刷新功能无法正常工作Swift 3

Question

因此，我有一个加载rss feed的应用程序，并且实现了刷新功能。 上传刷新，它会重新加载并添加新帖子（如果已发布），但以前的数据会保留在那里并添加到堆栈中。 检查代码和图像。 我在下面附上。

//
//  TableViewController.swift
//  WebView
//

import UIKit

class TableViewController: UITableViewController,XMLParserDelegate{

    var currentElement:String = ""
    var postTitle:String = ""
    var webLink:String = ""
    var feeds:[Model] = []
    var reload: UIRefreshControl! = UIRefreshControl()

    override func viewDidLoad() {
        super.viewDidLoad()
        //let urlToSend: NSURL = NSURL(string: "https://sensodyneforsensitiveteeth.wordpress.com/feed")!
        let urlToSend: NSURL = NSURL(string: "http://froshgeek.com/feed")!
        let parser = XMLParser(contentsOf: urlToSend as URL)!
        parser.delegate = self
        parser.parse()
        //reload
        reload!.attributedTitle = NSAttributedString(string: "Pull to reload the page")
        reload!.addTarget(self, action: #selector(TableViewController.reloadFunc), for: UIControlEvents.valueChanged)
        tableView.addSubview(reload)
        reload.endRefreshing()


        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem()
    }

    func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String]) {
        currentElement=elementName;
        if(elementName=="item")
        {
            postTitle = String()
            webLink = String()
        }
    }

    func parser(_ parser: XMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?) {
        if(elementName=="item"){
            let feed: Model = Model()
            feed.postTitle = postTitle
            feed.webLink = webLink
            feeds.append(feed)

        }
    }

    func parser(_ parser: XMLParser, foundCharacters string: String) {
        let data = string.replacingOccurrences(of: "^\\s*", with: "", options: .regularExpression)
        if (!data.isEmpty){
            if currentElement  == "title" {
                postTitle += data
            }
            else if currentElement == "link" {
                webLink += data
            }
        }
    }

    func parser(_ parser: XMLParser, parseErrorOccurred parseError: Error) {
        print("Bad XML File, Please validate")
    }

    func reloadFunc(_ sender: AnyObject){

        viewDidLoad()

        self.tableView.reloadData()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // 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 feeds.count
    }


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

        let feeds: Model = self.feeds[indexPath.row]
        cell.textLabel?.text = feeds.postTitle

        return cell
    }

    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "webParse" {
            let feed: Model = feeds[tableView.indexPathForSelectedRow!.row]
            let pageView = segue.destination as! ViewController
            pageView.webLink = feed.webLink
        }
    }

    func parserDidEndDocument(_ parser: XMLParser){

        self.tableView.reloadData();
        self.refreshControl?.endRefreshing();
    } 
}

Model.swift

//
//  Model.swift
//  WebView
//

import Foundation

class Model {
    var postTitle:String = ""
    var webLink:String = ""
    var currentElement:String = ""

}

ViewController.swift

//
//  ViewController.swift
//  WebView
//

import UIKit

class ViewController: UIViewController, UIWebViewDelegate {

    @IBOutlet weak var showPage: UIWebView!
    var webLink: String = String()

    override func viewDidLoad() {
        super.viewDidLoad()
        let link : NSURL = NSURL(string: webLink)!
        let req : NSURLRequest = NSURLRequest(url: link as URL)
        showPage.loadRequest (req as URLRequest)
        showPage.delegate = self
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

重新加载时的屏幕截图

Answer 1

最后添加对象的原因是因为您需要在刷新数据之前清空数组。 同样，永远不要显式调用viewDidLoad ，您需要做的是使一个方法发出此API请求，并从viewDidLoad和refresh方法中调用该方法。

override func viewDidLoad() {
    super.viewDidLoad()
    //call function to get xml data
    self.getData()

    //reload
    reload!.attributedTitle = NSAttributedString(string: "Pull to reload the page")
    reload!.addTarget(self, action: #selector(TableViewController.reloadFunc), for: UIControlEvents.valueChanged)
    tableView.addSubview(reload)
    reload.endRefreshing()
}

func getData() {
    //Make array empty first
    feeds = []

    let urlToSend: NSURL = NSURL(string: "http://froshgeek.com/feed")!
    let parser = XMLParser(contentsOf: urlToSend as URL)!
    parser.delegate = self
    parser.parse()
}

现在在刷新操作方法reloadFunc调用此getData函数

func reloadFunc(_ sender: AnyObject){

    self.getData()
    self.tableView.reloadData()
}