iOS Error when sending email or sms

Question

I'm trying to send sms and email from an iOS app, but I encounter some problems.

I took the code from a tutorial, for example the sms code :

func sendMessage() {
    let prefs = NSUserDefaults.standardUserDefaults()
    var message = MFMessageComposeViewController()

    // Contacts
    var phoneNumbers = [String]()
    var phoneNumberNb: Int = prefs.objectForKey("phonenumberssaved")!.count
    for(var i = 0; i < phoneNumberNb; i++) {
        phoneNumbers.append(prefs.objectForKey("phonenumberssaved")!.objectAtIndex(i) as! String)
    }

    println(phoneNumbers)

    message.recipients = phoneNumbers
    message.body = self.messageText
    message.messageComposeDelegate = self

    self.presentViewController(message, animated: false, completion: nil)
} 

and I printed my datas (they seems to be ok), but when I try to send it, the app crash with a

'fatal error: unexpectedly found nil while unwrapping an Optional value' and it show me a strange file with a line highlighted : '0x4b5164 <+64>: trap'...

Answer 1

Use conditional unwrapping. Also, you don't need to process each array element:

func sendMessage() {
    let prefs = NSUserDefaults.standardUserDefaults()
    let message = MFMessageComposeViewController()

    // Contacts
    if let phoneNumbers = prefs.objectForKey("phonenumberssaved") as? [String] {
        println(phoneNumbers)

        message.recipients = phoneNumbers
        message.body = "some body"
        message.messageComposeDelegate = self

        self.presentViewController(message, animated: false, completion: nil)
    }
}

Answer 2

You can try this before init your "message", some device don't have option to send message:

if MFMessageComposeViewController.canSendText() {
    ...
}

Verify if phoneNumbers is not nil before setting message.recipients, this can be append if there is no phone number saved in user preferences.

And self.messageText is not nil too by the way.

Hope this can help you.