SDWebImage缓存图片和读取图片

NSString *urlStr；

NSUrl *url = [NSURL URLWithString:urlStr];

//缓存图片

SDWebImageManager *manager = [SDWebImageManager sharedManager];

if (![manager diskImageExistsForURL:url]) {

                [manager downloadWithURL:url options:0 progress:^(NSInteger receivedSize, NSInteger expectedSize) {

                    

                } completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, BOOL finished) {

                    

                }];

}

//根据缓存地址读取图片

SDImageCache *imageCache = [SDImageCache sharedImageCache];

UIImage *image = [imageCache imageFromDiskCacheForKey:urlStr];