See the Cocoa Design Patterns doc: "The Receptionist Design Pattern in Practice A KVO notification invokes the observeValueForKeyPath:ofObject:change:context: method implemented by an observer. If the change to the property occurs on a secondary thread, theobserveValueForKeyPath:ofObject:change:context: code executes on that same thread."
So you shouldn't use observeValueForKeyPath:ofObject:change:context to update the GUI in this context. I don't know of any better method than what the OP suggested. Cheers, Dave On 2012-03-23, at 6:32 PM, Jan E. Schotsman wrote: > Jonathan Taylor wrote: >> I have been struggling with a problem which I think I have eventually >> realised is down to me not handling multithreading issues properly. The >> situation is I have some computationally-demanding code that is running in a >> separate thread. This has input parameters and state variables associated >> with it. For diagnostic reasons I would like to be able to display the >> values of the state variables in the GUI. I had intended to do this just by >> binding to them. However I am getting occasional "message sent to >> deallocated instance" errors which I suspect are a symptom of the fact that >> I am Doing It Wrong. Further reading suggests that because of the way >> bindings work, modifying those state variables is leading to binding/gui >> type stuff happening away from the main thread, which appears not to be >> permitted. > I use KVO for this. Have your main thread observe the state variables > (declared as properties) and update the GUI in your > observeValueForKeyPath:ofObject:change:context: method. > I hope this is elegant enough for you ;-) > Jan E. > _______________________________________________ > > 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/dave.fernandes%40utoronto.ca > > 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]
