func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
return true
}//app启动后的回调函数
func applicationWillResignActive(application: UIApplication) {
}//应用挂起（锁屏）的回调函数
func applicationDidEnterBackground(application: UIApplication) {
}//app进入后台时候才调用的函数
func applicationWillEnterForeground(application: UIApplication) {
}//app回到前台时候才会被调用
func applicationDidBecomeActive(application: UIApplication) {
}//从休眠变成活跃状态时候调用
func applicationWillTerminate(application: UIApplication) {
}//程序退出时候调用