Alexey Nakhimov Alexey Nakhimov - 4 months ago 86
Objective-C Question

MFMailComposeViewController in Swift

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 = ["a.nakhimov@gmail.com"]
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.
}

override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}

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

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)
}
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