iOS: NSFetchedResultsController - Core Data - page 29

[[self tableView] deleteRowsAtIndexPaths:oldArray
withRowAnimation:UITableViewRowAnimationFade];
[[self tableView] insertRowsAtIndexPaths:newArray
withRowAnimation:UITableViewRowAnimationFade];
break ;
}
}
An NSFetchedResultsChangeInsert is fired when a new object is inserted that we
need to display in our UITableView . When we receive this call, we pass it along
to the UITableView and tell the table view what type of animation to use.
An NSFetchedResultsChangeDelete is fired when an existing object is removed. Just
as we do with an insert, we pass this information along to the UITableView and
tell it what type of animation to use when removing the row.
An NSFetchedResultsChangeUpdate is fired when an existing object has changed
internally, in other words, when one of its attributes has been updated. We
do not know from this call if it is an attribute that we care about. Instead of
spending time determining whether we should update the row, it is generally
cheaper to just update the row.
An NSFetchedResultsChangeMove is fired when a row is moved. The move could be
as a result of a number of factors but is generally caused by a data change
resulting in the row being displayed in a different location. In our example,
if the name or type of a recipe were altered, it would most likely cause this
change type. It is quite possible—and common—to receive an NSFetchedResults -
ChangeMove and an NSFetchedResultsChangeUpdate in the same batch of changes.
When this change type is received, we make two calls to the UITableView : one
to remove the row from its previous location and another to insert it into its
new location.
-controller: sectionIndexTitleForSectionName:
We use this method when we want to massage the data coming back from
our NSFetchedResultsController before it is passed to the UITableView for display. One
situation where this might be necessary is if we want to remove any extended
characters from the title before it is displayed; another example is if we want
to add something to the displayed title that is not in the data.
RecipesV1/PPRecipes/PPRMasterViewController.m
- (NSString*)controller:(NSFetchedResultsController*)controller
sectionIndexTitleForSectionName:(NSString*)sectionName
{
return [NSString stringWithFormat:@ "[%@]" , sectionName];
}