问题
I'm rewriting an Obj-C project using Swift 4 / Xcode 9.2
I have a large storyboard that I am breaking down into multiple storyboards. I did this previously without any issues. If I refactored a few views to their own storyboard then the views took the navigation item with them. now they disappear...
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My questions are ...
Is this an Xcode bug? or a new feature?
Obviously you can work around this as I have shown in the pictures but is there a way to stop the vanishing from happening?
回答1:
This is the way it's always been. In your storyboard, if a view controller is not a child of a navigation controller via root view controller or push segues, then by default no navigation bar is shown in the storyboard. You can force it on, though, by going to the Simulated Metrics section of the Attributes Inspector tab and selecting one of the navigation bar options for "Top Bar".
回答2:
Your view controller is no longer a child of a navigation controller, so it no longer automatically has a navigation item. If you need it to have a navigation item, drag a Navigation Item from the Object Library onto it. You will then be able to give the navigation item a title, and drag buttons and so forth onto the navigation item.
来源：https://stackoverflow.com/questions/48531564/where-is-uinavigationitem-disappearing-to-when-refactoring-views-to-storyboard