swift3 UIViewController 返回参数给上一级页面后如何更新页面内容？

Question

//获取Setting页面返回值
    @IBAction func onClose(segue: UIStoryboardSegue) {
        //同样也是暴力的强转...
        let nav2 = segue.source as! LifeTimeSettingViewController
        print("返回值：")
        print(nav2.myBirthday2.date)
        
        self.haveBirthday = Int(nav2.myBirthday2.date.timeIntervalSince1970)
        

        //以下代码载viewDidLoad也有，直接执行gcd会报错
        let haveBirthday2 = Int(nav2.myBirthday2.date.timeIntervalSince1970)
        remainingSeconds = totalLifeTime + haveBirthday2 - Int(currentTimeInterval)
        gcd(remainingSeconds)
   }

Answer 1

oc里面用protocol&delegate，把更新方法委托给上一级实现就行了，swift应该类似。