问题
I have created a volume controller for iTunes but I would like this app to place an icon on the OS X system menu bar and have my slider controller drop down.
回答1:
You need to create an NSStatusItem in your app. Have a look at the Status Bars documentation.
You would normally create a faceless background app by setting the LSUIElement key in your Info.plist file to YES and have the app create the status item on launch.
来源：https://stackoverflow.com/questions/2687938/how-to-add-my-program-to-the-os-x-system-menu-bar