有一个即时操作的项目，但是我想从另一个类中更改其属性的ViewController中的元素存在问题！我的第一种方法是从我的第二堂课中的ViewController实例化对象！在运行时返回零！

        func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
//        let mainstampvc = MainStampVc().storyboard?.instantiateViewController(withIdentifier: "mainstampvc") as? MainStampVc
//        mainstampvc?.setstampimage(imageURL: list_images[indexPath.row])
        
        let msvc = mainstampvc()
        mainstampvc?.setstampimage(imageURL: list_images[indexPath.row])
    }

我的第二种方法是在我的第二堂课中再次实例化整个ViewController。

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let mainstampvc = MainStampVc().storyboard?.instantiateViewController(withIdentifier: "mainstampvc") as? MainStampVc
    mainstampvc?.setstampimage(imageURL: list_images[indexPath.row])
}

我想要的是，当我单击我的UicollectionViewCell时，会更改我的MainViewController视图之一的背景。这是我所有的课程

viewcontroller.swift

import Foundation
import UIKit
class ViewController: UIViewController {
    @IBOutlet weak var stampholder: UIView!
    @IBAction func TextViewButton(_ sender: Any) {
        removerSubViews()
        addSubView(ViewName: "text")
    }
    @IBAction func AViewButton(_ sender: Any) {
        removerSubViews()
        addSubView(ViewName: "mohr")
    }
    @IBAction func BorderViewButton(_ sender: Any) {
    }
    @IBAction func DlViewButton(_ sender: Any) {
    }
    @IBOutlet weak var holderView: UIView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        addSubView(ViewName: "mohr")
        let mainstampvc = self.storyboard?.instantiateViewController(withIdentifier: "mainstampvc")
        let mainstampview = mainstampvc?.view
        mainstampview?.frame = stampholder.frame
        stampholder.addSubview((mainstampview)!)
    }
    func removerSubViews(){
            for view in self.holderView.subviews{
                view.removeFromSuperview()
            }
    }
    func addSubView(ViewName: String)
    {
        if let subview = Bundle.main.loadNibNamed(ViewName, owner: self, options: nil)?.first as? UIView {
            self.holderView.addSubview(subview);
        }
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

mohrcollectionview.swift

import Foundation
import UIKit
class MohrCollectionViewController: UIView,UICollectionViewDataSource,UICollectionViewDelegate{
    var mohrPath: String = ""
    var fileManager: FileManager!
    var list_images : [String] = []
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        fileManager = FileManager.default
        let currentDir = Bundle.main.resourcePath
        mohrPath = currentDir!
        let mohrsPath = try? fileManager.contentsOfDirectory(atPath: mohrPath + "/mohr")
        list_images = mohrsPath!
    }
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int{
        return list_images.count
    }
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        collectionView.register(UINib(nibName: "mohrcell", bundle: nil), forCellWithReuseIdentifier: "mohrcell")
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "mohrcell", for: indexPath) as! mohrCellController
        let image = UIImage(named: list_images[indexPath.row])
        cell.cellimage.image = image
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let mainstampvc = MainStampVc().storyboard?.instantiateViewController(withIdentifier: "mainstampvc") as? MainStampVc
        mainstampvc?.setstampimage(imageURL: list_images[indexPath.row])
    }
}

mainstampvc.swift

import Foundation
import UIKit
class MainStampVc: UIViewController{
    
    @IBOutlet weak var stampimage: UIImageView!
    override func viewDidLoad() {
        super.viewDidLoad()
        setstampimage(imageURL: "golbanafsh.png")
    }
    public func setstampimage(imageURL: String)
    {
        stampimage.image = UIImage(named: imageURL)
    }
}

