ios - UICollectionViewController 单元格在点击或滚动时消失

Question

我正在尝试在 tabBarController 上添加 CollectionView

对于网格集合View

所以我制作了一个 UICollectionViewController 作为另一个 swift 文件

我将 ViewController(导航 Controller )添加为 UICollectionViewController.view

但是当我点击 collectionView 时，单元格立即消失。

我想我确实按照指南搜索了两天..但我无法修复它......

有人说这是添加collectionView作为 subview 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)
    }
}

这是我的自定义单元格，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)
    }
}

所以我将 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

我不明白你在哪里设置collectionView的数据源。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