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问Swift 5-电子邮件类助手/经理
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Stack Overflow用户

提问于 2020-06-28 01:03:16

回答 3查看 987关注 0票数 1

编辑：

非常感谢Paulw11帮助我解决这个问题。为了便于重用，我在这里添加了完整的代码：

类：

import UIKit
import MessageUI

struct Feedback {
    let recipients: [String]
    let subject: String
    let body: String
    let footer: String
}

class FeedbackManager: NSObject, MFMailComposeViewControllerDelegate {

private var feedback: Feedback

private var completion: ((Result<MFMailComposeResult,Error>)->Void)?

override init() {
    fatalError("Use FeedbackManager(feedback:)")
}

init?(feedback: Feedback) {
    guard MFMailComposeViewController.canSendMail() else {
        return nil
    }
    
    self.feedback = feedback
}

func send(on viewController: UIViewController, completion:(@escaping(Result<MFMailComposeResult,Error>)->Void)) {
    
    let mailVC = MFMailComposeViewController()
    self.completion = completion
    
    mailVC.mailComposeDelegate = self
    mailVC.setToRecipients(feedback.recipients)
    mailVC.setSubject(feedback.subject)
    mailVC.setMessageBody("<p>\(feedback.body)<br><br><br><br><br>\(feedback.footer)</p>", isHTML: true)
    
    viewController.present(mailVC, animated:true)
}

func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
    if let error = error {
        completion?(.failure(error))
        controller.dismiss(animated: true)
    } else {
        completion?(.success(result))
        controller.dismiss(animated: true)
    }
}
}

主计长：

添加变量：

var feedbackManager: FeedbackManager?

使用：

    let feedback = Feedback(recipients: "String", subject: "String", body: "Body", footer: "String")
    if let feedManager = FeedbackManager(feedback: feedback) {
        self.feedbackManager = feedManager
        self.feedbackManager?.send(on: self) { [weak self] result in
            switch result {
            case .failure(let error):
                print("error: ", error.localizedDescription)
            // Do something with the error
            case .success(let mailResult):
                print("Success")
                // Do something with the result
            }
            self?.feedbackManager = nil
        }
    } else { // Cant Send Email: // Added UI Alert:
        let failedMenu = UIAlertController(title: "String", message: nil, preferredStyle: .alert)
        let okAlert = UIAlertAction(title: "String", style: .default)
        failedMenu.addAction(okAlert)
        present(failedMenu, animated: true)
    }

我正在尝试创建一个类来处理初始化MFMailComposeViewController以在应用程序中发送电子邮件。

我有问题让它起作用。好吧，如果它不起作用，它就不会崩溃。

类：

import UIKit
import MessageUI

struct Feedback {
    let recipients = "String"
    let subject: String
    let body: String
}

class FeedbackManager: MFMailComposeViewController, MFMailComposeViewControllerDelegate {
    
    func sendEmail(feedback: Feedback) {
        
        if MFMailComposeViewController.canSendMail() {
            
            self.mailComposeDelegate = self
            self.setToRecipients([feedback.recipients])
            self.setSubject("Feedback: \(feedback.subject)")
            self.setMessageBody("<p>\(feedback.body)</p>", isHTML: true)
            
        } else {
            print("else:")
            mailFailed()
        }
    }
    
    func mailFailed() {
        print("mailFailed():")
        let failedMenu = UIAlertController(title: "Please Email Me!", message: nil, preferredStyle: .alert)
        let okAlert = UIAlertAction(title: "Ok!", style: .default)
        failedMenu.addAction(okAlert)
        self.present(failedMenu, animated: true, completion: nil)
    }
    
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        controller.dismiss(animated: true)
    }
}

然后从不同的视图控制器调用它：

  let feedbackManager = FeedbackManager()
  feedbackManager.sendEmail(feedback: Feedback(subject: "String", body: "String"))
  self.present(feedbackManager, animated: true, completion: nil)
  tableView.deselectRow(at: indexPath, animated: true)

如果MFMailComposeViewController.canSendMail() ==是真的话，上面的功能就很好了。我面临的问题是，如果canSendMail()不是真，那么类显然无法初始化和崩溃。这很有道理。

错误：

Unable to initialize due to + [MFMailComposeViewController canSendMail] returns NO.

