在导航栏中显示搜索栏和大标题也无需在 iOS 13 上滚动

Question

我在 iOS 13 上将 UISearchController 附加到 navigationItem.searchController。这很好用：我可以使用漂亮的 iOS 13 风格的搜索栏。

不过，我希望默认看到大标题和搜索栏。

我设置navigationItem.hidesSearchBarWhenScrolling = false是因为我想在我的屏幕上永久看到搜索，但搜索栏默认替换大标题。

有谁知道这怎么可能？

Check this out

navigationItem.searchController = UISearchController(searchResultsController: nil)
navigationItem.hidesSearchBarWhenScrolling = false

实际上是这样的

这就是我需要实现的方式（大标题和搜索栏都可见）

Answer 1

试试这个，在我身边工作正常

    private var search = UISearchController(searchResultsController: nil)

    override func viewDidLoad() {
        super.viewDidLoad()
        search.searchBar.delegate = self
        search.searchBar.sizeToFit()
        search.obscuresBackgroundDuringPresentation = false
        search.hidesNavigationBarDuringPresentation = true
        self.definesPresentationContext = true
        search.searchBar.placeholder = "Search here"
        self.navigationItem.searchController = search
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        navigationItem.hidesSearchBarWhenScrolling = false
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        navigationItem.hidesSearchBarWhenScrolling = true
    }

对于大型导航栏使用这个

如需完整的应用程序导航栏支持，请在您的代码中添加此扩展。

import UIKit
extension UIViewController {


    open func showNavigationBar(_ large: Bool,
                                _ animated: Bool,
                                titleColor: UIColor,
                                barTintColor: UIColor,
                                fontSize: CGFloat) {

        navigationController?.navigationBar.barTintColor = barTintColor
        navigationController?.navigationBar.backgroundColor = barTintColor
        navigationController?.navigationBar.isTranslucent = true
        self.navigationController?.setNavigationBarHidden(false, animated: animated)
        if large {
            self.navigationController?.navigationBar.prefersLargeTitles = true
            if #available(iOS 13.0, *) {
                let appearance = UINavigationBarAppearance()
                appearance.backgroundColor = barTintColor
                appearance.titleTextAttributes = [.foregroundColor: titleColor]
                appearance.largeTitleTextAttributes = [NSAttributedString.Key.foregroundColor: titleColor,
                                                       NSAttributedString.Key.font: UIFont(resource: R.font.robotoMedium, size: fontSize)!]

                navigationController?.navigationBar.standardAppearance = appearance
                navigationController?.navigationBar.compactAppearance = appearance
                navigationController?.navigationBar.scrollEdgeAppearance = appearance
            } else {
                self.navigationController?.navigationBar.largeTitleTextAttributes = [NSAttributedString.Key.foregroundColor: titleColor,
                                                                                     NSAttributedString.Key.font: UIFont(resource: R.font.robotoMedium, size: fontSize)!]
            }
        } else {
            self.navigationController?.navigationBar.prefersLargeTitles = false
            self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedString.Key.foregroundColor: titleColor,
                                                                            NSAttributedString.Key.font: UIFont(resource: R.font.robotoMedium, size: 20.0)!]
        }
    }
}

然后简单的调用这个方法

self.showNavigationBar(true, true, titleColor: UIColor.blue, barTintColor: UIColor.red, fontSize: 32.0)

如果那么也不行，那么就用这个

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        search.searchBar.becomeFirstResponder()
    }

另一种解决方案是在情节提要中添加一个高度为 0 的 UIView 和带有安全区域的机顶盒和带有 UIScrollView/UICollectionView/UITableVIew 或其他可滚动视图的底部，并删除 TopSafeArea 和 ScrollableView 顶部之间的直接约束。我知道这可能不是解决方案，但我在情节提要中做到了。

Answer 2

对我来说，在 viewDidLoad() 方法中添加以下行后它就起作用了：

searchController.hidesNavigationBarDuringPresentation = true
navigationController?.navigationBar.prefersLargeTitles = true
navigationController!.navigationBar.sizeToFit()

Answer 3

我整天都在努力为我的应用实现同样的目标，我终于做到了。

我想在 UITableViewController 上添加一个 searchBar，我就是这样做的。

let searchController: UISearchController = {
    let searchController = UISearchController(searchResultsController: nil)
    
    searchController.searchBar.placeholder = "New Search"
    searchController.searchBar.searchBarStyle = .minimal
    searchController.dimsBackgroundDuringPresentation = false
    searchController.definesPresentationContext = true
    
   return searchController
}()

您首先使用闭包创建一个新的 UISearchController，这样您就可以在您的代码中全局使用它，并在将来更轻松地对其进行自定义。

之后在 viewDidLoad 中，设置 searchSontroller.searchResultsUpdater = self 和 navigationItem.searchController = searchController。

对我来说，经过大量试验和错误后，它可以完美运行，因为我以编程方式完成所有操作。

Answer 4

这段代码应该可以工作

class NavigationController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

        createCustomTabBar()
    }

    func createCustomTabBar() {
    
        let firstVC = UINavigationController(rootViewController: HomeVC())
        firstVC.title = "Home"
        firstVC.tabBarItem.image = UIImage(systemName: "house.fill")

        viewControllers = [firstVC]
    }

class HomeVC: UIViewController {
    let searchController = UISearchController(searchResultsController: nil)
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .white
        
        navigationController?.navigationBar.prefersLargeTitles = true
        navigationItem.title = "Home"
        navigationItem.searchController = searchController
    }
}