let label = UILabel(frame:CGRect(x:0,y:0,width:150,height:200)); 
         
        label.text="i am a  am a label am a label am a labellabel"; 
        label.font = UIFont.boldSystemFont(ofSize: 20) 
        label.font = UIFont.systemFont(ofSize: 20) 
        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=0 
        self.view.addSubview(label)