Question

Is there a general best-practices way of being notified when the current view controller is being dismissed (either popped or dismissModalDialog’d)? I can’t use -viewWillDisappear:, since that also gets called when another viewController is pushed atop the current one.

Answer 1

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        [self addObserver:self forKeyPath:@"parentViewController" options:0 context:NULL];
    }
    return self;
}


- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([@"parentViewController" isEqualToString:keyPath] && object == self) {
        if (!self.parentViewController)
            NSLog(@"Dismissed");
    }
}

- (void)dealloc
{
    [self removeObserver:self forKeyPath:@"parentViewController"];
    [super dealloc];
}