- (NSString *)cacheSizeFormat

{

    NSString *sizeUnitString;

    float size = [SDWebImageManager.sharedManager.imageCache getSize];

    if(size < ){

        sizeUnitString = [NSString stringWithFormat:@"%.1fb",size];

    }else if (size >  && size <  * ) {

        size /= 1024.0;

        sizeUnitString = [NSString stringWithFormat:@"%.1fkb",size];

    }

    else{

        size /= (1024.0 * );

        sizeUnitString = [NSString stringWithFormat:@"%.1fM",size];

    }

    return sizeUnitString;

}

else if ([selectText isEqualToString:@"清除缓存"]) {

   [[[SDWebImageManager sharedManager] imageCache] clearDisk];

   [[[SDWebImageManager sharedManager] imageCache] clearMemory];

   __weak typeof(self) weakSelf = self;

   dispatch_queue_t queue = dispatch_get_main_queue();

   dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), queue, ^{

       [MBProgressHUD showMessage:@"缓存清除成功"];

       [weakSelf reloadData];

   });

}