Zum Aktualisieren ziehen funktioniert nicht

Question

Ich baue meine App in Swift 3 mit Alamofire. Ich habe JSON-Daten, die in eine Listenansicht kommen. Jedes Mal, wenn ich den Inhalt aktualisiere, anstatt den Inhalt zu aktualisieren, fügt er einfach weitere Elemente am Ende der Liste in der Listenansicht hinzu, anstatt die sichtbare Liste zu aktualisieren. Ich weiß nicht, was ich falsch tun könnte, mein Code so weit ist:

import UIKit 
import Alamofire 
import SVProgressHUD 

struct postinput { 
    let mainImage : UIImage! 
    let name : String! 
    let author : String! 
    let summary : String! 
    let content : String! 


} 


class TableViewController: UITableViewController { 

    //var activityIndicatorView: UIActivityIndicatorView! 

    var postsinput = [postinput]() 

    var refresh = UIRefreshControl() 

    var mainURL = "https://www.example.com/api" 

    typealias JSONstandard = [String : AnyObject] 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     // Do any additional setup after loading the view, typically from a nib. 
     tableView.separatorStyle = UITableViewCellSeparatorStyle.none 


     self.tableView.addSubview(refresh) 

     //;refresh.attributedTitle = NSAttributedString(string: "Refreshing...", attributes:[NSForegroundColorAttributeName : UIColor.black]) 
     refresh.backgroundColor = UIColor(red:0.93, green:0.93, blue:0.93, alpha:1.0) 
     //refresh.tintColor = UIColor.white 

     refresh.addTarget(self, action: #selector(self.refreshData), for: UIControlEvents.valueChanged) 
     //refresh.addTarget(self, action: #selector(getter: TableViewController.refresh), for: UIControlEvents.valueChanged) 
     refresh.attributedTitle = NSAttributedString(string: "Updated: \(NSDate())") 


     //activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.gray) 
     //tableView.backgroundView = activityIndicatorView 

     callAlamo(url: mainURL) 


    } 

    func refreshData() { 

     Alamofire.request("https://www.example.com/api").responseJSON(completionHandler: { 
      response in 
      self.parseData(JSONData: response.data!) 
      self.tableView.separatorStyle = UITableViewCellSeparatorStyle.singleLine 

      DispatchQueue.main.async { 
       self.tableView.reloadData() 
       self.refresh.endRefreshing() 
      } 


     }) 



    } 



    func callAlamo(url : String){ 
     //activityIndicatorView.startAnimating() 
     SVProgressHUD.show(withStatus: "Loading...") 
     SVProgressHUD.setDefaultStyle(SVProgressHUDStyle.dark) 
     SVProgressHUD.setDefaultAnimationType(SVProgressHUDAnimationType.native) 
     SVProgressHUD.setDefaultMaskType(SVProgressHUDMaskType.black) 
     Alamofire.request(url).responseJSON(completionHandler: { 
      response in 
      self.parseData(JSONData: response.data!) 
      self.tableView.separatorStyle = UITableViewCellSeparatorStyle.singleLine 
      //self.activityIndicatorView.stopAnimating() 
      SVProgressHUD.dismiss() 


     }) 


    } 


    func parseData(JSONData : Data) { 
     do { 
      var readableJSON = try JSONSerialization.jsonObject(with: JSONData, options: .mutableContainers) as! JSONstandard 
      // print(readableJSON) 

      if let posts = readableJSON["posts"] as? [JSONstandard] { 
       for post in posts { 
        let title = post["title"] as! String 

        let author = post["author"] as! String 

        guard let dic = post["summary"] as? [String: Any], let summary = dic["value"] as? String else { 
         return 
        } 
        let str = summary.replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression, range: nil) 
        print(str) 

        guard let dic1 = post["content"] as? [String: Any], let content = dic1["value"] as? String else { 
         return 
        } 
        let str1 = content.replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression, range: nil) 
        print(str1) 





        //print(author) 

        if let imageUrl = post["image"] as? String { 
         let mainImageURL = URL(string: imageUrl) 
         let mainImageData = NSData(contentsOf: mainImageURL!) 
         let mainImage = UIImage(data: mainImageData as! Data) 

         postsinput.append(postinput.init(mainImage: mainImage, name: title, author: author, summary: summary, content: content)) 
        } 
       } 
       DispatchQueue.main.async { 
        self.tableView.reloadData() 
       } 
      } 


