Question

我试图在使用setImageFromURL下载后获取图像的大小：

UIImageView *img = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
[UIImageView setDefaultEngine:appDelegate.imageCache];
[img setImageFromURL:[NSURL URLWithString:@"http://testurl.com/testimg.jpg"]];
//img.frame = CGRectMake (0, 0, img.image.size.width, img.image.size.height);
[self.view addSubview:img];

我正在使用MKNetworkKit - 有没有办法在setImageFromURL方法中添加一个完成处理程序？

Answer 1

您可以应用自己的 completion block

很少有评论，请使用 Grand Central Dispatch 来提高此类情况下的代码效率和多核利用率。

示例：

- (void) setImageFromUrl:(NSString*)urlString { [self setImageFromUrl:urlString completion:NULL]; } - (void) setImageFromUrl:(NSString*)urlString completion:(void (^)(void))completion { dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ NSLog(@"Starting: %@", urlString); UIImage *avatarImage = nil; NSURL *url = [NSURL URLWithString:urlString]; NSData *responseData = [NSData dataWithContentsOfURL:url]; avatarImage = [UIImage imageWithData:responseData]; NSLog(@"Finishing: %@", urlString); if (avatarImage) { dispatch_async(dispatch_get_main_queue(), ^{ self.image = avatarImage; //Assign the image to ur ImageView. //get the image frame from ur ImageView.frame }); dispatch_async(dispatch_get_main_queue(), completion); } else { NSLog(@"-- impossible download: %@", urlString); } }); }

有关详细信息，请访问 iOS GCD magic

Answer 2

我能够通过添加这一行来实现：

 self.frame = CGRectMake(0, 0, fetchedImage.size.width, fetchedImage.size.height);

到UIImageView + MKNetworkKitAdditions.m：

if(imageCacheEngine) {
    self.imageFetchOperation = [imageCacheEngine imageAtURL:url
                   size:self.frame.size
      completionHandler:^(UIImage *fetchedImage, NSURL *url, BOOL isInCache) {

        self.frame = CGRectMake(0, 0, fetchedImage.size.width, fetchedImage.size.height);

        [UIView transitionWithView:self.superview
                          duration:isInCache?kFromCacheAnimationDuration:kFreshLoadAnimationDuration
                           options:UIViewAnimationOptionTransitionCrossDissolve | UIViewAnimationOptionAllowUserInteraction
                        animations:^{
                             self.image = fetchedImage;
                           } completion:nil];
          //[[NSNotificationCenter defaultCenter] postNotificationName:KW_IMAGE_LOADED object:nil];

      } errorHandler:^(MKNetworkOperation *completedOperation, NSError *error) {

        DLog(@"%@", error);
      }];
  } else {

    DLog(@"No default engine found and imageCacheEngine parameter is null")
  }

使用MKNetworkKit setImageFromURL时如何获取图像帧？

2 个答案: