swift 5.0 创建button方法

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.

        //创建视图
        let redV = UIView(frame: CGRect(x: , y: , width: , height: ))

        //设置视图的背景颜色
        redV.backgroundColor = UIColor.red;

        //添加到当前页面
        view.addSubview(redV);
        redV.center = view.center;

        let btn = UIButton(type: .contactAdd);
        redV .addSubview(btn);

        btn.addTarget(self, action: #selector(btnClicked), for: .touchUpInside);

    }

    @objc func btnClicked()->String{
        print(#function);
        return "";
    }
}

swift 创建 imageview

    let img = UIImageView(frame: CGRect(x: 100, y: 300, width: 50, height: 50))
    view .addSubview(img)
    img.image = UIImage.init(named: "22");