嵌入在NavigationItem中的断开的UISearchBar动画

看起来苹果仍需要解决在新的大标题风格中使用UISearchBar的问题。如果 UIViewController navigationItem.searchController 设置后,动画效果良好。在两个实例之间导航时 UIViewController 如果两者都有一个searchController集,那么就会出现您描述的导航栏高度跳到哪里的问题。

您可以通过创建 UISearchController viewDidAppear 被调用(而不是在 loadView )和设置 导航项。搜索控制器 至零开启 viewDidDisappear

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    DispatchQueue.main.async {
        let stvc = UITableViewController()
        stvc.tableView.dataSource = self

        let sc = UISearchController(searchResultsController: stvc)
        sc.searchResultsUpdater = self
        self.navigationItem.searchController = sc
    }
}

override func viewDidDisappear(_ animated: Bool) {
    super.viewDidDisappear(animated)

    self.navigationItem.searchController = nil
}

异步调度的原因是当设置 导航项。搜索控制器

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Only one palette with a top boundary edge can be active outside of a transition. Current active palette is <_UINavigationControllerManagedSearchPalette: 0x7fad67117e80; frame = (0 116; 414 0); layer = <CALayer: 0x60400002c8e0>>'

我知道这只是一个解决方法,但希望这能暂时帮助你,直到苹果解决了在两个视图控制器之间导航的问题 设置他们的 navigationItem .

这个 accepted answer navigationItem 如果第一个搜索栏处于活动状态,则在推送的视图控制器中。

answer by stu ,但不需要干预约束。该方法是在序列点确定搜索栏是否可见。如果是,我们指示目标视图控制器使其搜索栏在加载时可见。这意味着导航项动画的行为正确:

UIViewController1 和 UIViewController2 哪里 1 2

class ViewController1: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let searchController = UISearchController(searchResultsController: nil)
        searchController.obscuresBackgroundDuringPresentation = false
        navigationItem.searchController = searchController

        definesPresentationContext = true
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let viewController2 = segue.destination as? ViewController2, let searchController = navigationItem.searchController {

            // If the search bar is visible (but not active, which would make it visible but at the top of the view)
            // in this view controller as we are preparing to segue, instruct the destination view controller that its
            // search bar should be visible from load.
            viewController2.forceSearchBarVisibleOnLoad = !searchController.isActive && searchController.searchBar.frame.height > 0
        }
    }
}

class ViewController2: UITableViewController {

    var forceSearchBarVisibleOnLoad = false

    override func viewDidLoad() {
        super.viewDidLoad()

        let searchController = UISearchController(searchResultsController: nil)
        searchController.obscuresBackgroundDuringPresentation = false
        navigationItem.searchController = searchController

        // If on load we want to force the search bar to be visible, we make it so that it is always visible to start with
        if forceSearchBarVisibleOnLoad {
            navigationItem.hidesSearchBarWhenScrolling = false
        }
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        // When the view has appeared, we switch back the default behaviour of the search bar being hideable.
        // The search bar will already be visible at this point, thus achieving what we aimed to do (have it
        // visible during the animation).
        navigationItem.hidesSearchBarWhenScrolling = true
    }
}

我解决这个问题的方法是更新保持 UISearchBar UIViewController

下面的代码假设您有一个包含 UISearchController 实例 调用的子类 searchController

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    if
        animated
            && !searchController.isActive
            && !searchController.isEditing
            && navigationController.map({$0.viewControllers.last != self}) ?? false,
        let searchBarSuperview = searchController.searchBar.superview,
        let searchBarHeightConstraint = searchBarSuperview.constraints.first(where: {
            $0.firstAttribute == .height
                && $0.secondItem == nil
                && $0.secondAttribute == .notAnAttribute
                && $0.constant > 0
        }) {

        UIView.performWithoutAnimation {
            searchBarHeightConstraint.constant = 0
            searchBarSuperview.superview?.layoutIfNeeded()
        }
    }
}

您可以删除 performWithoutAnimation 和 layoutIfNeeded

我希望苹果能在稍后的iOS版本中解决这个问题,在撰写本文时,当前的版本是12.1.4。

在 VC1

override func viewDidLoad() {
   if #available(iOS 11.0, *) {
        navigationItem.hidesSearchBarWhenScrolling = false
        navigationItem.searchController = searchController
    }
}
override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    if #available(iOS 11.0, *) {
        navigationItem.hidesSearchBarWhenScrolling = true
    }
}

在 VC2 ,使用相同的代码。

这将比set更清楚地解决您的问题 serchController 到 nil

在花了几天时间解决和调查之后,我也遇到了同样的问题。最后,我创建了一个自定义视图,并用该视图替换标题视图。 iOS 11是个糟糕的苹果。

我在viewDidLoad()中添加了这段代码,当我移动到选项卡的b/w时,它正在工作

searchController.dimsBackgroundDuringPresentation