在SWIFT iOS中未调用委托

我创建了两个视图，一个用于协议和委托。对于第一个视图，不调用委托函数

我的FirstView控制器：这里我正在访问委托函数

import UIKit

class NextViewController: UIViewController,DurationSelectDelegate {
    //var secondController: DurationDel?

    var secondController: DurationDel = DurationDel()

    @IBAction func Next(sender : AnyObject)
    {
        let nextViewController = DurationDel(nibName: "DurationDel", bundle: nil)
        self.navigationController.pushViewController(nextViewController, animated: true)
    }


    override func viewDidLoad() {
        super.viewDidLoad()

        secondController.delegate=self
    }

    func DurationSelected() {
        println("SUCCESS")
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

我的SecondView控制器：我在这里创建委托

import UIKit

protocol DurationSelectDelegate {
    func DurationSelected()
}


class DurationDel: UIViewController {

    var delegate: DurationSelectDelegate?

    @IBAction func Previous(sender : AnyObject) {
        //let game = DurationSelectDelegate()
        delegate?.DurationSelected()
        self.navigationController.popViewControllerAnimated(true)
    }


    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

---

在我看来，似乎您正在推送一个尚未实际设置委托的视图控制器。如果您更改了“下一步”函数，以包含该行

nextViewController.delegate = self

---

你应该看到授权是有效的。在这样做的过程中，您可能还可以删除“secondController”的创建，因为这看起来是多余的。

您遵循的命名约定会让团队中的其他开发人员感到困惑。这个例子应该是

let durationDel = DurationDel(nibName: "DurationDel", bundle: nil)

正如@eakerod所提到的，您要设置的委托是

durationDel.delegate = self

---

您是否尝试过此，

delegate！。DurationSelected（）？是的。它因以下错误而崩溃致命错误：无法展开可选。无