iOS自定义UITableViewCell看起来并不完全相同

Question

我使用UIView的扩展来定制UITableViewCell显示：

import UIKit

private var materialKey = false
private var _cornerRadius = 3.0
private var _borderWidth = 0.0

extension UIView{

@IBInspectable var borderWidth:Double{
    get{
        return _borderWidth
    }

    set{
        _borderWidth = newValue
    }
}

@IBInspectable var cornerRadius:Double{
    get{
        return _cornerRadius
    }

    set{
        _cornerRadius = newValue
    }
}

@IBInspectable var materialDesign:Bool{
    get{
        return materialKey
    }

    set{
        materialKey = newValue
        if materialKey{
            self.layer.masksToBounds = false
            self.layer.cornerRadius = CGFloat(_cornerRadius)
            self.layer.shadowOpacity = 0.8
            self.layer.shadowRadius = 5.0
            self.layer.shadowOffset = CGSize(width: 0.0, height: 2.0)
            self.layer.shadowColor = UIColor(red: 157/255, green: 157/255, blue: 157/255, alpha: 1.0).cgColor
        }else{
            layer.cornerRadius = 0
            layer.shadowOpacity = 0
            layer.shadowRadius = 0
            layer.shadowColor = nil
        }
    }
}

但是，当我运行App（无论是真正的设备还是模拟器）时，它看起来像这样：

第一个Cell和另一个看起来不一样:( 谁能告诉我为什么???谢谢！