Swift

Question

我将在其中包含我的完整代码，但我会尝试给出相关位所在位置的指针。基本上，我从带有一些新数据的 Unwind Segue 返回到视图控制器。我在 'NBARotoHome' VC 中成功使用了该数据，但我还需要通过嵌入式导航控制器将部分数据传递到 'NBARotoTabPager' vc.

我正在尝试使用 'UpdateChildView' 委托（在第一段代码的顶部）并在“loadViewData()”中调用它的方法（在底部附近的 'if statement'第一个块）。

protocol UpdateChildView : class {
 func updateView()
 func test()
 var playerSelected: Player? { get set }
}



class RotoViewRoundCell: UITableViewCell{

@IBOutlet weak var categoryLabel: UILabel!

}

class RotoViewRoundHeader: UITableViewCell{

}


class NBARotoHome: UIViewController{


@IBOutlet weak var posPaidLabel: UILabel!
@IBOutlet weak var progressIndicator: UIProgressView!
@IBOutlet weak var vsLabel: UILabel!
@IBOutlet weak var fantasyFundsAmountLabel: UILabel!
@IBOutlet weak var fantasyFundsLabel: UILabel!
@IBOutlet weak var playerName: UILabel!
@IBOutlet weak var roundIndicator: UILabel!


var selectedPlayer: Player!

var firstNavController: UINavigationController!

weak var updateChildView : UpdateChildView?

override func viewDidLoad() {
    super.viewDidLoad()

    loadViewData()

    firstNavController = self.navigationController



    let rightBarButton = UIBarButtonItem(title: "Select", style: UIBarButtonItemStyle.plain, target: self, action: #selector(myRightSideBarButtonItemTapped(_:)))
    self.navigationItem.rightBarButtonItem = rightBarButton
    self.title = "NBA Roto"


}


func myRightSideBarButtonItemTapped(_ sender:UIBarButtonItem!){

    performSegue(withIdentifier: "ShowDraft", sender: nil)
}


override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    if segue.identifier == "ShowDraft" {
        let navVC = segue.destination as? UINavigationController
        let nbaDraftList = navVC?.viewControllers.first as! NBADraftList
        nbaDraftList.mainNavController = firstNavController
    }


    if (segue.identifier == "buyNavControllerChild"){

//            let navVC = segue.destination as? UINavigationController
//            let buyVC = navVC?.viewControllers.first as! NBARotoTabPager
//            buyVC.delegate = self

    }


}


override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)


}

@IBAction func prepareForUnwind(segue: UIStoryboardSegue) {



}

func loadViewData(){

    if((selectedPlayer) != nil){
        roundIndicator.text = "Upcoming: " + selectedPlayer.game_time
        playerName.text = selectedPlayer.Name
        vsLabel.text = selectedPlayer.visiting + " @ " + selectedPlayer.home
        fantasyFundsLabel.text = ""
        fantasyFundsAmountLabel.text = ""

          updateChildView?.test()
     //   updateChildView?.playerSelected = selectedPlayer
    //    updateChildView?.updateView()

    }else{
        roundIndicator.text = "Select a Player"
        playerName.text = "No Player Selected"
        vsLabel.text = "--"
        fantasyFundsLabel.text = "Fantasy Funds"
        fantasyFundsAmountLabel.text = ",000"

    }

}

}

因为我无法让委托工作，所以我一直在尝试在上面的 'prepare' 方法中设置它的委托属性 -'buyVC.delegate = self' - 但是我得到 'buyVC has no member delegate' 所以这是一个死胡同。

下一段代码是嵌入在导航控制器中的 NBARotoTabPager vc。由于我不再确定的原因，我决定将它作为 NBARotoHome 的子类，但它基本上是一个自定义标签页，使用分段控件在两个额外的 vc 之间切换。

此时最重要的一步就是让 'test' 函数工作（它只打印 'test'。它在下面的代码块中从 updateView 上方倒数第二个代码块中实现）。

class NBARotoTabPager: NBARotoHome, UpdateChildView{

@IBOutlet weak var segmentedControl: UISegmentedControl!
@IBOutlet weak var scoreKey: UIBarButtonItem!
@IBOutlet weak var standings: UIBarButtonItem!

 var playerSelected: Player?


