异步加载的图像

Question

我已经加载了一些图像，请告诉我如何使用异步加载的图像

Answer 1

你是说在后台下载图像？

本教程由杰夫·拉马什是一个很好的解决方案 - http://iphonedevelopment.blogspot.com/2010/05/downloading-images-for-table-without.html

Answer 2

。利用EGOImageView的假设你想在的UIImageView显示下载的图像，它真的很容易（只是一个占位符图像初始化和设置要下载的图像的URL）。

http://developers.enormego.com/view/what_if_images_on_the_iphone_were_as_easy_as_html

如果你不想显示图像，而只是希望异步下载，使用EGOImageLoader的。

只要确保你的类符合EGOImageLoaderObserver协议并实施2委托方法，你就大功告成了......

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
{ 
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
    if (self) 
    { 
     imageLoader = [EGOImageLoader sharedImageLoader]; // ivar, so we can remove the observer in the dealloc ... 
    } 
    return self; 
} 

- (void)dealloc 
{ 
    [imageLoader removeObserver:self]; 
    [super dealloc]; 
} 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    NSString *urlString = @"http://www.wimwauters.be/wp-content/uploads/2011/01/steve-jobs.jpg"; 
    NSURL *url = [NSURL URLWithString:urlString]; 
    [imageLoader loadImageForURL:url observer:self];    
} 

#pragma mark - EGOImageLoaderObserver 

- (void)imageLoaderDidLoad:(NSNotification*)notification 
{ 
    NSDictionary *userInfo = [notification userInfo]; 
    UIImage *theImage = [userInfo objectForKey:@"image"]; 

    // do something with the image, e.g. display it in an ImageView ... 
} 

- (void)imageLoaderDidFailToLoad:(NSNotification*)notification 
{ 
    NSDictionary *userInfo = [notification userInfo]; 
    NSError *error = [userInfo objectForKey:@"error"]; 
    if (error) 
    { 
    // handle the error 
    } 
}