[Rubycocoa-talk] Forcing a trip through the event loop?

[Dave H. <gr...@gr...>]

I have an outline display, with a convenient "+" button nearby. When I 
click the +, I want a new item to appear "underneath" my currently 
selected row, the current row to expand to expose the new item, and to 
select the new item.

I create the new item just fine, but I can't select the new thing 
because I can't expand the old thing. I can't expand the old thing 
because Cocoa doesn't know that it's expandable yet.

*IF* it already had an item underneath it, collapsed or not, then 
everything works find. It's only when it isn't an expandable item when 
I start that I get stuck.


		currentItem = @outlineView.itemAtRow(@outlineView.selectedRow)
		currentProject = Project.index(currentItem.to_i)
		newProject = currentProject.newProject('Unnamed')

[I'm not passing Ruby objects to the outlineView, just ID numbers.) If 
I now ask

		@outlineView.isExpandable(currentItem)

it's "false," no surprise there. Specifically, it's "0". If I try to 
update the view, things actually get worse....

		@outlineView.reloadItem(currentItem)
		@outlineView.isExpandable(currentItem)

Now the answer's "-1". "reloadItem" sets "needsDisplay" on the view, 
and it appears that "-1" is code for "this view's current status is not 
known."

OK, fine.

		self.window.display

Nope, doesn't help. Nothing happens until my entire little method has 
completed. The reload and display doesn't actually happen until Cocoa 
walks back through the input event loop, which it doesn't do until my 
code is done executing. :/ How can I get my code to *wait* until the 
reload/refresh/update/display has actually occurred? Or put another 
way, how can I get Cocoa to NOT wait to update the display? I don't 
know where to look for that sort of thing.