iPhone - EXC_BAD_ACCESS when setting nil to an IBOutlet - Memory Management

Question

I'm facing an annoying issue and I can't find out why.

I have a UIViewController I present in modal like that :

interviewsViewController *interviewsVC = [[interviewsViewController alloc] initWithNibName:nil bundle:nil];
[interviewsVC setManagedObjectContext:_managedObjectContext];

UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:interviewsVC];
[interviewsVC release];
[self presentModalViewController:navigationController animated:YES];
[navigationController release];

Then when I dismiss the view controller like this :

- (void)dismissViewController
{
     [self dismissModalViewControllerAnimated:YES];
}

The dealloc gets called :

- (void)dealloc
{
    [_managedObjectContext release];
    [_interviewsArray release];
    [scrollView release];
    [pageControl release];
}

Once the view controller is dismissed, I send an memory warning via the iPhone Simulator Menu and the viewdidunload method gets called :

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
    self.scrollView = nil;
    self.pageControl = nil;
}

But there's always an error EXC_BAD_ACCES on the self.scrollView = nil ... More specifically at this line :

@synthesize scrollView;

And I can't find out why ?

If I add a breakpoint on the line above this one, the scrollView is not a zombie or equal to 0x0 ...

Do you have an idea ?

PS : Here's the header :

#import <UIKit/UIKit.h>

@interface interviewsViewController : UIViewController <UIScrollViewDelegate>
{
    NSManagedObjectContext *_managedObjectContext;

    NSMutableArray *_interviewsArray;

    NSUInteger _fetchOffset;

    CGFloat _lastXValue;
}

@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
@property (nonatomic, retain) NSMutableArray *interviewsArray;

//IBOutlet
@property (nonatomic, retain) IBOutlet UIScrollView *scrollView;
@property (nonatomic, retain) IBOutlet UIPageControl *pageControl;

And I set the delegate of the scrollview in the XIB (not in the code).

Answer 1

You need to release properly in dealloc-

Use-

- (void)dealloc {
      [_managedObjectContext release];
      [_interviewsArray release];
      self.scrollView = nil;
      self.pageControl = nil;

      [super dealloc];
}

ViewDidUnload also be used as that will be helpfull in case of low memory warnings.