Swift macOS 弹出窗口检测更改暗模式

从图像中可以看出，我有一个弹出窗口。

我必须确保当屏幕模式发生变化（深色模式或浅色模式）时，弹出窗口的颜色会发生变化。

颜色取自资源，如下所示：

NSColor(named: "backgroundTheme")?.withAlphaComponent(1)

正如您从代码中看到的，在 init 函数中启动弹出窗口时，我相应地分配了颜色。

如何拦截模式的变化？

你能帮我个忙吗？

应用程序委托：

import Cocoa
import SwiftUI

@main
class AppDelegate: NSObject, NSApplicationDelegate {
    var popover = NSPopover.init()
    var statusBar: StatusBarController?
    
    func applicationDidFinishLaunching(_ aNotification: Notification) {
        let contentView = ContentView()
        popover.contentSize = NSSize(width: 560, height: 360)
        popover.contentViewController = NSHostingController(rootView: contentView)
        statusBar = StatusBarController.init(popover)
    }

    func applicationWillTerminate(_ aNotification: Notification) {
        // Insert code here to tear down your application
    }
}

状态栏控制器：

import AppKit
import SwiftUI

extension NSPopover {
    
    private struct Keys {
        static var backgroundViewKey = "backgroundKey"
    }
    
    private var backgroundView: NSView {
        let bgView = objc_getAssociatedObject(self, &Keys.backgroundViewKey) as? NSView
        if let view = bgView {
            return view
        }
        
        let view = NSView()
        objc_setAssociatedObject(self, &Keys.backgroundViewKey, view, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        NotificationCenter.default.addObserver(self, selector: #selector(popoverWillOpen(_:)), name: NSPopover.willShowNotification, object: nil)
        return view
    }
    
    @objc private func popoverWillOpen(_ notification: Notification) {
        if backgroundView.superview == nil {
            if let contentView = contentViewController?.view, let frameView = contentView.superview {
                frameView.wantsLayer = true
                backgroundView.frame = NSInsetRect(frameView.frame, 1, 1)
                backgroundView.autoresizingMask = [.width, .height]
                frameView.addSubview(backgroundView, positioned: .below, relativeTo: contentView)
            }
        }
    }
    
    var backgroundColor: NSColor? {
        get {
            if let bgColor = backgroundView.layer?.backgroundColor {
                return NSColor(cgColor: bgColor)
            }
            return nil
        }
        set {
            backgroundView.wantsLayer = true
            backgroundView.layer?.backgroundColor = newValue?.cgColor
        }
    }
}

class StatusBarController {
    private var popover: NSPopover
    private var statusBar: NSStatusBar
    var statusItem: NSStatusItem

    
    init(_ popover: NSPopover) {
        self.popover = popover
        self.popover.backgroundColor = NSColor(named: "backgroundTheme")?.withAlphaComponent(1)
        statusBar = NSStatusBar.init()
        statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)
        
        if let statusBarButton = statusItem.button {
            statusBarButton.image = #imageLiteral(resourceName: "Fork")
            statusBarButton.image?.size = NSSize(width: 18.0, height: 18.0)
            statusBarButton.image?.isTemplate = true
            statusBarButton.action = #selector(togglePopover(sender:))
            statusBarButton.target = self
            statusBarButton.imagePosition = NSControl.ImagePosition.imageLeft
        }
    }
    
    @objc func togglePopover(sender: AnyObject) {
        if(popover.isShown) {
            hidePopover(sender)
        }else {
            showPopover(sender)
        }
    }
    
    func showPopover(_ sender: AnyObject) {
        if let statusBarButton = statusItem.button {
            popover.show(relativeTo: statusBarButton.bounds, of: statusBarButton, preferredEdge: NSRectEdge.maxY)
        }
    }
    
    func hidePopover(_ sender: AnyObject) {
        popover.performClose(sender)
    }
    
}

有一些事情需要记住：

• 方法如.withAlphaComponent(_:)改变现有的NSColor更改为新颜色不会返回动态颜色。

• CGColor不具有动态能力。当转换一个NSColor to a CGColor using .cgColor，您正在从 a 的“当前”颜色进行转换NSColor.

所以你的hacky方式并不是真正实现你想要的东西的好方法。

根据你所说的，如果我理解正确的话，你想在弹出窗口的背景上添加颜色叠加，包括箭头部分。

您实际上可以在视图控制器中完成所有这些操作：

class PopoverViewController: NSViewController {
    /// for color overlay
    lazy var backgroundView: NSBox = {
        // 1. This extend the frame to cover arrow potion.
        let box = NSBox(frame: view.bounds.insetBy(dx: -13, dy: -13))
        box.autoresizingMask = [.width, .height]
        box.boxType = .custom
        box.titlePosition = .noTitle
        box.fillColor = NSColor(named: "backgroundTheme")
        return box
    }()
    
    /// for mounting SwiftUI views
    lazy var contentView: NSView = {
        let view = NSView(frame: view.bounds)
        view.autoresizingMask = [.width, .height]
        return view
    }()
    
    override func loadView() {
        view = NSView()
        
        // 2. This avoid clipping.
        view.wantsLayer = true
        view.layer?.masksToBounds = false

        view.addSubview(backgroundView)
        view.addSubview(contentView)
    }
}

注意1 and 2，这允许backgroundView超越view的边界，覆盖箭头部分。backgroundView is a NSBox接受动态的对象NSColor对象来设置其背景的样式。

请注意，如果您想更改颜色的不透明度，而不是.withAlphaComponent(_:)，更改资源的不透明度，位于 RGB 滑块的正下方。

contentView在这里作为 SwiftUI 视图的安装点。要从以下位置装载内容NSHostingController， 你可以做：

let popoverViewController = PopoverViewController()
_ = popoverViewController.view // this trigger `loadView()`, you don't need this for auto layout

let hostingController = NSHostingController(rootView: ContentView())
hostingController.view.frame = popoverViewController.contentView.bounds
hostingController.view.autoresizingMask = [.width, .height]

popoverViewController.contentView.addSubview(hostingController.view)
popoverViewController.addChild(hostingController)

这个添加hostingController's view作为子视图popoverViewController's contentView.

就是这样。

请注意我使用autoresizingMask而不是自动布局并将安装部件从PopoverViewController简单地回答我的问题。