NSURLSessionDownloadTask在斯威夫特

Question

有人能帮我把这句话翻译成Swift吗？

 NSURLSessionDownloadTask *task = [session downloadTaskWithRequest:request
            completionHandler:^(NSURL *localfile, NSURLResponse *response, NSError *error) {
            // this handler is not executing on the main queue, so we can't do UI directly here
               if (!error) {
                  if ([request.URL isEqual:self.imageURL]) {
                  // UIImage is an exception to the "can't do UI here"
                  UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:localfile]];
                  // but calling "self.image =" is definitely not an exception to that!
                  // so we must dispatch this back to the main queue
                  dispatch_async(dispatch_get_main_queue(), ^{ self.image = image; });
                  }
               }
            }];

completionHandler应该是这样的吗？

  completionHandler: { (localfile: NSURL!, response: NSURLResponse!, error: NSError!) in ...}

我一进去，它就不喜欢冒号了。

Answer 1

var session = NSURLSession.sharedSession()
var request = NSURLRequest(URL: NSURL(string: "http://api.openweathermap.org/data/2.5/weather?q=London,uk"))

var task = session.dataTaskWithRequest(request, completionHandler: { data, response, error in
        if !error {
            var string = NSString(data: data, encoding: 0)
            NSLog("%@", string)
        }
    })

task.resume()