UIActivityViewController句柄取消操作| Swift/Xcode

我无法在Swift中找到完整的代码，说明当用户按下；x"；在UIActivityViewController（右上）中，取消共享。

这就是我目前拥有的：

do {
                try pdfData.write(to: temporaryFileURL)
                let vc = UIActivityViewController(activityItems: [temporaryFileURL], applicationActivities: [])
                self.present(vc, animated: true, completion: nil)
            } catch {
                print(error)
            }

我发现这个Objective-C代码可能有用。有人能帮我把它转换成Swift，并告诉我如何用我目前拥有的东西来实现它吗？

vc.completionWithItemsHandler = ^(NSString *activityType,
                                                          BOOL completed,
                                                          NSArray *returnedItems,
                                                          NSError *error){
                    // react to the completion
                    if (completed) {
                        
                        // user shared an item
                        NSLog(@"We used activity type%@", activityType);
                        
                    } else {
                        
                        // user cancelled
                        NSLog(@"We didn't want to share anything after all.");
                    }
                    
                    if (error) {
                        NSLog(@"An Error occured: %@, %@", error.localizedDescription, error.localizedFailureReason);
                    }
                };

非常感谢。