1

我正在使用（尝试）AlamofireImage。我保存到缓存的图像并没有真正保存。

我的代码包括：

import Alamofire
import AlamofireImage

let imageCache = AutoPurgingImageCache(
    memoryCapacity: 100 * 1024 * 1024,
    preferredMemoryUsageAfterPurge: 60 * 1024 * 1024
)

然后我自己使用以下方法保存图像：

imageCache.add(image, withIdentifier: path)

但在下一次运行中，当我尝试使用相同的路径获取此图像时，它总是返回 nil：

if let image = imageCache.image(withIdentifier: path){
    return image
}
return nil

我究竟做错了什么？

  • 在运行\调试时我可以看到 imageCache-currentMemoryUsage = 0

谢谢。

4

2 回答 2

2

您不需要调用 add() 方法。我创建了包装 Alamofire Image 缓存的自定义类。

class ImageManager: NSObject {
    static let shared = ImageManager()
    private var imageDownloader: ImageDownloader!
    private var imageCache: AutoPurgingImageCache!


    // Configuration
    var maximumActiveDownloads = 5
    var placeholderImage: UIImage!
    var imageTransitionDuration: NSTimeInterval = 0.5

    // The total memory capacity of the cache in MB.
    var memoryCapacity: UInt64 = 150

    //The preferred memory usage after purge in MB. During a purge, images will be purged until the memory capacity drops below this limit.
    var memoryUsageAfterPurge: UInt64 = 60


    private override init() {
        super.init()

        imageCache = AutoPurgingImageCache(
            memoryCapacity: memoryCapacity * 1024 * 1024,
            preferredMemoryUsageAfterPurge: memoryUsageAfterPurge * 1024 * 1024
        )

        imageDownloader = ImageDownloader(
            configuration: ImageDownloader.defaultURLSessionConfiguration(),
            downloadPrioritization: .FIFO,
            maximumActiveDownloads: maximumActiveDownloads,
            imageCache: imageCache
        )

        UIImageView.af_sharedImageDownloader = imageDownloader
    }


    func setImageOrPlaceholder(onImageView imageView: UIImageView, stringURL: String?) {
        guard let correctURL = NSURL.getURL(fromString: stringURL) else {
            //debug("URL incorrect!: \(stringURL)", isError: true)

            imageView.image = placeholderImage
            return
        }

        let imageTransition: UIImageView.ImageTransition = .CrossDissolve(imageTransitionDuration)

        imageView.af_setImageWithURL(correctURL,
                                     placeholderImage: placeholderImage,
                                     filter: nil,
                                     imageTransition: imageTransition,
                                     completion: { response in
                                        //          debug("\(response.result.value)")
        })
    } }
于 2016-11-08T13:04:27.230 回答
0

但在下一次运行中，当我尝试使用相同的路径获取此图像时，它总是返回 nil：

这听起来像您正在重新启动您的应用程序。ImageCache 只是内存，当您重新启动应用程序时，您的应用程序的内存会被回收。

于 2017-02-22T20:58:27.027 回答