UIImageView+SDWebImage.h

#import 
     
      typedef void(^DownloadImageSuccessBlock)(UIImage *image);typedef void(^DownloadImageFailedBlock)(NSError *error);typedef void(^DownloadImageProgressBlock)(CGFloat progress);@interface UIImageView (SDWebImage)/** 异步加载图片 @param url 图片地址 @param imageName 占位图片名 */- (void)downloadImage:(NSString *)url placeholder:(NSString *)imageName;/** 异步加载图片，可以监听下载进度，成功或失败 @param url 图片地址 @param imageName 占位图片名 @param success 下载成功 @param failed 下载失败 @param progress 下载进度 */- (void)downloadImage:(NSString *)url          placeholder:(NSString *)imageName              success:(DownloadImageSuccessBlock)success               failed:(DownloadImageFailedBlock)failed             progress:(DownloadImageProgressBlock)progress;@end
     

UIImageView+SDWebImage.m

#import "UIImageView+SDWebImage.h"#import "UIImageView+WebCache.h"@implementation UIImageView (SDWebImage)- (void)downloadImage:(NSString *)url placeholder:(NSString *)imageName {        [self sd_setImageWithURL:[NSURL URLWithString:url] placeholderImage:[UIImage imageNamed:imageName] options:SDWebImageRetryFailed | SDWebImageLowPriority];}- (void)downloadImage:(NSString *)url placeholder:(NSString *)imageName success:(DownloadImageSuccessBlock)success failed:(DownloadImageFailedBlock)failed progress:(DownloadImageProgressBlock)progress {        [self sd_setImageWithURL:[NSURL URLWithString:url] placeholderImage:[UIImage imageNamed:imageName] options:SDWebImageRetryFailed | SDWebImageLowPriority progress:^(NSInteger receivedSize, NSInteger expectedSize, NSURL * _Nullable targetURL) {                progress(receivedSize * 1.0 / expectedSize);            } completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {                if (error) {                        failed(error);        } else {                        self.image = image;            success(image);        }    }];    }@end