pausing spritekit game on app launch / exit .. iOS8

Question

I've read everything I could find on this topic and still cant figure out my issue. I have tried pausing my game in every area of appdelegate

func applicationWillResignActive(application: UIApplication!) {
    NSNotificationCenter.defaultCenter().postNotificationName("pauseGameScene", object: self)
}

func applicationDidEnterBackground(application: UIApplication!) {
    NSNotificationCenter.defaultCenter().postNotificationName("pauseGameScene", object: self)
}

func applicationWillEnterForeground(application: UIApplication!) {
    NSNotificationCenter.defaultCenter().postNotificationName("pauseGameScene", object: self)
}

func applicationDidBecomeActive(application: UIApplication!) {
    NSNotificationCenter.defaultCenter().postNotificationName("pauseGameScene", object: self)
}

In my controller:

override func viewDidLoad() {
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "pauseGame:", name: "pauseGameScene", object: nil)
}

func pauseGame(){
    self.skView.paused = true
    self.skView.scene!.paused = true
}

i know pauseGame works because if i toggle it with a button in my scene, it will stop the game. Even if I pause my skview and scene directly after they are loaded in the controller.. the game will not be paused on launch. It's easy to pause the game when I'm in-game. but for some reason whenever i exit and resume the app, the game will un-pause itself.

i notice if i get hacky and use some kind of delay.. i can get it to work. but obviously this is very stupid.. i just need to know where the game is unpausing itself!

func delay(delay:Double, closure:()->()) {
    dispatch_after(
        dispatch_time(
            DISPATCH_TIME_NOW,
            Int64(delay * Double(NSEC_PER_SEC))
        ),
        dispatch_get_main_queue(), closure)
}

func pauseGame(sender: UIButton!){

    delay(2) {
        println("blah")
        self.skView.paused = true
        self.skView.scene!.paused = true
    }
}

Answer 1

Here's a way to keep the view paused after returning from background mode.

Xcode 7 (see below for Xcode 8 instructions)

In the storyboard,

1) Change the class of the view to MyView

In the View Controller,

2) Define an SKView subclass with a boolean named stayPaused

class MyView: SKView {
    var stayPaused = false

    override var paused: Bool {
        get {
            return super.paused
        }
        set {
            if (!stayPaused) {
                super.paused = newValue
            }
            stayPaused = false
        }
    }

    func setStayPaused() {
        if (super.paused) {
            self.stayPaused = true
        }
    }
}

3) Define the view as MyView

4) Add a notifier to set the stayPaused flag

class GameViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        if let scene = GameScene.unarchiveFromFile("GameScene") as? GameScene {
            // Configure the view.
            let skView = self.view as MyView

            NSNotificationCenter.defaultCenter().addObserver(skView, selector:Selector("setStayPaused"), name: "stayPausedNotification", object: nil)

In the App Delegate,

5) Post a notification to set the stay paused flag when the app becomes active

func applicationDidBecomeActive(application: UIApplication) {
    NSNotificationCenter.defaultCenter().postNotificationName("stayPausedNotification", object:nil)
}

Xcode 8

In the storyboard,

1) Change the class of the view from SKView to MyView

In the View Controller,

2) Define an SKView subclass with a boolean named stayPaused

class MyView: SKView {
    var stayPaused = false

    override var isPaused: Bool {
        get {
            return super.isPaused
        }
        set {
            if (!stayPaused) {
                super.isPaused = newValue
            }
            stayPaused = false
        }
    }

    func setStayPaused() {
        if (super.isPaused) {
            self.stayPaused = true
        }
    }
}

3) Define the view as MyView

4) Add a notifier to set the stayPaused flag

class GameViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        if let view = self.view as! MyView? {
            NotificationCenter.default.addObserver(view, selector:#selector(MyView.setStayPaused), name: NSNotification.Name(rawValue: "stayPausedNotification"), object: nil)

In the App Delegate,

5) Post a notification to set the stay paused flag when the app becomes active

func applicationDidBecomeActive(_ application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "stayPausedNotification"), object: nil)
}

Answer 2

Here is an Obj-C example completely based on answer given by 0x141E, without subclassing a view. In my case, because I have internal game states, like finished, paused and started, I had to make an additional check in overridden setPaused: method. But this worked flawlessly for me and definitely it is the one possible way to go.

AppDelegate.m

- (void)applicationDidBecomeActive:(UIApplication *)application {

    [[NSNotificationCenter defaultCenter] postNotificationName:@"stayPausedNotification" object:nil];
}

GameScene.m

@interface GameScene()

@property (nonatomic, assign) BOOL stayPaused;

@end

@implementation GameScene

//Use initWithCoder: if you load a scene from .sks file, because initWithSize is not called in that case.

-(instancetype)initWithSize:(CGSize)size{ 

    if(self = [super initWithSize:size]){

        _stayPaused = NO;


         //register to listen for event
        [[NSNotificationCenter defaultCenter]
         addObserver:self
         selector:@selector(setStayPaused)
         name:@"stayPausedNotification"
         object:nil ];
    }
    return self;
}

-(void)setStayPaused{

    self.stayPaused = YES;
}

-(void)setPaused:(BOOL)paused{

    if (!self.stayPaused) {
        [super setPaused:paused];
    }
    self.stayPaused = NO;
}

-(void)willMoveFromView:(SKView *)view{

    [[NSNotificationCenter defaultCenter] removeObserver:self  name:@"stayPausedNotification" object:nil];
}

@end