Ensure phone number UITextField has a "+" prefix - swift

Question

I have several UITextField where a user can insert phone numbers into it. When I click the send button, it sends an automated message to the numbers listed. Everything works well but what I want to do is that when I click on the Send Button, I want it to check if the UITextFields that has text in it has a + symbol in front of the phone number listed before connecting with my server to send the automated message. How do I go about sending an alert to the user if the phone number listed does not have a + symbol?
ViewController:
class ViewController: UIViewController {
#IBOutlet weak var scrollviewcontact: UIScrollView!
#IBOutlet weak var viewcontact: UIView!
#IBOutlet weak var phonenumber: UITextField!
#IBOutlet weak var phonenumber1: UITextField!
#IBOutlet weak var phonenumber2: UITextField!
#IBOutlet weak var phonenumber3: UITextField!
var currentTextField: UITextField?
private let contactPicker = CNContactPickerViewController()
override func viewDidLoad() {
super.viewDidLoad()
phonenumber.textContentType = .telephoneNumber
phonenumber1.textContentType = .telephoneNumber
phonenumber2.textContentType = .telephoneNumber
phonenumber3.textContentType = .telephoneNumber
}
#IBAction func sendbutton(_ sender: Any) {
var numArray: Array<Any>
numArray = [phonenumber.text!, phonenumber1.text!, phonenumber2.text!, phonenumber3.text!]
let Url = String(format: "//URL")
guard let serviceUrl = URL(string: Url) else { return }
var request = URLRequest(url: serviceUrl)
request.httpMethod = "POST"
request.setValue("Application/json", forHTTPHeaderField: "Content-Type")
guard let httpBody = try? JSONSerialization.data(withJSONObject: numArray, options:[]) else {
return
}
request.httpBody = httpBody
let session = URLSession.shared
session.dataTask(with: request) { (data, response, error) in
if let response = response {
print(response)
}
if let data = data {
do {
let json = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.allowFragments)
print("json ", json)
} catch {
print(error)
}
}
}.resume()
}
extension ViewController: CNContactPickerDelegate {
func contactPicker(_ picker: CNContactPickerViewController, didSelect contact: CNContact) {
let phoneNumberCount = contact.phoneNumbers.count
guard phoneNumberCount > 0 else {
dismiss(animated: true)
return
}
if phoneNumberCount == 1 {
setNumberFromContact(contactNumber: contact.phoneNumbers[0].value.stringValue)
}else{
let alertController = UIAlertController(title: "Select one of the numbers", message: nil, preferredStyle: .alert)
for i in 0...phoneNumberCount-1 {
let phoneAction = UIAlertAction(title: contact.phoneNumbers[i].value.stringValue, style: .default, handler: {
alert -> Void in
self.setNumberFromContact(contactNumber: contact.phoneNumbers[i].value.stringValue)
})
alertController.addAction(phoneAction)
}
let cancelAction = UIAlertAction(title: "Cancel", style: .destructive, handler: {
alert -> Void in
})
alertController.addAction(cancelAction)
dismiss(animated: true)
self.present(alertController, animated: true, completion: nil)
}
}
func setNumberFromContact(contactNumber: String) {
var contactNumber = contactNumber.replacingOccurrences(of: "-", with: "")
contactNumber = contactNumber.replacingOccurrences(of: "(", with: "")
contactNumber = contactNumber.replacingOccurrences(of: ")", with: "")
contactNumber = contactNumber.replacingOccurrences(of: " ", with: "")
currentTextField?.text = String(contactNumber)
}
func contactPickerDidCancel(_ picker: CNContactPickerViewController) {
}
}
The goal that I'm trying to achieve is that when the Send Button is clicked, it checks which UITextField has text in it, and if it doesn't have a + as a prefix, an alert message should pop up.

Answer 1

You can try
let numArray = [phonenumber.text!, phonenumber1.text!, phonenumber2.text!, phonenumber3.text!]
guard numArray.filter { $0.hasPrefix("+") }.count == numArray.count else {
// alert with message make sure all textfields has + prefix
return
}

Answer 2

You can use the hasPrefix method. For example:
for num in numArray {
if num.hasPrefix("+") {
// do something
} else {
// do something else
}
}