UISwitch

class ViewController: UIViewController,UITextFieldDelegate {

    var switchView:UISwitch!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        switchView = UISwitch()
        switchView.center = CGPoint(x: 100.0, y: 60.0)
        switchView.isOn = false
        switchView.addTarget(self, action: #selector(switchAction(s:)), for: .valueChanged)
        self.view.addSubview(switchView)
    }
    
    @objc func switchAction(s:UISwitch) -> Void {
        if s.isOn {
            NSLog("开")
        } else {
            NSLog("关")
        }
    }
}