Swift - 程序进入后台，以及应用终止时调用的方法

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        return true
    }
  
    //当应用进入后台时其作用
    func applicationDidEnterBackground(application: UIApplication) {
       saveData()
    }
    
    //当应用终止的时候起作用
    func applicationWillTerminate(application: UIApplication) {
        saveData()
    }
    
    func saveData(){
        //获取导航控制器
        let navigation = self.window?.rootViewController as UINavigationController
        //获取导航控制器的根视图控制器
        var controller:ViewController = navigation.viewControllers.first! as ViewController
        //执行ViewController的自定义数据保存方法
        controller.saveData()
    }
    
    func applicationWillResignActive(application: UIApplication) {
    }

    func applicationWillEnterForeground(application: UIApplication) {
    }

    func applicationDidBecomeActive(application: UIApplication) {
    }
}