MFMailComposeViewController、Swift 4、Xcode 9

我的 MFMailComposeViewControllerDelegate 函数有问题。

func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
    controller.dismiss(animated: true, completion: nil)
}

警告说

实例方法'mailComposeController(:didFinishWith:error:)' 几乎匹配可选要求 'mailComposeController(协议“MFMailComposeViewControllerDelegate”的 :didFinishWith:error:)'

将“mailComposeController(_:didFinishWith:error:)”设置为私有以消除此警告

我需要将用户返回到应用程序并在单击取消后关闭 MFMailComposeViewController 并且不会触发此功能。

是的，我添加了代表composeVC.mailComposeDelegate = self

如果有人遇到类似的问题，我将不胜感激。谢谢

EDIT

仅当我将语言设置为 Swift 4 时，才会发生这种行为。我刚刚返回了几次提交，它在 Swift 3.2 上运行得非常好

基本上，这是代码：

class TechSupportVC: UIViewController, MFMailComposeViewControllerDelegate {
    let composeVC = MFMailComposeViewController()

override func viewDidLoad() {
    super.viewDidLoad()

    composeVC.mailComposeDelegate = self
    composeVC.setToRecipients(["[email protected] /cdn-cgi/l/email-protection"])
    composeVC.setSubject("My message")
}

func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
    controller.dismiss(animated: true, completion: nil)
}

@IBAction func sendPressed(_ sender: Any) {
    guard MFMailComposeViewController.canSendMail() else {
        showMailServiceErrorAlert()
        return
    }

    composeVC.setMessageBody("Test credentials: \(firstAndLastNameTextField.text!)\nPhone: \(numberTextField.text!)\n\n\(messageTextView.text!)", isHTML: false)

    self.present(composeVC, animated: true, completion: nil)
}

}

我无法申请Đorđe 的解决方案， https://stackoverflow.com/a/48708308/1162044 this 其他答案 https://stackoverflow.com/a/39623586/1162044帮助过我。

func mailComposeController(_ controller: MFMailComposeViewController,
                           didFinishWith result: MFMailComposeResult,
                           error: Swift.Error?) {
    controller.dismiss(animated: true, completion: nil)
}

Adding Swift.前缀为Error?解决了问题。