MacOS Playground：如何更改背景颜色？

Question

我正在尝试更改主视图的背景颜色：

import AppKit
import PlaygroundSupport

class ViewController : NSViewController {
    override func loadView() {
        let nibFile = NSNib.Name("MyView")
        var topLevelObjects : NSArray?
        Bundle.main.loadNibNamed(
            nibFile, owner:nil, topLevelObjects: &topLevelObjects)
        let views = (topLevelObjects as! Array<Any>).filter { $0 is NSView }
        self.view = views[0] as! NSView
        self.view.layer?.backgroundColor = NSColor.white.cgColor
    }
}

PlaygroundPage.current.liveView = ViewController()

但视图不会改变颜色：

还有“Hello world”标签是从哪里来的？

非常感谢您的帮助

Answer 1

您只需将视图的 WantLayer 属性设置为 true

let view = views[0] as! NSView
view.wantsLayer = true
view.layer?.backgroundColor = NSColor.blue.cgColor