Checking the value in textfield before alert controller hides - iOS swift - ios

Question

What I am trying to do is that I am taking user's contact number (mobile number) if it is correct then it should continue the signup otherwise the alert controller should not hide and show some error
let alertController = UIAlertController(title: "Phone Number", message: "Please enter your number", preferredStyle: .alert)
alertController.addTextField {
(textField) -> Void in
textField.tag = 128
textField.delegate = self
textField.placeholder = "923xxxxxxxxx"
}
alertController.addAction(UIAlertAction(title: "Continue", style: .default, handler: {
alert -> Void in
let textField = alertController.textFields![0] as UITextField
if (textField.text?.count)! == 12 && ((textField.text?.substring(to: 3))!) == "923" {
//my code
}
else {
//should show/keep alert controler
}
}))
self.present(alertController, animated: true, completion: nil)

Answer 1

Try out this,
let alertController = UIAlertController(title: "Phone Number", message: "Please enter your number", preferredStyle: .alert)
alertController.addTextField {
(textField) -> Void in
textField.tag = 128
textField.delegate = self
textField.placeholder = "923xxxxxxxxx"
}
alertController.addAction(UIAlertAction(title: "Continue", style: .default, handler: {
alert -> Void in
let textField = alertController.textFields![0] as UITextField
if (textField.text?.count)! == 12 && ((textField.text?.substring(to: 3))!) == "923"
{
//my code
}
else
{
//alert with error
let alertControllerError = UIAlertController(title: "error", message: "error here", preferredStyle: .alert)
alertControllerError.addAction(UIAlertAction(title: "ok", style: .default, handler: { alert -> Void in
}))
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + .seconds(1)) {
self.present(alertControllerError, animated: true, completion: nil)
}
}
}))
self.present(alertController, animated: true, completion: nil)

Answer 2

You could disable the button (UIAlertAction) by default. Then listen to text changes in your UITextField and update the button accordingly:
var autoEnableAlertAction: UIAlertAction?
func presentAlertController() {
// alert controller
let ac = UIAlertController(title: "Registration", message: "Please enter your phone number.", preferredStyle: .Alert)
// alert action - disabled by default
let okAction = UIAlertAction(title: "OK", style: .Default, handler: nil)
okAction.enabled = false
ac.addAction(okAction)
// store a reference to the alert action to enable / disable it later
autoEnableAlertAction = okAction
ac.addTextFieldWithConfigurationHandler { tf in
// listen for changes in the textfield
tf.addTarget(self, action: #selector(self.checkTextFieldText(_:)), forControlEvents: .EditingChanged)
}
presentViewController(ac, animated: true, completion: nil)
}
#objc func checkTextFieldText(textField: UITextField) {
autoEnableAlertAction?.enabled = textField.text?.characters.count >= 5
}
Sorry for my answer being a Swift 2 version... :)

Answer 3

func presentAlertController()
{
let alertController = UIAlertController(title: "Phone Number", message: "Please enter your number", preferredStyle: .alert)
alertController.addTextField {
(textField) -> Void in
textField.tag = 128
textField.placeholder = "923xxxxxxxxx"
}
alertController.addAction(UIAlertAction(title: "Continue", style: .default, handler: {
alert -> Void in
let textField = alertController.textFields![0] as UITextField
if (textField.text?.count)! == 12 && textField.text?.prefix(3) == "923"
{
print("sucess")
}
else
{
print("Incorrect Number")
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + .seconds(2)) {
self.presentAlertController(parameters: parameters)
}
}
}))
alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler:{
alert -> Void in
}))
self.present(alertController, animated: true, completion: nil)
}