self.navigationItem.rightBarButtonItem vs self.nav

问题:

I'm somewhat confused about using self.navigationItem.rightBarButtonItem and self.navigationController.navigationItem.rightBarButtonItem.

Which one is correct way?

回答1:

The first, i.e. self.navigationItem.rightBarButtonItem.

Every view controller has an associated navigation item. This is what is displayed in a navigation bar. So it's the current view controller's navigation item that you want to manipulate. If you manipulated the navigation controller's navigation item then that would show if the navigation controller (also a view controller) were itself shown inside another navigation controller.