Handling certain errors in Parse - ios

Question

I'm looking to create certain events when certain error codes occur in my program. For instance, if there is an error code 200, I need to let the user know they are missing the username field. Or for an error code 125, I need to let them know they did not enter a valid email address when creating for an account. How do I target these error codes specifically? I have tried the code below with no success, what am I doing wrong and is this possible?
if error.code == 125 {
var invalidEmail:UIAlertView = UIAlertView(title: Please try again, message: "That does not look like a real email address. Please enter a real one.", delegate: self, cancelButtonTitle: "Try again")
invalidEmail.show()
}
The error that xCode is telling me is that I have an unresolved identifier 'error'. There is an instance of this in the parse starter project file 'AppDelegate.swift' that calls the following code and it seems to work perfectly fine.
func application(application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: NSError) {
if error.code == 3010 {
println("Push notifications are not supported in the iOS Simulator.")
} else {
println("application:didFailToRegisterForRemoteNotificationsWithError: %#", error)
}
}
My code
#IBAction func signupTapped(sender: AnyObject) {
let fullname = fullnameField.text
let email = emailField.text
let username = usernameField.text
let password = passwordField.text
var user = PFUser()
user.username = username
user.password = password
user.email = email
// other fields can be set just like with PFObject
user["fullname"] = fullname
if error.code == 125 {
let alert = UIAlertController(title: "Please try again", message: "That does not look like a valid email address.", preferedStyle: .Alert)
alert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: nil))
presentViewController(alert, animated: true)
}
if fullname.isEmpty || email.isEmpty || username.isEmpty || password.isEmpty {
let emptyFieldsError:UIAlertView = UIAlertView(title: "Please try again", message: "Please fill out all the fields so that we can create your account.", delegate: self, cancelButtonTitle: "Try again")
emptyFieldsError.show()
}
user.signUpInBackgroundWithBlock {
(succeeded: Bool, error: NSError?) -> Void in
if let error = error {
let errorString = error.userInfo?["error"] as? NSString
// Show the errorString somewhere and let the user try again.
} else {
// Hooray! Let them use the app now.
}
}
}

Answer 1

There is no error defined where you have your code. You can only reference error from inside a scope in which it exists.
user.signUpInBackgroundWithBlock {
(succeeded: Bool, error: NSError?) -> Void in
if let error = error {
let errorString = error.userInfo?["error"] as? NSString
// PUT YOUR ERROR HANDLING CODE HERE
} else {
}
}

Answer 2

As #Larme already pointed out, UIAlertView is deprecated, so you should use UIAlertController:
if error.code == 125 {
let alert = UIAlertController(title: "Please try again", message: "That does not look like a valid email address.", preferedStyle: .Alert)
alert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: nil))
presentViewController(alert, animated: true)
}