var imageView：UIImageView！
2 override func viewDidLoad() {
3 super.viewDidLoad()
4 // Do any additional setup after loading the view,
typically from a nib.
5 let rect = CGRect(x：0, y：80, width：320, height：
6 self.imageView = UIImageView(frame：rect)
7
8 let image = UIImage(named：“lock”)
9 imageView.image = image
10
11 imageView.isUserInteractionEnabled = true
12 self.view.addSubview(self.imageView)
13
14 let guesture = UITapGestureRecognizer (target：self,action：#selector(ViewController.singleTap))
15 imageView.addGestureRecognizer(guesture)
16 }
17 func singleTap()
18 {
19 let image = UIImage(named：“unlock”)
20 imageView.image = image
21 }
