在storyboard中添加扩展属性设置

extension UIView {  //需要添加扩展的空间
    @IBInspectable var cornerRadius:CGFloat {
         get{
              return layer.cornerRadius      
              }
         set{
                layer.cornerRadius = newValue
                layer.masksToBounds​ = (newValue>0)
              }​
         }
}