Why does my NSTimer selector never fire? Is it because it's in GLKitViewController instead of UIViewController?

Question

At a certain state in the program, I call a method with this as the body:

self.timeStartedDisplayingTime = [NSDate date];
self.stopButton.enabled = YES;

[NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(updateElapsedTime:) userInfo:nil repeats:YES];

I've verified that this method is indeed called.

However, the corresponding selector's body:

NSTimeInterval elapsedTimeDisplayingECG = [self.timeStartedDisplayingECG timeIntervalSinceDate:[NSDate date]];
self.elapsedTimeValueLabel.text = [NSString stringWithFormat:@"%f", elapsedTimeDisplayingECG];

Is never called. I've put a breakpoint on it and it's never reached. Why is this exactly? It's in a GLKitViewController instead if that's relevant.

Did you verify that the code that launches the timer gets called? — Richard J. Ross III, Jan 31 '14 at 19:44
Take a look at this thread, this might point to a real reason http://stackoverflow.com/questions/10080932/glkviewcontrollerdelegate-getting-blocked — Arthur Shinkevich, Jan 31 '14 at 19:44

score -1 · Answer 1 · answered Feb 01 '14 at 21:32

-1

Your timer gets thrown away right after creating it. You need to retain is somewhere.

Define a property

@property (strong) NSTimer *myTimer;

and assign your timer to this:

self.myTimer = [NSTimer scheduledTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(updateElapsedTime:) userInfo:nil repeats:YES];

answered Feb 01 '14 at 21:32

343max

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timers are retained by the runloop till fired or invalidate so this isn't it – Daij-Djan Feb 01 '14 at 21:41

Why does my NSTimer selector never fire? Is it because it's in GLKitViewController instead of UIViewController?

1 Answers1