Is there a way to track character remove in empty uitextfield?

Question

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool

is not invoked when textfield is already empty and back button is pressed

I want to resign first responder and make previous uitextfield in the view become first responder

is there a way to achieve that?

Answer 1

In order to achieve what you want you have to subclass the UITextField and create a custom protocol which will notify you every time the delete is pressed:

protocol CustomTextFieldDelegate: AnyObject {
    func deleteBackwardPressed()
}

class CustomTextField: UITextField {

    weak var deleteDelegate: CustomTextFieldDelegate?

    override func deleteBackward() {
        super.deleteBackward()
        deleteDelegate?.deleteBackwardPressed()
    }
}

When creating your UIViewController it should conform to the CustomTextFieldDelegate. Also do not forget to assign the delegate to your custom textfield. A simplified ViewController would look something like this:

class ViewController: UIViewController, CustomTextFieldDelegate {
    private var isTextFieldEmpty = false
    private let customTextField = CustomTextField()

    override func viewDidLoad() {
         super.viewDidLoad()
         customTextField.deleteDelegate = self
    }

    func deleteBackwardPressed() {
        if isTextFieldEmpty {
            customTextField.resignFirstResponder()
        } else {
            isTextFieldEmpty = customTextField.text?.count == 0
        }
    }
}