问题
I have an app with a UISearchController. This element of the UI is completely set up in code like this:
searchController = UISearchController(searchResultsController: nil)
searchController.searchResultsUpdater = self
searchController.searchBar.delegate = self
searchController.dimsBackgroundDuringPresentation = false
searchController.hidesNavigationBarDuringPresentation = false
searchController.searchBar.searchBarStyle = UISearchBarStyle.Minimal
searchController.searchBar.frame = CGRectMake(searchController.searchBar.frame.origin.x, searchController.searchBar.frame.origin.y, searchController.searchBar.frame.size.width, 44.0)
I am then adding it to my tableView's tableHeaderView
tableView.tableHeaderView = searchController.searchBar
Everything seems to be working fine, but when it's active and I select an item in my tableView, my app segues to another view controller with the search controller persisting in the view. I'm unsure as to how this is possible since the search controller should be a subview of the table view in another view controller. How can I prevent this from happening?
回答1:
You can hide the searchController manually by setting the active property to false in prepareForSegue. Add the below code in prepareForSegue()
searchController.active = false
Alternatively, you should add the following line in viewDidLoad() to get the default behaviour
definesPresentationContext = true
From the documentation for definesPresentationContext
A Boolean value that indicates whether this view controller's view is covered when the view controller or one of its descendants presents a view controller.
Discussion
When a view controller is presented, iOS starts with the presenting view controller and asks it if it wants to provide the presentation context. If the presenting view controller does not provide a context, then iOS asks the presenting view controller's parent view controller. iOS searches up through the view controller hierarchy until a view controller provides a presentation context. If no view controller offers to provide a context, the window's root view controller provides the presentation context.
If a view controller returns true, then it provides a presentation context. The portion of the window covered by the view controller's view determines the size of the presented view controller's view. The default value for this property is false.
Important note (from @paulvs in the comments)
Little gotcha. Set definesPresentationContext on the view controller, not the search controller, I think this is worth emphasising.
回答2:
If you manage your own transitions and use popToViewController to leave the view, provide the context on the searchController instead of the view
searchController.definesPresentationContext = true
or you will get an error
popToViewController:transition: called on <UINavigationController 0x7f984204f800> while an existing transition or presentation is occurring; the navigation stack will not be updated
来源：https://stackoverflow.com/questions/29472011/uisearchcontroller-persisting-after-segue