On Dec 6, 2010, at 17:16, [email protected] wrote: > On Dec 6, 2010, at 5:37 PM, Gustavo Pizano wrote: > >> Hello. >> >> My application is saving some data, and it takes a while to do it, it can be >> 1 second to 10 sec around.. Im doing some image processing, The thing is.. >> >> I send the saving operation in another thread using the NSThread + >> detachNewThreadSelector:toTarget:withObject: method, and in the main thread >> I update a UIActivityIndicator, and stop it when I receive the >> NSThreadWillExitNotification. The problem is that when it takes long to >> save, it may seem the app is somehow stuck, even the spinning indicator is >> running. I wanted to change the ActivityIndicator to a progressview, but >> then I can't make it work because the saving process not on the main thread, >> i think.. correct me if Im wrong, Im not so much familiar with multithreaded >> apps. >> >> As for the saving process, what I do is the following. >> >> I have a Parent view which contains subviews, these subviews are drawing >> images. The user can modify this images, (scale and rotate), so when I save >> i encode these views so it will save the view's transform, and then I >> archive the data I encoded for all these subviews. > > > <your code deleted> > > You are correct that you cannot call GUI methods from other threads, but > NSObject (which all your UI objects inherit from) has the method. > > - (void)performSelectorInBackground:(SEL)aSelector withObject:(id)arg > > So from your other thread, you can update the progress indicator by using it > to call a method that updates the progress. > > > This is even easier if you are targeting iOS 4.0 and higher using Blocks and > GrandCentral Dispatch. > > Code typed in email (i.e., not tested): > > dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, > 0), ^{ > // code you want implemented on another thread goes here: > > dispatch_async(dispatch_get_main_queue(), ^{ > // code executed on main thread goes here (i.e., updating the > progress indicator in your case > > }); > }); > > HTH, > Dave
Maybe I'm missing something but aren't the UI actions supposed to happen in the main thread, in this case, he should really call "performSelectorOnMainThread:withObject:waitUntilDone:"? -Laurent. -- Laurent Daudelin AIM/iChat/Skype:LaurentDaudelin http://www.nemesys-soft.com/ Logiciels Nemesys Software [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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
