SDWebImage

SDWebImage是一个可以自动管理图片加载的类库 --- 图片加载非常耗费流量 --- 在移动平台上要非常小心 --- 本地缓存

》SDWenImage功能强大 --- 有一个UIImageView的category，用法简单

- (void)setImageWithURL:(NSURL *)url 

 》SDWebImageManager,使用它可以进行一些异步加载的工作，参考文档：

https://github.com/rs/SDWebImage#readme

SDWebImage --- 简化网络图片出路

1》导入UIImageView+WebCache，调用TableView的数据源代理方法- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath;用sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder 异步加载图片

#import "UIImageView+WebCache.h"

...

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cell_id = @"myTableViewCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cell_id forIndexPath:indexPath];

    if (cell == nil)
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
                                       reuseIdentifier:MyIdentifier] autorelease];
    }
// 给imageView异步加载图片
   [cell.imageView sd_setImageWithURL:[NSURL URLWithString:self.pictureStringArray[indexPath.row]] placeholderImage:[UIImage imageNamed:@"1.jpg"]];


    cell.textLabel.text = @"111;
    return cell;
}

 2》SDWebImageManager

     The SDWebImageManager is the class behind the UIImageView+WebCache category. It ties theasynchronous downloader with the image cache store. You can use this classe directly to benefitsfrom web image downloading with caching in another context than a UIView

     下面是如何使用SDWebImageManager一个简单的例子：

SDWebImageManager *manager = [SDWebImageManager sharedManager];

UIImage *cachedImage = [manager imageWithURL:url];

if (cachedImage)
{
    // Use the cached image immediatly
}
else
{
    // Start an async download
    [manager downloadWithURL:url delegate:self];
}

  》遵守SDWebImageManagerDelegate协议，实现webImageManager：didFinishWithImage：

- (void)webImageManager:(SDWebImageManager *)imageManager didFinishWithImage:(UIImage *)image
{
    // Do something with the downloaded image
}