如何在Mac上检测外部显示器的连接和断开连接？ [英] How can you detect the connection and disconnection of external monitors on the Mac?

问题描述

您是否知道如何检测可可应用程序中插入/未插入的其他屏幕？

Do you have any idea how I can detect additional screens being plugged in / unplugged in a Cocoa application?

我想检测用户插入或插入的时刻拔出另一个屏幕到他的Mac。我该怎么办？

I want to detect the moment when the user plugs or unplugs another screen to his Mac. How could I do this?

推荐答案

您的答案就在Quartz中。

Your answer lies in Quartz.

#include <ApplicationServices/ApplicationServices.h>

CGError CGDisplayRegisterReconfigurationCallback (
    CGDisplayReconfigurationCallBack proc,
    void *userInfo
);

然后您的proc如下：

And then your proc looks like:

 MyCGDisplayReconfigurationCallBack(
    CGDirectDisplayID display,
    CGDisplayChangeSummaryFlags flags,
    void *userInfo) {

    if (flags & kCGDisplayAddFlag || flags & kCGDisplayRemoveFlag) {
        DoStuff(display, flags, userInfo);
    }
}

在Swift5中：

extension ScreenDetector {

static let callback: CGDisplayReconfigurationCallBack = { (displayId, flags, userInfo) in
    guard let opaque = userInfo else {
        return
    }
    let mySelf = Unmanaged<ScreenDetector>.fromOpaque(opaque).takeUnretainedValue()

    if flags.contains(.addFlag) {
        //Add Display...
    }else if flags.contains(.removeFlag) {
        //Removed Display...
    }

}

func addObervers() {
    let userData = Unmanaged<ScreenDetector>.passUnretained(self).toOpaque()
    CGDisplayRegisterReconfigurationCallback(ScreenDetector.callback, userData)
}

func removeObservers() {
    let userData = Unmanaged<ScreenDetector>.passUnretained(self).toOpaque()
    CGDisplayRemoveReconfigurationCallback(ScreenDetector.callback, userData)
}

}

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