Macos OS X在应用程序打开、退出和更改焦点时发出通知

当其他应用程序打开或退出时，或者当不同的窗口（侦听应用程序或其他应用程序）被置于最前沿时，有没有办法通知cocoa应用程序？

您可以向共享工作区通知中心添加观察员：

[[[NSWorkspace sharedWorkspace] notificationCenter] addObserverForName:NSWorkspaceDidActivateApplicationNotification object:nil queue:[NSOperationQueue currentQueue] usingBlock:^(NSNotification *note) {
    NSRunningApplication *frontmostApplication = [[note userInfo] objectForKey:NSWorkspaceApplicationKey];
}];

// from NSWorkspace.h
APPKIT_EXTERN NSString * NSWorkspaceWillLaunchApplicationNotification;  //  see above
APPKIT_EXTERN NSString * NSWorkspaceDidLaunchApplicationNotification;   //  see above
APPKIT_EXTERN NSString * NSWorkspaceDidTerminateApplicationNotification;    //  see above
APPKIT_EXTERN NSString * const NSWorkspaceDidHideApplicationNotification NS_AVAILABLE_MAC(10_6);
APPKIT_EXTERN NSString * const NSWorkspaceDidUnhideApplicationNotification NS_AVAILABLE_MAC(10_6);
APPKIT_EXTERN NSString * const NSWorkspaceDidActivateApplicationNotification NS_AVAILABLE_MAC(10_6);
APPKIT_EXTERN NSString * const NSWorkspaceDidDeactivateApplicationNotification NS_AVAILABLE_MAC(10_6);

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哦，记住在解除分配时删除观察者！