如何将数据从子视图控制器传递到父视图控制器？在 swift

Question

我创建了一个 activity，当点击其中一个文本字段时，它会弹出一个带有产品列表的子项（警告对话框），但是当我点击列表中的一个项目时，我无法显示它在警报解除后提交的文本上。

这是父视图

import Foundation
import UIKit

class ViewAward: UIViewController{

@IBOutlet var tfMCN: UITextField!
@IBOutlet var tfAmount: UITextField!
@IBOutlet var tfProduct: UITextField!
@IBOutlet var tfTotal: UITextField!

override func viewDidLoad() {
    super.viewDidLoad()

    let rightAddBarButtonItem:UIBarButtonItem = UIBarButtonItem(title: "Send", style: UIBarButtonItemStyle.Plain, target: self, action: #selector(ViewAward.searchTapped))

    self.navigationItem.setRightBarButtonItems([rightAddBarButtonItem], animated: true)

    let state = String(ViewPopUpProduct.Product.ProductDescription)
    print("My view state:"+state)

    self.tfProduct.text = state
    tfProduct.addTarget(self, action:  #selector(ViewAward.productTapped), forControlEvents: UIControlEvents.TouchDown)

}

func searchTapped(sender:UIButton) {

    let alertController = UIAlertController(
        title: "Award",
        message:"Award successfully posted!",
        preferredStyle: UIAlertControllerStyle.Alert)
    alertController.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default,handler: nil))

    self.presentViewController(alertController, animated: true, completion: nil)
}

func productTapped(textfield: UITextField){

    //tfProduct.endEditing(true)
    tfProduct.resignFirstResponder()

    let popOverVC = UIStoryboard(name:"Main",bundle:nil).instantiateViewControllerWithIdentifier("sbPopUpID") as! ViewPopUpProduct

    self.addChildViewController(popOverVC)

    popOverVC.view.frame = self.view.frame

    self.view.addSubview(popOverVC.view)

    popOverVC.didMoveToParentViewController(self)

}
}

以及当用户点击项目时的这个

import UIKit

class ViewPopUpProduct: UIViewController {

@IBOutlet var tableView: UITableView!

var productDescription = ["Product 1","Product 2","Product 3"]
var productID = ["prdct1","prdct2","prdct3"]


// Global Variables 
struct Product {
    static var ProductID = String()
    static var ProductDescription = String()
}

override func viewDidLoad() {
    super.viewDidLoad()
    self.showAnimate()
    self.view.backgroundColor = UIColor.blackColor().colorWithAlphaComponent(0.4)

    // Do any additional setup after loading the view.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func cancelPopUp(sender: AnyObject) {
    self.removeAnimate()
}


func showAnimate()
{
    self.view.transform = CGAffineTransformMakeScale(1.3, 1.3)
    self.view.alpha = 0.0;
    UIView.animateWithDuration(0.25, animations: {
        self.view.alpha = 1.0
        self.view.transform = CGAffineTransformMakeScale(1.0, 1.0)
    });
}

func removeAnimate()
{
    UIView.animateWithDuration(0.25, animations: {
        self.view.transform = CGAffineTransformMakeScale(1.3, 1.3)
        self.view.alpha = 0.0;
        }, completion:{(finished : Bool)  in
            if (finished)
            {
                self.view.removeFromSuperview()
            }
    });
}

//Mark - Table View

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return self.productID.count
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = self.tableView.dequeueReusableCellWithIdentifier("cell",forIndexPath: indexPath) as! ProductViewCell

    cell.productLabel.text = productDescription[indexPath.row]

    return cell
}

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

    tableView.deselectRowAtIndexPath(indexPath, animated: true)

    Product.ProductID = String(productID[indexPath.row])
    Product.ProductDescription = String(productDescription[indexPath.row])

    self.removeAnimate()

}

}

Answer 1

实现回调功能以传递数据的方法很少。

代表
使用块回调
Post通知

但我建议使用委托，这是最好的方式，Post通知也是一种方式，但我不想偏爱。

Answer 2

您可以使用protocols/delegate

这是一个非常非常直接的解释，没有废话： https://www.youtube.com/watch?v=guSYMPaXLaw

或者在你的情况下你也可以使用 NSNotificationCenter

你可以这样做：

"sender" 视图控制器可以

let nc = NSNotificationCenter.defaultCenter()
nc.postNotificationName("printValue", object: nil, userInfo: ["value" : "Pass Me this string"])

接收器视图控制器然后可以收听通知。

let nc = NSNotificationCenter.defaultCenter()
nc.addObserver(self, selector: #selector(printValue), name: "printValue", object: nil)

func printValue(notification:NSNotification) {
    let userInfo:Dictionary<String,String> = notification.userInfo as! Dictionary<String,String>
    let item = userInfo["value"]! as String

    print(item,self)
}

Answer 3

我通常为此目的使用闭包。比委托更简单、更简洁：

class MainViewController: UIViewController {

    func showChildViewController() {
        guard let vc = storyboard?.instantiateViewControllerWithIdentifier("ChildViewController") as? ChildViewController else {
            return
        }
        vc.didSelectItem = { [weak self](item) in
            if let vc = self {
                // Do something with the item.
            }
        }
        presentViewController(vc, animated: true, completion: nil)
    }

}

class ChildViewController: UIViewController {

    var didSelectItem: ((item: Item) -> Void)?

