在Swift的UITextfield中显示用户键入的密码

我有密码 UITextfield 当前作为安全入口打开的。我想向用户显示密码,他已键入通知文本再次在 UITextfield 当 UISwitch is turned on UITextfield UISwitch 当 已关闭。

@IBOutlet weak var existingPasswordTexfField: UITextField!
@IBOutlet weak var newPasswordTextField: UITextField!
@IBOutlet weak var changePasswordSwitch: UISwitch!

@IBAction func showPassword(_ sender: UISwitch) {
    if changePasswordSwitch.isOn {
        guard let oldText = existingPasswordTexfField.text else { return }

        if existingPasswordTexfField.isSecureTextEntry {
            existingPasswordTexfField.text = oldText
        } else {
            print("Pawword is already secure")
        }
    }
}