向下滚动后再次隐藏 SearchController

Question

我让 SearchController 与我的 TableView 一起显示，这是启动时与向上滚动时的样子：

这是完美的，因为我希望它在不使用时隐藏起来。但是，显示后，我无法通过向下滚动再次隐藏它。如何获得该功能？

import UIKit

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, UISearchControllerDelegate, UISearchResultsUpdating {
    
    @IBOutlet weak var tableView: UITableView!        
    
    func updateSearchResults(for searchController: UISearchController) {
        let searchBar = searchController.searchBar
        filterContentForSearchText(searchBar.text!)
    }

    var isSearchBarEmpty: Bool {
      return searchController.searchBar.text?.isEmpty ?? true
    }

    func filterContentForSearchText(_ searchText: String) {
      filteredStrings = stockArr.filter { (string: String) -> Bool in
        return string.lowercased().contains(searchText.lowercased())
      }
      tableView.reloadData()
    }
    var filteredStrings: [String] = []

    var searchController : UISearchController!

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.dataSource = self
        tableView.delegate = self
        

        let searchController = UISearchController(searchResultsController: nil)

        searchController.searchResultsUpdater = self

        searchController.obscuresBackgroundDuringPresentation = false

        searchController.searchBar.placeholder = "Search Candies"

        navigationItem.searchController = searchController
        navigationItem.hidesSearchBarWhenScrolling = false
        
        definesPresentationContext = true
  
    }
}

编辑：

我玩过添加

tableView.tableHeaderView = searchController.searchBar
navigationController?.navigationBar.prefersLargeTitles = true
navigationItem.title = "hello"

但它看起来不像普通的 SearchControllers（我不明白为什么我不能让它像其他人一样工作，它应该根据我在这里看到的内容自动具有此功能http://blog.eppz.eu/swiftui-search-bar-in-the-navigation-bar/)

Answer 1

您可能必须检查UITableView 的滚动方向并通过代码手动禁用UISearchController。方法如下：

var lastContentOffset: CGFloat = 0 // declare the previous offset for reference

override func viewDidLoad() {
    super.viewDidLoad()
    //...
    searchController = UISearchController(searchResultsController: nil) // remove let
    navigationItem.hidesSearchBarWhenScrolling = true
    //...
}

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    navigationItem.searchController = lastContentOffset < scrollView.contentOffset.y ? nil : searchController
}