How to use a UIActionSheet to confirm deletion of a UITableViewCell - ios

Question

I have a standard CoreData/NSFetchedResultsController/UITableView setup. There is no edit button on top, but right-swiping a row will reveal the delete button. If the delete button pressed, I want to pop up a UIActionSheet to confirm the deletion.
Before the UIActionSheet, I just implemented tableView:commitEditingStyle:forRowAtIndexPath: and in it, I called deleteObject: on the managedObjectContext for the indexPath and let the FetchedResultsController overrides handle the visual aspect of it.
Now, I have tableView:commitEditingStyoe:forRowAtIndexPath: create the UIActionSheet and show it. I implemented actionSheet:clickedButtonAtIndex: and put the deleteObject: in the case where the delete button is pressed. The problem is that I need the indexPath of the item to delete and it is no longer in scope.
Do I...
A) delete the ManagedObject in tableView:commitEditingStyle:forRowAtIndexPath: and either save or roll back in actionSheet:clickedButtonAtIndex: ?
B) store the index path as a property so I can set it in tableView:commitEditingStyle:forRowAtIndexPath: and read it in actionSheet:clickedButtonAtIndex:?
C) something else...
Option A seems like more overhead than necessary. Either way it will be deleted, just sometimes it will be rolled back.
Option B seems very hawkish. An external value like that doesn't seem to fit the object oriented model very well.
Is there a generic object in UIActionsSheet for passing in values like this? Or is there something else I'm missing?

Answer 1

I needed a similar solution. I solved this by creating an ivar NSIndexPath * currentPath; and used the following idea for tableView:commitEditingStyle:forRowAtIndexPath:
- (void) tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
UIAlertView * alert;
UITableViewCell * cell;
if (editingStyle == UITableViewCellEditingStyleDelete)
{
// save current indexPath
[currentPath release];
currentPath = [indexPath retain];
// display warning
alert = [[UIAlertView alloc] initWithTitle:#"Really?"
message:#"Are you really really sure you want to delete this item?"
delegate:self
cancelButtonTitle:#"Cancel"
otherButtonTitles:#"Delete", nil];
[alert show];
[alert release];
// clear delete confirmation from table view cell
cell = [tableView cellForRowAtIndexPath:indexPath];
[cell setEditing:NO animated:NO];
[cell setEditing:YES animated:YES];
};
return;
}
If the user taps the delete button, I then remove the row from the UITableViewCell and remove the entry from the data source. If they tap cancel, I simply ignore the action.

Answer 2

Instead of the indexPath I would store the managed object itself in a property in the -tableView:commitEditingStyle:forRowAtIndexPath: method:
self.deleteCandidate = [self.controller objectAtIndexPath:indexPath]
and then delete that object (or not) in -actionSheet:clickedButtonAtIndex:, and set self.deleteCandidate = nil in either case.
The reason is that the fetched results controller objects might change between those two methods being called.
Another option is to use "Associative References" (objc_setAssociatedObject, objc_getAssociatedObject) to store a reference from the UIActionSheet to the object in question.