On Thu, Feb 9, 2012 at 8:01 AM, Gilles Celli <[email protected]> wrote: > Hi, > > I searched the mailing-list but didn't find an answer….so sorry if this was > posted before: > > I've setup a document based application which can read large ASCII data files > (>150MB). > > When opening the document the method readFromURL:ofType:error is used which > then opens a small feedback window > showing the file name and an animated progress bar with a "Cancel" NSButton.
If you're targeting Snow Leopard or later, you should override +canConcurrentlyReadDocumentsOfType: to return YES. That will cause -initWithContentsOfURL:ofType:error: (and therefore -readFromURL:ofType:error:) to execute on a background thread. Then you get to the canceling part. The traditional approach would be to set a flag when the user clicks Cancel, and periodically check this flag from within your -readFromURL:… implementation, returning an NSUserCancelledError if you detect it has been set. A more modern approach might be to use NSOperationQueue. Instead of a loop, -readFromURL:… would divide its work into operations and enqueue those on a queue. Clicking the Cancel button would enqueue an operation that would shut down the -readFromURL:'s operation queue and cause it to return an NSUserCancelledError. --Kyle Sluder _______________________________________________ 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]
