从服务器视频 url 创建的缩略图图像在滚动 tableview 时不断变化

Question

在我的应用程序中，我已经成功地从视频 url 创建了缩略图图像并显示在表格单元格中，但问题是当我滚动表格视图单元格时，缩略图图像不断变化。如何解决这个问题。请帮我解决这个问题，因为我尝试过搜索但没有运气

我的代码尝试过： 我的单元类代码：-

class VideoCell: UITableViewCell {

    static let cellID = "VideoCell"
      
    //MARK:- Outlets
    @IBOutlet weak var videoThumbImage: UIImageViewX!
    @IBOutlet weak var dateLbl: UILabel!
    @IBOutlet weak var mainView: UIViewX!
    @IBOutlet weak var userProfileImage: UIImageViewX!
    @IBOutlet weak var playBtn: UIButton!
    
    //MARK:- Properties
    var chatObj:ModelOldMessagesMessages? {
        didSet {
            configure()
        }
    }
    
    //MARK:- Life Cycle
    override func awakeFromNib() {
        super.awakeFromNib()
        
        self.mainView.layer.cornerRadius = 10
        self.mainView.layer.maskedCorners = [.layerMaxXMaxYCorner,.layerMaxXMinYCorner,.layerMinXMaxYCorner]
    }
    
    //MARK:- Helpers
    private func configure() {
        guard let obj = chatObj else {return}
        
        if let msgStr = obj.chatMsgText, let time = obj.chatMsgDatetime, time.count > 0, msgStr.count > 0 {
            let time = convertUTCToLocal(timeString: time)
            self.dateLbl.text = changeDateForamte(time!, conVertFormate: "hh:mm a", currentDateFormate: "yyyy-MM-dd HH:mm:ss ")
            
            let imgStr = WS_Chat_DownloadFile + msgStr
            let url = URL(string: imgStr)!
            
            self.getThumbnailImageFrom(fileUrl: url) { (image) in
               self.videoThumbImage.image = image
            }
        }
        if let tmpImgURL = obj.adminImage, tmpImgURL.count > 0 {
            let img = WS_DownloadImage + tmpImgURL
            self.userProfileImage.loadImage(img)
        }
        
    }
    
    fileprivate func getThumbnailImageFrom(fileUrl: URL, completion: @escaping (_ image: UIImage?) -> Void){
        DispatchQueue.global().async {
             let asset = AVAsset(url: fileUrl)
             let imgGenerator = AVAssetImageGenerator(asset: asset)
             imgGenerator.appliesPreferredTrackTransform = true
            
             let thumbnailTime = CMTimeMake(value: 2, timescale: 1)
            
            do {
                let thumbnailCGImage = try imgGenerator.copyCGImage(at: thumbnailTime, actualTime: nil)
                let finalImage = UIImage(cgImage: thumbnailCGImage)
                
                DispatchQueue.main.async {
                    completion(finalImage)
                }
                
            } catch let err {
                print(err.localizedDescription)
                DispatchQueue.main.async {
                    completion(nil)
                }
            }
        }
    }

我的 cellforrow 函数

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
    
        let dict = oldMessageArr[indexPath.row]
         
let videoCell = tableView.dequeueReusableCell(withIdentifier: VideoCell.cellID) as! VideoCell
            videoCell.chatObj = dict
            videoCell.playBtn.tag = indexPath.row
            videoCell.playBtn.addTarget(self, action: #selector(handlePlayBtn), for: .touchUpInside)
        return videoCell
    }

根据计时器调用聊天 api 的主控制器类文件代码：

//MARK:- Life Cycle

override func viewDidLoad() {
    super.viewDidLoad()
    registerCell()
    setupRefreshControl()
}

override func viewWillAppear(_ animated: Bool) {
    WS_GetOldMessagesAPI()
    self.newMessagesLoadTimer.invalidate()
}

func setupRefreshControl() {
    refresher.tintColor = .black
    refresher.addTarget(self, action: #selector(refreshData), for: .valueChanged)
    self.tableView.addSubview(refresher)
}

