iOS dismiss UIAlertView beforing showing another

I have a Utils class which shows UIAlertView when certain notifications are triggered. Is there a way to dismiss any open UIAlertViews before showing a new one?

Currenty I am doing this when the app enters the background using

[self checkViews:application.windows];

on applicationDidEnterBackground

- (void)checkViews:(NSArray *)subviews {
    Class AVClass = [UIAlertView class];
    Class ASClass = [UIActionSheet class];
    for (UIView * subview in subviews){
        if ([subview isKindOfClass:AVClass]){
            [(UIAlertView *)subview dismissWithClickedButtonIndex:[(UIAlertView *)subview cancelButtonIndex] animated:NO];
        } else if ([subview isKindOfClass:ASClass]){
            [(UIActionSheet *)subview dismissWithClickedButtonIndex:[(UIActionSheet *)subview cancelButtonIndex] animated:NO];
        } else {
            [self checkViews:subview.subviews];
        }
    }
}

This makes it easy on applicationDidEnterBackground as I can use application.windows

Can I use the AppDelegate or anything similar to get all the views, loop through them and dismiss any UIAlertViews?