swift - 无法关闭邮件 View Controller

Question

此代码有效并显示所有已填写的电子邮件表单并发送电子邮件就好了，只是在发送或尝试取消后无法将其关闭。

我确信我遗漏了一些简单的东西。 我也意识到如果出现错误我什么都没有，但此时它可以工作并发送电子邮件，但我无法将其关闭

尝试了我在网上找到的一些建议，还有其他方法可以做到这一点，但我试图理解为什么这不起作用所以希望这种方式(或关闭)起作用.... xcode 10.2.1

import UIKit
import MessageUI

class ViewController: UIViewController, MFMailComposeViewControllerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBAction func sendEmail(_ sender: Any) {

        sendEmail()

        }

    func sendEmail() {
        if MFMailComposeViewController.canSendMail() {
            let mail = MFMailComposeViewController()
            mail.mailComposeDelegate = self
            mail.setToRecipients(["xxx@xx.com"])
            mail.setSubject("test  ")
            mail.setPreferredSendingEmailAddress("xxx@jxxx.com")

            present(mail, animated: true)   

        } else {
            //show failure alert
        }

        func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {

            controller.dismiss(animated: true, completion: nil)

        }

    }

可以很好地编译和发送电子邮件，只是不能关闭 Controller

Answer 1

所有委托(delegate)方法都应该在类范围内，在您当前的代码 didFinishWith 中，应该将邮件嵌套在 sendEmail

中

import UIKit
import MessageUI

class ViewController: UIViewController, MFMailComposeViewControllerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBAction func sendEmail(_ sender: Any) { 
        sendEmail() 
    }

    func sendEmail() {
        if MFMailComposeViewController.canSendMail() {
            let mail = MFMailComposeViewController()
            mail.mailComposeDelegate = self
            mail.setToRecipients(["xxx@xx.com"])
            mail.setSubject("test  ")
            mail.setPreferredSendingEmailAddress("xxx@jxxx.com") 
            present(mail, animated: true)   

        } else {
            //show failure alert
        } 
    }

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