Question

I made a multiview app based on this Tutorial.Here is my code in the appdelegate.h

@class Disclaimerviewcontroller;

@interface GAINSAppDelegate : NSObject <UIApplicationDelegate> {
    Disclaimerviewcontroller *firstview;

}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain )Disclaimerviewcontroller *firstview;

-(void)switchview :(UIView *)view1 toview:(UIView *)view2;
@end

and in the “.m” i have the following

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    [self.window makeKeyAndVisible];
    Disclaimerviewcontroller *aview = [[Disclaimerviewcontroller alloc]initWithNibName:@"Disclaimerviewcontroller"bundle:nil];
    self.firstview = aview;
    [_window addSubview:aview.view];
    [aview release];
    return YES;
}

-(void)switchview :(UIView *)view1 toview:(UIView *)view2{

    [UIView beginAnimations:@"Animation" context:nil];
    [UIView setAnimationDuration:0.50];
    [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:self.window cache:YES];
    [view1 removeFromSuperview];
    [_window addSubview:view2];
    [UIView commitAnimations];


}

and the dealloc

- (void)dealloc
{   [firstview release];
    [_window release];
    [super dealloc];
}

from there on when ever I want to switch to another view I use the following code

-(IBAction)switchtodisclaimer2:(id)sender{

    GAINSAppDelegate *delegate = (GAINSAppDelegate *)[[UIApplication sharedApplication]delegate];
    Disclaimerviewcontrller2 *disclaimview2 = [[Disclaimerviewcontrller2 alloc]initWithNibName:@"Disclaimerviewcontrller2" bundle:nil];
    [delegate switchview:self.view toview:disclaimview2.view];


}

just like in the tutorial. but when I did an analyze test. xcode warned be of possible memory leak in the above code. so i added (in the above case) [disclaimerview2 release];and when I run the program I get EX_BAD_ACCES error. I thought since it was initwithnibname it was an autorelease ?. I’m confused now. the tutorial doesn’t seem to be addressing this at all.

Answer 1

The rule for memory ownership is this :

If your method name starts with ‘alloc’, ‘init’, ‘copy’, ‘mutableCopy’ or ‘new’ they you are responsible for releasing it, either with release or with autorelease

So yes, you do have a memory leak so you should release ‘disclaimview2’ with [disclaimview2 release]

However, the reason that you are crashing is because of another bug somewhere in your code.

If you are going to pass it into your delegate, your delegate should retain it – otherwise, the delegate will try to use it at some point in the future but will have been deallocated.