ARC frees my view controller view is visible

Question

I have a simple app with a single view, on it there's a button. When clicking the button, it adds a 2nd view. This 2nd view has a simple toolbar with a single UIBarButtonItem on it. It is registered to fire a message of my view controller.

But as soon as I click the button the app crashes. Enabling Zombies, I see that my view controller got fired. Adding a dealloc function, with a call to NSLog(), I see that as soon as my view get visible, my view controller gets dismissed!

Also no message like shouldAutorotateToInterfaceOrientation is triggered.

My ViewController .h :

#import <UIKit/UIKit.h>

@interface IssueViewController : UIViewController
{
    IBOutlet UIBarButtonItem *button;
}

@property (nonatomic, readonly) UIBarButtonItem *button;

- (IBAction)buttonTapped:(id)sender;

+ (void)showSelfInView:(UIView *)view;

@end

Its .m :

#import "IssueViewController.h"

@interface IssueViewController ()

@end

@implementation IssueViewController

@synthesize button;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    self.button.target = self;
    self.button.action = @selector(buttonTapped:);

}

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

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (void)dealloc
{
    NSLog(@"Got dealloc");
}

+ (void)showSelfInView:(UIView *)view
{
    IssueViewController *ivc = [[IssueViewController alloc] init];
    [view addSubview:ivc.view];
}

- (IBAction)buttonTapped:(id)sender
{
    [self.view removeFromSuperview];
}


@end

Code used to trigger display of the 2nd view:

[IssueViewController showSelfInView:self.view];

Anyone knows what I'm doing wrong? Why doesn't my UIViewController get retained at least until the view get removed?

EDIT

I know about ARC, strong & weak references... In non ARC-code, in showSelfInView: I'd retain the view controller, and I would autorelease it in buttonTapped.

That's an ok way to achieve that, to me. And I would like to know if I'm missing something with ARC, or with the way I use my view/viewController. Since the view is still visible, to me, its viewController shouldn't get dealloc-ed. Is there any way to prevent that, besides of creating my own strong reference to the view controller?

REPHRASED

Is there any non-patchy non-dirty way to have a view controller remains allocated until its view gets removed from display. I consider any pointer from view controller to itself as dirty, though that's the way I'm currently using.

Marcio Marcio · Accepted Answer · 2012-07-17T15:57:13

You must keep a strong reference to the instance of IssueViewController if you don't want arc to release it right away (at the end of the scope where the instance is defined).

ARC frees my view controller view is visible

2 Answers