override func viewDidLoad() {



    navigationController?.navigationBar.barTintColor = UIColor(red: 27/255, green: 27/255, blue: 27/255, alpha: 1)


    scoreKey.setTitleTextAttributes([NSFontAttributeName: UIFont(name: "Helvetica", size: 13.0)!], for: UIControlState.normal)
    scoreKey.tintColor = UIColor.blue

    standings.setTitleTextAttributes([NSFontAttributeName: UIFont(name: "Helvetica", size: 13.0)!], for: UIControlState.normal)
    standings.tintColor = UIColor.blue

    setupView()
}

private func setupView() {
    setupSegmentedControl()
    updateView()
}

private func setupSegmentedControl() {
    // Configure Segmented Control
    segmentedControl.removeAllSegments()
    segmentedControl.insertSegment(withTitle: "Live", at: 0, animated: false)
    segmentedControl.insertSegment(withTitle: "Avg / +", at: 1, animated: false)
    segmentedControl.addTarget(self, action: #selector(selectionDidChange(_:)), for: .valueChanged)
    segmentedControl.selectedSegmentIndex = 0
}

func selectionDidChange(_ sender: UISegmentedControl) {
    updateView()
}


private lazy var viewLiveTab: NBARotoLive = {
    // Load Storyboard
    let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)

    // Instantiate View Controller
    var viewController = storyboard.instantiateViewController(withIdentifier: "NBARotoLive") as! NBARotoLive


    if((self.playerSelected) != nil){
        viewController.selectedPlayer = self.playerSelected
    }


    // Add View Controller as Child View Controller
    self.add(asChildViewController: viewController)

    return viewController
}()

private lazy var viewAvgsTab: NBARotoAvgs = {
    // Load Storyboard
    let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)

    // Instantiate View Controller
    var viewController = storyboard.instantiateViewController(withIdentifier: "NBARotoAvgs") as! NBARotoAvgs

    if((self.playerSelected) != nil){
        viewController.selectedPlayer = self.playerSelected
    }


    // Add View Controller as Child View Controller
    self.add(asChildViewController: viewController)

    return viewController
}()

private func add(asChildViewController viewController: UIViewController) {
    // Add Child View Controller
    addChildViewController(viewController)

    // Add Child View as Subview
    view.addSubview(viewController.view)

    // Configure Child View
    viewController.view.frame = view.bounds
    viewController.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]

    // Notify Child View Controller
    viewController.didMove(toParentViewController: self)
}

private func remove(asChildViewController viewController: UIViewController) {
    // Notify Child View Controller
    viewController.willMove(toParentViewController: nil)

    // Remove Child View From Superview
    viewController.view.removeFromSuperview()

    // Notify Child View Controller
    viewController.removeFromParentViewController()
}

internal func test(){
    print("test")
}

internal func updateView() {

    if segmentedControl.selectedSegmentIndex == 0 {



        let position = viewAvgsTab.tableView.contentOffset.y;
        viewLiveTab.tableView.contentOffset = CGPoint(x:0, y:position);


        remove(asChildViewController: viewAvgsTab)
        add(asChildViewController: viewLiveTab)

    } else {

        let position = viewLiveTab.tableView.contentOffset.y;
        viewAvgsTab.tableView.contentOffset = CGPoint(x:0, y:position);

        remove(asChildViewController: viewLiveTab)
        add(asChildViewController: viewAvgsTab)
    }
}

}

我看过很多例子，但我不理解整个 'setting the delegate' 事情，即 theSecondViewController.delegate = self。有时我会看到不需要这样做的例子。有时我的 VC 似乎甚至没有代表属性。所以我不确定这是否是我的具体问题，但任何方向都将不胜感激。谢谢

Answer 1

实现委托分为三个步骤。

创建协议..（您已经通过创建 updateChildView 协议完成了此操作）
您需要在 class 中实施此协议，您希望接收和处理此数据..（您还没有完成此步骤，这就是为什么您不能设置 buyVC.delegate = self）
您需要在 ViewController2 中添加一个名为 "delegate" 的属性并将其作为您在步骤 1 中的协议类型（您尚未完成此步骤并且没有属性在 vc2 中调用了 "delegate" .. 这就是你得到这个错误的原因 'buyVC has no member delegate')

这是一个简单的例子：

协议：

protocol UpdateChildView{ //removed :class
  func updateView()
  func test()
  var playerSelected: Player? { get set }
}

Viewcontroller答：

class NBARotoHome: UIViewController, UpdateChildView { //added conformance to the protocol

  //add the methods for conforming to protocol and add your implementation

   func updateView() {
        //add your implementation
   }
   func test(){
        //add your implementation
   }
   var playerSelected: Player? {
        //add your implementation
   }

  prepare(for: Segue) {
    /** code for passing data **/
    let navVC = segue.destination as? UINavigationController
    let buyVC = navVC?.viewControllers.first as! NBARotoTabPager
    buyVC.delegate = self
            //sets the delegate in the new viewcontroller 
            //remember.. delegate is a property in the next vc
           // and the property only accepts any viewcontroller that is implements updatechildview protocol
    present(vc2)
    }
  }

视图控制器2：

class viewControllerB: UIViewController {

  var delegate: UpdateChildView? //add this

  viewdidload {
      delegate?.test() //call the func in the previous vc
  }
}

Swift - 通过导航控制器委托

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