在MFMailComposeViewController不能按取消或发送按钮后，予以驳回。我已经添加MFMailComposeViewControllerDelegate了课程，但是仍然无法正常工作吗？
这是我的代码：
func sendEmail() {
let MailVC = MFMailComposeViewController()
MailVC.mailComposeDelegate = self
MailVC.setToRecipients(["\(emailLabel?.text)"])
MailVC.setSubject("Set your subject here!")
MailVC.setMessageBody("Hello this is my message body!", isHTML: false)
// Present the view controller modally.
self.present(MailVC, animated: true, completion: nil)
}
func mailComposeController(controller: MFMailComposeViewController,
didFinishWithResult result: MFMailComposeResult, error: NSError?) {
// Dismiss the mail compose view controller.
controller.dismiss(animated: true, completion: nil)
}