无法检测到EKEventEditViewController中的崩溃

Question

when i click on done button at EKEventEditViewController then app gets crashed saying "exc_bad_access".I also used break point to detect it but cannot find it. There is nothing about crash in gdb. Where should i check crash. Done-button do not shift control to EKEventEditViewDelegate - method. It just crash.Help me out plz.

here is my code

-(void)viewWillAppear:(BOOL)animated
{

EKEventEditViewController *addController = [[EKEventEditViewController alloc] 
 initWithNibName:nil bundle:nil];
addController.eventStore = self.eventStore;
addController.event = event;
addController.editViewDelegate = self;
[self presentModalViewController:addController animated:YES]; 
[super viewWillAppear:YES];

}

 #pragma mark - 
 #pragma mark EKEventEditViewDelegate

- (void)eventEditViewController:(EKEventEditViewController *)controller 
      didCompleteWithAction:(EKEventEditViewAction)action {

NSError *error = nil;
EKEvent *thisEvent = controller.event;

switch (action) {

         case EKEventEditViewActionCanceled:    
         break;

    case EKEventEditViewActionSaved:
            [controller.eventStore saveEvent:controller.event  
                    span:EKSpanThisEvent error:&error]; 
        break;

    case EKEventEditViewActionDeleted:
        [controller.eventStore removeEvent:thisEvent span:EKSpanThisEvent 
                     error:&error];
        break;

    default:
        break;
}

[controller dismissModalViewControllerAnimated:YES];
[self backTopreviousController];
}

-(void)backTopreviousController
{
  [self.navigationController popToRootViewControllerAnimated:YES];
 }

Answer 1

exc_bad_access suggests that you're accessing memory that has been deallocated (probably a mememory management problem). These issues are a bit hard to tackle because you might release an object (which you should not) at some point and you only run into a problem a little later when accessing this object.

You can try the following:

1. Click the "Run Button Dropdown"
2. From the list choose Profile
3. The program "Instruments" should open where you can also choose Zombies
4. Now you can interact with your app and try to cause the error
5. As soon as the error happens you should get a hint on when your object was released and therefore deallocated.

_{(source: dimzzy.com )}

Answer 2

Your code is crashing because of the following lines.

[controller dismissModalViewControllerAnimated:YES];
[self backTopreviousController];

either you want to pop or dismiss. But not both. It depends how you have called this class. Push or presentModal !

Answer 3

Debug the program after setting a breakpoint at the beginning of eventEditViewController:didCompleteWithAction . Once your program reaches the breakpoint execute step by step.

Doing like this, you will know either:

1. which statement makes the program crash, or

2. that the program crashes before even entering that method.

In case 1, you should inspect each object you send a message to and make sure it has not been deallocated. In case 2, you should inspect the action definition that is associated to the Done button.