导航堆栈之前视图之间的协议委托

Question

View1 转至 导航控制器 - View2 转至 View3

我正在尝试创建从 View3 到 View1 的协议委托

在视图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
        }
    }
}

在视图3中

weak var delegate: NormalUserDelegate?

func test() {

self.delegate?.showAddressView()

}

协议

protocol NormalUserDelegate: class {
    func showAddressView()
}

我无法让它工作。有什么想法吗？

Answer 1

在我看来，您有 2 个不错的选择来使用委托模式。 1个糟糕的选择，但它很笨拙和懒惰，然后你就有了广播接收器模式。

2 个不错的选择

1 - 向前传递委托

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 - 将第三个控制器传递给第二个控制器

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 可怕的选择

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。但是广播接收器模式可能更好，因为它会更干净。 VC2 不需要向 3 转发任何内容。只要确保您的通知命名空间足够具体，以后不会被其他任何东西捕获。

Answer 2

如果我正确理解您的场景，您需要两个委托，每个委托将数据传递回之前的 UIViewController。据我所知，您无法绕过辅助 UIViewController。

Answer 3

您缺少的是一个路由器类，这是我如何实现它的一个简单示例。

protocol RoutingView1{
func openView2()
}

protocol RoutingView2{
func openView3()
}

protocol RoutingView3{
func foo()
}

class View1{

func foo(){
//this will get called when View3 calls its RootingView3.foo()
}
}

class Router: RoutingView1, RoutingView2{

var rootView: View1

func start() -> UIViewController{
view.routingDelegate = self
rootView = view1
}

func openView2(){
let vc = View2()
vc.routingDelegate = self
rootView.push()
}

func openView3(){
let vc = View3()
vc.routingDelegate = self
rootView.push()
}

func foo(){
rootView.foo()
}

Answer 4

放松转场

如果您使用的是界面生成器，则使用展开转场可能是最简单/最干净的。

1. 在 VC1 中创建界面构建器操作：

   class VC1: UIViewController {
   
       @IBAction func backToVC1(_ segue: UIStoryboardSegue) {
           self.showAddress()
       }
   
       func showAddress() {
           addressView.isHidden = false
       }
   }
   

2. 在您的 VC3 故事板中，按住控件并单击视图控制器图标，将鼠标拖到退出图标上并释放。单击以选择您在 VC1 中创建的展开转场。

3. 创建转场后，在文档大纲中选择它。

4. 并在属性检查器中命名。

5. 最后，在你的 VC3 代码中调用 segue。

   class VC3: UIViewController {
   
       func test() {
           self.performSegue(withIdentifier: "unwindToVC1", sender: self)
       }
   }
   

Answer 5

我认为您可以在这种情况下使用SwiftEventBus。 Link

示例：

@IBAction func clicked(sender: AnyObject) {
     count++
     SwiftEventBus.post("doStuffOnBackground")
 }

 @IBOutlet weak var textField: UITextField!

 var count = 0

 override func viewDidLoad() {
     super.viewDidLoad()

     SwiftEventBus.onBackgroundThread(self, name: "doStuffOnBackground") { notification in
         println("doing stuff in background thread")
         SwiftEventBus.postToMainThread("updateText")
     }

     SwiftEventBus.onMainThread(self, name: "updateText") { notification in
         self.textField.text = "\(self.count)"
     }
}

//Perhaps on viewDidDisappear depending on your needs
override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    SwiftEventBus.unregister(self)
}

Answer 6

**Just set delegate of view 2 as a delegate of view 3 as below:**

 class View1: UIViewController, NormalUserDelegate {

       @objc func showAddressView() {

            addressView.isHidden = false
        }
    // Going to view 2 by any means i.e segue , navigation set  
       func goToView2Controller(){
         if let view2 = self.storyboard?.instantiateViewController(withIdentifier: "View2") as? View2
            {
              view2.delegate = self
            }
        self.navigationController?.pushViewController(view2, animated: true)

       }
    }

    class View2: UIViewController {
     weak var delegate: NormalUserDelegate?

    // Going to view 3 by any means i.e segue or other means  
       func goToView3Controller(){
         if let view3 = self.storyboard?.instantiateViewController(withIdentifier: "View3") as? View3
            {
              view3.delegate = self.delegate
            }
         self.navigationController?.pushViewController(view3, animated: true)
       }

    }

    class View3: UIViewController {
     weak var delegate: NormalUserDelegate?


    func test() {

      self.delegate?.showAddressView()

    }

    }