使用url中的uitableview缓存UIImage [英] Cache UIImage using uitableview from url

问题描述

我有一个uitableview，其中包含两个UImage的自定义单元格.徽标图像来自在线网站，这就是为什么需要缓存图像的原因.像现在这样加载图像:

I hava a uitableview , with custom cell containing two UImages. The logo images are taken from an online website, that's why there's a need to cache the images. Loading the image till now is made like this :

 NSURL * imageURL = [NSURL URLWithString:[arra1 objectAtIndex:indexPath.row / 2]];
 NSData * imageData = [NSData dataWithContentsOfURL:imageURL];

 NSURL * imageURL2 = [NSURL URLWithString:[arra2 objectAtIndex:indexPath.row / 2]];
 NSData * imageData2 = [NSData dataWithContentsOfURL:imageURL2];

 cell.ima1.image = [UIImage imageWithData:imageData];
 cell.ima2.image2 = [UIImage imageWithData:imageData2];

我从搜索中学到的是dataWithContentsOfURL不是异步的，滚动时会花费很多时间.我尝试了几种方法，但我似乎找不到正确的方法.这是我第一次缓存UIImages，我非常感谢实现的详细说明，因此我可以从完成工作中学习.非常感谢

What i learned from searching , is that dataWithContentsOfURL is not asynchronous , and while scrolling it will take a lot of time. I tried several methods but i can't seem to get to right one. This is my first time caching UIImages , i would highly appreciate a detailed explanation with implementation so i could learn aside from getting the job done. Many Thanks

推荐答案

我使用的是完美的库

• SDWebImage

您只需要将 #import< SDWebImage/UIImageView + WebCache.h> 导入项目，并且还可以在仅使用以下代码下载图像时定义占位符:

You just need to #import <SDWebImage/UIImageView+WebCache.h> to your project, and you can define also the placeholder when image is being downloaded with just this code:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *MyIdentifier = @"MyIdentifier";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];

    if (cell == nil)
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
                                       reuseIdentifier:MyIdentifier] autorelease];
    }

    // Here we use the new provided setImageWithURL: method to load the web image
    [cell.imageView setImageWithURL:[NSURL URLWithString:@"http://www.domain.com/path/to/image.jpg"]
                   placeholderImage:[UIImage imageNamed:@"placeholder.png"]];

    cell.textLabel.text = @"My Text";
    return cell;
}

它还缓存下载的图像，并为您提供出色的性能.

It also cache downloaded images and gives you great performance.

希望它会对您有所帮助！

Hope it will help you!

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