NSInternalInconsistencyException (invalid number of rows)

Question

Whenever I have data in my UITableView and I start deleting, it works fine. However, when I get to the last object in the table, and delete it, it crashes.

Answer 1

If you delete the last row in your table, the UITableView code expects there to be 0 rows remaining. It calls your UITableViewDataSource methods to determine how many are left. Since you have a "No data" cell, it returns 1, not 0. So when you delete the last row in your table, try calling -insertRowsAtIndexPaths:withRowAnimation: to insert your "No data" row. Also, you should not call -reloadData anywhere in this method. -endUpdates will take care of reloading the affected rows. Try this out:

-(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source
        if ([myData count] >= 1) {
            [tableView beginUpdates];
            [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
            [myData removeObjectAtIndex:[indexPath row]];

            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentsDirectory = [paths objectAtIndex:0];
            NSString *somepath = [documentsDirectory stringByAppendingPathComponent:@"something.plist"];
            [myData writeToFile:somepath atomically:YES];

            if ([myData count] == 0) {
                [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
            }
            [tableView endUpdates];
        }
    }   
}

Answer 2

The method tableView:numberOfRowsInSection must always return exact number of rows:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    // Return the number of rows in the section.
    return [myData count];
}

After having deleted last row, you may want to delete the whole section. Simply call deleteSections:withRowAnimation: within a beginUpdates and endUpdated block;

-(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source
        [tableView beginUpdates];
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
        [myData removeObjectAtIndex:[indexPath row]];
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString *somepath = [documentsDirectory stringByAppendingPathComponent:@"something.plist"];
        [myData writeToFile:somepath atomically:YES];
        if ([myData count] == 0) {
            // NEW! DELETE SECTION IF NO MORE ROWS!
            [tableView deleteSections:[NSIndexSet indexSetWithIndex:[indexPath section]] withRowAnimation:UITableViewRowAnimationFade];
        }
        [tableView endUpdates];
    }   
}

Answer 3

first remove from myData and then delete from tableview.

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

if (editingStyle == UITableViewCellEditingStyleDelete) {
        //somehting...
        [myData removeObjectAtIndex:[indexPath row]];
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
        //somehting...
    }
}   

}