滚动后，TableViewCell中的标签和图像正在消失

Question

在我的iOS应用程序中，我已经创建了表格和其他许多东西，但现在，在实施一个＆＃34;评论＆＃34;标签和＆＃34; reviewCell＆＃34;中的图像在向下滚动并再次向上滚动后消失，我无法弄清楚原因！ 我已经调试了代码但是一切都设置正确。

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "reviewCell", for: indexPath) as! ReviewCell
    let review = self.reviews[indexPath.row]

    if review.authorName == nil{
        self.reviews[indexPath.row].authorName = NSLocalizedString("ANONYMOUS", comment: "")
        cell.authorLabel.text = NSLocalizedString("ANONYMOUS", comment: "")
    }
    else{
        cell.authorLabel.text = review.authorName
    }
    cell.ratingView.rating = Double(review.rating)
    cell.reviewTextLabel.text = review.text
    if(self.reviewProfileImages[indexPath.row] == nil){
        cell.profileImage.image = UIImage()
        downloadImageAndSaveForKey(key: indexPath.row, url: review.profile_photo_url);
    }
    else{
        cell.profileImage.image = self.reviewProfileImages[indexPath.row]!;
    }

    return cell
}

ReviewCell：

class ReviewCell: UITableViewCell {

    @IBOutlet weak var profileImage: UIImageView!
    @IBOutlet weak var authorLabel: UILabel!
    @IBOutlet weak var ratingView: CosmosView!
    @IBOutlet weak var reviewTextLabel: UILabel!
    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }

}

图像保存在Map [Int：UIImage]中，以防止每次都下载图像。

不滚动（在模拟器上，图像和作者标签加载仅显示几毫秒）：

故事板：

修改

DownloadImageAndSaveForKey函数

func downloadImageAndSaveForKey(key: Int, url: String){
        let catPictureURL = URL(string: url)!
        let session = URLSession(configuration: .default)
        let downloadPicTask = session.dataTask(with: catPictureURL) { (data, response, error) in
            if let e = error {
                print("Error downloading cat picture: \(e)")
            } else {
                if (response as? HTTPURLResponse) != nil {
                    if let imageData = data {
                        self.reviewProfileImages[key] = UIImage(data: imageData)
                        DispatchQueue.main.async {
                            self.tableView.reloadData()
                        }
                    } else {
                        print("Couldn't get image: Image is nil")
                    }
                } else {
                    print("Couldn't get response code for some reason")
                }
            }
        }
        downloadPicTask.resume()
    }

EDIT2

打印第0行（所有内容都正确显示）：Row 0, authorLabelText: Optional("Anonymous"), profile image Optional(<UIImage: 0x1d40bc380>, {128, 128})

打印第0行（滚动后，消失）：Row 0, authorLabelText: Optional("Anonymous"), profile image Optional(<UIImage: 0x1d40bc380>, {128, 128})