arrays - 将 SearchBar 添加到 uitableview 在过滤过程中遇到错误

Question

我正在学习如何将 ui TableView 的搜索栏添加到我的 swift 项目中，我点击了此链接，https://www.youtube.com/watch?v=XtiamBbL5QU我被困在代码的一半。在我项目的这一行中

 self.countries.filter { (Country:String) -> Bool in
            <#code#>
        }

我有这个错误String' 不可转换为 'HistoryViewController.CountryHistoryViewController 是我的 TableView Controller 的名称。在我的教程项目中，唯一不同的是我有一个名为 Countries 的数组，其中包含多行字典。我将在这里发布我的其他部分代码

import UIKit

class HistoryViewController: UITableViewController , UISearchResultsUpdating {


    var searchController : UISearchController!
    var resultsController = UITableViewController()


    var myPlistArray: [String] = []

    override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat
    {
        return 115 //or whatever you need
    }

    struct Country : Decodable {
        let flagEmoji, Abb, countryName, pName : String

        private enum CointryKeys : String, CodingKey { case flagEmoji, Abb, countryName, pName }
    }

    var countries = [Country]()

    func updateSearchResults(for searchController: UISearchController) {
        //Filter through currencies

        self.countries.filter { (Country:String) -> Bool in
            <#code#>
        }

        // Update the results Table View

    }




    override func viewDidLoad() {
        super.viewDidLoad()


        self.searchController = UISearchController(searchResultsController: self.resultsController)
        self.tableView.tableHeaderView = self.searchController.searchBar
        self.searchController.searchResultsUpdater = self

        let url = Bundle.main.url(forResource: "Curr", withExtension: "plist")!
        let data = try! Data(contentsOf: url)


        do {

            countries = try PropertyListDecoder().decode([Country].self, from: data)
        } catch {
            // Handle error
            print(error)
        }
        print(countries)
        print("countries.count:", countries.count)


    }

    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        return countries.count
    }


    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        print("hiiii")

        let cell = tableView.dequeueReusableCell(withIdentifier: "historyCell", for: indexPath) as! TableViewCellforHistory

        // Configure the cell...


        cell.lblCellHistory.text = countries[indexPath.row].countryName
        cell.lblEmoji.text = countries[indexPath.row].flagEmoji
        cell.lblCurrencyName.text = countries[indexPath.row].pName

        return cell
    }
 }

Answer 1

如下更改 filter 闭包，因为 countries 是一个 Country 数组，但您将其视为 String(通过执行 Country: String)，

 self.countries.filter { country -> Bool in
      return country.countryName == "Pakistan"
 }

或

 self.countries.filter { (country: Country) -> Bool in
      return country.countryName == "Pakistan"
 }

或者简单地说，

self.countries.filter { $0.countryName == "Pakistan" }

编辑

要获取国家列表 names(即 [String])，您必须在过滤结果上使用 map，如下所示，

let filteredCountryNames = self.countries.filter { (country: Country) -> Bool in
          return country.countryName == "Pakistan"
     }.map { $0.countryName }