文章目录类 方法 协议 分类解析SDWebImageOperation NSOperation的分类UIImageView+WebCache UIImageView分类UIView+WebCache UIView分类UIView+WebCacheOperation UIView分类SDWebImageCombinedOperation 继承自NSObjectSDWebImageManagerSDWebImageManagerDelegateSDImageCache 协议SDImageLoader 协议SDWebImageDownloader 下载类，此分类遵循SDImageLoa
