如何在ios上缓存图像

我目前有一个数组，其中包含许多名为

images

的图像URL，它们被放入我的表中，如下所示：

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

    SimpleTableCell *cell = (SimpleTableCell *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"SimpleTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];
    }

    NSLog(@"indexPath.row=%ld", (long)indexPath.row);
    NSLog(@"images[indexPath.row]=%@", [images objectAtIndex:indexPath.row]);

    NSString *stringy = @"http://www.tragicclothing.co.uk/";
    NSString *link = [stringy stringByAppendingString: images[indexPath.row]];
    NSString* encodedString = [link stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSData * imageData = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString:encodedString]];
    cell.thumbnailImageView.image = [UIImage imageWithData: imageData];
    cell.backgroundColor = [UIColor clearColor];
    cell.opaque = NO;
    cell.backgroundView = nil;

    return cell;
}

但这会在滚动时造成很大的延迟。如何缓存数据？为了防止这种滞后？我见过，但我不太知道如何使用它！看起来很复杂

我应该用吗

SDImageCache *imageCache = [[SDImageCache alloc] initWithNamespace:@"myNamespace"];
[imageCache queryDiskCacheForKey:myCacheKey done:^(UIImage *image)
{
    // image is not nil if image was found
}];

---

没有什么是简单的

它产生了以下解决方案

向Cocoa Touch框架添加web映像和缓存管理的UIImageView类别

异步图像下载程序

具有自动缓存过期处理的异步内存+磁盘映像缓存

#import <SDWebImage/UIImageView+WebCache.h>

NSString* encodedString = [link stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

[cell.thumbnailImageView setImageWithURL:[NSURL URLWithString:encodedString]
               placeholderImage:[UIImage imageNamed:@"placeholder.png"]];

#导入
NSString*encodedString=[link stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]；
[cell.thumbnailImageView setImageWithURL:[NSURL URLWithString:encodedString]
占位符图像：[UIImage ImageName:@“placeholder.png”]；

您将SDWebImage称为复杂？你还想要什么？只需调用方法[myImage setImage…”。。。。[myImage setImage…”延迟不仅仅是滚动造成的。你正在同步下载图像，这是你的问题！@Cyrille我如何一次下载所有图像。我想做一种无限滚动类型的东西…你不需要一次下载所有图像，让图像异步下载。+1显然，带有

\importUIImageView

类别的code>。谢谢rob！我会在有机会时添加导入内容（现在在手机上：-s）

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

    SimpleTableCell *cell = (SimpleTableCell *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"SimpleTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];
    }

    NSLog(@"indexPath.row=%ld", (long)indexPath.row);
    NSLog(@"images[indexPath.row + 7]=%@", [images objectAtIndex:indexPath.row + 7]);


    NSString *stringy = @"http://www.tragicclothing.co.uk/";
    NSString *link = [stringy stringByAppendingString: images[indexPath.row + 7]];
    NSString* encodedString = [link stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    [cell.thumbnailImageView setImageWithURL:[NSURL URLWithString:encodedString] placeholderImage:[UIImage imageNamed:@"Comp 2_00000.png"]];
    cell.backgroundColor = [UIColor clearColor];
    cell.opaque = NO;
    cell.backgroundView = nil;


    return cell;
}