如何推送不在导航控制器中的视图控制器？迅速

Question

我有两个 ViewController，TimeZonesTable 和 ResultsTableController。

TimeZonesTable 包括一个搜索栏。搜索结果显示在ResultsTableController中。

点击 ResultsTableController 中的结果会将时区保存到 Core Data 并（应该）关闭 ResultsTableController 并重新加载 TimeZonesTable 以显示所有已保存的时区。

在关闭 ResultsTableController 后，我无法让 TimeZonesTable 重新加载。

我尝试在ResultsTableController 的viewWillDisappear 函数中重新加载TimeZonesTable 表，但它不起作用。

任何帮助将不胜感激。

注意：ResultsTableController 不在导航控制器中。

时区表

import UIKit
import CoreData

class TimeZonesTable: UITableViewController, UISearchResultsUpdating, UISearchControllerDelegate, UISearchBarDelegate {

    var cities: [Zone] = []
    var savedCities: [SavedCity] = [] {
        didSet {
            refreshData()
        }
    }
    var resultsTableController: ResultsTableController!

    override func viewDidLoad() {

        getSavedCities()
        getAvailableCities()

        navigationItem.leftBarButtonItem = editButtonItem
        navigationItem.leftBarButtonItem?.tintColor = UIColor.label

        resultsTableController = ResultsTableController()

        let searchController = UISearchController(searchResultsController: resultsTableController)

        searchController.searchResultsUpdater = self
        searchController.searchBar.autocapitalizationType = .none

        if #available(iOS 11.0, *) {
            // For iOS 11 and later, place the search bar in the navigation bar.
            navigationItem.searchController = searchController

            // Make the search bar always visible.
            navigationItem.hidesSearchBarWhenScrolling = false
        } else {
            // For iOS 10 and earlier, place the search controller's search bar in the table view's header.
            tableView.tableHeaderView = searchController.searchBar
        }

        searchController.delegate = self
        searchController.searchBar.delegate = self // Monitor when the search button is tapped.
        definesPresentationContext = true

    }

    func getAvailableCities() {

        let config = URLSessionConfiguration.default
        let session = URLSession(configuration: config)
        let url = Bundle.main.url(forResource: "data", withExtension: "json")!

        let task = session.dataTask(with: url) { data, response, error in

            // Check for errors
            guard error == nil else {
                print ("error: \(error!)")
                return
            }
            // Check that data has been returned
            guard let content = data else {
                print("No data")
                return
            }

            do {
                let decoder = JSONDecoder()
                decoder.keyDecodingStrategy = .convertFromSnakeCase
                let fetchedData = try decoder.decode([Zone].self, from: content)

                for city in fetchedData {
                    self.cities.append(city)
                }

            } catch let err {
                print("Err", err)
            }
        }
        // Execute the HTTP request
        task.resume()
    }

    // MARK: - Table view data source
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return savedCities.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "timeZoneCell") as! TimeZoneCell

        if let city = savedCities[indexPath.row].cityName {

            cell.cityName.text = "\(city)"

            if let date = savedCities[indexPath.row].formattedDate {

                let formatter = DateFormatter()
                formatter.dateFormat = "yyyy-MM-dd"
                let formattedDate = formatter.date(from: date)

                formatter.dateFormat = "EEE, d MMM yyyy"
                let dateString = formatter.string(from: formattedDate!)

                cell.cityDate.text = dateString
            }

            if let time = savedCities[indexPath.row].formattedTime {

                let formatter = DateFormatter()
                formatter.dateFormat = "HH:mm:ss"
                let formattedTime = formatter.date(from: time)

                formatter.dateFormat = "HH:mm"
                let timeString = formatter.string(from: formattedTime!)

                cell.currentCityTime.text = timeString
            }
        }
        return cell
    }

    func updateSearchResults(for searchController: UISearchController) {

        let searchBar = searchController.searchBar
        filterContentForSearchText(searchBar.text!)
    }