任何帮助将不胜感激

2

所以这是我的代表代码，但仍然没有：（

//
//  MohrCollectionViewController.swift
//  Mohrem
//
//  Created by shayan rahimian on 12/18/17.
//  Copyright © 2017 shayan rahimian. All rights reserved.
//
import Foundation
import UIKit

class MohrCollectionViewController: UIView,UICollectionViewDataSource,UICollectionViewDelegate,UpdateBackgroundDelegate{
    var updatedelegate:UpdateBackgroundDelegate? = nil
    func updateBackground(imageURL: String) {
        print("mohr update back ground e balaE")
        if updatedelegate == nil {
            print("no delegate")
        }else{
            updatedelegate?.updateBackground(imageURL: imageURL)
        }
    }
    var mohrPath: String = ""
    var fileManager: FileManager!
    var list_images : [String] = []
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        fileManager = FileManager.default
        let currentDir = Bundle.main.resourcePath
        mohrPath = currentDir!
        let mohrsPath = try? fileManager.contentsOfDirectory(atPath: mohrPath + "/mohr")
        list_images = mohrsPath!
    }
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int{
        return list_images.count
    }
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        collectionView.register(UINib(nibName: "mohrcell", bundle: nil), forCellWithReuseIdentifier: "mohrcell")
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "mohrcell", for: indexPath) as! mohrCellController
        let image = UIImage(named: list_images[indexPath.row])
        cell.cellimage.image = image
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        self.updateBackground(imageURL: list_images[indexPath.row])
    }
    
}

//
//  MainStampvc.swift
//  Mohrem
//
//  Created by shayan rahimian on 12/19/17.
//  Copyright © 2017 shayan rahimian. All rights reserved.
//
import Foundation
import UIKit
protocol UpdateBackgroundDelegate : class {
    func updateBackground(imageURL: String)
}
class MainStampVc: UIViewController{
    @IBOutlet weak var stampimage: UIImageView!
    override func viewDidLoad() {
        super.viewDidLoad()
        updateBackground(imageURL: "biggolabi.png")
        
    }
    func updateBackground(imageURL: String) {
        // update your background in this funcion
        print("extension")
        print(imageURL)
        stampimage.image = UIImage(named: imageURL)
    }
}

我做错了吗？

您可以将UiviewController引用到MohrCollectionViewController（您应该在构造时避免混淆）。然后，每当您需要更新背景时，您都会在参考上调用相关功能。

class ViewController : UIViewController {
    ...
    override func viewDidLoad() {
        ...
        let view = addSubView(ViewName: "mohr")
        view?.vc = self
    }
    func addSubView(ViewName: String) -> UIView?
    {
        if let subview = Bundle.main.loadNibNamed(ViewName, owner: self, options: nil)?.first as? UIView {
            self.holderView.addSubview(subview);
            return subview
        }
    }
    return nil
}
class MohrCollectionView {
     func updateVcBackground() {
         vc?.updateBackground()
     }
     var vc : ViewController? = nil
}

这样做的一种清洁方法是使用代表。委托使用协议来定义两个类之间的接口。

protocol UpdateBackgroundDelegate : class {
    func updateBackground()
}
class ViewController : UIViewController, UpdateBackgroundDelegate {
    ...
    override func viewDidLoad() {
        ...
        let view = addSubView(ViewName: "mohr")
        view?.updateBackgroundDelegate = self
    }
    func updateBackground() {
        // update your background in this funcion
    }
}
class MohrCollectionView {
     func updateVcBackground() {
         updateBackgroundDelegate?.updateBackground()
     }
     var updateBackgroundDelegate : UpdateBackgroundDelegate? = nil
}

用于使委托工作做以下操作：

在收集视图类中首先声明代表

protocol UpdateBackgroundDelegate : class {
func updateBackground(imageURL: String)
}

创建一个像

的变量

var updateDelegate: UpdateBackgroundDelegate?

并将其粘贴到您的CollectionView类下方，从您要触发更改背景颜色的位置

在"集合视图"选择委托中，添加此代码
的行
```
updateDelegate.updateBackground(imageUrl: yourUrl) 
```
在必须进行颜色更改的视图中，创建您的CollectionView实例并添加此行的代码
```
collectionView.updateDelegate = self 
```

终于添加此扩展名

class ViewController :UpdateBackgroundDelegate {
   func updateBackground(imageUrl: yourUrl) {
      //write code to load image from url
   }
}

Acess UiviewController元素来自另一个类

2

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