swift - UIView 阴影不可见

Question

我有一个名为 containerView 的 UIView。

在创建 UIView 并将其添加到主视图后，我试图添加一点阴影。我的代码:

    let containerView = UIView()

    let bg_clear = UIColor(hexString: "#34495E")
    containerView.backgroundColor = bg_clear


    containerView.layer.cornerRadius =  15
    containerView.clipsToBounds = false

    containerView.dropShadow() // Generate Shadow

    view.addSubview(containerView)

    containerView.translatesAutoresizingMaskIntoConstraints = false
    containerView.heightAnchor.constraint(equalToConstant: 50).isActive = true
    containerView.widthAnchor.constraint(equalToConstant: 300).isActive = true
    containerView.centerXAnchor.constraint(equalTo: tabBar.centerXAnchor).isActive = true

生成阴影的代码:

extension UIView {

    func dropShadow(scale: Bool = true) {
        layer.masksToBounds = false
        layer.shadowColor = UIColor(hexString: "#000000").cgColor
        layer.shadowOpacity = 0.5
        layer.shadowOffset = CGSize(width: -1, height: 1)
        layer.shadowRadius = 1

        layer.shadowPath = UIBezierPath(rect: bounds).cgPath
        layer.shouldRasterize = true
        layer.rasterizationScale = scale ? UIScreen.main.scale : 1
   }
}

Answer 1

这应该有所帮助:

extension UIView {

    func addShadow(withOpacity opacity:Float, radius:CGFloat, andColor color:UIColor) {
         self.layer.shadowColor         = color.cgColor
         self.layer.shadowOffset        = CGSize(width:-1.0, height:1.0)
         self.layer.shadowOpacity       = opacity
         self.layer.shadowRadius        = radius
    }
}

示例:

containerView.addShadow(withOpacity: 0.4, radius: 0.4, andColor: .black)