Storyboard loading only once

Question

Explanation

I'm trying to build a simple email code in separate swift files (in this case: GameViewController.swift and MailViewController.swift).

What should happen: I gotta touch the screen in GameViewController to call MailViewController, and when canceling or sending an email, it shall go back to GameViewController.

What is happening: It calls MailViewController and go back when touching Cancel or Send, but only once. When I try to do it again (even when closing and opening the app again) a black screen shows up when trying to get back to GameViewController.

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Code

You can download the code below by clicking here.

GameViewController

import UIKit
import SpriteKit

class GameViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Set view size.
        let scene = GameScene(size: view.bounds.size)

        // Configure the view.
        let skView = view as! SKView
        skView.showsFPS = true
        skView.showsNodeCount = true

        /* Sprite Kit applies additional optimizations to improve rendering performance */
        skView.ignoresSiblingOrder = true

        /* Set the scale mode to scale to fit the window */
        scene.scaleMode = .ResizeFill

        skView.presentScene(scene)

        //Register mail observer (so I can call from GameScene)
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(self.openMailViewController), name: "openMailViewController", object: nil)
    }

    override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask {
        if UIDevice.currentDevice().userInterfaceIdiom == .Phone {
            return .Landscape
        } else {
            return .Landscape
        }
    }
}

extension GameViewController{

    func openMailViewController(){
        self.performSegueWithIdentifier("openMailViewController", sender: self)
    }
}

MailViewController

import UIKit
import SpriteKit
import MessageUI

class MailViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        self.openMailController()
    }

    override func supportedInterfaceOrientations() -> UIInterfaceOrientationMask {
        if UIDevice.currentDevice().userInterfaceIdiom == .Phone {
            return .AllButUpsideDown
        } else {
            return .All
        }
    }
}

//Mail
extension MailViewController: MFMailComposeViewControllerDelegate {

    func openMailController() {

        let mailComposerVC = MFMailComposeViewController()
        mailComposerVC.mailComposeDelegate = self //extremely important to set the mailComposeDelegate property, not the delegate property

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

    func mailComposeController(controller: MFMailComposeViewController, didFinishWithResult result: MFMailComposeResult, error: NSError?) {

        //dismiss mail
        self.dismissViewControllerAnimated(true, completion: nil)

        //go back to the game
        backToGameViewController()
    }
}

extension MailViewController{

    func backToGameViewController(){
        self.performSegueWithIdentifier("backToGameViewController", sender: self)
    }
}

Main.storyboard

Thanks in advance,
Luiz.

Answer 1

Try removing the reverse segue back in the storyboard from the MailViewController to the GameViewController. And in your MailViewController, use this function to go back:

func backToGameViewController(){
    dismissViewControllerAnimated(true, completion: nil)
}

Change the function to following :

func mailComposeController(controller: MFMailComposeViewController, didFinishWithResult result: MFMailComposeResult, error: NSError?) {

        //dismiss mail
        self.dismissViewControllerAnimated(true) {
            //go back to the game
            self.backToGameViewController()
        }

    }

Also try this on your device, not on the simulator. Simulator returns an error while trying to open the MFMailComposeViewController.

A segue creates a new object, and pushes that on the stack, you would not want to create repeated stacks of objects on top of each other..

Hope this helps.

Answer 2

If you replace

self.performSegueWithIdentifier("backToGameViewController", sender: self)

with

self.dismissViewControllerAnimated(true, completion: nil)

your code will work, but I don't think it's actually what you want to do.

The reason this works is from your game controller you're presenting MailViewController, which is then presenting an MFMailComposeViewController. Since you're presenting two at once, you're getting an odd double animation where a blank view slides up before the mail view slides up. In order to fully dismiss the mail views then, you need to call dismissViewController twice.

A better approach would be to present the MFMailComposeController directly from GameController.