延时NSTimer

import Foundation
import UIKit

class YijfkController:UIViewController{
override func viewDidLoad() {
super.viewDidLoad()
tishi.hidden = true

}
@IBOutlet var quxiao:UIButton!
@IBOutlet var text:UITextView!
@IBOutlet var tishi:UILabel!
var isEmpty=true

@IBAction func OnBackup(sender:AnyObject){
self.dismissViewControllerAnimated(true, completion:{})
}

//func textViewShou
@IBAction func feedback(sender:AnyObject){
var a=[String]()
var b=[String]()
a.append("text")
b.append(self.text.text)
let dic=NSDictionary(objects: b, forKeys: a)
HttpRequest.post(urlString: "http://59.78.93.208:9097//AdviseInsert", postParams: dic, completion: {(data) -> Void in
if data == "1" {
self.tishi.hidden = false
NSTimer.scheduledTimerWithTimeInterval(1.5, target: self, selector: "hidden", userInfo: nil, repeats: false)
}
})

}

func hidden() {
tishi.hidden = true
}
}