Remove Row from UITableView - objective-c

Question

Please read before marking as duplicate....
I am currently trying to remove rows from a UITableView but without any result.
I have a delete button on the cell of the UITableView. Once selected i hope to remove that row.
When the delete button is selected it calls the following method
- (void)didClickOnCellAtIndex:(NSInteger)cellIndex withData:(id)data
{
[self.mainTableView beginUpdates];
NSIndexPath *path = [NSIndexPath indexPathForItem:cellIndex inSection:0];
//
[self.mainTableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:path] withRowAnimation:UITableViewRowAnimationFade];
[filteredSubArrayForExpandableSection removeObjectAtIndex:cellIndex];
[appDelegate.managedObjectContext deleteObject:[self.fetchedResultsController objectAtIndexPath:path]];
[appDelegate.managedObjectContext save:nil];
[self.mainTableView endUpdates];
//
// Save the context.
NSError *error;
if (![appDelegate.managedObjectContext 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]);
// abort();
}
}
The above code will return the following issue
Reason: Invalid update: invalid number of rows in section 0. The
number of rows contained in an existing section after the update (8)
must be equal to the number of rows contained in that section before
the update (8), plus or minus the number of rows inserted or deleted
from that section (0 inserted, 1 deleted) and plus or minus the number
of rows moved into or out of that section (0 moved in, 0 moved out)
When i reload the app the row still remains.
Ok so the number of rows in this case should be 7!
So logically I added the following code in between the beginUpdates and endUpdates method.
numberOfRows = numberOfRows - 1;
This however returns the following error
-[ViewController deleteRow:]: unrecognized selector sent to instance 0x7a278a00 (lldb)
I can load up the app and the row has been deleted as it should but obviously the app crashed out prior to this.
if i remove the deleteRowsAtIndexPaths method from the didClick method and use the following NSFetchedController Delegate method i get the exact same above issues
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {
switch (type) {
case NSFetchedResultsChangeInsert: {
[self.mainTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
}
case NSFetchedResultsChangeDelete: {
[self.mainTableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
}
case NSFetchedResultsChangeUpdate: {
//[self configureCell:(TSPToDoCell *)[self.tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
NSLog(#"results changed update called");
break;
}
case NSFetchedResultsChangeMove: {
[self.mainTableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[self.mainTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
}
Update
number of rows method
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (canExpand) {
//if can expand section becomes top row for expansion effect thus we need to add 1 to show ALL rows
return numberOfRows + 1;
}
else
{
//if cannot expand section we remove 1 from total
return numberOfRows -1 ;
}
return 0 ;
}
any help regarding this will be greatly received
Thanks