委托函數未調用

Question

因此，我嘗試使用協議和委托來連接兩個功能，以便在這種情況下可以在不同文件中的collectionView變量上執行某些操作。

import Foundation
import UIKit
protocol EventCollectionCellDelegate: NSObjectProtocol {
    func setupCollectionView(for eventCollectionView: UICollectionView?)
}
class EventCollectionCell:UICollectionViewCell {
    weak var delegate: EventCollectionCellDelegate?

    var eventArray = [EventDetails](){
        didSet{
            self.eventCollectionView.reloadData()
        }
    }

    var enentDetails:Friend?{
        didSet{

            var name = "N/A"
            var total = 0
            seperator.isHidden = true
            if let value = enentDetails?.friendName{
                name = value
            }
            if let value = enentDetails?.events{
                total = value.count
                self.eventArray = value
                seperator.isHidden = false
            }
            if let value = enentDetails?.imageUrl{
                profileImageView.loadImage(urlString: value)
            }else{
                profileImageView.image = #imageLiteral(resourceName: "Tokyo")
            }

            self.eventCollectionView.reloadData()
            setLabel(name: name, totalEvents: total)
        }
    }

    let container:UIView={
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.layer.cornerRadius = 16
        view.layer.borderColor = UIColor.lightGray.cgColor
        view.layer.borderWidth = 0.3
        return view
    }()
    //profile image view for the user
    var profileImageView:CustomImageView={
        let iv = CustomImageView()
        iv.layer.masksToBounds = true
        iv.layer.borderColor = UIColor.lightGray.cgColor
        iv.layer.borderWidth = 0.3
        iv.translatesAutoresizingMaskIntoConstraints = false
        return iv
    }()
    //will show the name of the user as well as the total number of events he is attending
    let labelNameAndTotalEvents:UILabel={
        let label = UILabel()
        label.textColor = .black
        label.translatesAutoresizingMaskIntoConstraints = false
        label.numberOfLines = 0
        return label
    }()

    let seperator:UIView={
        let view = UIView()
        view.backgroundColor = .lightGray
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()

    //collectionview that contains all of the events a specific user will be attensing
    let flow = UICollectionViewFlowLayout()
    lazy var eventCollectionView = UICollectionView(frame: .zero, collectionViewLayout: flow)

//    var eventCollectionView:UICollectionView?

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.setUpCell()
        self.setupCollectionView(for: eventCollectionView)
    }
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    func setupCollectionView(for eventCollectionView: UICollectionView?){
        delegate?.setupCollectionView(for: eventCollectionView)
    }
    }

這是創建其中具有collectionView的collectionViewCell的文件。 我正在嘗試使用委托模式對該collectionView執行一些操作。 我的問題是委托函數永遠不會在隨附的viewController中調用。 我覺得我做的一切正確，但是隨附的vc中什么也沒發生。 任何人都注意到可能出了什么問題。 我已經在下面顯示了VC的代碼

class FriendsEventsView: UIViewController,UICollectionViewDelegate,UICollectionViewDataSource,UICollectionViewDelegateFlowLayout,EventCollectionCellDelegate {
    var friends = [Friend]()
    var followingUsers = [String]()
    var height:CGFloat = 0
    var notExpandedHeight : CGFloat = 50
    var isExpanded = [Bool]()
    //so this is the main collectonview that encompasses the entire view
    lazy var mainCollectionView:UICollectionView={
        // the flow layout which is needed when you create any collection view
        let flow = UICollectionViewFlowLayout()
        //setting the scroll direction
        flow.scrollDirection = .vertical
        //setting space between elements
        let spacingbw:CGFloat = 5
        flow.minimumLineSpacing = spacingbw
        flow.minimumInteritemSpacing = 0
        //actually creating collectionview
        let cv = UICollectionView(frame: .zero, collectionViewLayout: flow)
        //register a cell for that collectionview
        cv.register(EventCollectionCell.self, forCellWithReuseIdentifier: "events")
        cv.translatesAutoresizingMaskIntoConstraints = false
        //changing background color
        cv.backgroundColor = .white
        //sets the delegate of the collectionView to self. By doing this all messages in regards to the  collectionView will be sent to the collectionView or you.
        //"Delegates send messages"
        cv.delegate = self
        //sets the datsource of the collectionView to you so you can control where the data gets pulled from
        cv.dataSource = self
        //sets positon of collectionview in regards to the regular view
        cv.contentInset = UIEdgeInsetsMake(spacingbw, 0, spacingbw, 0)
        return cv

