＆＃34;无法读取数据＆＃34;将stringUrl转换为图像时

Question

我在UITableViewCell中有一个UICollectionView，我的缓冲区中有图像url，我想下载并在我的CollectionView中显示图像。

但不知道为什么显示无法读取数据 以下是我的代码： -

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "BrandImagesCell", for: indexPath) as! BrandImagesCell

    //let StrUrl = NSURL(string: self.arrImages[indexPath.row])! as URL
    let urlPath: String = self.arrImages[indexPath.row]
    let StrUrl: NSURL = NSURL(string: urlPath)!

    cell.brandImage.downloadedFrom(url: StrUrl as URL, contentMode: .scaleToFill)

    return cell
}  

下载图片的方法： -

extension UIImageView {
func downloadedFrom(url: URL, contentMode mode: UIViewContentMode = .scaleAspectFit) {
    contentMode = mode
    URLSession.shared.dataTask(with: url) { (data, response, error) in
        guard
            let httpURLResponse = response as? HTTPURLResponse, httpURLResponse.statusCode == 200,
            let mimeType = response?.mimeType, mimeType.hasPrefix("image"),
            let data = data, error == nil,
            let image = UIImage(data: data)
            else { return }
        DispatchQueue.main.async() { () -> Void in
            self.image = image
        }
        }.resume()
    }
}  

我的数组中有所有图片网址（self.arrImages） 我该怎么做才能下载在collectionView中显示它？ 感谢