iphone - 使用 MKNetworkKit setImageFromURL 时如何获取图像帧？

Question

我正在尝试使用 setImageFromURL 下载图像后获取图像的大小:

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——有没有办法将完成处理程序添加到 setImageFromURL 方法？

Answer 1

您可以应用自己的完成 block

评论不多，这种情况请使用Grand Central Dispatch来提高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);  
        }  
    });     
}  

更多详情，请访问 iOS GCD magic