Parse email and username login - ios

Question

I'm trying to login a user by using the username or email. Right now my code works to log the user in by only Username. I'm using a "PFUser.logInWithUsername", but I'd also like to login with the users email. I'm trying to change my code to allow the user to have the choice to either email or a username. Here is my code.
#IBAction func LogInButton(_ sender: AnyObject) {
// login functions
PFUser.logInWithUsername(inBackground: UsernameOrEmail.text!, password: Password.text!) { (user:PFUser?, error:Error?) -> Void in
if error == nil {
// remember user or save in App Memeory did the user login or not
UserDefaults.standard.set(user!.username, forKey: "username")
UserDefaults.standard.synchronize()
// call login function from AppDelegate.swift class
let appDelegate : AppDelegate = UIApplication.shared.delegate as! AppDelegate
// Delay the dismissal by 5 seconds
let delay = 1.0 * Double(NSEC_PER_SEC)
var time = DispatchTime.now() + Double(Int64(delay)) / Double(NSEC_PER_SEC)
DispatchQueue.main.asyncAfter(deadline: time, execute: {
appDelegate.login()
})
} else {
}

Answer 1

You can use a regex pattern to detect if the user enters an email. If the detection returns false, then you "know" that the user entered their username.
This is what I use in my applications(works ok):
//A function that returns true or false based on the input. True if email, false if something else.
func isValidEmail(email:String) -> Bool {
let emailRegEx = "[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"
let emailTest = NSPredicate(format:"SELF MATCHES %#", emailRegEx)
return emailTest.evaluate(with: email)
}
//check if user enters email or not:
if isValidEmail(email: user!.username){
//email adress detected
}else{
//username detected
}
EDIT:
As I understand your problem the function above will solve your problem. I have provided a some code for you to test out.
I do not know what PFUser is capable of, but I assume there is a function for login with username and another for email.
//A function that returns true or false based on the input. True if email, false if something else.
func isValidEmail(email:String) -> Bool {
let emailRegEx = "[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,}"
let emailTest = NSPredicate(format:"SELF MATCHES %#", emailRegEx)
return emailTest.evaluate(with: email)
}
#IBAction func LogInButton(_ sender: AnyObject) {
//check if user enters username or email
if let usercredentials = UsernameOrEmail.text { //get the username from textfield
if isValidEmail(email: usercredentials){
//user did enter his email as login credential
PFUser.logInWithEmail(inBackground: usercredentials, password: Password.text!) { (user:PFUser?, error:Error?) -> Void in
if error == nil {
//do your login stuff here
} else {
}
}else{
//user did enter his username as login credential
PFUser.logInWithUsername(inBackground: usercredentials, password: Password.text!) { (user:PFUser?, error:Error?) -> Void in
if error == nil {
//do your login stuff here
} else {
}
}else{
//textfield not accessible
}
}