \(textField.text!)")
        } else {
            print("TF 1 is Empty...")
        }

        if textField2.text != "" {
            print(textField2.text!)
            print("TF 2 : \(textField2.text!)")
        } else {
            print("TF 2 is Empty...")
        }
    }

    //Step : 3
    //For first TF
    alert.addTextField { (textField) in
        textField.placeholder = "Enter your first name"
        textField.textColor = .red
    }
    //For second TF
    alert.addTextField { (textField) in
        textField.placeholder = "Enter your last name"
        textField.textColor = .blue
    }

    //Step : 4
    alert.addAction(save)
    //Cancel action
    let cancel = UIAlertAction(title: "Cancel", style: .default) { (alertAction) in }
    alert.addAction(cancel)
    //OR single line action
    //alert.addAction(UIAlertAction(title: "Cancel", style: .default) { (alertAction) in })

    self.present(alert, animated:true, completion: nil)

}

For more explanation https://medium.com/@chan.henryk/alert-controller-with-text-field-in-swift-3-bda7ac06026c