Swift - Execute performSegue under conditions - ios

Question

My intention is to run performSegue solely if all textfields are filled. If not, the button is not supposed to work - to be exact, performSegue shall not be executed.
My approach was to put performSegue inside of an if statement, but somehow it's being ignored and performSegue is being executed anyways, even though both fields are empty. Is there another more successful approach?
#IBAction func buttonAdd(_ sender: Any) {
if (addKmInput.text! != "" && addPriceInput.text != "") {
...
performSegue(withIdentifier: "goBackToSecond", sender: self)
}
}
#IBOutlet weak var addKmInput: UITextField!
#IBOutlet weak var addPriceInput: UITextField!
New version:
#IBAction func buttonAdd(_ sender: Any) {
performSegue(withIdentifier: "goBackToSecond", sender: self)
}
override func shouldPerformSegue(withIdentifier identifier: String, sender: Any?) -> Bool {
switch identifier {
case "goBackToSecond":
return shouldGoBackToSecond()
default:
return true
}
}
func shouldGoBackToSecond() -> Bool {
guard let kmInput = addKmInput.text, let priceInput = addPriceInput.text else { return false }
return !kmInput.isEmpty && !priceInput.isEmpty
}

Answer 1

Try following solution:
#IBAction func buttonAdd(_ sender: Any) {
if shouldGoBackToSecond() {
performSegue(withIdentifier: "goBackToSecond", sender: self)
}
}
func shouldGoBackToSecond() -> Bool {
guard let kmInput = addKmInput.text, let priceInput = addPriceInput.text else { return false }
return !kmInput.isEmpty && !priceInput.isEmpty
}

Answer 2

use str.isEmpty to check if the string int he textField is empty :
if let t1 = addKmInput?.text, let t2 = addPriceInput?.text, !t1.isEmpty, !t2.isEmpty {
...
performSegue(withIdentifier: "goBackToSecond", sender: self)
}
and you should ideally use this delegate to deny segue performance:
override func shouldPerformSegue(withIdentifier identifier: String, sender: Any?) -> Bool {
return true //return true/false conditionally. returning false will prevent segue performance.
}