Restart animation when returning to foreground

Question

I'm having an issue restarting an animation when the app returns to the foreground. I checked this solution, but it's not working for me.

In my App Delegate, I'm cancelling the animation when the app resigns

func applicationWillResignActive(application: UIApplication) {
    let rootVC = window?.rootViewController as! ViewController
    rootVC.boardImage.layer.removeAllAnimations()
}

And I'm posting a notification to the View Controller when the app enters the foreground

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

The View Controller has an observer that calls the method, but the animation isn't restarting.

Called Method:

func playAnimation(notification: AnyObject) {
    gameLogic.boardFlash(boardImage)
}

the boardFlash animation:

func boardFlash(board: UIImageView) {
    let options:UIViewAnimationOptions = [.Autoreverse, .Repeat]

    UIView.animateWithDuration(0.3, delay: 1.0, options: [options], animations: {
        board.alpha = 0.0
        }, completion: nil)
}

I checked that everything is getting called, but the animation isn't running. Any help will be greatly appreciated. Thanks!

are you reseting the alpha of the board back to 1.0 before calling the animation method? — Blake Lockley, Mar 08 '16 at 02:43
Yes, it is. It runs the same animation when the view loads originally. That one works fine. — D. Greg, Mar 08 '16 at 02:45
sorry, my comment wasn't very clear, I mean, when you first create the view you are trying to animate it has an alpha of 1, and then you animate it the first time o zero, after the first time the animation has run, have you set the alpha of board back to one again? — Blake Lockley, Mar 08 '16 at 02:49
i didnt see you had autoreverse in the options! my bad, sorry — Blake Lockley, Mar 08 '16 at 02:50
@BlakeLockley Thanks for your help. If you Make your comment into an answer, I'll mark it as the answer (or cut and paste mine) — D. Greg, Mar 08 '16 at 04:11

score 2 · Accepted Answer · answered Mar 08 '16 at 03:06

2

I solved it thanks to @BlakeLockley comment.

I set the board Image View alpha to 1.0 in the observer method call.

func playAnimation(notification: AnyObject) {
    boardImage.alpha = 1.0
    gameLogic.boardFlash(boardImage)
}

Now it works fine. Interesting solution though.

answered Mar 08 '16 at 03:06

D. Greg

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Im glad i could indirectly help, haha! It must be a matter of swift thinking that the alpha was still set to zero behind the scenes or something, Im gonna have a look see if I can find the reason why. – Blake Lockley Mar 08 '16 at 04:14

Restart animation when returning to foreground

1 Answers1