Cancel a timed event in Swift?

Question

I want to run a block of code in 10 seconds from an event, but I want to be able to cancel it so that if something happens before those 10 seconds, the code won't run after 10 seconds have gone by.

I've been using this, but it's not cancellable:

static func delay(delay:Double, closure:()->()) {
  dispatch_after(
    dispatch_time(
      DISPATCH_TIME_NOW,
      Int64(delay * Double(NSEC_PER_SEC))
    ),
    dispatch_get_main_queue(), closure
  )
}

How can I accomplish this?

Answer 1

Swift 3 has DispatchWorkItem:

let task = DispatchWorkItem { print("do something") }

// execute task in 2 seconds
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 2, execute: task)

// optional: cancel task
task.cancel()