iOS 第三方框架-SDWebImage

- (void)sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder;

- (void)sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options;

- (void)sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder completed:(SDWebImageCompletionBlock)completedBlock;

- (void)sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options progress:(SDWebImageDownloaderProgressBlock)progressBlock completed:(SDWebImageCompletionBlock)completedBlock;

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *ID = @"app";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:ID];
    }
    
    // 取出模型
    HMApp *app = self.apps[indexPath.row];
    
    // 设置基本信息
    cell.textLabel.text = app.name;
    cell.detailTextLabel.text = app.download;
    
    // 下载图片
    NSURL *url = [NSURL URLWithString:app.icon];
    UIImage *placeholder = [UIImage imageNamed:@"placeholder"];
    
    SDWebImageOptions options = SDWebImageRetryFailed | SDWebImageLowPriority;
    
    [cell.imageView sd_setImageWithURL:url placeholderImage:placeholder options:options progress:^(NSInteger receivedSize, NSInteger expectedSize) { // 这个block可能会被调用多次
        NSLog(@"下载进度：%f", (double)receivedSize / expectedSize);
    } completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
        NSLog(@"----图片加载完毕---%@", image);
    }];
    return cell;
}

/**
 *  当app接收到内存警告
 */
- (void)applicationDidReceiveMemoryWarning:(UIApplication *)application
{
    SDWebImageManager *mgr = [SDWebImageManager sharedManager];
    
    // 1.取消正在下载的操作
    [mgr cancelAll];
    
    // 2.清除内存缓存
    [mgr.imageCache clearMemory];
}