ios - 无法以编程方式在我的导航栏中获取 UISearchController

Question

我有一个主视图 Controller ，它有一个全屏 UITableView，它由来自 Firebase 的值和下面的 TabBarController 填充。 UITableView 的所有代码都以编程方式处理。我需要添加两个选项:首先，用于查询结果的搜索栏和用于从 Firebase 获取的各种类别的过滤器选项。

这是我从 ViewController 更新的代码:

import UIKit
import Firebase

class PostTable: UIViewController, UITableViewDelegate, UITableViewDataSource, UISearchControllerDelegate,UISearchResultsUpdating {

    func updateSearchResults(for searchController: UISearchController) {

    }

    var tableView:UITableView!

    var posts = [Post]()

    var searchController : UISearchController!


    override func viewDidLoad() {
        super.viewDidLoad()

        if Auth.auth().currentUser == nil {
            switchStoryboard()
        }

        tableView = UITableView(frame: view.bounds, style: .plain)
        view.addSubview(tableView)

        let cellNib = UINib(nibName: "PostTableViewCell", bundle: nil)
        tableView.register(cellNib, forCellReuseIdentifier: "postCell")
        var layoutGuide:UILayoutGuide!

        layoutGuide = view.safeAreaLayoutGuide

        tableView.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor).isActive = true
        tableView.topAnchor.constraint(equalTo: layoutGuide.topAnchor).isActive = true
        tableView.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor).isActive = true
        tableView.bottomAnchor.constraint(equalTo: layoutGuide.bottomAnchor).isActive = true

        tableView.delegate = self
        tableView.dataSource = self
        tableView.tableFooterView = UIView()
        tableView.reloadData()

        searchController = UISearchController(searchResultsController: nil)
        searchController.delegate = self
        searchController.searchResultsUpdater = self
        searchController.dimsBackgroundDuringPresentation = false // displays tableview

        let scb = self.searchController.searchBar
        scb.tintColor = UIColor.white
        scb.placeholder = "SEARCH"
        scb.barTintColor = UIColor.white

        if let textfield = scb.value(forKey: "searchField") as? UITextField {
            textfield.textColor = UIColor.green
            if let backgroundview = textfield.subviews.first {
                backgroundview.backgroundColor = UIColor.white
                backgroundview.layer.cornerRadius = 10
                backgroundview.clipsToBounds = true
            }
        }

        if #available(iOS 11.0, *) {
            navigationItem.searchController = searchController
            navigationItem.hidesSearchBarWhenScrolling = false
        } else {
            self.tableView.tableHeaderView = searchController.searchBar
            searchController.searchBar.tintColor = UIColor.green
            searchController.searchBar.barTintColor = UIColor.green
        }
        definesPresentationContext = true


        observePosts()
    }

Answer 1

添加UISearchController的变量

var searchController : UISearchController!

&然后在viewDidLoad中添加代码

    searchController = UISearchController(searchResultsController: nil)
    searchController.delegate = self
    searchController.searchResultsUpdater = self
    searchController.dimsBackgroundDuringPresentation = false // displays tableview

    let scb = self.searchController.searchBar
    scb.tintColor = UIColor.white
    scb.placeholder = "SEARCH"
    scb.barTintColor = UIColor.white

    if let textfield = scb.value(forKey: "searchField") as? UITextField {
        textfield.textColor = UIColor.greenColor
        if let backgroundview = textfield.subviews.first {
            backgroundview.backgroundColor = UIColor.white
            backgroundview.layer.cornerRadius = 10
            backgroundview.clipsToBounds = true
        }
    }

    if #available(iOS 11.0, *) {
        navigationItem.searchController = searchController
        navigationItem.hidesSearchBarWhenScrolling = false
    } else {
        self.tableView.tableHeaderView = searchController.searchBar
        searchController.searchBar.tintColor = UIColor.greenColor
        searchController.searchBar.barTintColor = UIColor.greenColor
    }
    definesPresentationContext = true