Delete rows with CoreData and AlertView

[Argus]

I'm working on an app using CoreData that lets user add or delete items to a TableView. Before deleting an item, I'd like to give them the option to verify they really want to delete with an AlertView.

I have the AlertView setup here:

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

		NSString *message = [[NSString alloc] initWithFormat:@"Do you really want to delete ?"];
		
		UIAlertView *alert = [[UIAlertView alloc] 
							  initWithTitle: @"Alert" 
							  message: message 
							  delegate: self
							  cancelButtonTitle: @"Cancel"
							  otherButtonTitles: @"OK", nil];
		
		[alert show];
		[alert release];
[message release];

That's working fine and the buttons are set up properly.

I've put the call to delete the object here:

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

	if (buttonIndex == 1) {
	
		NSIndexPath *indexPath = [myTableView indexPathForSelectedRow];
	
		NSManagedObjectContext *context = [fetchedResultsController managedObjectContext];
		[context deleteObject:[fetchedResultsController objectAtIndexPath:indexPath]];

		
		NSError *error;
		if (![context save:&error]) {
			// Update to handle the error appropriately.
			NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
			exit(-1);  // Fail
			
		}  
	}	
	
	else {
	}
}

I thought it was working fine because it deleted the item in the first row.

The problem is is that it always deletes the top row, no matter what row I've selected. i.e., if I've added 3 items (3 rows) to the table view, when I try to delete the 3rd row and hit the delete button, the top row disappears. When I hit delete again, the 2nd row (now the top row) disappears.

If someone could point me in the right direction on using an Alert View with CoreData I'd appreciate it. I couldn't find anything to help at the Developer web site.

[Argus]

Bump. Anyone have any ideas on this one. Thanks.

[gammapoint]

Originally Posted by Argus

Bump. Anyone have any ideas on this one. Thanks.

I had the same issue. I use an instance variable to store the index path when the user decides to delete (in my case mark the row inactive). The -inactive method is called when the user selects a row & hits the delete/inactive button. When the user selects a row a check is make to make sure the selected row is not already inactive. Note: The Vacation object has a BOOL attribute called "active". For a demo visit our website at www.gamma-point.com.

Here's the code:

In the .h file for the table view controller:

NSIndexPath * inactiveIndexPath;

}
@property (nonatomic, retain) NSIndexPath * inactiveIndexPath;

In the .m file for the table view controller:

@synthesize inactiveIndexPath;

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    NSUInteger ints[2] = {[indexPath section],[indexPath row]};
    inactiveIndexPath = [[NSIndexPath alloc] initWithIndexes:ints length:2];
    NSLog(@"Selected ( %d, %d)", [inactiveIndexPath section], [inactiveIndexPath row]);
    NSManagedObject *aVacationDBobject = [self.fetchedResultsController objectAtIndexPath:inactiveIndexPath];
    if (![[aVacationDBobject valueForKey:@"active"] boolValue]) {
        [self.tableView deselectRowAtIndexPath:inactiveIndexPath animated:YES];
        [inactiveIndexPath release];
        inactiveIndexPath = nil;
    }
}

- (void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath {
    if (inactiveIndexPath != nil) {
        [inactiveIndexPath release];
        inactiveIndexPath = nil;
        }

    
}
-(void) inactive {
    
    if (inactiveIndexPath == nil) {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Select Row" 
                                                        message:@"Please select a vacation entry to mark it inactive." 
                                                       delegate:nil   cancelButtonTitle:@"OK"  otherButtonTitles:nil];
        [alert show];
        
        [alert release];
        return;
    } else {
        UIActionSheet *actionSheet = [[UIActionSheet alloc] 
                                      initWithTitle:@"Inactivate a Vacation entry" 
                                      delegate:self 
                                      cancelButtonTitle:@"No Way!"
                                      destructiveButtonTitle:@"Yes, I'm Sure!" 
                                      otherButtonTitles:nil];
        [actionSheet showInView:self.view];
        [actionSheet release]; 
    }
}


- (void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex {
    if (inactiveIndexPath == nil) {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Select Row" 
                                                        message:@"Please select a vacation entry to mark it inactive." 
                                                       delegate:nil   cancelButtonTitle:@"OK"  otherButtonTitles:nil];
        [alert show];
        
        [alert release];
        return;
    }
    
    
        
    [self.tableView deselectRowAtIndexPath:inactiveIndexPath animated:YES];
    
    
    if (buttonIndex == [actionSheet cancelButtonIndex]) return;
    
    //Find the event date
    NSManagedObject *aVacationDBobject = [self.fetchedResultsController objectAtIndexPath:inactiveIndexPath];
    NSString *dateForEvent = [aVacationDBobject valueForKey:@"date"];
    
    NSLog(@" DB Access for marking the vacation inactive for date %@", dateForEvent);
    //Find the vacation object in the DB
    ProCalendarAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    NSManagedObjectContext *context = [appDelegate managedObjectContext];
    
    NSError *error;

    NSFetchRequest *request = [[NSFetchRequest alloc] init];
    NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Vacation"     inManagedObjectContext:context];
    [request setEntity:entityDescription];
    
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"(date = %@)",dateForEvent];
    [request setPredicate:pred];
    NSManagedObject *aVacationMO = nil;
    NSArray *objects = [context executeFetchRequest:request error:&error];
    if (objects == nil){
        NSLog(@"There was an error!");
        // Do whatever error handling is appropriate
    }
    if ([objects count] > 0) {
        NSLog(@"Overriding the table entry for date %@", dateForEvent);
        aVacationMO = [objects objectAtIndex:0];
    }
    else{
        NSLog(@"Event not found");
        if (inactiveIndexPath != nil) {
            [inactiveIndexPath release];
            inactiveIndexPath = nil;
        }
        return;
    }
    
    //mark the active flag in DB to NO
    NSNumber *active = [NSNumber numberWithBool:NO];
    [aVacationMO setValue: active forKey:@"active"];
    
    //Cancel the alarm for this event
    NSData *data = [aVacationMO valueForKey:@"alarm"];
    UILocalNotification *alarm = [NSKeyedUnarchiver unarchiveObjectWithData:data];
    
    AlarmUtil *alarmUtil = [[AlarmUtil alloc] init];
    [alarmUtil cancelAlarm:alarm];
    [alarmUtil release];
    
    //mark the event for this vacation entry as inactive or delete the event row??
    
    if (context != nil) {
        if ([context hasChanges] && ![context save:&error]) {
            /*
             Replace this implementation with code to handle the error appropriately.
             
             abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
             */
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            NSLog(@"Event not marked inactive");
            return;
        }
    }
    

    
    
    
    
    //reload the cell
    [self.tableView reloadRowsAtIndexPaths:[NSArray    arrayWithObject:inactiveIndexPath] withRowAnimation:UITableViewRowAnimationFade];

        [self displayTotals];
    
    if (inactiveIndexPath != nil) {
        [inactiveIndexPath release];
        inactiveIndexPath = nil;
    }
    

    
}