NSStatusBar hidden in Mac OS X Lion

I'm currently developing a status bar application. It's quite important to know if the status bar is hidden because an application entered the full screen mode. Is there a way to know that?

Thanks in 开发者_开发百科advance.

Pretty much the only notification you're going to get is from NSWorkspaceActiveSpaceDidChangeNotification. Besides that, NSRunningApplication might be of a little help but you can't immediately distinguish if an app is in fullscreen because (on the user-end), an app's fullscreen mode is handled entirely by the Dock app.