重构AlamofireImage in Swift 3

Question

我是Swift3编程的新手，已经接管并试图重构Swift 2.2到Swift 3中的现有应用程序。我发现Alamofire有一个新库AlamofireImage。

在那个库中，我看到有一个imageCache，并且正在考虑是否应该重构当前的imageCache代码以使用它。我的问题是它是否比目前的实施具有主要的优势或效率，如果是的话，它们是什么？任何其他改进此代码的建议也会受到赞赏。

let imageCache = AutoPurgingImageCache()似乎是一个更简单和可读的实现。

这是当前的imageCache。

class ShoppingManager { 
    static let sharedManager = ShoppingManager() 
    let imageCache = NSCache<AnyObject, AnyObject>() 

这是原始的Swift 2代码来加载图像和缓存它。

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

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! ProductsCollectionViewCell 

    // Configure the cell 
    cell.lblProduct.text = "" 
    cell.backgroundColor = UIColor.white 
    cell.imgProduct.image = nil 

    //load Cell Image 

    let shopItem = shopItems[indexPath.row] 
    cell.alamoFireRequest?.cancel() 

    if let image = ShoppingManager.sharedManager.imageCache.object(forKey: shopItem.imgUrl! as AnyObject) as? UIImage { 
     cell.imgProduct.image = image 
    } else { 
     cell.alamoFireRequest = Alamofire.request(.GET, shopItem.imgUrl!).response(completionHandler: { (_, _, data: Data?, error: NSError?) -> Void in 
      if error == nil && data != nil { 
       let img = UIImage(data: data!) 
       cell.imgProduct.image = img 
       ShoppingManager.sharedManager.imageCache.setObject(img!, forKey: shopItem.imgUrl!) 
      } 
     }) 
    } 
return cell 

} 

这是我已经重构到现在的Swift3代码。

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

     let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! ProductsCollectionViewCell 

     // Configure the cell 
     cell.lblProduct.text = "" 
     cell.backgroundColor = UIColor.white 
     cell.imgProduct.image = nil 

     //load Cell Image 

     let shopItem = shopItems[indexPath.row] 
     cell.alamoFireRequest?.cancel() 

    if let image = ShoppingManager.sharedManager.imageCache.object(forKey: shopItem.imgUrl! as AnyObject) as? UIImage { 
     cell.imgProduct.image = image 
    } else { 
     cell.alamoFireRequest = Alamofire.request(shopItem.imgUrl!).responseImage { response in 
      guard let img = response.result.value else { 
      // Handle error 
      return 
     } 
      cell.imgProduct.image = img 
      ShoppingManager.sharedManager.imageCache.setObject(img, forKey: shopItem.imgUrl! as AnyObject) 
     }    
    } 

    return cell 

    } 

Answer 1

你检查了他们的示例代码。

作为％的抽样码，这是很容易：

imageView.af_setImage(
      withURL: URL(string: URLString)!, 
      placeholderImage: placeholderImage, 
      filter: AspectScaledToFillSizeWithRoundedCornersFilter(size: size, radius: 20.0), 
      imageTransition: .crossDissolve(0.2) 
) 


imageView.af_cancelImageRequest() 

参考：https://github.com/Alamofire/AlamofireImage/blob/master/Example/ImageCell.swift

或结帐AlamofireImageView：​​

public func af_setImage

此方法支持高速缓存。