Ik vond de harde manier dat
navigationController.navigationBarHidden = NO;
navigationController.navigationBar.hidden = NO;
are not the same thing. In fact, if I use the first syntax to hide the nav bar, then I cannot use the second syntax to show it: it simply won't do anything. Moreover, the first syntax to show/hide the nav bar always works for me, while the second syntax works some times, but not always. I haven't been able to determine exactly when it would work en when not.
As I was stuck with fixing somebody else's code (a reasonably large app: over 20 UIViewControllers), I had to do a global search for
navigationBar.hidden en replace it with
navigationBarHidden. After that, I had to do a global search for
navigationBar setHidden: en replace with
navigationBarHidden syntax. This eventually fixed the issue.
Yet, I want to understen why the two different options are provided en what the real difference between them is.