在swift中通过共享UIActivityViewController在电子邮件中添加主题

我使用共享UIActivityViewController来共享数据.

我的代码:

                 dispatch_async(dispatch_get_main_queue()) { () -> Void in
                    let activityViewController : UIActivityViewController = UIActivityViewController(
                        activityItems: [text!], applicationActivities: nil)
                    // This line remove the arrow of the popover to show in iPad
                    activityViewController.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection()
                    activityViewController.popoverPresentationController?.sourceRect = CGRect(x: 150, y: 150, width: 0, height: 0)

                    // Anything you want to exclude
                    activityViewController.excludedActivityTypes = [
                        UIActivityTypePostToWeibo,
                        UIActivityTypePrint,
                        UIActivityTypeAssignToContact,
                        UIActivityTypeSaveToCameraRoll,
                        UIActivityTypeAddToReadingList,
                        UIActivityTypePostToFlickr,
                        UIActivityTypePostToVimeo,
                        UIActivityTypePostToTencentWeibo
                    ]

                    self.presentViewController(activityViewController, animated: true, completion: nil)

                }

我可以显示短信,电子邮件和笔记,我可以在短信,电子邮件和笔记中添加正文.但我对电子邮件有疑问,我只在电子邮件中添加正文,我还想在电子邮件中添加电子邮件主题.怎么做 ？非常感谢你.

只需将标题的值设置为您的标题,如下所示:

activityViewController.setValue("This is my title", forKey: "Subject")