let label = UILabel(frame:CGRect(x:,y:,width:,height:));

        label.text="i am a  am a label am a label am a labellabel";

        label.font = UIFont.boldSystemFont(ofSize: )

        label.font = UIFont.systemFont(ofSize: )

        label.textColor=UIColor.cyan

        label.backgroundColor=UIColor.blue

        label.textAlignment=NSTextAlignment.center

        label.shadowColor=UIColor.orange

        //设置label行数 ,0表示无限行，（不超过label的宽高）

        label.numberOfLines=

        self.view.addSubview(label)