Swift - 通过导航控制器委托
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【中文标题】Swift - 通过导航控制器委托【英文标题】：Swift - Delegate through Nav Controller 【发布时间】：2017-05-01 03:09:57 【问题描述】：我将在其中包含我的完整代码，但我会尝试指出相关位的位置。基本上，我从 Unwind Segue 返回到带有一些新数据的视图控制器。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其中一些数据传递给“NBARotoTabPager”vc。
我正在尝试使用“UpdateChildView”委托（在第一个代码块的顶部）并在“loadViewData()”中调用它的方法（在靠近第一个块底部的“if 语句”中）来执行此操作.
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 = "$10,000"
因为我无法让代理工作，所以我一直在尝试在上面的“准备”方法中设置其代理属性 -'buyVC.delegate = self' - 但我得到的是 'buyVC没有成员代表”，所以这是一条死胡同。
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，我决定将其设为 NBARotoHome 的子类，但它基本上是一个自定义选项卡寻呼机，它使用分段控件在两个额外的 vcs 之间切换。
此时最重要的一步是让“test”函数工作（它只是打印“test”。它在下面的代码块中实现，从底部倒数第二个 updateView）。
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)
我查看了很多示例，但我不理解整个“设置委托”的内容，即 theSecondViewController.delegate = self.有时我会看到您不需要这样做的示例。而其他时候，我的 VC 似乎甚至没有委托财产。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
【问题讨论】：
【参考方案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）
您需要在您希望接收和处理此数据的类中实现此协议。（您尚未完成此步骤，这就是您无法设置 buyVC.delegate = self 的原因）
您需要在 ViewController2 中添加一个名为“delegate”的属性，并在步骤 1 中将其作为您的协议类型（您尚未完成此步骤，并且 vc2 中没有名为“delegate”的属性..这就是为什么你得到这个错误'buyVC没有成员代表'）
这是一个简单的例子：
协议：
protocol UpdateChildView //removed :class
func updateView()
func test()
var playerSelected: Player? get set
视图控制器 A：
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)
viewcontroller2：
class viewControllerB: UIViewController
var delegate: UpdateChildView? //add this
viewdidload
delegate?.test() //call the func in the previous vc
【讨论】：
谢谢，这绝对给了我一个清晰而有用的例子。我不确定这是否能满足我的特殊需求，因为我认为我需要在 viewControllerB 中实现方法的一致性和实现。这是完全奇怪和不可能的吗？ 协议只是给出一个类必须实现的所需方法和属性的列表。所以只要继承协议，实现需要的方法，应该没问题... 您的代码的问题是您在 NBARtoHome 视图控制器中有一个 updateChildView 属性，并且未设置，因此为 nil。 尝试将 NBArtolive viewcontroller 设置为 NBARtoHome.updatechildview 属性中的一个属性，您应该可以调用测试函数 所以我让协议按照您在示例中显示的方式工作。我真正的问题是我想从 LoadViewData()（NBARotoHome 中的最后一个方法）调用 updateView()（NBATabPager 中的最后一个方法）。您的意思是将 NBARotoTabPager 设置为 NBARotoHome.loadViewData() 中的属性吗？还是我都倒退了？以上是关于Swift - 通过导航控制器委托的主要内容，如果未能解决你的问题，请参考以下文章