How can I rewrite this in swift 4 or 5

Question

I get an error saying 'characters' is unavailable: Please use String directly.


extension LoginViewController : UITextFieldDelegate {

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

        if let username = self.usernameField.text,
            let password = self.passwordField.text {

            if ((username.characters.count > 0) && //This is where I get the error
                (password.characters.count > 0)) { //This is where I get the error
                self.loginButton.isEnabled = true
            }
        }

        return true
    }

}

How can I fix this?

username and password are Strings . The error message is giving you a hint here. — Warren Burton, Apr 01 '20 at 23:34
`username.count` and `password.count`? The `count` property is a direct part of String class, at least in Swift 5. See https://stackoverflow.com/questions/24037711/get-the-length-of-a-string — Sean Skelly, Apr 01 '20 at 23:50
Does this answer your question? [Get the length of a String](https://stackoverflow.com/questions/24037711/get-the-length-of-a-string) — John Montgomery, Apr 01 '20 at 23:54

score 2 · Accepted Answer · answered Apr 01 '20 at 23:49

Simply remove .characters

extension LoginViewController : UITextFieldDelegate {

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

        if let username = self.usernameField.text,
            let password = self.passwordField.text {

            if username.count > 0 &&
                password.count > 0 {
                self.loginButton.isEnabled = true
            }
        }

        return true
    }

}

score 2 · Answer 2 · answered Apr 02 '20 at 08:24

2

you don't need to state characters to count since it will already be counted when you type username.count or password.count

if ((username.count > 0) && (password.count > 0)) {

answered Apr 02 '20 at 08:24

galvatron

21
3

score 2 · Answer 3 · answered Apr 02 '20 at 08:29

In Swift never check for empty string or empty collection type with .count > 0, there is the dedicated method isEmpty.

And in Swift parentheses around if expressions are not needed and the && operator can be replaced with a comma

if !self.usernameField.text!.isEmpty, !self.passwordField.text!.isEmpty {
    self.loginButton.isEnabled = true
}

The text property of UITextField is never nil so force unwrapping is fine.

How can I rewrite this in swift 4 or 5

3 Answers3