如何从 class 邮件中关闭 MFMailComposeViewController？

Question

我已将邮件功能从我的 UIviewController 中分离出来，并将它们放入 class“邮件”中。工作正常，但现在我确实无法关闭我的“MFMailComposeViewController”。未调用委托“mailComposeController”，有什么解决办法吗？

import Foundation
import MessageUI


class Mail: UIViewController, MFMailComposeViewControllerDelegate{

    static func createMail2(
        fromViewController:UIViewController,
        recipients  :String,
        messageTitle:String,
        messageText :String,
        attachment  :AnyObject?)
    {

        
        if MFMailComposeViewController.canSendMail() {
            let mail = MFMailComposeViewController()
            //mail.mailComposeDelegate = self //Cannot assign value of type 'Mail.Type' to type 'MFMailComposeViewControllerDelegate?'
            mail.mailComposeDelegate? = fromViewController as! MFMailComposeViewControllerDelegate //added ? (optional)
            

            mail.setToRecipients([recipients])   //(["mail@to.me"])
            mail.setSubject(messageTitle)        //("your subject text")
            mail.setMessageBody(messageText, isHTML: false)
            
            //ggf. Attachment beifügen>>>
            if attachment != nil {
                //attachment vorhanden, also anhängen
                
                let attachName = "\(messageTitle).pdf"
                
                mail.addAttachmentData(
                    attachment as! Data,
                    mimeType: "application/octet-stream", //für binäre Daten, funktioniert immer
                    fileName: attachName)
            }//end if attachment
            //<<<ggf. Attachment beifügen

            
            // Present the view controller modally
            fromViewController.present(mail, animated: true)  //show mail
        } else {
            // show failure alert
            print("Mail services are not available")
            
            let alert = UIAlertController(title: "Mail error", message: "Your device has not been configured to send e-mails", preferredStyle: .alert)
            let okAction = UIAlertAction(title: "OK", style: .default, handler: nil)
            alert.addAction(okAction)
            fromViewController.present(alert,animated: true, completion: nil)
        }//end if else
    }//end func createMail
    
    
    //mail delegate
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        //It’s called when the user dismisses the controller, either by sending the email or canceling the action. Either way, you have to dismiss the controller manually.
        
        //ggf. noch aktionen...
        
        controller.dismiss(animated: true) //remove the mail view
    }//end func mailComposeController
}//end class Mail

Answer 1

您作为 fromViewController 的参数传递的 UIViewController 应该符合 MFMailComposeViewControllerDelegate 协议并且您应该在该控制器的定义中实现 mailComposeController(_: didFinishWith: .

class Mail: UIViewController {

    static func createMail2(
        fromViewController: UIViewController,
        recipients  :String,
        messageTitle:String,
        messageText :String,
        attachment  :AnyObject?) {

        if MFMailComposeViewController.canSendMail() {
            let mail = MFMailComposeViewController()
            if let fromViewController = fromViewController as? MFMailComposeViewControllerDelegate {
                mail.mailComposeDelegate = fromViewController
            } else {
                print("fromViewController needs to conform to MFMailComposeViewControllerDelegate")
            }
            //...
        }
    }
}

Answer 2

您需要创建邮件控制器的静态共享实例并将 if 设置为 mailComposeDelegate。您还应该在邮件控制器中创建一个控制器属性以保留对调用邮件编辑器的视图控制器的引用，并将您的 createMail 声明为实例方法（非静态）：

import UIKit
import MessageUI

class MailComposer: NSObject, MFMailComposeViewControllerDelegate {
    static let shared = MailComposer()
    private var controller: UIViewController?
    func compose(controller: UIViewController, recipients: String,
                 messageTitle: String, messageText: String, fileURL: URL? = nil) { //, completion: @escaping ((MFMailComposeResult, Error?) -> Void)) {
        self.controller = controller
        if MFMailComposeViewController.canSendMail() {
            let mail = MFMailComposeViewController()
            mail.mailComposeDelegate = MailComposer.shared
            mail.setToRecipients([recipients])
            mail.setSubject(messageTitle)
            mail.setMessageBody(messageText, isHTML: false)
            if let fileURL = fileURL {
                do {
                    try mail.addAttachmentData(Data(contentsOf: fileURL), mimeType: "application/octet-stream", fileName: fileURL.lastPathComponent)
                } catch {
                    print(error)
                }
            }
            controller.present(mail, animated: true)
        } else {
            let alertController = UIAlertController(title: "Mail Compose Error",
                message: "Your device has not been configured to send e-mails",
                preferredStyle: .alert)
            alertController.addAction(.init(title: "OK", style: .default) { _ in
                alertController.dismiss(animated: true)
            })
            controller.present(alertController, animated: true)
        }
    }
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        // You should switch the result only after dismissing the controller
        controller.dismiss(animated: true) {
            let message: String
            switch result {
            case .sent: message = "Message successfully sent!"
            case .saved: message = "Message saved!"
            case .cancelled: message = "Message Canceled!"
            case .failed:  message = "Unknown Error!"
            @unknown default: fatalError()
            }
            let alertController = UIAlertController(title: "Mail Composer",
                message: message,
                preferredStyle: .alert)
            alertController.addAction(.init(title: "OK", style: .default) { _ in
                alertController.dismiss(animated: true)
            })
            self.controller?.present(alertController, animated: true) {
                self.controller = nil
            }
            
        }
    }
}

用法：

class ViewController: UIViewController {
    override func viewDidLoad() {
           super.viewDidLoad()
    }
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        let recipients = "user@email.com"
        let messageTitle = "New Message"
        let messageText = "Mail Test"
        MailComposer.shared.compose(controller: self, recipients: recipients, messageTitle: messageTitle, messageText: messageText)
    }
}

如何从 class 邮件中关闭 MFMailComposeViewController？

How to dismiss MFMailComposeViewController from class mail?

swift

mfmailcomposeviewcontroller