ios - Swift 图像缓存不重新加载

Question

我在使用此 UIImageView 扩展正确缓存 JSON 图像时遇到问题。当我第一次打开应用程序并向下滚动页面时，图像加载正确。然而，当我向上滚动时，它们不会重新加载并且完全消失。任何人都可以看到代码有什么问题吗？

   let imageCache = NSCache<AnyObject, AnyObject>()

   extension UIImageView   {

    func loadImageUsingUrlString(urlString: String) {
        let url = NSURL(string: urlString)

        if let imageFromCache = imageCache.object(forKey: urlString as AnyObject) as? UIImage   {
            self.image = imageFromCache
            return
        }

        URLSession.shared.dataTask(with: url! as URL) { (data, response, error) in

            if error != nil {
                print(error ?? "URLSession error")
                return
            }

            DispatchQueue.main.async {

                let imageToCache = UIImage(data: data!)

                imageCache.setObject(imageToCache!, forKey: urlString as AnyObject)

                self.image = imageToCache
            }
        }.resume()
    }
}

这是 cell.swift 文件中的片段

let imageCache = NSCache<AnyObject, AnyObject>()

func setupThumbnailImage() {
    if let thumbnailImageUrl = television?.poster_url   {

        let urlPrefix = "https://www.what-song.com"
        let urlSuffix = thumbnailImageUrl

        let urlCombined = urlPrefix + urlSuffix

        thumbnailImageView.loadImageUsingUrlString(urlString: urlCombined)

    }
}

Answer 1

我建议使用kingFisher，它非常易于使用，并且它管理从缓存线程等开始的所有操作。

           let imageResource = ImageResource(downloadURL:URL(string: imagePath )!,cacheKey: imagePath )
           viewImage.kf.indicatorType = .activity
           viewImage.kf.setImage(with: resource)

其中imagePath是你的图片的url，viewImage是你的imageView