我不知道该怎么做才能解决这个问题。我尝试过将FeedbackManager从MFMailComposeViewController更改为UIViewController。这似乎是可行的，但因为它在堆栈上添加了一个视图，所以导致了一个奇怪的图形显示。

我可以做的另一件事是导入MessageUI，并为我希望能够发送电子邮件的每个控制器遵守MFMailComposeViewController。这样，在尝试初始化canSendMail()之前，我可以对照FeedbackManager()进行检查。但这似乎也不是最好的答案。

不然我该怎么做呢？

编辑:我已经让代码来处理这个问题了，但是，在显示MFMailComposeViewController之前，将视图添加到堆栈中是一个很糟糕的转变。

class FeedbackManager: UIViewController, MFMailComposeViewControllerDelegate {
    
    func sendEmail(feedback: Feedback, presentingViewController: UIViewController) -> UIViewController {
        
        if MFMailComposeViewController.canSendMail() {
            
            let mail = MFMailComposeViewController()
            mail.mailComposeDelegate = self
            mail.setToRecipients([feedback.recipients])
            mail.setSubject("Feedback: \(feedback.subject)")
            mail.setMessageBody("<p>\(feedback.body)</p>", isHTML: true)
            
             present(mail, animated: true)
            return self
        } else {
            print("else:")
            return mailFailed(presentingViewController: presentingViewController)
        }
    }
    
    func mailFailed(presentingViewController: UIViewController) -> UIViewController {
        print("mailFailed():")
        let failedMenu = UIAlertController(title: "Please Email Me!", message: nil, preferredStyle: .alert)
        let okAlert = UIAlertAction(title: "Ok!", style: .default)
        failedMenu.addAction(okAlert)
        return failedMenu
    }
    
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        controller.dismiss(animated: true)
        self.dismiss(animated: false)
    }
}

messageui

ios

swift

mfmailcomposeviewcontroller

class-hierarchy

回答 3

Stack Overflow用户

回答已采纳

发布于 2020-06-29 00:43:10

子类MFMailComposeViewController是错误的方法。这个类的意思是“原样”。如果您愿意，可以构建一个包装类：

struct Feedback {
    let recipients = "String"
    let subject: String
    let body: String
}

class FeedbackManager: NSObject, MFMailComposeViewControllerDelegate {
    
    private var feedback: Feedback
    
    private var completion: ((Result<MFMailComposeResult,Error>)->Void)?
    
    override init() {
        fatalError("Use FeedbackManager(feedback:)")
    }
    
    init?(feedback: Feedback) {
        guard MFMailComposeViewController.canSendMail() else {
            return nil
        }
        
        self.feedback = feedback
    }
    
    func send(on viewController: UIViewController, completion:(@escaping(Result<MFMailComposeResult,Error>)->Void)) {
        
        let mailVC = MFMailComposeViewController()
        self.completion = completion
        
        mailVC.mailComposeDelegate = self
        mailVC.setToRecipients([feedback.recipients])
        mailVC.setSubject("Feedback: \(feedback.subject)")
        mailVC.setMessageBody("<p>\(feedback.body)</p>", isHTML: true)
        
        viewController.present(mailVC, animated:true)
    } 
    
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        if let error = error {
            completion?(.failure(error))
        } else {
            completion?(.success(result))
        }
    }
}

然后从视图控制器中使用它：

let feedback = Feedback(subject: "String", body: "Body")
if let feedbackMgr = FeedbackManager(feedback: feedback) {
    self.feedbackManager = feedbackMgr
    feedback.send(on: self) { [weak self], result in 
        switch result {
            case .failure(let error):
                // Do something with the error
            case .success(let mailResult):
                // Do something with the result
        }
        self.feedbackManager = nil
    }
} else {
    // Can't send email
}

您将需要在属性中保存对FeedbackManager的强引用，否则它将在包含的函数退出时立即释放。我上面的代码引用了一个属性

var feedbackManager: FeedbackManager?

