【问题标题】:tableviewController pagination retrieved my data from server twice and not all data Is retrieved from the servertableviewController 分页从服务器检索了我的数据两次,但并非所有数据都是从服务器检索的
【发布时间】:2021-03-07 10:06:26
【问题描述】:

我有一个带有 3 个单元格的 tableviewController,一个用于从服务器获取图像和文本,第二个用于仅获取文本,第三个用于实现带有活动指示器的分页,如下图 the 3 cells image


这是分页的响应:

{
    "statusCode": 200,
    "message": "Success",
    "data": {
        "result": [
            {
                "id": 28,
                "profileId": 12,
                "creatorId": 8,
                "postText": "اهلا وسهلا",
                "commentsCount": 0,
                "interactionsCount": 0,
                "createdAt": "2021-03-06T15:45:24.756Z",
                "updatedAt": "2021-03-06T15:45:24.756Z",
                "profile": {
                    "id": 12,
                    "logo": "https://onebusinessqrcode.s3.us-east-2.amazonaws.com/b562b93c-e278-5027-b615-edd399878c1a.jpg",
                    "name": "abdallah eslah",
                    "category": "Ecommerce",
                    "subCategory": "ElectronicMarket"
                },
                "creator": {
                    "id": 8,
                    "name": "abdallah eslah",
                    "image": "https://onebusinessqrcode.s3.us-east-2.amazonaws.com/0d362ee3-78e3-584a-8c34-6a91afa9dbda.png",
                    "email": "abdallaheslah@yahoo.com",
                    "mobile": "201094339599"
                },
                "media": [
                    {
                        "id": 396,
                        "postId": 28,
                        "media": "https://onebusinessqrcode.s3.us-east-2.amazonaws.com/2ad0ce30-a387-5c73-846a-eb414108fb72.jpg",
                        "createdAt": "2021-03-06T15:45:25.438Z",
                        "updatedAt": "2021-03-06T15:45:25.438Z"
                    }
                ]
            },
            {
                "id": 5,
                "profileId": 12,
                "creatorId": 8,
                "postText": "My new product",
                "commentsCount": 2,
                "interactionsCount": 0,
                "createdAt": "2021-03-01T07:13:39.400Z",
                "updatedAt": "2021-03-01T07:17:15.905Z",
                "profile": {
                    "id": 12,
                    "logo": "https://onebusinessqrcode.s3.us-east-2.amazonaws.com/b562b93c-e278-5027-b615-edd399878c1a.jpg",
                    "name": "abdallah eslah",
                    "category": "Ecommerce",
                    "subCategory": "ElectronicMarket"
                },
                "creator": {
                    "id": 8,
                    "name": "abdallah eslah",
                    "image": "https://onebusinessqrcode.s3.us-east-2.amazonaws.com/0d362ee3-78e3-584a-8c34-6a91afa9dbda.png",
                    "email": "abdallaheslah@yahoo.com",
                    "mobile": "201094339599"
                },
                "media": [
                    {
                        "id": 395,
                        "postId": 5,
                        "media": "https://onebusinessqrcode.s3.us-east-2.amazonaws.com/74c28cd0-47be-5053-85ca-c887cc36c781.jpg",
                        "createdAt": "2021-03-01T07:13:40.377Z",
                        "updatedAt": "2021-03-01T07:13:40.377Z"
                    }
                ]
            }
        ],
        "thisPage": 1,
        "allPages": 1,
        "count": 2
    }
}

所以我在下面的请求中使用它们来获取数据并实现分页:


//Used Variables in the request 
 var posts = [Posts]()
 var pictures = [UIImage]()

//Pagination Vars
 var allPages = 1
 var thisPage = 1

override func viewDidLoad() {
  super.viewDidLoad()
self.refreshControl = UIRefreshControl()
    self.refreshControl?.addTarget(self, action: #selector(refreshData), for: .valueChanged)
    self.refreshData()
 }

// MARK: - List All Posts
    @objc func refreshData(){
        thisPage = 1
        loadPosts(page: 1, refresh: true)
        