     } 


     catch { 
      print(error) 
     } 


    } 


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

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

     // cell?.textLabel?.text = titles[indexPath.row] 

     let mainImageView = cell?.viewWithTag(2) as! UIImageView 

     mainImageView.image = postsinput[indexPath.row].mainImage 

     mainImageView.layer.cornerRadius = 5.0 
     mainImageView.clipsToBounds = true 

     //(cell?.viewWithTag(2) as! UIImageView).image = postsinput[indexPath.row].mainImage 

     let mainLabel = cell?.viewWithTag(1) as! UILabel 

     mainLabel.text = postsinput[indexPath.row].name 

     mainLabel.font = UIFont.boldSystemFont(ofSize: 18) 

     mainLabel.sizeToFit() 

     mainLabel.numberOfLines = 0; 

     let autLabel = cell?.viewWithTag(3) as! UILabel 

     autLabel.text = postsinput[indexPath.row].author 

     autLabel.font = UIFont(name: "Helvetica", size:16) 

     autLabel.textColor = UIColor(red: 0.8784, green: 0, blue: 0.1373, alpha: 1.0) /* #e00023 */ 

     let sumLabel = cell?.viewWithTag(4) as! UILabel 

     sumLabel.text = (postsinput[indexPath.row].summary).replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression, range: nil) 

     sumLabel.font = UIFont(name: "Helvetica", size:16) 

     sumLabel.textColor = UIColor(red:0.27, green:0.27, blue:0.27, alpha:1.0) 

     //let contentLabel = cell?.viewWithTag(0) as! UILabel 

     //contentLabel.text = (postsinput[indexPath.row].content).replacingOccurrences(of: "<[^>]+>", with: "", options: .regularExpression, range: nil) 



     //(cell?.viewWithTag(3) as! UILabel).text = postsinput[indexPath.row].author 

     return cell! 
    } 

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) { 
     SVProgressHUD.show() 
     let indexPath = self.tableView.indexPathForSelectedRow?.row 

     let vc = segue.destination as! nextVC 


     vc.articleImage = postsinput[indexPath!].mainImage 
     vc.articleMainTitle = postsinput[indexPath!].name 
     vc.articleContent = postsinput[indexPath!].content 
     SVProgressHUD.dismiss() 

     let backItem = UIBarButtonItem() 
     backItem.title = "Back" 
     navigationItem.backBarButtonItem = backItem // This will show in the next view controller being pushed 



    } 


    override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) { 
     if editingStyle == .delete { 
      postsinput.remove(at: indexPath.row) 
      tableView.deleteRows(at: [indexPath], with: .fade) 
     } else if editingStyle == .insert { 
      // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view. 
     } 
    } 

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


} 

Answer 1

Ihre Aufgabe hier zu ziehen, um zu aktualisieren, ist nur die Daten in Ihrer Liste aktualisieren und auch die neuen Elemente hinzufügen, wenn vorhanden. Was Sie also tun müssen, ist, dass Sie nicht jedes Mal, wenn Sie Pull-to-Refresh durchführen, die Elemente zu Ihrer Liste hinzufügen, sondern nur eine neue Liste, die vom Server zu Ihrem TableView kommt. Welches Sie haben das Array already postsinput so stellen Sie sicher, alle Elemente zu entfernen, bevor Sie es hinzufügen. Unten ist Ihr Code, wo Sie die Änderungen vornehmen können.

func parseData(JSONData : Data) { 

    postsinput.removeAll() 

    do { 

     ... 
     ... 
       if let imageUrl = post["image"] as? String { 
        let mainImageURL = URL(string: imageUrl) 
        let mainImageData = NSData(contentsOf: mainImageURL!) 
        let mainImage = UIImage(data: mainImageData as! Data) 

        postsinput.append(postinput.init(mainImage: mainImage, name: title, author: author, summary: summary, content: content)) 
       } 
      } 
      DispatchQueue.main.async { 
       self.tableView.reloadData() 
      } 
     ... 
     ... 
} 

Answer 2

Ihre Frage ist hier:

postsinput.append(postinput.init(mainImage: mainImage, name: title, author: author, summary: summary, content: content)) 

Sie immer wieder neue Daten zu den alten Daten angehängt wird. Wenn Sie die alten Daten vollständig löschen möchten, bevor Sie neue Daten hinzufügen, entfernen Sie einfach alle Elemente aus dem Array postsinput.