UICollectionView在多个单元格上显示相同的图像

Question

我面临一个非常奇怪的问题。我的UICollectionView为多个单元格渲染相同的图像。我正在从外部源加载图像。这是我的代码。

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

    let cell: TTElementViewCell? = collectionView.dequeueReusableCell(withReuseIdentifier:reuseIdentifier, for: indexPath) as? TTElementViewCell
    cell?.imageView.image = UIImage(named:"dummyImage.png")
    let uniqueImageName = TTApplicationModel.sharedModel.cacheKey(fbUrl: crItem.profileImageUrl)
    DispatchQueue.main.async {
        cell?.load(cacheKey: uniqueImageName, url: crItem.profileImageUrl)
    }
    return cell!
}

这是我在名为TTElementViewcell的自定义单元格类中的加载函数，它扩展了UICollectionViewCell。

func load(cacheKey:String,url:String){
    let loader = TTAsyncImageLoader()
    let uniqueImageName = TTApplicationModel.sharedModel.cacheKey(fbUrl: url)
    if uniqueImageName != ""{
        loader.load(cacheKey: uniqueImageName, url: URL(string:url)!, completion: { (image:UIImage?) in
            DispatchQueue.main.async {
                self.imageView.image = image!
            }
        })
    }
}

以下是TTAsyncImageLoader类的详细信息。

import UIKit
class TTAsyncImageLoader {
fileprivate let model = TTApplicationModel.sharedModel.imageCache

private func getDataFromUrl(url: URL, completion: @escaping (_ data: Data?, _  response: URLResponse?, _ error: Error?) -> Void) {
    URLSession.shared.dataTask(with: url) {
        (data, response, error) in
        completion(data, response, error)
        }.resume()
}

func load(cacheKey:String, url:URL,completion:@escaping (_ success:UIImage?)->Void) {
    if let image = self.model.object(forKey: cacheKey as AnyObject) as? UIImage{
        completion(image)
        return
    }
    self.getDataFromUrl(url: url) { (imgData:Data?, response:URLResponse?, error:Error?) in
        if error == nil{
            self.model.setObject(UIImage(data: imgData!)!, forKey: cacheKey as AnyObject)
            completion(UIImage(data: imgData!)!)
        }else{
            print("TTAsyncImageLoader::load \(error!.localizedDescription) ")
        }
    }
}
}

输出显示在图像中：