    // Filter results based on search text
    func filterContentForSearchText(_ searchText: String) {

        let filteredArray = cities.filter ({$0.cityName?.lowercased().range(of: searchText.lowercased()) != nil})

        resultsTableController.filteredCities = filteredArray
        resultsTableController.tableView.reloadData()
    }

    func getSavedCities() {
        if let context = (UIApplication.shared.delegate as? AppDelegate)?.persistentContainer.viewContext {
            if let timeZonesFromCD = try? context.fetch(SavedCity.fetchRequest()) {
                if let timeZones = timeZonesFromCD as? [SavedCity] {
                    savedCities = timeZones
                    tableView.reloadData()
                }
            }
        }
    }

    func refreshData() {

        for city in savedCities {

            let config = URLSessionConfiguration.default
            let session = URLSession(configuration: config)
            let originalUrl = "http://vip.timezonedb.com/v2.1/get-time-zone?key=\(apiKey)&format=json&by=city&city=\(city.cityName!)&country=\(city.countryCode!)"

            if let encodedUrl = URL(string: originalUrl.addingPercentEncoding(withAllowedCharacters: .urlFragmentAllowed)!) {

                let task = session.dataTask(with: encodedUrl) { data, response, error in

                    // Check for errors
                    guard error == nil else {
                        print ("error: \(error!)")
                        return
                    }
                    // Check that data has been returned
                    guard let content = data else {
                        print("No data")
                        return
                    }

                    do {
                        let decoder = JSONDecoder()
                        decoder.keyDecodingStrategy = .convertFromSnakeCase
                        let fetchedData = try decoder.decode(TimeZones.self, from: content)

                        if let data = fetchedData.zones?.first {

                            DispatchQueue.main.async {

                                // Update time and date
                                city.formatted = data.formatted
                                city.formattedTime = data.formatted!.components(separatedBy: " ").last!
                                city.formattedDate = data.formatted!.components(separatedBy: " ").first!
                                self.tableView.reloadData()

                            }
                        }
                    } catch let err {
                        print("Err", err)
                    }
                }
                // execute the HTTP request
                task.resume()
            }
        }
    }

    @IBAction func refreshButtonTapped(_ sender: Any) {
        getSavedCities()
    }
}

结果表控制器

import UIKit
import CoreData

class ResultsTableController: UITableViewController {

    var filteredCities = [Zone]()

    override func viewDidLoad() {
        super.viewDidLoad()

        self.tableView.register(UITableViewCell.self, forCellReuseIdentifier: "searchResultsCell")

    }

    // MARK: - Table view data source
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return filteredCities.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "searchResultsCell", for: indexPath)

        if let city = filteredCities[indexPath.row].cityName {

            if let country = filteredCities[indexPath.row].countryName {
                cell.textLabel?.text = "\(city.replacingOccurrences(of: "_", with: " ")), \(country)"
            }
        }
        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

        let selectedCity = filteredCities[indexPath.row]

        let config = URLSessionConfiguration.default
        let session = URLSession(configuration: config)
        let originalUrl = "http://vip.timezonedb.com/v2.1/get-time-zone?key=\(apiKey)&format=json&by=city&city=\(selectedCity.cityName!)&country=\(selectedCity.countryCode!)"

        if let encodedUrl = URL(string: originalUrl.addingPercentEncoding(withAllowedCharacters: .urlFragmentAllowed)!) {
            print(encodedUrl)

            let task = session.dataTask(with: encodedUrl) { data, response, error in

                // Check for errors
                guard error == nil else {
                    print ("error: \(error!)")
                    return
                }
                // Check that data has been returned
                guard let content = data else {
                    print("No data")
                    return
                }

                do {
                    let decoder = JSONDecoder()
                    decoder.keyDecodingStrategy = .convertFromSnakeCase
                    let fetchedData = try decoder.decode(TimeZones.self, from: content)

                    if let city = fetchedData.zones?.first {

                        DispatchQueue.main.async {

                            if let context = (UIApplication.shared.delegate as? AppDelegate)?.persistentContainer.viewContext {

                                let savedCity = SavedCity(context: context)

