Table View Crash after Deleting All Rows

[architectpianist]

Hi,
I have a table view that manages a list of objects, stored in a property self.equations. I have a button that pulls up an action sheet, which then clears the self.equations array and the table view.

-(void)clearEquations:(id)sender
{
	UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:nil 
															 delegate:self 
													cancelButtonTitle:@"Cancel" 
											   destructiveButtonTitle:@"Clear" 
													otherButtonTitles:nil];
	actionSheet.actionSheetStyle = UIActionSheetStyleBlackTranslucent;
	[actionSheet showInView:self.view];
}

-(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
	[actionSheet dismissWithClickedButtonIndex:buttonIndex animated:YES];
	if (buttonIndex == 0)
	{
		[self.equations removeAllObjects];
		[self refreshEquations];
		NSMutableArray *indexPaths = [NSMutableArray array];
		for (int i = 0; i < [equationLayers count]; i++)
			[indexPaths addObject:[NSIndexPath indexPathForRow:i inSection:0]];
		[tableView deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationRight];
		if (self.delegate != nil)
			[self.delegate editedEquations:self.equations];
	}
}

The code runs fine if I use [tableView reloadData] instead of [tableView deleteRowsAtIndexPaths:withRowAnimation], but I'd like the row deletion to be animated. This code gives SIGABRT and in the console, it says:

*** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-1912.3/UITableView.m:1046

What does the warning mean, and how can I get around it?
Thanks!

[BrianSlick]

I'm going to guess there is more to the error message than that. I suspect that refreshEquations is re-populating your array, so your objects count vs. number of rows is off.

[architectpianist]

Okay, here's the refreshEquations code:

-(void)refreshEquations
{
	if ([self.equations count] == 0)
	{
		//Show a view behind the table view with a label "no equations"
	}
	else
	{
		VSMathTypesetter *typesetter = [[VSMathTypesetter alloc] init];
		VSValueCalculator *calculator = [[VSValueCalculator alloc] init];
		[equationLayers removeAllObjects];

		//Populate equationLayers with CALayers from self.equations strings
	}	
}

It doesn't seem that self.equations is being modified by refreshEquations. A log at the end of the method shows an empty array. I'll take a look at the data count vs number of rows being off.
Thanks for the reply!

[BrianSlick]

What is the rest of the crash message?

[architectpianist]

Eureka! The error is here:

-(void)refreshEquations
{
	if ([self.equations count] == 0)
	{
		//Show a view behind the table view with a label "no equations"
	}
        //...
}

The problem is, the code is going through the first conditional without updating equationLayers. The update included removing all the objects. EquationLayers regulates the tableView, so you can see how equationLayers was persisting.
Thanks for your input!