    }()

    lazy var eventCollectionView:UICollectionView={
        let flow = UICollectionViewFlowLayout()
        flow.scrollDirection = .vertical
        let spacingbw:CGFloat = 5
        flow.minimumLineSpacing = 0
        flow.minimumInteritemSpacing = 0
        let cv = UICollectionView(frame: .zero, collectionViewLayout: flow)
        //will register the eventdetailcell
        cv.translatesAutoresizingMaskIntoConstraints = false
        cv.backgroundColor = .white
        cv.register(EventDetailsCell.self, forCellWithReuseIdentifier: "eventDetails")
        cv.delegate = self
        cv.dataSource = self
        cv.contentInset = UIEdgeInsetsMake(spacingbw, 0, spacingbw, 0)
        cv.showsVerticalScrollIndicator = false
        cv.bounces = false
        return cv
    }()

    func setupCollectionView(for eventCollectionView: UICollectionView?) {
        print("Attempting to create collectonView")
        eventCollectionView?.backgroundColor = .blue
    }

    //label that will be displayed if there are no events
    let labelNotEvents:UILabel={
        let label = UILabel()
        label.textColor = .lightGray
        label.translatesAutoresizingMaskIntoConstraints = false
        label.numberOfLines = 0
        label.font = UIFont.italicSystemFont(ofSize: 14)
        label.text = "No events found"
        label.isHidden = true
        return label
    }()


    override func viewDidLoad() {
        super.viewDidLoad()
        //will set up all the views in the screen
        self.setUpViews()
        self.navigationItem.rightBarButtonItem = UIBarButtonItem(image: #imageLiteral(resourceName: "close_black").withRenderingMode(.alwaysOriginal), style: .done, target: self, action: #selector(self.goBack))
    }

    func setUpViews(){
        //well set the navbar title to Friends Events
        self.title = "Friends Events"
        view.backgroundColor = .white

        //adds the main collection view to the view and adds proper constraints for positioning
        view.addSubview(mainCollectionView)
        mainCollectionView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 0).isActive = true
        mainCollectionView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: 0).isActive = true
        mainCollectionView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: 0).isActive = true
        mainCollectionView.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 0).isActive = true
        //adds the label to alert someone that there are no events to the collectionview and adds proper constrains for positioning
        mainCollectionView.addSubview(labelNotEvents)
        labelNotEvents.centerYAnchor.constraint(equalTo: mainCollectionView.centerYAnchor, constant: 0).isActive = true
        labelNotEvents.centerXAnchor.constraint(equalTo: mainCollectionView.centerXAnchor, constant: 0).isActive = true
        //will fetch events from server
        self.fetchEventsFromServer()

    }
    // MARK: CollectionView Datasource for maincollection view
//woll let us know how many cells are being displayed
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        print(friends.count)
        isExpanded = Array(repeating: false, count: friends.count)
        return friends.count
    }
    //will control the size of the cell that is displayed in the containerview
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        height = 100
        let event = friends[indexPath.item]
        if let count = event.events?.count,count != 0{
            height += (CGFloat(count*40)+10)
        }
        return CGSize(width: collectionView.frame.width, height: height)
    }
    //will do the job of effieicently creating cells for the eventcollectioncell
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "events", for: indexPath) as! EventCollectionCell
        cell.delegate = self
        cell.enentDetails = friends[indexPath.item]
        cell.eventCollectionView = eventCollectionView
        return cell
    }

}

為了簡化起見，我將代碼縮減為我認為回答該問題所需的代碼。 任何幫助表示贊賞

Answer 1

您可以在setupCollectionView之后設置delegate 。 在您的情況下，您不能在設置delegate之前調用setupCollectionView ，因為setupCollectionView在init調用的