UICollectionViewController单元在点击或滚动时消失

Question

我正在尝试在tabBarController上添加CollectionView

用于网格collectionView

所以我制作了一个UICollectionViewController作为另一个快捷文件

我以UICollectionViewController.view的身份添加到ViewController（导航控制器）

但是当我点击collectionView时，单元会立即消失。

我想我确实遵循了指南并搜索了两天..但是我无法解决...

有人说这是将collectionView添加为子视图的问题，但我不明白

这是自定义UICollectionView，MyFeedController.swift

import UIKit

class MyFeedController: BaseListController, UICollectionViewDelegateFlowLayout {

    let cellId = "cellId"

    override func viewDidLoad() {
        super.viewDidLoad()

        collectionView.backgroundColor = .purple

        collectionView.register(MyFeedCell.self, forCellWithReuseIdentifier: cellId)
        collectionView.delegate = self


        if let layout = collectionViewLayout as? UICollectionViewFlowLayout {
            layout.scrollDirection = .vertical
        }
    }

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 10
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! MyFeedCell
        cell.backgroundColor = .red
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let screenSize: CGRect = UIScreen.main.bounds
        let screenWidth = screenSize.width
        return .init(width: (screenWidth - 4 - 4) / 3, height: (screenWidth - 4 - 4) / 3)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 2
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 2
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return .init(top: 2, left: 0, bottom: 2, right: 0)
    }
}

这是我自定义的单元格MyFeedCell.swift，很简单

//
//  MyFeedCollectionController.swift
//  My-Lord-Cat
//
//  Created by Cory Kim on 17/07/2019.
//  Copyright © 2019 Cory Kim. All rights reserved.
//

import UIKit

class MyFeedController: BaseListController, UICollectionViewDelegateFlowLayout {

    let cellId = "cellId"

    override func viewDidLoad() {
        super.viewDidLoad()

        collectionView.backgroundColor = .purple

        collectionView.register(MyFeedCell.self, forCellWithReuseIdentifier: cellId)
        collectionView.delegate = self


        if let layout = collectionViewLayout as? UICollectionViewFlowLayout {
            layout.scrollDirection = .vertical
        }
    }

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 10
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! MyFeedCell
        cell.backgroundColor = .red
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let screenSize: CGRect = UIScreen.main.bounds
        let screenWidth = screenSize.width
        return .init(width: (screenWidth - 4 - 4) / 3, height: (screenWidth - 4 - 4) / 3)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 2
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 2
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return .init(top: 2, left: 0, bottom: 2, right: 0)
    }
}

因此我将MyFeedController添加到MyPageController（这是一个UIViewController）

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = .white

        navigationController?.navigationBar.isHidden = true

        setupLayout()
        setupMyFeedGridCollectionView()
    }

    // other views are set on setupLayout()

    fileprivate func setupMyFeedGridCollectionView() {

        let myFeedController = MyFeedController()

        view.addSubview(myFeedController.view)
        myFeedController.view.anchor(top: infoStackView.bottomAnchor, leading: view.leadingAnchor, bottom: view.bottomAnchor, trailing: view.trailingAnchor, padding: .init(top: 10, left: 0, bottom: 0, right: 0))
    // anchor method is extension for autolayout
    }

Answer 1

我看不到您在哪里设置collectionView的dataSource。在此行设置一个断点，以确保它被调用：

let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! MyFeedCell