swit -> 毛玻璃效果

'

        let blurEffect = UIBlurEffect(style: .dark)
        //接着创建一个承载模糊效果的视图
        let blurView = UIVisualEffectView(effect: blurEffect)
        //设置模糊视图的大小（全屏）
        blurView.frame = CGRect(x: 0, y: 0, width: screenHeight, height: screenHeight)
        blurView.alpha = 0.95
        oprCoverBackShot.addSubview(blurView)
        oprCoverBackShot.clipsToBounds = true;

        imageview.addSubview(oprCoverBackShot)