ios - 如何从url中提取图片

Question

我正在尝试从 url 中提取图像并将其放置在 ImageView 中。

这是我的代码，但它不起作用:

NSURL *imageURL = [NSURL URLWithString:@"http://www.huffingtonpost.com/entry/china-trump-sovereignity_us_5852000ee4b02edd4115d99b"];
NSData *imageData = [NSData dataWithContentsOfURL:imageURL];
UIImage *image = [UIImage imageWithData:imageData];
_imageView.image = image;

如何提取图像？ (网址只是一个例子)

Answer 1

您可以尝试使用此异步下载:

    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
    NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration];
    NSURL *urlPic = [NSURL URLWithString:[NSString stringWithFormat:@"http://www.huffingtonpost.com/entry/china-trump-sovereignity_us_5852000ee4b02edd4115d99b"]];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:urlPic cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:timeOutTime];
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

        if(!error) {
            dispatch_async(dispatch_get_main_queue(), ^{
                UIImage *image = [UIImage imageWithData:data];                
            });
        } else {
           //Fail
        }
    }];
    [task resume];