swift pdf文件未附加到电子邮件

我有下面的代码,假设它附加了一个名为“file.pdf”的文件,该文件是这样创建并放在临时目录中的

pdfFileUrl = "\(NSTemporaryDirectory())file.pdf" 

但这封电子邮件没有我的附件,因为我期待它

@IBAction func sendEmail(sender: AnyObject) {

    createReportPDF()

    if MFMailComposeViewController.canSendMail() {
        let mail = MFMailComposeViewController()
        mail.mailComposeDelegate = self
        mail.setToRecipients(["dpreston10@gmail.com"])
        mail.setMessageBody("<p>You're so awesome!</p>", isHTML: true)
        if let filePath = NSBundle.mainBundle().pathForResource(pdfFileUrl, ofType: "pdf") {
            print("File path loaded.")

            if let fileData = NSData(contentsOfFile: filePath) {
                print("File data loaded.")
                mail.addAttachmentData(fileData, mimeType: "application/pdf", fileName: "file.pdf")
            }
        }

        presentViewController(mail, animated: true, completion: nil)
    } else {
        // show failure alert
    }
}