dealloc on tableViewContoller causing crash when using popViewController on NavContr

[shimmy]

Hi

I have a table view with a list of cells (which have sliders and labels in them, so not typical cells, but I think everything is released there when necessary, but I've always been a bit confused by tableViews: eg in this code, the list is short and I had trouble with it, so I gave all the cells custom identifiers so they wouldn't try to reuse them... Is that really bad? The list is only about 10 items long) and I replaced the default back button with a bar button system Cancel button and an alert that confirms you want to cancel and discard all changes. The cancel button links to a function which puts up the alert and then a delegate function calls the pop view controller on the navigation controller. It successfully goes back to the previous view, but then after a second it crashes. I added NSZombieEnabled and it showed me that the app was crashing on [super dealloc]; in the popped view controller's dealloc function. I would try to do it without using the pop, but the fact that this doesn't work probably means there is a bug in my memory management but I am not sure where.

The error said: Thread 1: Program received signal "EXC_BAD_ACCESS"

There seems to be a few people with similar issues, but no definitive answers that solve the problem.

The push onto the navigation controller stack from the first view controller

-(IBAction) beginNewTest {
    NSLog(@"Beginning new test.  FirstViewController.m");
    TestListViewController* testListViewController = [[TestListViewController alloc] init];
    testListViewController.title = @"New Test";
 
    [self.navigationController pushViewController:testListViewController animated:YES];
    [testListViewController release];
    
    NSLog(@"Complete initialization and loading of test list view controller.  Pushed onto navigation stack.  FirstViewController.m");
}

//the init function in the TestListViewController


-(id) init {
    if (self = [super initWithStyle: UITableViewStylePlain]) {
        //initialize here
        UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelTest)];  //make it cancel
        [self.navigationItem setHidesBackButton:TRUE];
        [self.navigationItem setLeftBarButtonItem:cancelButton];
        [cancelButton release];
    }
    return self;    
    
}


//The problem occurs with or without the alertview, so that's not causing it...  

-(void) cancelTest {
    NSLog(@"Cancelling test  TestListViewController.m");
    UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"Canceling Test" message:@"Are you sure you want to cancel the test?  All unsaved data will be lost." delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK", nil];
    [alert show];
    [alert release];
    
}
-(void) alertView: (UIAlertView *)alertView clickedButtonAtIndex: (NSInteger)buttonIndex {
    if (buttonIndex == 1)
        [self.navigationController popViewControllerAnimated:YES];
    else
        return;
}


//Here's the dealloc
- (void)dealloc {
	NSLog(@"Dealloc function reached.  TestListViewController.m");
    [scoreForTest release]; //an ns dictionary allocated in viewdidload
    
    [super dealloc]; //crashes here acc. to NSZombieEnabled
}

Any ideas?

Thanks!

[BrianSlick]

I love it when people show everything except what is important. Like this:

[scoreForTest release]; //an ns dictionary allocated in viewdidload

So, perhaps you should show that.

[shimmy]

Originally Posted by BrianSlick

I love it when people show everything except what is important. Like this:

[scoreForTest release]; //an ns dictionary allocated in viewdidload

So, perhaps you should show that.

- (void)viewDidLoad {
    [super viewDidLoad];
	startDateTime = [NSDate date]; //get start time, and will compare with end time to determine time to score.  May want to only set this after first score has been altered
	if (scoreForTest == nil) {
		//dictionary with integer values for scores (initialized to -1 so no ambiguity)
		NSArray* arrayOfScores = [NSArray arrayWithObjects:[NSNumber numberWithInt:-1], [NSNumber numberWithInt:-1], [NSNumber numberWithInt:-1],
															[NSNumber numberWithInt:-1], [NSNumber numberWithInt:-1], [NSNumber numberWithInt:-1],
															[NSNumber numberWithInt:-1], [NSNumber numberWithInt:-1], [NSNumber numberWithInt:-1],
															[NSNumber numberWithInt:-1], nil];
		
		scoreForTest = [[NSMutableDictionary alloc] initWithObjects:arrayOfScores forKeys:self.arrayOfTestTitles];
	}
	self.editing = NO;
	UIButton* infoButton = [UIButton buttonWithType:UIButtonTypeInfoLight];
	[infoButton addTarget:self action:@selector(requestHelp:) forControlEvents:UIControlEventTouchUpInside];
	[infoButton setFrame:CGRectMake(10, 0, 20, 20)];
	UIBarButtonItem *infoBarButton = [[UIBarButtonItem alloc] initWithCustomView:infoButton];
	self.navigationItem.rightBarButtonItem = infoBarButton;
	

	[infoButton release];
}

[BrianSlick]

infoButton should not be released, and I suggest you read the properties link in my signature.

[shimmy]

Originally Posted by BrianSlick

infoButton should not be released, and I suggest you read the properties link in my signature.

Why shouldn't it be released?


EDIT: Oh sorry. It should be releasing inforBarButton, not infoButton.

EDIT 2: Reading through your properties guide -- very informative! Do you think this is causing my problems?

EDIT 3: The changes I made (releasing infoBarButton instead of infoButton and also modifying the allocation of score for test based on your guide) has fixed the problem! Thank you very much! I was always very confused by the memory management, especially with properties, and your guide has helped clear a lot of that up already. I suggest everyone take a look at it.