AppDelegate instance variable getting zombie

In the AppDelegate I have a user variable in order to be accessible throughout the application. Tha AppDelegate code is the following:

@interface MyAppDelegate : NSObject <UIApplicationDelegate, ...> {

@private User *_appUser;
...
}

- (void)setUser:(User *)value;
- (User *)appUser;

- (void)setUser:(User *)value
{
   @synchronized(self)
   {
    if(_appUser != value)
    {
        [_appUser release];
        _appUser = [value retain];
        [NSUserDefaultsManager SaveUser:_appUser];
    }
}

}

- (User *)appUser
{
   if(_appUser == nil)
    return [NSUserDefaultsManager GetUser];
else
    return _appUser;
}

The first time, when the user registers, I s开发者_如何学编程et the user via a ViewController by doing

[((MyAppDelegate *)[[UIApplication sharedApplication] delegate]) setUser:user];

The thing is that when I need to get the user by doing

User *user = [((MyAppDelegate *)[[UIApplication sharedApplication] delegate]) appUser];

in the appUser method of the AppDelegate, the _appUser ivar is Zombie. Any workaround for that? Thank you in advance.

Is your getter method the culprit? You are returning the _appUser without the usual retain/autorelease pattern. Can you resolve the problem by making your getter method:

- (User *)appUser
{
   if(_appUser == nil)
    return [NSUserDefaultsManager GetUser];
else
    return [[_appUser retain] autorelease];
}

or...

- (User *)appUser
{
    if(_appUser == nil)
      _appUser = [[NSUserDefaultsManager GetUser] retain];
    return [[_appUser retain] autorelease];
 }