macos - 如何为 NSView 显示阴影？

Question

我在这里和其他博客中浏览了很多主题，但无法解决这个问题。我在窗口的内容 View 中添加了一个 subview 。这是 Storyboard——

-

我已经将 customView 的导出拖到 View Controller ，这里是 View Controller 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 -

但是阴影没有出现，这是屏幕截图 - .

我无法解决看似微不足道的问题。我错过了什么？感谢您的帮助。

Answer 1

如果我添加以下行，它就解决了问题-

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，也许这里有人会指出。