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
    }
}

It looks like sprite kit is automatically pausing the view and the scene prior to an app entering background mode. It also un-pauses the view/scene after willEnterForeground/didBecomeActive are called. — 0x141E, Oct 11 '14 at 21:46
yeah thats exactly what i've noticed. is there any way to prevent this behavior? — hamobi, Oct 12 '14 at 07:29
I suspect it's a bug in sprite kit because the game resumes after didBecomeActive is called. — 0x141E, Oct 12 '14 at 07:45

0x141E · Accepted Answer · 2018-08-18T09:13:50.523

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)
}

it kind of sucks that we have to subclass an skview to make something work that should already work. but hey, at least it works — hamobi, Dec 14 '14 at 08:08
Thanks a lot! Also if you don't want to create one more class - override pause property of SKScene instead of SKView — serg_ov, Mar 29 '15 at 21:35
@0x141 Yeap, this works. I've added Obj-C example which worked for me (without subclassing the view). — Whirlwind, Aug 12 '15 at 13:27
How would I use this Pause system with my Pause function inside my GameScene ? and make it editable by the button that I have already set there ? — Abdou023, Oct 18 '15 at 22:47
@Abdou023 you will need to pause/resume the `SKView` when the user taps on the pause button. The code will keep the view paused when the user presses the Home button and then restarts the app by tapping on its icon. — 0x141E, Oct 19 '15 at 10:13
The pause button works fine, but when the app comes from background the pause menu doesn't show, does it has something to with pausing the entire skView ? like stopping animations ? — Abdou023, Oct 19 '15 at 22:57
Could you please tak a look here: http://stackoverflow.com/questions/33327226/spritekit-pause-screen-doesnt-show-when-didbecomeactive — Abdou023, Oct 26 '15 at 23:05

score 2 · Answer 2 · answered Aug 12 '15 at 13:25

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

Whirlwind Could you please tell me how to do the same implementation in swift without subclassing a view — Pruthvi Hariharan, May 18 '16 at 14:51

score 0 · Answer 3 · answered Sep 03 '15 at 03:10

I recently encountered the same issue. The stayPaused solution works fine for me. Thanks guys:)

However, I think the mechanism you use to set stayPaused is NOT robust. Just by calling setStayPaused once on App becoming active is not enough, engineers in apple may change the code of Sprite Kit and call setPaused(false) MORE THAN ONCE on activating (In fact, I think they just did!). The second setPaused(false) will resume the game as you set stayPaused back to false on the first call.

My suggestion is to directly set the stayPaused property yourself in your pauseGame/resumeGame functions, and remove the "self.stayPaused = NO;" from setPaused function. In this way, the default behavior of SpriteKit can do whatever it likes, but the game will stay paused as long as we want.

pausing spritekit game on app launch / exit .. iOS8

3 Answers3

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