    }



@objc func loadPosts(page: Int,refresh: Bool = false) {
        
        if refresh {
   
            refreshControl?.beginRefreshing()
        }
        let profileId = UserDefaults.standard.value(forKey: "id") as? Int ?? 0
        
        var urlBuilder?.queryItems = [
        URLQueryItem(name: "profileId", value:"\(profileId)"), URLQueryItem(name: "page", value:"\(page)")
    ]
        
        guard let url = urlBuilder?.url else { return }
        
        var request = URLRequest(url: url)
        
        let token = UserDefaults.standard.value(forKey: "token") as? String ?? ""
        
        request.httpMethod = "GET"
        
        request.setValue(token, forHTTPHeaderField: "x-auth-token")
        
        // send request
        URLSession.shared.dataTask(with: request) { (data, response, error) in
            DispatchQueue.main.async {
                
                if refresh {
                    self.posts.removeAll()
                    self.refreshControl?.endRefreshing()
                }
                
                // error occured
                if error != nil {
                    Helper().showAlert(title: "Server Error", message: error!.localizedDescription, in: self)
                    return
                }
                
                do {
                    // access data - safe mode
                    guard let data = data else {
                        Helper().showAlert(title: "Data Error", message: error!.localizedDescription, in: self)
                        return
                    }
                    
                    // converting data to JSON
                    let json = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? NSDictionary
                    
                    guard let parsedJSON = json else {
                        print("Parsing Error")
                        return
                    }
                    
                    if let data = parsedJSON["data"] as? NSDictionary {
                        self.allPages = data["allPages"] as? Int ?? 1

                        let object = Posts()

                        object.allPages = self.allPages
                      
                        if let posts = data["result"] as? [NSDictionary] {
                            for item in posts {
                                
                                
                                if let interactionsCount = item["interactionsCount"] as? Int {
                                    
                                    object.interactionsCount = interactionsCount
                                    
                                    
                                }
                                
                                
                                if let commentCounts = item["commentsCount"] as? Int {
                                    object.commentCounts = commentCounts
                                    
                                }
                                if let postMedia = item["media"] as? [NSDictionary] {
                                    if postMedia.count > 0 {
                                        let icon_images = postMedia
                                        
                                        object.multiImageIcon = icon_images
                                        //                                                                                                                            self.multiImages_Icon.isHidden = false
                                        if let media = postMedia[0]["media"] as? String {
                                            object.image = media
                                        }
                                    }
                                    
                                }
                                
                                if let profile = item["profile"] as? NSDictionary {
                                    
                                    if profile.count > 0 {
                                        
                                        if let name = profile["name"] as? String {
                                            
                                            object.name = name
                                            
                                        }
                                        
                                        if let logo = profile["logo"] as? String {
                                            
                                            object.ava = logo
                                            
                                            
                                        }
                                    }
                                }
                                
                                object.text = item["postText"] as? String
                                object.name = item["name"] as? String
                                object.date = item["createdAt"] as? String
                                object.id = item["id"] as? Int
                                object.ava = item["logo"] as? String
                                object.commentCounts = item["commentsCount"] as? Int
                                object.interactionsCount = item["interactionsCount"] as? Int
                                object.allPages = item["allPages"] as? Int
                                
                                self.posts.append(object)
                                self.tableView.reloadData()
                                
                            }
                        }
                    }
                } catch {
                    Helper().showAlert(title: "JSON Error", message: error.localizedDescription, in: self)
                    return
                }
            }
        }.resume()
    }

最后是自定义数据源:

// MARK: - 表格视图数据源

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

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

    if thisPage < allPages && indexPath.row == posts.count - 1 {
        let cell = tableView.dequeueReusableCell(withIdentifier: "loading")
        return cell!
        
    }else {
        
        let pictureUrl = posts[indexPath.row].image ?? ""
    
        if pictureUrl.isEmpty == true {
        
        //5)=> accessing the text cell from main.storyboard
         let cell = tableView.dequeueReusableCell(withIdentifier: "NoPicCell", for: indexPath) as! NoPicCell
        
        
        cell.fullNameLabel.text = posts[indexPath.row].name?.capitalized ??
            UserDefaults.standard.value(forKey: "name") as? String
        
        cell.fullNameLabel.textColor = .label
        
        let postText = posts[indexPath.row].text
        
        cell.postTextLabel.text = postText
        cell.postTextLabel.textColor = .label
        
        let dateString = posts[indexPath.row].date
        
        let formatterGet = DateFormatter()
        formatterGet.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
        
