[iOS] SDWebImage 刷新图片缓存方法

将 SDWebImageManager.m 文件中的 downloadImageWithURL 方法中的 ( 代码在176行 )

if (image && options & SDWebImageRefreshCached) {
  // force progressive off if image already cached but forced refreshing
  downloaderOptions &= ~SDWebImageDownloaderProgressiveDownload;
  // ignore image read from NSURLCache if image if cached but force refreshing
  downloaderOptions |= SDWebImageDownloaderIgnoreCachedResponse;
}

替换成

if (image && options & SDWebImageRefreshCached) {
  // force progressive off if image already cached but forced refreshing
  downloaderOptions &= ~SDWebImageDownloaderProgressiveDownload;
  // remove SDWebImageDownloaderUseNSURLCache flag
  downloaderOptions &= ~SDWebImageDownloaderUseNSURLCache;
  // ignore image read from NSURLCache if image is cached but force refreshing
  downloaderOptions |= SDWebImageDownloaderIgnoreCachedResponse;
}

之后在工程中使用如下方法:

[self.imageView sd_setImageWithURL:[NSURL URLWithString:url] placeholderImage:[UIImage new] options:SDWebImageRefreshCached];