CODEWITHSUNDEEP
swiftmacos
yesthisisjoe
yesthisisjoe

Reputation: 2035

OSX/Swift: Call function at a specific date/time

I'm trying to get my app to call a function at specific time intervals. For example, I might want the function to be called every hour on the hour, so at 1:00 AM, 2:00 AM, and so on. I have tried doing this with an NSTimer, but I find that it has trouble staying in sync when resuming after the machine sleeps or is powered off. Is there a way for my app to detect when we have reached a specific date and time and to call a function at that time? Thanks.

Upvotes: 2

Views: 1333

Answers (3)

mrkbxt
mrkbxt

Reputation: 491

You could use a helper method similar to below in combination with the NSTimer. The timer could fire its selector function every sec/minute/etc in which you pass this helper a pair of currentDate/endDate and when the returned value is <= 0 then execute your timed event function once with a flag and move your endDate forward an hour.

func timeBetween(currentDate: NSDate, endDate: NSDate) -> Double
{
    let calendar = NSCalendar.currentCalendar()

    let components = calendar.components([.Second], fromDate: currentDate, toDate: endDate, options: [])

    return Double(components.second)
}

Upvotes: 1

Marc Khadpe
Marc Khadpe

Reputation: 2002

You could try Grand Central Dispatch. Specifically use dispatch_walltime() to create a dispatch_time_t representing the time you want the job to run and then use dispatch_after() to submit the job to Grand Central Dispatch for execution at the specified time.

Upvotes: 3

Marcelo Cantos
Marcelo Cantos

Reputation: 185862

Run it every minute and test whether ≥ 1h has elapsed since the last invocation.

Upvotes: 1

Related Questions