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POWhy is a CoreData forceFetch required after a delete on the iPad but not the iPhone?
 

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  1. POWhy is a CoreData forceFetch required after a delete on the iPad but not the iPhone?
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    <p>When the following code is run on the iPhone (ios 3.1) the count of fetched objects <em>after</em> the delete is one less than before the delete. But on the iPad (ios 3.2) the count remains the same. This inconsistency was causing a crash on the iPad because elsewhere in the code, soon after the delete, fetchedObjects is called and the calling code, trusting the count, attempts access to the just-deleted object's properties, resulting in a NSObjectInaccessibleException error (see below). A fix has been to use that commented-out call to performFetch, which when executed makes the second call to fetchObjects yield the same result as on the iPhone without it. My question is: Why is the iPad producing different results than the iPhone? This is the second of these differences that I've discovered and posted recently.</p> <pre><code>-(NSError*)deleteObject:(NSManagedObject*)mo; { NSLog(@"\n\nNum objects in store before delete: %i\n\n", [[self.fetchedResultsController fetchedObjects] count]); [self.managedObjectContext deleteObject:mo]; // Save the context. NSError *error = nil; if (![self.managedObjectContext save:&amp;error]) { } // [self.fetchedResultsController performFetch:&amp;error]; // force a fetch NSLog(@"\n\nNum objects in store after delete (and save): %i\n\n", [[self.fetchedResultsController fetchedObjects] count]); return error; } </code></pre> <p>(The full NSObjectInaccessibleException is: "Terminating app due to uncaught exception 'NSObjectInaccessibleException', reason: 'CoreData could not fulfill a fault for '0x1dcf90
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    1. COUpdate: I have an interesting reply from someone on the Apple Dev forum. You experts might be interested. I'm going to try this if I can figure out exactly what he's suggesting. "Try adding an empty -controllerDidChangeContent: method to your FRC delegate. - Ben"
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    2. COWhat Ben suggested fixed the problem. I simply added an empty -controllerDidChangeContent: method to my FRC delegate. Of course now I've gotta find out why. I asked Ben for more info and if he coughs it up you'll see it here. Hopefully this question and answer is useful to others.
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    3. COJust add the following lines to your FRC delegate: - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller { }
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