代表未在SWIFT iOS中调用

Question

I am Created 2 Views, One is and Used Protocol and Delegate. For first view the Delegate function is not called.

My FirstView Controller : Here I am Accessing the Delegate Function.

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.
    }

}

My SecondView Controller : Here I Am creating Delegate.

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.
    }

}

Answer 1

To me, it looks like you're pushing a view controller that you haven't actually set the delegate for. If you change your "Next" function, to include the line

nextViewController.delegate = self

You should see that the delegation works. In doing this, you can also probably remove the creation of "secondController", as it looks like that's redundant.

Answer 2

The naming convention you have followed would confuse fellow developers in your team. The instance should have been

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

And then as @Eagerod mentioned, the delegate you would set is

durationDel.delegate = self