        let date = formatterGet.date(from: dateString ?? "")
        
        let formatterShow = DateFormatter()
        formatterShow.dateFormat = "MMMM dd yyyy - HH:mm"
        
        cell.dateLabel.text = formatterShow.string(from: date ?? Date())
        
        let postStars = posts[indexPath.row].interactionsCount ?? 0
        
        cell.starCountTwo.text = "\(postStars )"
        cell.starCountTwo.textColor = .label
        
        let postComments = posts[indexPath.row].commentCounts ?? 0
        
        cell.commentCountOne.text = "\(postComments)"
        cell.commentCountOne.textColor = .label
        
        let avaPath = UserDefaults.standard.value(forKey: "logo") as? String
        
        let ava = posts[indexPath.row].ava
        
        Helper().downloadImage(from: (ava ?? avaPath)! , showIn: cell.avaImageViewNoPic, orShow: "user.png")
        
        // Rounded corners
        cell.avaImageViewNoPic.layer.cornerRadius = cell.avaImageViewNoPic.frame.width / 2
        cell.avaImageViewNoPic.clipsToBounds = true
        
        cell.commentsButton.tag = indexPath.row
        cell.starButtonTwo.tag = indexPath.row
        cell.optionButton.tag = indexPath.row
        
        pictures.append(UIImage())
        
        return cell

    } else {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "PicCell", for: indexPath) as! PicCell
        
        let postText = posts[indexPath.row].text
        cell.postTextLabel.text = postText
        cell.postTextLabel.textColor = .label
        
        cell.fullNameLabel.text = posts[indexPath.row].name?.capitalized ?? UserDefaults.standard.value(forKey: "name") as? String
        
        cell.fullNameLabel.textColor = .label
        
        let dateString = posts[indexPath.row].date
        
        let formatterGet = DateFormatter()
        formatterGet.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
        
        let date = formatterGet.date(from: dateString!)
        
        let formatterShow = DateFormatter()
        formatterShow.dateFormat = "MMMM dd yyyy - HH:mm"
        
        cell.dateLabel.text = formatterShow.string(from: date!)
        
        let postStars = posts[indexPath.row].interactionsCount ?? 0
        
        cell.starCountPic.text = "\(postStars )"
        cell.starCountPic.textColor = .label
        
        let postComments = posts[indexPath.row].commentCounts ?? 0
        
        cell.commentCountOne.text = "\(postComments)"
        cell.commentCountOne.textColor = .label
        
        let ava = posts[indexPath.row].ava
        
        let avaPath = UserDefaults.standard.value(forKey: "logo") as? String
        
        Helper().downloadImage(from: (ava ?? avaPath)! , showIn: cell.avaImageViewPic, orShow: "user.png")
        
        // Rounded corners
        cell.avaImageViewPic.layer.cornerRadius = cell.avaImageViewPic.frame.width / 2
        cell.avaImageViewPic.clipsToBounds = true
        
        cell.commentsButton.tag = indexPath.row
        cell.starButtonTwo.tag = indexPath.row
        cell.optionButton.tag = indexPath.row

        let pictureString = posts[indexPath.row].image
        
        let pictureURL = URL(string: pictureString ?? "")
        
        
        cell.pictureImageView.kf.setImage(with: pictureURL)
        
        if timelinePosts.count != pictures.count {
            
        }else{
            print("Pic cashed")
            DispatchQueue.main.async {
                

            }
            
    }
        
        cell.commentsButton.tag = indexPath.row
        cell.starButtonTwo.tag = indexPath.row
        cell.optionButton.tag = indexPath.row
        
    return cell
        }
    }
}

willDisplay 方法:


override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        if thisPage < allPages && indexPath.row == posts.count - 1 {
            thisPage = thisPage + 1
        loadPosts(page: thisPage,refresh: false)
        }
    }

【问题讨论】:

    标签: swift xcode uitableview nsurlsession codable


    【解决方案1】:

    将重载行移出 for 循环

      self.posts.append(object) 
    } 
    self.tableView.reloadData()
    

    【讨论】:

    • 通过在 if refresh { refreshControl?.beginRefreshing() } 中删除 posts.removeAll() 解决。我现在编辑了问题我需要从服务器中删除重复的帖子我得到了数据 twise
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