@objc func refreshData() {
   self.WS_GetOldMessagesAPI()
}

@objc func timerAction() {
    self.newMessagesLoadTimer.invalidate()
    self.WS_getNewMessage()
}
 

func WS_getNewMessage()
    {
        var url = String()
        
        let model = ApiUtillity.sharedInstance.getLoginModel()
        
        if let c_id = model?.loginDataResult?.chatRoomsId {
            self.chatRoomId = c_id
        }
        
        var offset = Int()
        let dict = oldMessageArr.last
        if let offID = dict?.chatMsgId {
            offset = offID
        }
        
        url = WS_GET_OldChatMessage+"\(chatRoomId)"+"?"+"offsetID=\(offset)"
        
        APIClient<ModelBaseOldMessages>().API_GET(Url: url, Params: noParams, Authentication: true, Progress: false, Alert: true, Offline: false, SuperVC: self, completionSuccess: { (modelResponse) in
            
            if(modelResponse.success == true) {
                if offset == 0 {
                    self.getNewMessageArr.removeAll()
                    if let data = modelResponse.oldMessagesMessages, data.count != 0 {
                        for item in data {
                            if let id = item.chatMsgId, self.newMessageIDsArr.contains(id) == false {
                                self.newMessageIDsArr.append(id)
                                self.getNewMessageArr.append(item)
                                self.tableView.scrollToBottom()
                            }
                        }
                     
                        self.newMessagesLoadTimer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(self.timerAction), userInfo: nil, repeats: true)
                        self.tableView.reloadData()
                    }
                } else {
                    if let data = modelResponse.oldMessagesMessages, data.count != 0 {
                        for item in data {
                            if let id = item.chatMsgId, self.newMessageIDsArr.contains(id) == false {
                                self.newMessageIDsArr.append(id)
                                self.getNewMessageArr.append(item)
                            }
                        }
                        
                        self.newMessagesLoadTimer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(self.timerAction), userInfo: nil, repeats: true)
                        self.tableView.reloadData()
                    }
                }
            } else {
                self.newMessagesLoadTimer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(self.timerAction), userInfo: nil, repeats: true)
                self.tableView.reloadData()
            }
        }) { (failed) in
            self.tableView.reloadData()
        }
    }

    func WS_GetOldMessagesAPI() {
        
        var url = String()
        var offset = Int()
        
        let model = ApiUtillity.sharedInstance.getLoginModel()
        
        if let c_id = model?.loginDataResult?.chatRoomsId {
            self.chatRoomId = c_id
        }
        
        let dict = oldMessageArr.first
        if let offID = dict?.chatMsgId {
            offset = offID
        }
        
        url = WS_GET_OldChatMessage+"\(chatRoomId)"+"?"+"offsetID=\(offset)"
        
        APIClient<ModelBaseOldMessages>().API_GET(Url: url, Params: noParams, Authentication: true, Progress: true, Alert: true, Offline: false, SuperVC: self, completionSuccess: { (modelResponse) in
            
            print("---------------------")
            print("Result:",modelResponse.toJSONString(prettyPrint: true)!)
            print("---------------------")
            
            if(modelResponse.success == true) {
                if let data = modelResponse.oldMessagesMessages, data.count != 0 {
                    let neweReverseData = data.reversed()
                    for item in neweReverseData
                    {
                        if let id = item.chatMsgId, self.oldMessageIDsArr.contains(id) == false
                        {
                            self.oldMessageIDsArr.insert(id, at: 0)
                            self.oldMessageArr.insert(item, at: 0)
                        }
                    }
                    self.refresher.endRefreshing()
                    self.reloadTable()
                    
                    self.tableView.scrollToRow(at: IndexPath.init(row: data.count - 1, section: 0), at: .top, animated: false)
                }
                self.WS_getNewMessage()
            } else {
                self.refresher.endRefreshing()
                self.reloadTable()
            }
        }) { (failed) in
            self.refresher.endRefreshing()
            self.reloadTable()
        }
    }

Answer 1

在配置函数的开头，在获取和设置缩略图之前，添加

self.videoThumbImage.image = nil