Thank you to everyone whose helped me with this problem. I now have the solution I needed, and (as usual) I've learned a whole lot that will be useful in the future.
As always, this is an incredibly useful resource! On 15 Mar 2013, at 02:16, Seth Willits <[email protected]> wrote: > On Mar 14, 2013, at 11:22 AM, Pax wrote: > >> I don't really know how to describe what I'm trying to do except as a >> 'Pseudo' Singleton. I have a class with an NSWindow, which displays >> information. It is run by selecting an NSMenuItem called 'More >> Information…' >> >> My issue is that I only want one instance of the Information class to be >> loaded at a given time (and therefore only one information window on screen >> at a given time). If the information window is already loaded and it is >> then reselected from the menu then the existing window needs to be brought >> to the front - nothing more. >> >> I have currently resolved it by making my class a singleton… > > I don't see anything to "resolve" so for the sake of clarification… > > There's no reason to make your class a singleton just because you only want > one instance of it. Just don't create a second instance if you already have > one. Your "More Information" menu item is hooked up to some controller > already — presumably the application delegate. All that controller has to do > is maintain and reuse a reference to your InformationWindow. > > > >> … but that's not the right answer because it means that I can't release >> information window… > > > Right. This is the reason you don't want a singleton or "pseudo" singleton. > There's no fancy pattern needed: > > > - (IBAction)showInformation:(id)sender > { > if (!_infoWindowController) { > _infoWindowController = [[InformationWindowController alloc] > init]; > [[NSNotificationCenter defaultCenter] addObserver:self > selector:@selector(infoWindowWillClose:) name:NSWindowWillCloseNotification > object:_infoWindowController.window]; > } > > [_infoWindowController showWindow:nil]; > } > > > - (void)infoWindowWillClose:(NSNotification *)notification; > { > [[NSNotificationCenter defaultCenter] removeObserver:self > name:NSWindowWillCloseNotification object:_infoWindowController.window]; > [_infoWindowController autorelease]; > _infoWindowController = nil; > } > > > -- > Seth Willits > > > > _______________________________________________ > > Cocoa-dev mailing list ([email protected]) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/cocoa-dev/45rpmlists%40googlemail.com > > This email sent to [email protected] _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
