Question

I want to enable an UIAlertView-Request before the user can delete an item from my tableview. But the indexPath seems to be “nil”…

That is my coding:

The header-file looks like that ..

    @interface ReturnRootViewController : UITableViewController <NSFetchedResultsControllerDelegate> {
    // ..
        NSIndexPath                 *deleteSelectedRow;     
    }

    // ..
    @property (nonatomic, retain) NSIndexPath                   *deleteSelectedRow;

    @end

.. the implemtation file looks like that ..

    - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

    if (editingStyle == UITableViewCellEditingStyleDelete) {
        NSUserDefaults *setting = [NSUserDefaults standardUserDefaults];
        [setting synchronize];

        // for the UIAlert-View handling:
        deleteSelectedRow = indexPath;

        if ([setting boolForKey:@"delete_preference"]) {

            // Sicherheitsabfrage vor dem Löschen
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Achtung", @" ")
                                                            message:NSLocalizedString(@"Sind Sie sicher, dass Sie den Eintrag löschen wollen?", @" ")
                                                           delegate:self
                                                  cancelButtonTitle:NSLocalizedString(@"Nein", @"Nein")
                                                  otherButtonTitles:NSLocalizedString(@"Ja", @"Ja"), nil];
            [alert show];
            [alert release];


        } else {
          // just the case you override the settings
            [moc deleteObject:[fetchedResultsController objectAtIndexPath:deleteSelectedRow]];

            NSError *error = nil;
            if (![moc save:&error]) {
                NSLog(@"Ungelöstes Problem %@, %@", error, [error userInfo]);
                abort();
            }
        }

    }   
}

and last but not least the method for the uialertview-handling:

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
    if (buttonIndex == 1) {

        // Delete request
        [moc deleteObject:[fetchedResultsController objectAtIndexPath:deleteSelectedRow]];
// ..

and that is the place where my app dumps! deleteSelectedRow is nil.
by the way: deleteSelectedRow is not nil in the else-Statement from the tableview:commitEditingStyle-method! I’m fully helpless.

Before iOS 5 it works like that …

Thanks for any hints.
ifeelhorst

Answer 1

As it is now, indexPath could be released by the time the alert view is clicked/returns. Change

deleteSelectedRow = indexPath;

to

self.deleteSelectedRow = indexPath; // to retain it

or (to make a copy of it)

self.deleteSelectedRow = [[indexPath copy] autorelease]; 

This does not explain why it is nil however, try putting a breakpoint on that line and on the alert view clickedButtonAtIndex callback to see what happens.