    @IBAction func buttonPressed() {
        didSelectItem?(item: <#your item goes here#>)
    }

}

Answer 4

我的首选肯定是 Custom Delegate，它更快更完美。（如果您可以使用闭包作为回调，那么这也是一个不错的选择。选择委托来稍微解释一下您的代码。）
请尽可能避免使用 NSNotificationCenter，因为使用它时需要处理的事情太多，而且它比代理慢一点。您也可能很容易遇到错误。

现在这是我的代码。

1. Child ViewController 设置。

   //  TrendingProductPageViewController.swift
   //  buddyiOSApp
   //
   //  Created by Tuhin Samui on 5/21/16.
   //  Copyright © 2016 Buddy. All rights reserved.
   //

    import UIKit

    protocol TrendingProductsCustomDelegate: class { //Setting up a Custom delegate for this class. I am using `class` here to make it weak.
        func sendDataBackToHomePageViewController(categoryToRefresh: String?) //This function will send the data back to origin viewcontroller.
    }


    class TrendingProductPageViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, NetworkReachabilityDelegate {

        @IBOutlet weak var productListTableView: UITableView! //Having a tableview outlet here from storyboard itself. BTW not going to explain with tableView delegate and datasource, Sorry..:(

        weak var customDelegateForDataReturn: TrendingProductsCustomDelegate? //Please use weak reference for this to manage the memory issue.


func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
            let rowNumberFromTable: Int = indexPath.row //Getting the index of the selected cell.
            let dataToSendBack = moreMenuTableData[rowNumberFromTable] as! String //This is an array which contains the data for the tableview. Getting the exact data which is selected on the table.
            customDelegateForDataReturn?.sendDataBackToHomePageViewController?(dataToSendBack) //Now sending the selected data back to parent viewController using the custom delegate which I made before.                 presentingViewController?.dismissViewControllerAnimated(true, completion: nil) //Dismissing the viewController here.
    }

2。 Parent ViewController 代码在这里。

class HomePageViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, TrendingProductsCustomDelegate, UINavigationControllerDelegate{ //Adding the protocol here as `TrendingProductsCustomDelegate`

@IBAction func topTrendingProductsBtnAction(sender: UIButton) { //Normal IBAction of UIButton as you are using.
        let trendingProductsPageForAnimation = storyboard!.instantiateViewControllerWithIdentifier("showTrendingProductpage") as! TrendingProductPageViewController //You can understand this right. Same as yours.
        trendingProductsPageForAnimation.customDelegateForDataReturn = self //Setting up the custom delegate for this class which I have written on the presenting class.
        trendingProductsPageForAnimation.modalPresentationStyle = UIModalPresentationStyle.FullScreen
        presentViewController(trendingProductsPageForAnimation, animated: true, completion: nil) //Same as yours.
    }


func sendDataBackToHomePageViewController(categoryToRefresh: String?) { //Custom delegate function which was defined inside child class to get the data and do the other stuffs.
        if categoryToRefresh != nil {
            print("Got the data is \(categoryToRefresh)")
        }
    }

}

希望这对您有所帮助。如有任何错误，请见谅。

Answer 5

在 ChildVC(ViewPopUpProduct) 中添加 ParentVC 的实例

class ViewPopUpProduct: UIViewController {
  var parentVC = ViewAward? //ParentView
  var someValueToSend : String? 
  .
  .
  .
  fun sendData(){
    // After fetching some value call this function from child
    parentVC.result = someValueToSend
    self.view.removeFromSuperview()
  }
}

在父视图中调用子视图（子视图）共享实例

class ViewAward: UIViewController{

   var result = String?//Variable to store result from child

   func productTapped(textfield: UITextField){

    //tfProduct.endEditing(true)
    tfProduct.resignFirstResponder()

    let popOverVC = UIStoryboard(name:"Main",bundle:nil).instantiateViewControllerWithIdentifier("sbPopUpID") as! ViewPopUpProduct

    popOverVC.parentVC = self//Sharing Parent Views Instance

    self.addChildViewController(popOverVC)

    popOverVC.view.frame = self.view.frame

    self.view.addSubview(popOverVC.view)

    popOverVC.didMoveToParentViewController(self)
 }
}

删除子视图后访问结果变量并享受！

如何将数据从子视图控制器传递到父视图控制器？在 swift

How to pass data from child to parent view controller? in swift

ios

swift

xcode

childviewcontroller

childviews