ios6 remove last cell in section causing error - uitableview

Question

I am getting this error when deleting the last row in the section of a UITableView.
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of sections. The number of sections contained in the table view after the update (2) must be equal to the number of sections contained in the table view before the update (3), plus or minus the number of sections inserted or deleted (0 inserted, 0 deleted).'
My table has 3 sections IF an array has a count above 0 (users can add locations themselves). If the array is equal to 0 then the table contains only 2 section, which is where I think the problem lies, I just can't figure it out.
The code I have for deleting the cells and updating the arrays is:
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell* delCell = [tableView cellForRowAtIndexPath:indexPath];
delName = delCell.textLabel.text;
[self deleteLocation];
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
}
-(void)deleteLocation {
NSLog(#"Name = %#",delName);
NSUserDefaults *customLocations = [NSUserDefaults standardUserDefaults];
NSUserDefaults *sharedPref = [NSUserDefaults standardUserDefaults];
[customLocations removeObjectForKey:delName];
[customLocations synchronize];
[customLoc removeObject:delName];
saveCustomLoc = [NSArray arrayWithArray:customLoc];
[sharedPref setObject:saveCustomLoc forKey:#"CustomLocations"];
[sharedPref synchronize];
NSLog(#"%#",saveCustomLoc);
NSLog(#"%lu",(unsigned long)[saveCustomLoc count]);
[self showAlert];
}
- (void) showAlert {
UIAlertView *alert = [[UIAlertView alloc]
initWithTitle:#"Location Deleted"
message:#"The location has been deleted"
delegate:nil
cancelButtonTitle:#"Ok"
otherButtonTitles:nil];
[alert show];
}
This works great until the final cell.
An example of how my table is set up is:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;
{
if ([customLoc count] == 0) { // If there is no data in the custom locations array the don't include that section
if (section == 0) {
return [serverSelection count];
}
else {
return [qServerSelection count];
}
}
else {
if (section == 0) {
return [customLoc count];
}
else if (section == 1) {
return [serverSelection count];
}
else {
return [qServerSelection count];
}
}
So the headings/number of rows/number of sections etc. is dependent on the contents of an Array. The fact that the section the cells are being removed from disappears (or rather suddenly has 4 cells in as section 1 moves to section 0) I think is causing the issue.
Any ideas how to work around this?

Answer 1

After looking into this some more I found out (with the help of some Apple forum members) that when removing the last row from a section you also need to explicitly delete the section as well.
I also added table update code at the beginning and the end as shown below:
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView beginUpdates];
UITableViewCell* delCell = [tableView cellForRowAtIndexPath:indexPath];
delName = delCell.textLabel.text;
[self deleteLocation];
if ([customLoc count] == 0) {
[tableView deleteSections:[NSIndexSet indexSetWithIndex:indexPath.section] withRowAnimation:UITableViewRowAnimationTop];
}
else {
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
}
[tableView endUpdates];
}
So, if my array is 0 (in effect the last row is being deleted) the section itself is removed.