Need lazy table image load for images in app's Documents folder

I have my images into my iPhone applicati开发者_高级运维on's documents directory.

I load them into table. But I want them to load as lazy table images.

I have searched the web, but found the links where images are loaded from server. How can I load them from my documents directory?

I tried this link but it didn't work for me:

Lazy load images for UITableViewCells from NSDocumentDirectory?

A working solution that downloads images from a server can easily be modified to load from the NSDocumentsDirectory. Here's a simple implementation that you can create as a stand-alone class or integrate into an existing class. I did not include 100% of the code, just put in enough to show loading the images. imageLoader.h needs to define a protocol including imageLoader:didLoadImage:forKey: and the iVars/properties for _delegate and _images.

// imageLoader.m

// assumes that that images are cached in memory in an NSDictionary
- (UIImage *)imageForKey:(NSString *)key
{
    // check if we already have the image in memory
     UImage *image = [_images objectForKey:key];

    // if we don't have an image:
    // 1) start a background task to load an image from available sources
    // 2) return a default image to display while loading
    if (!image) {
        // this is the simplest example of background execution
        // if you need more control use NSOperationQueue or Grand Central Dispatch
        [self performSelectorInBackground:@selector(loadImageForKey) withObject:key];
        image = [self defaultImage];
    }

    return image;
}

// attempts to load an image from available sources and notifies the delegate when done
- (void)loadImageForKey:(NSString *)key
{
    NSAutoReleasePool *pool = [[NSAutoReleasePool alloc] init];

    // attempt to load the image from a file
    UIImage *image = [UIImage imageWithContentsOfFile:[self imagePathForKey]];

    // if no image, attempt to load the image from an URL here if desired

    // if no image, return default or notFound image
    if (!image) {
        image = [self notFoundImage];
    }

    if ([_delegate respondsTo:@selector(imageLoader:didLoadImage:ForKey:)]) {
        // this message will be sent on the same thread as loadImageForKey
        // you can either modify this to send the message on the main thread
        // or ensure the delegate does any desired UI changes on the main thread
        [_delegate imageLoader:self didLoadImage:image forKey:key];
    }

    [pool release];
}

// returns a path to the image in NSDocumentDirectory
- (NSString)imagePathForKey:(NSString *)key
{
    NSString *path;
    // your implementation here
    return path;
}