Swift 4 local variable value assignment - ios

Question

I am trying to recovery a value from firebase database and compare it with a UITextField value, in case of matching, I save it to a var that I will us. The problem is that the variable in question has a default value just when I use it.
Above I show my func code where the variable affected is "codeRecovered":
#IBAction func signUpAction(_ sender: AnyObject)
{
var codeRecovered: String = ""
if emailSignUpTextField.text == "" || self.secretCodeTextField.text == "" {
let alertController = UIAlertController(title: "Error", message: "Please enter your email, pin code and password", preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)
alertController.addAction(defaultAction)
present(alertController, animated: true, completion: nil)
} else {
self.dbHandler = self.ref?.child("Companies").observe(.value, with: { (snapshot) in
for child in snapshot.children {
let snap = child as! DataSnapshot
let value = snap.value as! [String:String]
if let auxSecretCode = value["secretCode"]
{
if auxSecretCode == self.secretCodeTextField.text{
print("Value recovered OK(works fine): \(auxSecretCode)")
codeRecovered = auxSecretCode
print("Recovered value saved OK(works fine): \(codeRecovered)")
}
}
}
})
//Here codeRecovered is already ""
print("\(codeRecovered) is the recovered value(empty) and \(self.secretCodeTextField.text ?? "def") is the textField value")
if codeRecovered != self.secretCodeTextField.text{
let alertController = UIAlertController(title: "Error", message: "Please enter a correct pin code", preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)
alertController.addAction(defaultAction)
present(alertController, animated: true, completion: nil)
}
//....

Answer 1

Async calls with sync result use....
#IBAction func signUpAction(_ sender: AnyObject)
{
var codeRecovered: String = ""
if emailSignUpTextField.text == "" || self.secretCodeTextField.text == "" {
let alertController = UIAlertController(title: "Error", message: "Please enter your email, pin code and password", preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)
alertController.addAction(defaultAction)
present(alertController, animated: true, completion: nil)
} else {
self.dbHandler = self.ref?.child("Companies").observe(.value, with: { (snapshot) in
for child in snapshot.children {
let snap = child as! DataSnapshot
let value = snap.value as! [String:String]
if let auxSecretCode = value["secretCode"]
{
if auxSecretCode == self.secretCodeTextField.text{
print("Value recovered OK(works fine): \(auxSecretCode)")
codeRecovered = auxSecretCode
print("Recovered value saved OK(works fine): \(codeRecovered)")
}
}
}
//Here codeRecovered is already ""
print("\(codeRecovered) is the recovered value(empty) and \(self.secretCodeTextField.text ?? "def") is the textField value")
if codeRecovered != self.secretCodeTextField.text{
let alertController = UIAlertController(title: "Error", message: "Please enter a correct pin code", preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)
alertController.addAction(defaultAction)
present(alertController, animated: true, completion: nil)
}
})
to use your codeRecovered in a sequence it must be within self.dbHandler = self.ref?.child("Companies").... block because it runs in async thread