Swift 延遲運行代碼

// // DelayRun.swift // // Created by XuQing on 16/7/1. // Copyright © 2016年 xuqing. All rights reserved. // import Foundation typealias Task = (cancel : Bool) -> () func DelayRun(time:NSTimeInterval, task:()->()) -> Task? { func dispatch_later(block:()->()) { dispatch_after( dispatch_time( DISPATCH_TIME_NOW, Int64(time * Double(NSEC_PER_SEC))), dispatch_get_main_queue(), block) } var closure: dispatch_block_t? = task var result: Task? let delayedClosure: Task = { cancel in if let internalClosure = closure { if (cancel == false) { dispatch_async(dispatch_get_main_queue(), internalClosure); } } closure = nil result = nil } result = delayedClosure dispatch_later { if let delayedClosure = result { delayedClosure(cancel: false) } } return result; } func cancel(task:Task?) { task?(cancel: true) }