Appdelegate中的全局變量在swift中

Question

我將一些數據從viewcontroller保存到appdelegate變量並從另一個視圖控制器中獲取它.Below是app delegate的代碼

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

用於設置mainDic的代碼

func filterResponse(response:NSDictionary){

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

用於獲取字典的代碼。

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

問題是我得到的輸出為零。請讓我正確。

Answer 1

這是你的錯誤

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

您需要訪問現有的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

Answer 3

func appDelegate() -> AppDelegate {
  return UIApplication.sharedApplication().delegate as! AppDelegate
}