ios - 导航堆栈之前 View 之间的协议(protocol)委托(delegate)

Question

View1 转至导航 Controller - View2 转至View3

我正在尝试创建从 View3 到 View1 的协议(protocol)委托(delegate)

在 View 1

class NormalUser: UIViewController, NormalUserDelegate {

    @objc func showAddressView() {
        addressView.isHidden = false
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        if let conn = self.storyboard?.instantiateViewController(withIdentifier: "View") as? View
        {
            conn.delegate = self
        }
    }
}

在 View 3

weak var delegate: NormalUserDelegate?

func test() {

self.delegate?.showAddressView()

}

协议(protocol)

protocol NormalUserDelegate: class {
    func showAddressView()
}

我无法让它发挥作用。有什么想法吗？

Answer 1

在我看来，你有两个不错的选择来使用委托(delegate)模式。 1 个可怕的选项可以工作，但它很老套且懒惰，然后你就有了广播接收器模式。

2个不错的选择

1 - 将委托(delegate)向前传递

class VC1: UIViewController, SomeDelegate {

    func delegateFunction() {}

    func showNextVC() {
        let next = VC2()
        next.forwardingDelegate = self
        present(next, animated: true)
    }
}

class VC2: UIViewController {
    var forwardingDelegate: SomeDelegate? = nil

    func showNextVC() {
        let next = VC3()
        next.delegate = forwardingDelegate
        present(next, animated: true)
    }
}

2 - 将第三个 Controller 传递给第二个 Controller

class VC1: UIViewController, SomeDelegate {

    func delegateFunction() {}

    func showNextVC() {
        let final = VC3()
        final.delegate = self

        let next = VC2(withControllerToPresent: final)
        present(next, animated: true)
    }
}

class VC2: UIViewController {
    let controller: UIViewController

    init(withControllerToPresent controller: UIViewController) {
        self.controller = controller
        super.init(withNibName: nil, bundle: nil 
    }

    func showNextVC() {
        present(controller, animated: true)
    }
}

class VC3: UIViewController { 
    var delegate: SomeDelegate? = nil
}

1 个糟糕的选择

使用单例/全局变量...(请不​​要)

个人意见

我已经完成了前两个选项......它们有效。但广播接收器模式可能更好，因为它更干净。 VC2 不需要将任何内容转发到 3。只需确保您的通知的命名空间足够具体，以免以后被其他任何内容捕获。