Programmatically creating button in swift language for ios

var button=UIButton(frame: CGRectMake(20, 20, 280, 40));

        button.backgroundColor=UIColor.blueColor();

        button.setTitle("ravi kumar", forState: .Normal);

        button.setTitleColor(UIColor.yellowColor(), forState: .Normal);

        button.alpha=0.2;

        button.layer.borderWidth=0.3;

        button.layer.cornerRadius=2;

        button.addTarget(self, action: "pressme", forControlEvents: .TouchUpInside);

        button.titleLabel.textAlignment=NSTextAlignment.Center;

        self.view.addSubview(button);