Question

I am having a Navigation based app with a few buttons on the first View (not using ARC). By touching one button optionPressed gets triggered to push to another View.

When I analyse the code for leaks. I get the following warning. “Potential leak of an object” [self.displayViewController setCurrentPhoto:sender.currentTitle];

How should I release the self.displayViewController and where if that’s the cause.

.h

#import <UIKit/UIKit.h>
#import "DisplayViewController.h"

@class DisplayViewController;

@interface Pocket_DjangoViewController : UIViewController 


- (IBAction)optionPressed:(UIButton *)sender;

@property (retain, nonatomic) DisplayViewController *displayViewController;


@end

.m

- (IBAction)optionPressed:(UIButton *)sender 
{

    if (!self.displayViewController) {
        self.displayViewController = [[DisplayViewController alloc] initWithNibName:@"DisplayViewController" bundle:nil];
    }

    [self.displayViewController setCurrentPhoto:sender.currentTitle];
    [self.navigationController pushViewController:self.displayViewController animated:YES];

    //[self.displayViewController release];
    //self.displayViewController = nil;
}

Answer 1

The leak stems for this line:

self.displayViewController = [[DisplayViewController alloc] initWithNibName:@"DisplayViewController" bundle:nil];

you should have:

self.displayViewController = [[[DisplayViewController alloc] initWithNibName:@"DisplayViewController" bundle:nil] autorelease];

In your actual code, you are creating an object:

[[DisplayViewController alloc] initWithNibName:@"DisplayViewController" bundle:nil]; 

which is already retained; then you assign it to a retain property:

@property (retain, nonatomic) DisplayViewController *displayViewController;

and this will create a retain unbalance, as the original alloc is never released and only the retain called by the property is eventually released.