crash on deleteRowsAtIndexPaths - iphone

Question

My application crashes when I'm deleting row from table. Here is my sources where the bug is detected and stack trace. Thanx!
//delete row from database
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"\ncommitEditingStyle");
//delete user from Users table with specified ID
if(editingStyle == UITableViewCellEditingStyleDelete)
{
//Get the object to delete from the array.
[dbManager open: #DB_FILE_NAME];
//get userID from array usersIDList[row] = userID!
NSNumber *usersID = [usersIDList objectAtIndex: [indexPath row]];
[dbManager deleteUserWithID: [usersID intValue] table: #TABLE_USERS fieldName: #"UserID" ];
[dbManager close];
//Delete the object from the table.
[self.tableView deleteRowsAtIndexPaths:
[NSArray arrayWithObject: indexPath]
withRowAnimation: UITableViewRowAnimationFade];
}
}
- (void)deleteRowsAtIndexPaths:(NSArray *)indexPaths withRowAnimation:(UITableViewRowAnimation)animation
{
NSLog(#"\ndeleteRowsAtIndexPaths");
}
[Session started at 2010-11-15 18:01:23 +0200.]
2010-11-15 18:01:25.052 PhoneBook[12397:207] ******* Accessibility Status Changed: On
2010-11-15 18:01:25.101 PhoneBook[12397:207] ********** Loading AX for: com.yourcompany.PhoneBook ************
2010-11-15 18:01:30.060 PhoneBook[12397:207]
deleteBtnUserClick
2010-11-15 18:01:31.878 PhoneBook[12397:207]
commitEditingStyle
2010-11-15 18:01:31.881 PhoneBook[12397:207] *** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-1262.60.3/UITableView.m:920
2010-11-15 18:01:31.883 PhoneBook[12397:207] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (6) must be equal to the number of rows contained in that section before the update (6), plus or minus the number of rows inserted or deleted from that section (0 inserted, 1 deleted).'
*** Call stack at first throw:
(
0 CoreFoundation 0x02510b99 __exceptionPreprocess + 185
1 libobjc.A.dylib 0x0266040e objc_exception_throw + 47
2 CoreFoundation 0x024c9238 +[NSException raise:format:arguments:] + 136
3 Foundation 0x000b8e37 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 116
4 UIKit 0x00338d37 -[UITableView(_UITableViewPrivate) _endCellAnimationsWithContext:] + 8719
5 UIKit 0x00328511 -[UITableView deleteRowsAtIndexPaths:withRowAnimation:] + 56
6 UIKit 0x0aaca8fc -[UITableViewAccessibility(Accessibility) deleteRowsAtIndexPaths:withRowAnimation:] + 74
7 PhoneBook 0x00003491 -[RootViewController tableView:commitEditingStyle:forRowAtIndexPath:] + 392
8 UIKit 0x0032596d -[UITableView(UITableViewInternal) animateDeletionOfRowWithCell:] + 101
9 UIKit 0x0aacde92 -[UITableViewCellAccessibility(SafeCategory) deleteConfirmationControlWasClicked:] + 62
10 UIKit 0x002be7f8 -[UIApplication sendAction:to:from:forEvent:] + 119
11 UIKit 0x00349de0 -[UIControl sendAction:to:forEvent:] + 67
12 UIKit 0x0034c262 -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 527
13 UIKit 0x0034ae0f -[UIControl touchesEnded:withEvent:] + 458
14 UIKit 0x002e23d0 -[UIWindow _sendTouchesForEvent:] + 567
15 UIKit 0x002c3cb4 -[UIApplication sendEvent:] + 447
16 UIKit 0x002c89bf _UIApplicationHandleEvent + 7672
17 GraphicsServices 0x02d6c822 PurpleEventCallback + 1550
18 CoreFoundation 0x024f1ff4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
19 CoreFoundation 0x02452807 __CFRunLoopDoSource1 + 215
20 CoreFoundation 0x0244fa93 __CFRunLoopRun + 979
21 CoreFoundation 0x0244f350 CFRunLoopRunSpecific + 208
22 CoreFoundation 0x0244f271 CFRunLoopRunInMode + 97
23 GraphicsServices 0x02d6b00c GSEventRunModal + 217
24 GraphicsServices 0x02d6b0d1 GSEventRun + 115
25 UIKit 0x002ccaf2 UIApplicationMain + 1160
26 PhoneBook 0x000026ec main + 102
27 PhoneBook 0x0000267d start + 53
)
terminate called after throwing an instance of 'NSException'

Answer 1

I've seen this before and it is definitely that you have forgotten to update source of data which fill up table. But that part of code is missing.
The method which caused this is
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return ;
}

Answer 2

Yes, the problem was in method numberOfRowsInSection
So, to leave troubles you should:
In function commitEditingStyle delete data from your array, database etc.
Decrement your current row count.
[tableView beginUpdates];
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject: indexPath] withRowAnimation:UITableViewRowAnimationFade];
[tableView endUpdates];
And all be OK!

Answer 3

Updated Swift 4.2
If you are about to remove last row in section, you should remove entire section instead of row. To do that:
tableView.beginUpdates()
dataArray.remove(at: row)
if tableView.numberOfRows(inSection: section) == 1 {
tableView.deleteSections(IndexSet(integer: section), with: .automatic)
}
else {
tableView.deleteRows(at: indexPath, with: .fade)
}
tableView.endUpdates()

Answer 4

Pretty clear from the error message:
'Invalid update: invalid number of
rows in section 0. The number of rows
contained in an existing section after
the update (6) must be equal to the
number of rows contained in that
section before the update (6), plus or
minus the number of rows inserted or
deleted from that section (0 inserted,
1 deleted).'
The object you are trying to delete doesn't get deleted in your datasource.
If I assume that your UITableViewDataSource uses dbManager too, you have to fix dbManager to actually delete the object.

Answer 5

I got the same error and reason was I delete the last row in the table and
my numberOfSectionsInTableView implementation return rowsArray count which was 0..
changing to minimum of 1 solve the case