MFMailComposeViewController、Swift 4、Xcode 9

MFMailComposeViewController, Swift 4, Xcode 9

提问by ?or?e Nilovi?

I have a problem with MFMailComposeViewControllerDelegate function.

我对 MFMailComposeViewControllerDelegate 函数有问题。

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

The warning says

警告说

Instance method 'mailComposeController(:didFinishWith:error:)' nearly matches optional requirement 'mailComposeController(:didFinishWith:error:)' of protocol 'MFMailComposeViewControllerDelegate'

Make 'mailComposeController(_:didFinishWith:error:)' private to silence this warning

实例方法 'mailComposeController( :didFinishWith:error:)' 几乎匹配协议 'MFMailComposeViewControllerDelegate' 的可选要求 'mailComposeController(:didFinishWith:error:)'

将 'mailComposeController(_:didFinishWith:error:)' 设为私有以消除此警告

I need to return the user to the App and dismiss MFMailComposeViewController after clicking cancel and this function is not triggered.

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

Yes, I added the delegate composeVC.mailComposeDelegate = self

是的，我添加了委托 composeVC.mailComposeDelegate = self

If someone had a similar problem, I would appreciate the help. Thanks

如果有人有类似的问题，我将不胜感激。谢谢

EDIT

编辑

This behavior is happening only when I set the language to Swift 4. I just went back few commits and it's working perfectly fine with Swift 3.2

只有当我将语言设置为 Swift 4 时才会发生这种行为。我只返回了几次提交，并且它在 Swift 3.2 中运行良好

Basically, this is the code:

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]"])
    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)
}

}

}

回答by Boris Y.

It wasn't possible for me to apply ?or?e's solution,this other answerhelped me.

我无法应用?or?e 的解决方案，这个其他答案帮助了我。

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

Adding Swift.prefix to Error?solves the problem.

添加Swift.前缀来Error?解决问题。

回答by jeffjv

I had the same issue where the mailComposeControlerdelegate wasn't getting called after canceling or sending the mail. xCode gave me the same warning about adding private. I did not have an issue an enumeration named Error as the others had.

我遇到了同样的问题，mailComposeControler即在取消或发送邮件后没有呼叫代表。xCode 给了我关于添加私有的相同警告。我没有像其他人那样遇到名为 Error 的枚举问题。

The only way I could fix it was to specifically define the function as public.

我可以修复它的唯一方法是将函数明确定义为public.

public func mailComposeController(_ controller: MFMailComposeViewController,
                                  didFinishWith result: MFMailComposeResult, error: Error?) {
    // Check the result or perform other tasks.

    // Dismiss the mail compose view controller.
    self.dismiss(animated: true, completion: nil)
}

After doing that it worked fine.

这样做之后，它工作得很好。

This was in Swift 4.0, xCode 10.1.

这是在 Swift 4.0，xCode 10.1 中。

回答by ?or?e Nilovi?

EDIT:

编辑：

After adding other classes to the project I encountered the same problem again and realized that conversion was not the problem.

在项目中添加其他类后，我再次遇到同样的问题，并意识到转换不是问题。

The problem was that I have an enumeration named Error, that's why the parameter error: was not recognizing the Swift Error class, so the warning was correct.

问题是我有一个名为 Error 的枚举，这就是参数 error: 无法识别 Swift Error 类的原因，所以警告是正确的。

I came to edit the answer and I saw that Boris Y.wrote the fix for this, so I'll accept his answer.

我是来编辑答案的，我看到鲍里斯 Y.为此编写了修复程序，所以我会接受他的答案。