如何使用 Swift 和 Cocoa 获取当前活动的 window

我目前正在开发一个 Safari 应用扩展，它由两部分组成：

• 仅主机状态栏应用程序
• Safari 扩展

此外，主机应用程序提供了一个全局快捷方式，可在状态栏中打开一个弹出窗口。 但是，我想检查哪个应用程序的 window 当前处于活动状态，因为如果 Safari window 当前处于活动状态，我不想打开弹出窗口。 有什么方法可以使用 Swift 找出哪个应用程序的 window 当前处于活动状态？

谢谢您的帮助。

因此，根据 Alexander 和 Wileke 的评论，我想我找到了解决方案。

使用NSWorkspace.shared.frontmostApplication您可以检查 Safari 当前是否处于活动状态。 但正如 Wileke 所指出的，这并不意味着它有一个活跃的 window。 因此，我们使用CGWindowListCopyWindowInfo首先获取所有windows，并通过比较PID检查其中是否至少有一个属于Safari。

这样，我们可以肯定地说 Safari 当前必须有一个活动的 window 接收关键事件。 This must be true as there is now way that Safari is front most without any windows or that Safari as an window but is not front most at the same time.

好吧，除非我错过了什么。 但现在它有效。

这是我想出的代码：

func safariIsActive() -> Bool {
        // Get the app that currently has the focus.
        let frontApp = NSWorkspace.shared.frontmostApplication!

        // Check if the front most app is Safari
        if frontApp.bundleIdentifier == "com.apple.Safari" {
            // If it is Safari, it still does not mean, that is receiving key events
            // (i.e., has a window at the front).
            // But what we can safely say is, that if Safari is the front most app
            // and it has at least one window, it has to be the window that
            // crrently receives key events.
            let safariPID = frontApp.processIdentifier

            // With this procedure, we get all available windows.
            let options = CGWindowListOption(arrayLiteral: CGWindowListOption.excludeDesktopElements, CGWindowListOption.optionOnScreenOnly)
            let windowListInfo = CGWindowListCopyWindowInfo(options, CGWindowID(0))
            let windowInfoList = windowListInfo as NSArray? as? [[String: AnyObject]]

            // Now that we have all available windows, we are going to check if at least one of them
            // is owned by Safari.
            for info in windowInfoList! {
                let windowPID = info["kCGWindowOwnerPID"] as! UInt32
                if  windowPID == safariPID {
                    return true
                }
            }
        }
        return false
    }