macos – 如何显示NSView的阴影？

我在这里和其他博客中经历了很多线程,但无法解决这个问题.我在窗口的内容视图中添加了一个子视图.这是故事板 –

–

我拖出了customView的插座来查看控制器,这里是视图控制器的代码 –

import Cocoa
import QuartzCore

class ViewController: NSViewController {

    @IBOutlet weak var customView: NSView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        self.view.wantsLayer = true
        self.customView.wantsLayer = true
        self.customView.layer?.backgroundColor = NSColor.redColor().CGColor
        self.customView.layer?.cornerRadius = 5.0
        self.customView.layer?.shadowOpacity = 1.0
        self.customView.layer?.shadowColor = NSColor.blackColor().CGColor
        self.customView.layer?.shadowOffset = NSMakeSize(0,-3)
        self.customView.layer?.shadowRadius = 20
    }

    override var representedobject: AnyObject? {
        didSet {
        // Update the view,if already loaded.
        }
    }
}

我在我的项目中添加了QuartzCore框架工作 –

但阴影没有出现,这里是屏幕截图 –
.

我无法解决看起来微不足道的事情.我错过了什么？谢谢你的帮助.

如果我添加以下行,它解决了问题 –

self.customView.shadow = NSShadow()

最终代码是 –

import Cocoa
import QuartzCore

class ViewController: NSViewController {

    @IBOutlet weak var customView: NSView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        self.view.wantsLayer = true
        self.view.superview?.wantsLayer = true
        self.customView.wantsLayer = true
        self.customView.shadow = NSShadow()
        self.customView.layer?.backgroundColor = NSColor.redColor().CGColor
        self.customView.layer?.cornerRadius = 5.0
        self.customView.layer?.shadowOpacity = 1.0
        self.customView.layer?.shadowColor = NSColor.greenColor().CGColor
        self.customView.layer?.shadowOffset = NSMakeSize(0,0)
        self.customView.layer?.shadowRadius = 20
    }

    override var representedobject: AnyObject? {
        didSet {
        // Update the view,if already loaded.
        }
    }


}

我无法确定问题可能是这里有人会指出它.