Why the navigation header is hidden in ios13?

Question

When i add with PushViewController the navigation header remains visible with this code:

View viewp = new View();
NavigationController.PushViewController(viewp, false);

but when i add with PresentViewControllerAsync the navigation header is hidden, what is wrong?

viewp.ModalPresentationStyle = UIModalPresentationStyle.FullScreen;
this.PresentViewController(viewp, true, null);

i am using ios13, what is my wrong? the buttons right and left do not show

You can share two screenshots to show difference between them , this will be helpful to know whether it's an issue in iOS 13 . — Junior Jiang, Nov 11 '19 at 08:41
Okey ,thanks for updating question .If the buttons right and left is in Navigation bar , when using `PresentViewController` then it will not show .Have a look at my answer . — Junior Jiang, Nov 12 '19 at 01:47
If answer be helpful , remember to mark ot vote up later when have time.Thanks in advance *.^ — Junior Jiang, Nov 19 '19 at 01:11

score 1 · Accepted Answer · answered Nov 11 '19 at 07:43

There is nothing wrong with them , it's a normal phenomenon .

PushViewController need Root View Controller is NavigationController , it only can be used in NavigationController .Therefore , when invoking need as follow :

NavigationController.PushViewController(xxx)

That also is the reason can see Navigation Bar by this method. Next page is under Navigation Controller . Have a look at UINavigationController and pushViewController:animated: defined :

However , PresentViewController can be invoked no matter root view controller wherther be NavigationController or Other controller . It just presents a view controller in the dialog controller’s window. Then there will not show navigation bar in next view , because it's not under the stack of Navigation Controller Stack.

Here are some good discussion about difference between them for reference.

1 Answers1