如何在InterfaceBuilder中显示自定义UIViews？

import UIKit

@IBDesignable class CustomView: UIView {

    @IBInspectable var borderColor: UIColor = UIColor.black {
        didSet {
            layer.borderColor = borderColor.cgColor
        }
    }

    @IBInspectable var borderWidth: CGFloat = 0.0 {
        didSet {
            layer.borderWidth = borderWidth
        }
    }

    @IBInspectable var cornerRadius: CGFloat = 0.0 {
        didSet {
            layer.cornerRadius = cornerRadius
        }
    }

    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        layer.borderColor = borderColor.cgColor
        layer.borderWidth = borderWidth
        layer.cornerRadius = cornerRadius
    }
}