Question

MFMailComposeViewController.canSendMail（）为true，gmail屏幕显示正确的收件人电子邮件ID，主题和正文。但是发送按钮被禁用。此外，当我按下取消按钮滑块时，会出现两个选项：删除和取消。删除不起作用，我无法从邮件编辑器返回到我以前的控制器。

Gmail已在我的iphone上设置并且运行正常。我无法弄清楚出了什么问题，有人可以帮忙吗？

MFMailComposeViewController.canSendMail() {
    if (selectedEntry!.notifyType == "Email") {
        let mailComposeVC = MFMailComposeViewController()
        mailComposeVC.mailComposeDelegate = self
        let target:String = (selectedEntry?.targetString)!
        mailComposeVC.setToRecipients([target])
        mailComposeVC.setSubject("Test")
        mailComposeVC.setMessageBody("Hello ", isHTML: false)
        // present the message view controller
        self.present(mailComposeVC, animated: true, completion: nil)
    }
} else {
    print("MAIL services are not available")
    return
}



func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?)
{
    switch (result)
    {
    case .sent:
        print("email sent.")
        break
    case .cancelled:
        print("email cancelled.")
        break
    case .failed:
        print("failed sending email")
        break
    default:
        break
    }
    controller.dismiss(animated: true, completion: nil)
}

Answer 1

很遗憾，MFMailComposeViewController由本机邮件应用程序提供支持。取自Apple documentation：

如果用户选择发送邮件，则该邮件会在用户的邮件应用发件箱。邮件应用最终负责发送消息。

由于在设备上设置了Gmail帐户，因此即使从设备“卸载”了邮件应用，canSendMail也会返回true。该应用程序并未真正卸载，而是隐藏了。如果您尝试以以下方式检查该应用程序是否存在，则会收到误报。

let mailURL = URL(string: "mailto:?to=\(emailAddress)")!
let canSendEmail = UIApplication.shared.canOpenURL(mailURL)

使用UIApplication.shared.open(mailURL)打开经过验证的网址将显示一条警报，询问您是否要重新安装该应用程序。

Restore "Mail"? alert

根据this response，此问题仅在iOS 12或更高版本中存在。

Answer 2

与 Swift 5 配合良好。

首先，对用于发送电子邮件的 viewController 进行扩展：

import UIKit
import Foundation
import MessageUI
import LocalAuthentication

extension viewControllerThatSendsTheEmail: MFMailComposeViewControllerDelegate
{
  func mailComposeController( _ controller: MFMailComposeViewController, didFinishWith result:MFMailComposeResult, error: Error?)
   {
    if let _ = error
    {
        controller.dismiss(animated: true)
        return
    }
    switch result
    {
    case.cancelled:
        print("CANCELLED")
    case.failed:
        print("FAILED")
    case.saved:
        print("SAVED")
    case.sent:
        print("EMAIL SENT")
    @unknown default:
        fatalError()
    }
    controller.dismiss(animated: true)
  }
}

那么你的函数：

@objc func sendEmailButtonTap()
{
    guard MFMailComposeViewController.canSendMail()
        else
    {
        return
    }
    let sending = MFMailComposeViewController()
    sending.mailComposeDelegate = self
    sending.setToRecipients(["awesomeDeveloper@apple.com"])
    sending.setSubject("AWRSOME APP")
    sending.setMessageBody("THIS APP IS SO AWESOME!", isHTML: false)
    present(sending, animated: true)
}

MFMailComposeViewController发送和取消都不起作用

2 个答案: