//网络图像获取

-(void)imageDownLoadByUrlASYNC:(NSString *)url

Complete:(complete)finished

{

   //异步并列执行  

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{     UIImage *image = nil;

 NSURL *myUrl = [NSURL

URLWithString:url];

  // NSData *responseData = [NSData

dataWithContentsOfURL:myUrl];

  NSError *error;

NSData *responseData =

[NSData dataWithContentsOfURL:myUrl options:NSDataReadingMappedIfSafe error:&error];

 image = [UIImage

imageWithData:responseData];

  //跳回主队列执行

dispatch_async(dispatch_get_main_queue(),

^{

//在主队列中进行ui操作

 finished(image);

  });

});

}

//接收图片的处理

  UIImageView *imageView =

[imageViewArray objectAtIndex:i];

 UIActivityIndicatorView

*activeView = [activeViewArray objectAtIndex:i];

  [activeView startAnimating];

 [imageView

imageDownLoadByUrlASYNC:[imageDownLoadURL objectAtIndex:i] Complete:^(UIImage *image) {

if(image)

imageView.image = image;

 else

 {

imageView.image = [UIImage

imageNamed:@"no.jpeg"];

 }

  [activeView

stopAnimating];

}];