Password Text Field on iOS 12 with an icon on the right to reveal the password

UIShowHideTextField_iOS12.swift

class UIShowHideTextField: UnderlinedTextField {
    
    let rightButton  = UIButton(type: .custom)
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
    }
    
    required override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
       
    func commonInit() {
        rightButton.frame = CGRect(x:0, y:0, width:32, height:32)
        rightButton.setImage(UIImage(named: "eye_inactive") , for: .normal)
        rightButton.imageView?.contentMode = .scaleAspectFit
        rightButton.imageEdgeInsets = UIEdgeInsets(top: 3.0, left: 3.0, bottom: 3.0, right: 3.0)
        
        rightButton.addTarget(self, action: #selector(toggleShowHide), for: .touchUpInside)
        
        rightButton.translatesAutoresizingMaskIntoConstraints = false
        
        rightViewMode = .always
        rightView = rightButton
        isSecureTextEntry = true
        
        self.addTarget(self, action: #selector(textDidChange), for: .editingChanged)
    }
    
    @objc func toggleShowHide(button: UIButton) {
        toggle()
    }
    
    func toggle() {
        if (text == "")  {
            return
        }
        isSecureTextEntry = !isSecureTextEntry
        if isSecureTextEntry {
            rightButton.setImage(UIImage(named: "eye_not_visible") , for: .normal)
        } else {
            rightButton.setImage(UIImage(named: "eye_visible") , for: .normal)
        }
    }
    
    @objc func textDidChange() -> Void {
        if (text == "")  {
            rightButton.setImage(UIImage(named: "eye_inactive") , for: .normal)
        } else if isSecureTextEntry {
            rightButton.setImage(UIImage(named: "eye_not_visible") , for: .normal)
        } else {
            rightButton.setImage(UIImage(named: "eye_visible") , for: .normal)
        }
    }
}