UiTabBarController crashes on popToRootViewController

Question

My application crashes when selecting a tab. Here is the code that crashes.

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
if ([viewController isKindOfClass:[UINavigationController class]]) {
    [(UINavigationController*)viewController popToRootViewControllerAnimated:NO];
}


}

This is the code that is the problem. Apparently when I popToRoot controller a message is sent to a dealloced object.

DealElementDisplayController *dealElementDisplayController = [[DealElementDisplayController alloc] initWithStores:storeIds :YES];
            dealElementDisplayController.title = [NSString stringWithFormat:@"%@ Products", store.companyName];
            [self.navigationController pushViewController:dealElementDisplayController animated:YES];

Here is the exception.

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0xe0000008
Crashed Thread:  0

Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libobjc.A.dylib                 0x3648af78 objc_msgSend + 16
1   UIKit                           0x320e809c -[UITableView(UITableViewInternal)             _createPreparedCellForGlobalRow:withIndexPath:] + 540
    2   UIKit                           0x320e717a -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow:] + 1070
3   UIKit                           0x320e6904 -[UITableView layoutSubviews] + 200
4   UIKit                           0x3208b0d8 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 176
5   CoreFoundation                  0x34fc81f4 -[NSObject performSelector:withObject:] + 36
6   QuartzCore                      0x36b53a9e -[CALayer layoutSublayers] + 210
7   QuartzCore                      0x36b536b6 CA::Layer::layout_if_needed(CA::Transaction*) + 210
8   QuartzCore                      0x36b5783c CA::Context::commit_transaction(CA::Transaction*) + 220
9   QuartzCore                      0x36b57578 CA::Transaction::commit() + 308
10  QuartzCore                      0x36b7f90a CA::Transaction::flush() + 38
11  QuartzCore                      0x36b7f8dc +[CATransaction flush] + 28
12  UIKit                           0x32096152 _afterCACommitHandler + 46
13  CoreFoundation                  0x3503db14 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 12
14  CoreFoundation                  0x3503bd50 __CFRunLoopDoObservers + 252
15  CoreFoundation                  0x3503c0aa __CFRunLoopRun + 754
16  CoreFoundation                  0x34fbf49e CFRunLoopRunSpecific + 294
17  CoreFoundation                  0x34fbf366 CFRunLoopRunInMode + 98
18  GraphicsServices                0x362bb432 GSEventRunModal + 130
19  UIKit                           0x320b5e76 UIApplicationMain +

Here is the stack trace from Zombie Profile. I am using ARC.

   0 CoreFoundation ___forwarding___
   1 CoreFoundation _CF_forwarding_prep_0
   2 UIKit -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:withIndexPath:]
   3 UIKit -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:]
   4 UIKit -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow:]
   5 UIKit -[UITableView layoutSubviews]
   6 UIKit -[UIView(CALayerDelegate) layoutSublayersOfLayer:]
   7 CoreFoundation -[NSObject performSelector:withObject:]
   8 QuartzCore -[CALayer layoutSublayers]
   9 QuartzCore CA::Layer::layout_if_needed(CA::Transaction*)
  10 QuartzCore CA::Context::commit_transaction(CA::Transaction*)
  11 QuartzCore CA::Transaction::commit()
  12 QuartzCore +[CATransaction flush]
  13 UIKit _afterCACommitHandler
  14 CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__
  15 CoreFoundation __CFRunLoopDoObservers
  16 CoreFoundation __CFRunLoopRun
  17 CoreFoundation CFRunLoopRunSpecific
  18 CoreFoundation CFRunLoopRunInMode
  19 GraphicsServices GSEventRunModal
  20 GraphicsServices GSEventRun
  21 UIKit UIApplicationMain

Is the view you're navigating to a UITableViewController? Have you tried putting a break in your - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath method to see if it's rendering? — Matt Hudson, Mar 31 '12 at 16:16
It never gets there. It makes it to viewWillAppear and then throws the exception. There is nothing in viewWillAppear that could trigger the exception. — kgibbon, Mar 31 '12 at 16:57

score 0 · Answer 1 · answered Apr 06 '12 at 14:59

0

It was due to calling popToRootViewController when the navigation controller is already on the root controller.

answered Apr 06 '12 at 14:59

kgibbon

726
1
15
37

score 0 · Answer 2 · answered Mar 31 '12 at 18:35

The reason for exception in your application is not due to issue with following code

   - (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
      {
        if ([viewController isKindOfClass:[UINavigationController class]]) {
        [(UINavigationController*)viewController popToRootViewControllerAnimated:NO];
      }
    }

I think when you are tapping on tab bar, the navigation controller pops DealElementDisplayController, and one of the unallocated/released variable in DealElementDisplayController is released again. This may be the reason for your crash. Check in your -(void)dealloc code in DealElementDisplayController, to ensure you have done everything perfect. Use zombie in instruments to check for exceptions. zombie is well suited to detect exceptions related to memory management.

I am using ARC. I do not implement the dealloc method in DealElementDisplayController — kgibbon, Mar 31 '12 at 19:30

UiTabBarController crashes on popToRootViewController

2 Answers2