[iPad] How can I get the popoverController pointer in the viewController

Question

UIViewController* viewController = [[UIViewController alloc] init];
UINavigationController* navcontroller = [[UINavigationController alloc] initWithRootViewController:viewController];
UIPopoverController* aPopover = [[UIPopoverController alloc] initWithContentViewController:navcontroller];
[aPopover presentPopoverFromBarButtonItem:buttonID permittedArrowDirections:arrowDirections animated:YES]; // popup the popoverView
precondition：I can't pass the popoverController point to the viewController directly.
How can I get the popoverController pointer in the viewController?
I try to use the following function, but it can't get the popoverController:
self.navigationController.parentViewController
Message was edited by: MarginD

Answer 1

There is no "book box in preferences' general".
There is a new iBooks application that appears on Mavericks' dock.  It looks like this:
Go there to add books from your Mac to your iPad.