Error passing value to view controller on dismiss | Swift 5 - ios

Question

Error transferring value from one view controller to another on dismiss.
I have a value in ViewController2 that I would like to transfer to ViewController1 on dismiss. In view ViewController2 I do the following to dismiss:
func OtherFunction() {
passAndDismiss(scannedScript: stringCodeValue)
}
Note: stringCode value is indeed being passed as a String to scannedScript
func passAndDismiss(scannedScript: String) {
dismiss(animated: true, completion: {
let viewcontroller = ViewController1()
viewcontroller.Textfield1.text = scannedScript
})
}
The error occurs on line:
viewcontroller.Textfield1.text = scannedScript
The error I get is:
Unexpectedly found nil while implicitly unwrapping an Optional value

Answer 1

Two fatal issues:
ViewController1() is a new instance of the controller which is not the instance in the storyboard.
Solution: You need the real instance either with a segue or with instantiation from the storyboard.
Even if ViewController1() was the expected controller the outlets are not connected right after the initialization.
Solution: You have to declare a temporary property for the string in ViewController1 and assign the value to the label in viewDidLoad

Answer 2

Here you are initialising viewcontroller with wrong way. You should load from xib or storyboard.
In your way not initialise xib or storyboards’ ui element objects. Here textfield object nil and you are trying to access text property of that. That’s why app crashed. You should use following way:
let myViewController = MyViewController(nibName: "MyViewController", bundle: nil)
OR
let storyboard = UIStoryboard(name: "MyStoryboardName", bundle: nil)
let controller = storyboard.instantiateViewController(withIdentifier: "someViewController")
If you are not using xib or storyboard then please initialise textfield object in that controller’s init method