Intercepting NSMenu key events

Question

I am making a search field, which opens a NSMenu similar to Finder and Mail

The only problem, which drives me crazy, is that i cannot intercept the key events, once the menu is open

• I even subclassed the NSApplication sendEvent, but was surprised to find out, that during menu, there is no call to Applications sendAction:

• I subclassed performKeyEquivalent: NSMenu but it is not called

 - (BOOL)performKeyEquivalent:(NSEvent *)theEvent

• I am listening for the delegate call on menuHasKeyEquivalent: but it doesn't get called

 - (BOOL)menuHasKeyEquivalent:(NSMenu*)menu forEvent:(NSEvent*)event target:(id*)target action:(SEL*)action

How to intercept the keyboard input during NSMenu

Answer 1

It is possible with a usage of Carbon event handlers. These functions allow interception of keyboard events while menu is open: GetEventDispatcherTarget() and InstallEventHandler(). This is a hack, but in fact, it works reliably across all MacOSX versions starting from 10.7. Here's the source code that could be used as a reference implementation: https://github.com/mikekazakov/MGKMenuWithFilter