swift3.0 延时执行

let time: TimeInterval = 1.0

DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + time) {

//code

print("1 秒后输出")

}

---

import Foundation

typealias Task = (_ cancel : Bool) -> Void

func delay(_ time: TimeInterval, task: @escaping ()->()) ->  Task? {

func dispatch_later(block: @escaping ()->()) {

let t = DispatchTime.now() + time

DispatchQueue.main.asyncAfter(deadline: t, execute: block)

}

var closure: (()->Void)? = task

var result: Task?

let delayedClosure: Task = {

cancel in

if let internalClosure = closure {

if (cancel == false) {

DispatchQueue.main.async(execute: internalClosure)

}

}

closure = nil

result = nil

}

result = delayedClosure

dispatch_later {

if let delayedClosure = result {

delayedClosure(false)

}

}

return result

}

func cancel(_ task: Task?) {

task?(true)

}

/*****使用*****/

//调用

delay(2) { print("2 秒后输出") }

//取消

let task = delay(5) { print("拨打 110") }

// 仔细想一想..

// 还是取消为妙..

cancel(task)