MFMailComposeViewController in Swift

Question

This is sample code:

import UIKit
import MessageUI

class ViewController: UIViewController, MFMailComposeViewControllerDelegate {

    @IBAction func showEmail(sender : AnyObject) {
        var emailTitle = "Test Email"
        var messageBody = "This is a test email body"
        var toRecipents = ["[email protected]"]
        var mc: MFMailComposeViewController = MFMailComposeViewController()
        mc.mailComposeDelegate = self
        mc.setSubject(emailTitle)
        mc.setMessageBody(messageBody, isHTML: false)
        mc.setToRecipients(toRecipents)

        self.presentViewController(mc, animated: true, completion: nil)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    func mailComposeController(controller:MFMailComposeViewController, didFinishWithResult result:MFMailComposeResult, error:NSError) {
        switch result {
        case MFMailComposeResultCancelled:
            NSLog("Mail cancelled")
        case MFMailComposeResultSaved:
            NSLog("Mail saved")
        case MFMailComposeResultSent:
            NSLog("Mail sent")
        case MFMailComposeResultFailed:
            NSLog("Mail sent failure: %@", [error.localizedDescription])
        default:
            break
        }
        self.dismissViewControllerAnimated(false, completion: nil)
    }
}

In function mailComposeController I get an error on every case expression:

Could not find an overload '~=' that accepts the supplied arguments.

What am I doing wrong?

Answer 1

I compared MFMailComposeResult documentation on both Xcode 5 and Xcode 6. In Swift, MFMailComposeResult is a struct

struct MFMailComposeResult {
    init(_ value: CUnsignedInt) // available in iPhone 3.0
    var value: CUnsignedInt
}

with MFMailComposeResultCancelled as a constant of type MFMailComposeResult:

var MFMailComposeResultCancelled: MFMailComposeResult { get }

while it's an enum in Objective-C:

 enum MFMailComposeResult {
    MFMailComposeResultCancelled,
    MFMailComposeResultSaved,
    MFMailComposeResultSent,
    MFMailComposeResultFailed
};
typedef enum MFMailComposeResult MFMailComposeResult;   // available in iPhone 3.0

In order to make your code work, you will have to compare their values which are CUnsignedInt.

So you will have to type the following code:

func mailComposeController(controller:MFMailComposeViewController, didFinishWithResult result:MFMailComposeResult, error:NSError) {
    switch result.value {
    case MFMailComposeResultCancelled.value:
        println("Mail cancelled")
    case MFMailComposeResultSaved.value:
        println("Mail saved")
    case MFMailComposeResultSent.value:
        println("Mail sent")
    case MFMailComposeResultFailed.value:
        println("Mail sent failure: \(error.localizedDescription)")
    default:
        break
    }
    self.dismissViewControllerAnimated(false, completion: nil)
}