虽然这样可以工作，但更好的UX是直接检查canSendMail并禁用/隐藏允许他们发送反馈的UI组件

票数 4

Stack Overflow用户

发布于 2020-06-28 05:13:30

您可以按以下方式更改代码。

struct Feedback {
    let recipients = "String"
    let subject: String
    let body: String
}

class FeedbackManager: NSObject, MFMailComposeViewControllerDelegate {
    
    func sendEmail(presentingViewController: UIViewController)) {
        
        if MFMailComposeViewController.canSendMail() {
            
            let mail = MFMailComposeViewController()
            mail.mailComposeDelegate = self
            mail.setToRecipients([feedback.recipients])
            mail.setSubject("Feedback: \(feedback.subject)")
            mail.setMessageBody("<p>\(feedback.body)</p>", isHTML: true)
            presentingViewController.present(mail, animated: true)
            
        } else {
            print("else:")
            mailFailed(presentingViewController: presentingViewController)
        }
    }
    
    func mailFailed(presentingViewController: UIViewController) {
        print("mailFailed():")
        let failedMenu = UIAlertController(title: "Please Email Me!", message: nil, preferredStyle: .alert)
        let okAlert = UIAlertAction(title: "Ok!", style: .default)
        failedMenu.addAction(okAlert)
        presentingViewController.present(failedMenu, animated: true, completion: nil)
    }
    
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        controller.dismiss(animated: true)
    }
}

现在，mailComposer可以从另一个UIViewController类打开，如下所示。

let feedbackManager = FeedbackManager()
feedbackManager.sendEmail(presentingViewController: self)

希望它能帮上忙

票数 0

Stack Overflow用户

发布于 2020-06-28 19:31:57

首先添加一个检查.canSendMail是否为真的类来解决这个问题。如果是的话，它就会打开邮政发送类来表示MFMailComposeViewController。

这是我提出的唯一允许MFMailComposeViewController成为自己的MFMailComposeViewControllerDelegate的解决办法。同时，如果.canSendMail = false，也可以防止崩溃。

import UIKit
import MessageUI

struct Feedback {
    let recipients = ["Strings"]
    let subject: String
    let body: String
}

class FeedbackManager {

    func tryMail() -> Bool {
        if MFMailComposeViewController.canSendMail() {
            return true
        } else {
            return false
        }
    }

    func mailFailed() -> UIViewController {
        let failedMenu = UIAlertController(title: "Please Email Me!", message: nil, preferredStyle: .alert)
        let okAlert = UIAlertAction(title: "Ok!", style: .default)
        failedMenu.addAction(okAlert)
        return failedMenu
    }
}

class PostalManager: MFMailComposeViewController, MFMailComposeViewControllerDelegate {

    func sendEmail(feedback: Feedback) -> MFMailComposeViewController {
        if MFMailComposeViewController.canSendMail() {
            self.mailComposeDelegate = self
            self.setToRecipients(feedback.recipients)
            self.setSubject("Feedback: \(feedback.subject)")
            self.setMessageBody("<p>\(feedback.body)</p>", isHTML: true)
        }
        return self
    }

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

呼叫：

let feedbackManager = FeedbackManager()
let feedback = Feedback(subject: "String", body: "Body")

switch feedbackManager.tryMail() {

case true:
let postalManager = PostalManager()
present(postalManager.sendEmail(feedback: feedback), animated: true)
case false:
present(feedbackManager.mailFailed(), animated: true)
}

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/62617112

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