NSTimer lag fire after background

Question

timer = [NSTimer bk_timerWithTimeInterval:60 block:^(NSTimer *timer) { ....} repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];


+ (id)bk_timerWithTimeInterval:(NSTimeInterval)inTimeInterval block:(void (^)(NSTimer *timer))block repeats:(BOOL)inRepeats
{
    NSParameterAssert(block != nil);
    return [self timerWithTimeInterval:inTimeInterval target:self selector:@selector(bk_executeBlockFromTimer:) userInfo:[block copy] repeats:inRepeats];
}

+ (void)bk_executeBlockFromTimer:(NSTimer *)aTimer {
    void (^block)(NSTimer *) = [aTimer userInfo];
    if (block) block(aTimer);
}

If I fold and unfold application after a few minutes, almost always the timer is firing immediately and sometimes it fire with delay. Why the timer does not always work immediately?

You mean you don't stop the timer when the app goes to the background? — Wain, Mar 04 '14 at 19:48
possible duplicate of [Scheduled NSTimer when app is in background?](http://stackoverflow.com/questions/8415870/scheduled-nstimer-when-app-is-in-background) — jscs, Mar 04 '14 at 19:49
Yes, i don't stop timer when the app goes to the background. — Fanruten, Mar 04 '14 at 20:37

score -1 · Answer 1 · answered Mar 04 '14 at 20:23

-1

try to add this in "didFinishLaunchingWithOptions" in your Appdelegate

__block UIBackgroundTaskIdentifier locationUpdater =[[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{

        [[UIApplication sharedApplication] endBackgroundTask:locationUpdater];

        locationUpdater=UIBackgroundTaskInvalid;

    } ];

answered Mar 04 '14 at 20:23

chawki

867
1
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Needless to say, this only gives you a finite amount of time (a few minutes) before your app is truly suspended. – Rob Mar 04 '14 at 20:37
I dont' want execute timer in the background. I want the timer fire immediately after the app go to the foreground. – Fanruten Mar 04 '14 at 20:41

NSTimer lag fire after background

1 Answers1