                                if let offSet = city.gmtOffset {

                                    savedCity.formattedDate = city.formatted!.components(separatedBy: " ").first!
                                    savedCity.formattedTime = city.formatted!.components(separatedBy: " ").last!
                                    savedCity.formatted = city.formatted
                                    savedCity.countryCode = city.countryCode
                                    savedCity.formattedCityName = city.zoneName!.components(separatedBy: "/").last!
                                    savedCity.countryName = city.countryName
                                    savedCity.gmtOffset = Int32(offSet)
                                    savedCity.zoneName = city.zoneName
                                    savedCity.cityName = city.cityName

                                }
                                // Save to core data
                                (UIApplication.shared.delegate as? AppDelegate)?.saveContext()
                            }
                        }
                    }
                } catch let err {
                    print("Err", err)
                }
            }
            // execute the HTTP request
            task.resume()
            self.dismiss(animated: true, completion: nil)
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        let vc = TimeZonesTable()
        vc.refreshData()
    }
}

Answer 1

由于您在 TimeZoneTable 与 ResultTable 中没有不同的功能，因此我只需像这样在 TimeZoneTable 中进行过滤：

首先添加一个新的变量：

var allCities:[Zone] = []

然后更改您的 getCities 以将数据复制到新的 var

func getSavedCities() {
    if let context = (UIApplication.shared.delegate as? AppDelegate)?.persistentContainer.viewContext {
        if let timeZonesFromCD = try? context.fetch(SavedCity.fetchRequest()) {
            if let timeZones = timeZonesFromCD as? [SavedCity] {
                savedCities = timeZones
                allCities = timeZones
                tableView.reloadData()
            }
        }
    }
}

最后为您的 SearchTextView 创建一个 IBAction 以更改文本

@IBAction func searchTextViewChanged(_ sender: Any) {
    savedCities = allCities
    savedCities = savedCities.filter {
        ($0.countryName.lowercased().contains(searchTextView.text) ||
        filterString == "")
    }
    tableView.reloadData()
}

这种方法可以帮助您处理重复的代码，并且您需要管理的视图更少我看不出拥有 2 个几乎相同的视图控制器会带来什么好处

希望这会有所帮助，即使它在技术上并不完全符合您的要求，我认为这是一种更清洁的过滤 tableView 的方法

Answer 2

在这里设置一个委托并在ResultsTableController中添加avaibale

resultsTableController = ResultsTableController() 
resultsTableController.delegate = self

然后

    // Save to core data
(UIApplication.shared.delegate as? AppDelegate)?.saveContext()
self.delegate?.reload()
 self.dismiss(animated: true, completion: nil)

Answer 3

您可以创建协议并获取回调。按照步骤操作，您的问题将得到解决。

第 1 步：创建协议

//Step #1
protocol ResultsTableControllerDelegate {
    func didSavedTimeZone()
}

第 2 步：分配代表

import UIKit
import CoreData


class TimeZonesTable: UITableViewController, UISearchResultsUpdating, UISearchControllerDelegate, UISearchBarDelegate {
    //Your code
    var resultsTableController: ResultsTableController!

    override func viewDidLoad() {
        // Your code

        resultsTableController = ResultsTableController()

        //Step #2
        resultsTableController.resultsDelegate = self //Asign delegate here

        // Your code

    }
}

*第 3 步：在您的班级中实施委托并做任何您需要的事情*

//Step #3
extension TimeZonesTable: ResultsTableControllerDelegate {
    func didSavedTimeZone() {
        //Reload your data or Table
    }
}

第四步：在结果控制器中创建委托

import UIKit
import CoreData

class ResultsTableController: UITableViewController {

    //Step #4
    var resultsDelegate: ResultsTableControllerDelegate?

    //Your code
}

第 5 步：保存数据后调用 Delegate

注意： 请在关闭控制器之前调用委托

import UIKit
import CoreData

class ResultsTableController: UITableViewController {

    //Step #4
    var resultsDelegate: ResultsTableControllerDelegate?

    //Your code
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

        //Your code
        //Step #5
        resultsDelegate?.didSavedTimeZone()
        self.dismiss(animated: true, completion: nil)
        //Your code
    }

}