Appdelegate中的全局变量在swift中

Question

我将一些数据从viewcontroller保存到appdelegate变量并从另一个视图控制器中获取它.Below是app delegate的代码

class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
var navigationController: UINavigationController?
var mainDic:NSMutableDictionary?

用于设置mainDic的代码

func filterResponse(response:NSDictionary){

    var appDelegate=AppDelegate()
    appDelegate.mainDic=response.mutableCopy() as? NSMutableDictionary
}

用于获取字典的代码.

let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
println(appDelegate.mainDic)

问题是我得到的输出为零.请让我正确.

Answer 1

这是你的错误

var appDelegate=AppDelegate() //You create a new instance, not get the exist one

您需要访问现有的AppDelegate

let appDelegate = UIApplication.shared.delegate as! AppDelegate

Answer 2

Swift 4.0

 let appDelegate = UIApplication.shared.delegate as! AppDelegate 
 let aVariable = appDelegate.value

Swift 3.0

let appDelegate = UIApplication.shared.delegate as! AppDelegate
let aVariable = appDelegate.someVariable

Swift 2.0

let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let aVariable = appDelegate.someVariable