Attempting to load the view of a view controller while it is deallocating… UISearchController

问题

I have code that creates a UISearchController\' in my UIVIew\'sviewDidLoad`.

 self.resultSearchController = ({
        let controller = UISearchController(searchResultsController: nil)
        controller.searchResultsUpdater = self
        controller.searchBar.delegate = self
        controller.dimsBackgroundDuringPresentation = false
        controller.searchBar.sizeToFit()
        controller.hidesNavigationBarDuringPresentation = false //prevent search bar from moving
        controller.searchBar.placeholder = \"Search for song\"

        self.myTableView.tableHeaderView = controller.searchBar

        return controller

    })()

Right after this closure finishes, this warning appears in the console:

Attempting to load the view of a view controller while it is deallocating is not allowed and may result in undefined behavior (<UISearchController: 0x154d39700>)

I don\'t get what I am doing wrong. This similar question is not really my situation (At least I don\'t think so). What is going on?

回答1:

UISearchController's view has to be removed from its superview before deallocate. (guess it is a bug)

Objective-C...

-(void)dealloc { 
    [searchController.view removeFromSuperview]; // It works!
}

Swift 3...

deinit {
    self.searchController.view.removeFromSuperview()
}

I struggled with this issue for a couple of weeks. ^^

回答2:

Solved! It was a simple fix. I changed this code

class ViewController: UITableViewController, UISearchResultsUpdating, UISearchBarDelegate {

    var resultSearchController = UISearchController()

to this:

 class ViewController: UITableViewController, UISearchResultsUpdating, UISearchBarDelegate {

    var resultSearchController: UISearchController!

This fixes the problem.

回答3:

Here is the Swift version that worked for me (similar toJJHs answer):

deinit{
    if let superView = resultSearchController.view.superview
    {
        superView.removeFromSuperview()
    }
}

回答4:

class SampleClass: UITableViewController, UISearchBarDelegate {

private let searchController =  UISearchController(searchResultsController: nil)

 override func viewDidLoad() {
        super.viewDidLoad()

        searchController.loadViewIfNeeded() // Add this line before accessing searchController
 }

}

回答5:

Hacking together a few solutions I managed to get mine working by adding lines to viewDidLoad before fully setting up the UISearchController:

override func viewDidLoad() {
    super.viewDidLoad()
    self.navigationItem.rightBarButtonItem = self.editButtonItem()

    if #available(iOS 9.0, *) {
        self.resultSearchController.loadViewIfNeeded()// iOS 9
    } else {
        // Fallback on earlier versions
        let _ = self.resultSearchController.view          // iOS 8
    }
    self.resultSearchController = ({
        let controller = UISearchController(searchResultsController: nil)
        controller.searchResultsUpdater = self
        controller.dimsBackgroundDuringPresentation = false
        controller.searchBar.sizeToFit()

        self.tableView.tableHeaderView = controller.searchBar

        return controller
    })()

    self.tableView.reloadData()

}

回答6:

In Swift2 I got the same error message due to an obvious bug:

let alertController = UIAlertController(title: "Oops",
    message:"bla.", preferredStyle: UIAlertControllerStyle.Alert)

alertController.addAction(UIAlertAction(title: "Ok", 
     style: UIAlertActionStyle.Default,handler: nil))

self.presentViewController(alertController, animated: true, completion: nil)

Due to a stupid copy error from myself, I had not included the self.presentViewController line. This caused the same error.

回答7:

In Swift 2.2 version that worked for me

deinit {
    self.searchController?.view.removeFromSuperview()
}

I think it's helpful!

回答8:

Mine is working like this

func initSearchControl(){

        searchController = UISearchController(searchResultsController: nil)

        if #available(iOS 9.0, *) {
            searchController.loadViewIfNeeded()
        } else {
            let _ = self.searchController.view
        }

        searchController.searchResultsUpdater = self
        searchController.dimsBackgroundDuringPresentation = false
        definesPresentationContext = true
        tableView.tableHeaderView = searchController.searchBar
        searchController.searchBar.sizeToFit()
    }

searchController.loadViewIfNeeded() solves the problem but you need to call it after initializing the searchController

回答9:

Creating a search controller in viewDidLoad() and setting its search bar as the navigation item's title view doesn't create a strong reference to the search controller, which is why it's deallocated.

So instead of doing this:

override func viewDidLoad() {
    super.viewDidLoad()
    // Create search controller
    let searchController = UISearchController(searchResultsController: nil)
    // Add search bar to navigation bar
    navigationItem.titleView = searchController.searchBar
    // Size search bar
    searchController.searchBar.sizeToFit()
}

You should do this:

var searchController: UISearchController!

override func viewDidLoad() {
    super.viewDidLoad()
    // Create search controller
    searchController = UISearchController(searchResultsController: nil)
    // Add search bar to navigation bar
    navigationItem.titleView = searchController.searchBar
    // Size search bar
    searchController.searchBar.sizeToFit()
}

回答10:

I used Derek's answer, but had to change it slightly. The answer that was provided crashed for me because the call to loadViewIfNeeded() happened before the resultSearchController was defined. (My declaration was

var resultSearchController: UISearchController!

). So I just moved it afterwards and it worked.

If I left out the call entirely, the bug remained, so I'm sure it is an essential part of the answer. I was unable to test it on iOS 8.

回答11:

It's not a bug. It seems that you have to avoid creating ViewControllers without presenting them. So after SomeViewController() or let variable: SomeViewController you have to call something like this self.presentViewController(yourViewController ...etc). If you don't do that, you will get this warning when this view controller will be dealocated.

回答12:

It seem the view is lazy loaded, if you allocated the controller and never show it, the view is not loaded. In this case, if the controller is deallocated, you will received this warning. you could show it once, or call it's loadViewIfNeed() method, or use 'let _ = controller.view' to force load the view to avoid this warning.

回答13:

I'm a bit late to the party, but here's my solution:

var resultSearchController: UISearchController!

override func viewDidLoad()
{
    super.viewDidLoad()

    self.resultSearchController = ({
        let searchController = UISearchController(searchResultsController: nil)
        searchController.searchResultsUpdater = self
        searchController.dimsBackgroundDuringPresentation = false
        searchController.searchBar.sizeToFit()
        return searchController
    })()

    self.tableView.tableHeaderView = self.resultSearchController.searchBar
    self.tableView.reloadData()
}

I hope it works for you.

来源：https://stackoverflow.com/questions/32282401/attempting-to-load-the-view-of-a-view-controller-while-it-is-deallocating-uis

标签

ios

swift

uisearchcontroller