Reading from NSMutableArray Exception

[architectpianist]

Hi,
This is a strange problem. Look at the code below:

    static NSString *CellIdentifier = @"Cell";
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }
	if (self.rowTitles != nil)
		cell.textLabel.text = [self.rowTitles count] > indexPath.row ? [self.rowTitles objectAtIndex:indexPath.row] : @"0";
	cell.selectionStyle = UITableViewCellSelectionStyleNone;
	
	UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(170, 30, 500, 22)];
	textField.keyboardType = UIKeyboardTypeNumberPad;
        NSLog(@"The string at index is %@.", [self.values objectAtIndex:indexPath.row]);
	if (self.values != nil)
		textField.text = [self.values count] > indexPath.row ? [self.values objectAtIndex:indexPath.row] : @""; //Exception!!
	cell.accessoryView = textField;
    
    return cell;

The strangest thing is that the NSLog shows that there is a string at that index. However, when I set the textField's text (I tried using the setter without success), it causes the following exceptions:

2011-05-13 15:10:49.966 My App HD[1475:707] -[NSCFNumber _isNaturallyRTL]: unrecognized selector sent to instance 0x405e1d0
2011-05-13 15:10:49.983 My App HD[1475:707] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFNumber _isNaturallyRTL]: unrecognized selector sent to instance 0x405e1d0'
*** Call stack at first throw:
(
	0   CoreFoundation                      0x3604064f __exceptionPreprocess + 114
	1   libobjc.A.dylib                     0x35b99c5d objc_exception_throw + 24
	2   CoreFoundation                      0x360441bf -[NSObject(NSObject) doesNotRecognizeSelector:] + 102
	3   CoreFoundation                      0x36043649 ___forwarding___ + 508
	4   CoreFoundation                      0x35fba180 _CF_forwarding_prep_0 + 48
	5   UIKit                               0x367958a7 -[UITextField setText:] + 38
	6   My Grapher HD                       0x0002078f -[VSRawDataInputController tableView:cellForRowAtIndexPath:] + 590
	7   UIKit                               0x367d99ed -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:withIndexPath:] + 516
	8   UIKit                               0x367d976b -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:] + 34
	9   UIKit                               0x367d20cd -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow:] + 936
	10  UIKit                               0x367d127d -[UITableView layoutSubviews] + 140
	11  UIKit                               0x3677d5fb -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 26
	12  CoreFoundation                      0x35fadf03 -[NSObject(NSObject) performSelector:withObject:] + 22
	13  QuartzCore                          0x317ccbb5 -[CALayer layoutSublayers] + 120
	14  QuartzCore                          0x317cc96d CALayerLayoutIfNeeded + 184
	15  QuartzCore                          0x317d21c5 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 212
	16  QuartzCore                          0x317d1fd7 _ZN2CA11Transaction6commitEv + 190
	17  QuartzCore                          0x317cb055 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 56
	18  CoreFoundation                      0x36017a35 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 16
	19  CoreFoundation                      0x36019465 __CFRunLoopDoObservers + 412
	20  CoreFoundation                      0x3601a75b __CFRunLoopRun + 854
	21  CoreFoundation                      0x35faaec3 CFRunLoopRunSpecific + 230
	22  CoreFoundation                      0x35faadcb CFRunLoopRunInMode + 58
	23  GraphicsServices                    0x312e441f GSEventRunModal + 114
	24  GraphicsServices                    0x312e44cb GSEventRun + 62
	25  UIKit                               0x367a6d69 -[UIApplication _run] + 404
	26  UIKit                               0x367a4807 UIApplicationMain + 670
	27  My Grapher HD                       0x00002abb main + 70
	28  My Grapher HD                       0x00002a70 start + 40
)
terminate called after throwing an instance of 'NSException'

The strings in the array were created with [NSString stringWithFormat:@"%g", number];
Please help if there's something I'm missing - thanks!

[JasonR]

Your NSLog does not prove the object is a string, as %@ will print the description of any object. According to the error message, you have an NSNumber. Double check the code that fills that array in the first place.

[architectpianist]

Well, here's how I determined that it is an NSString:

if ([[self.values objectAtIndex:indexPath.row] isKindOfClass:[NSString class]])
        NSLog(@"%@ is a string.", [self.values objectAtIndex:indexPath.row]);

And the number of rows is the count of the values array, so it is being populated.

[architectpianist]

JasonR, you're right, it turned out that I was using a for loop to get numbers from a string, and at the end I was adding an NSNumber with the last number instead of an NSString (aka inconsistency). I thought I was getting the exception before the NSLog, but in fact the if statement above was being skipped because it was an NSNumber.

Thanks for your help!