objective c - How does Apple update the Airport menu while it is open? (How to change NSMenu when it is already open)

Question

I've got a statusbar item that pops open an NSMenu, and I have a delegate set and it's hooked up correctly (-(void)menuNeedsUpdate:(NSMenu *)menu works fine). That said, that method is setup to be called before the menu is displayed, I need to listen for that and trigger an asynchronous request, later updating the menu while it is open, and I can't figure out how that's supposed to be done.

Thanks :)

EDIT

Ok, I'm now here:

When you click on the menu item (in the status bar), a selector is called that runs an NSTask. I use the notification center to listen for when that task is finished, and write:

[[NSRunLoop currentRunLoop] performSelector:@selector(updateTheMenu:) target:self argument:statusBarMenu order:0 modes:[NSArray arrayWithObject:NSEventTrackingRunLoopMode]];

and have:

- (void)updateTheMenu:(NSMenu*)menu {
    NSMenuItem *mitm = [[NSMenuItem alloc] init];
    [mitm setEnabled:NO];
    [mitm setTitle:@"Bananas"];
    [mitm setIndentationLevel:2];
    [menu insertItem:mitm atIndex:2];
    [mitm release];
}

This method is definitely called because if I click out of the menu and immediately back onto it, I get an updated menu with this information in it. The problem is that it's not updating -while the menu is open-.

Answer 1

Menu mouse tracking is done in a special run loop mode (NSEventTrackingRunLoopMode). In order to modify the menu, you need to dispatch a message so that it will be processed in the event tracking mode. The easiest way to do this is to use this method of NSRunLoop:

[[NSRunLoop currentRunLoop] performSelector:@selector(updateTheMenu:) target:self argument:yourMenu order:0 modes:[NSArray arrayWithObject:NSEventTrackingRunLoopMode]]

You can also specify the mode as NSRunLoopCommonModes and the message will be sent during any of the common run loop modes, including NSEventTrackingRunLoopMode.

Your update method would then do something like this:

- (void)updateTheMenu:(NSMenu*)menu
{
    [menu addItemWithTitle:@"Foobar" action:NULL keyEquivalent:@""];
    [menu update];
}