Elements visually disappear from CustomCell after TableView reload-CodePudding

I have a UITableView with sections that is used to display my app's settings. The table's data is a dictionary. Each cell in the table contains a title, description and a switch to represent the setting status.

Whenever the user interacts with one of the switches - the description in at least one of the table cells disappears visually - even though the relevant string is still there in the data dictionary.

I've been cracking my head around it for days now. What am I missing or doing wrong?

This is my data dictionary:

var appSettings: [String:SettingModel] = [
    "Search results": SettingModel(
        sectionTitle: "Search results",
        options: [
            "Save filters": SingleSetting (
                title: "Save filters",
                description: "Allow us to save filters when entering back to the app",
                status: .off
            ),
            "Save search results": SingleSetting (
                title: "Save search results",
                description: "Allow us to save your search result preferences for next search",
                status: .off
            )
        ]
    ),
    "App preferences": SettingModel(
        sectionTitle: "App preferences",
        options: [
            "Notification": SingleSetting (
                title: "Notification",
                description: "",
                status: .on
            )
        ]
    )
]

And here is my UITableView codes:

Setting up the table view -

   func setupTableView() {
    tableView.register(UINib(nibName: Constants.NibNames.APP_SETTING, bundle: nil), forCellReuseIdentifier: Constants.TableCellsIdentifier.SETTING)
    tableView.register(UINib(nibName: Constants.NibNames.APP_SETTING_SECTION, bundle: nil), forHeaderFooterViewReuseIdentifier: Constants.TableCellsIdentifier.SETTING_SECTION)
    tableView.dataSource = self
    tableView.delegate = self
}

My TableView delegate functions -

// MARK: - UITableViewDataSource
extension SettingsViewController: UITableViewDataSource {
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return viewModel.appSettings.count
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        let sectionKey = viewModel.sectionsSortedKeys[section]!
        return viewModel.appSettings[sectionKey]!.options.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: Constants.TableCellsIdentifier.SETTING, for: indexPath) as! AppSettingCell
        cell.delegate = self
        
        let sectionKey = viewModel.sectionsSortedKeys[indexPath.section]!
        var rowKey: String {
            switch sectionKey {
            case Constants.AppSettingsSectionTitles.SEARCH:
                if indexPath.row == 1 {
                    return Constants.AppSettings.SAVE_FILTERS
                } else {
                    return Constants.AppSettings.SEARCH_RESULTS
                }
            case Constants.AppSettingsSectionTitles.PREFERENCES:
                return Constants.AppSettings.NOTIFICATION
            default:
                return ""
            }
        }
        
        cell.settingTitle.text = viewModel.appSettings[sectionKey]!.options[rowKey]?.title
        cell.settingDescription.text = viewModel.appSettings[sectionKey]!.options[rowKey]?.description
        
        var settingSwitchImage: UIImage
        switch viewModel.appSettings[sectionKey]!.options[rowKey]?.status {
        case .on:
            settingSwitchImage = UIImage(named: "switch-on")!
            break
        case .off:
            settingSwitchImage = UIImage(named: "switch-off")!
            break
        default:
            settingSwitchImage = UIImage(named: "switch-disabled")!
            break
        }
        cell.settingSwitchImageView.image = settingSwitchImage
        
        return cell
    }
}

// MARK: - UITableViewDelegate
extension SettingsViewController: UITableViewDelegate {
    
    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let view = tableView.dequeueReusableHeaderFooterView(withIdentifier: Constants.TableCellsIdentifier.SETTING_SECTION) as! SettingSectionCell
        view.sectionLabel.text = viewModel.sectionsSortedKeys[section]
        return view
    }
    
    
    func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 32
    }
}

And my cell delegate function -

// MARK: - AppSettingCellDelegate
extension SettingsViewController: AppSettingCellDelegate {

    func settingCellDidPress(settingText: String) {
        print("CURRENT APP SETTINGS ARRAY:")
        print(self.viewModel.appSettings)
        viewModel.updateSetting(settingTitle: settingText) {
            DispatchQueue.main.async {
                print("UPDATED APP SETTINGS ARRAY:")
                print(self.viewModel.appSettings)
                self.tableView.reloadData()
            }
        }
    }
}

My AppSettingsCell code -

protocol AppSettingCellDelegate {
    func settingCellDidPress(settingText: String)
}

class AppSettingCell: UITableViewCell {

    @IBOutlet weak var settingTitle: UILabel!
    @IBOutlet weak var settingDescription: UILabel!
    @IBOutlet weak var settingSwitchImageView: UIImageView!
    
    var delegate: AppSettingCellDelegate?
    
    
    override func awakeFromNib() {
        super.awakeFromNib()
        
        setTextLineSpacing()
        setCellColorDesign()
        setGestureRecognizer()
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
    }

    

    func setTextLineSpacing() {
        let attributedString = NSMutableAttributedString(string: settingDescription.text!)
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = 10
        attributedString.addAttribute(NSAttributedString.Key.paragraphStyle, value:paragraphStyle, range:NSMakeRange(0, attributedString.length))
        settingDescription.attributedText = attributedString
    }
    

    func setCellColorDesign() {
        let bgColorView = UIView()
        bgColorView.backgroundColor = UIColor.clear
        self.selectedBackgroundView = bgColorView
    }
    

    func setGestureRecognizer() {
        settingSwitchImageView.addGestureRecognizer(UITapGestureRecognizer(target: settingSwitchImageView, action: #selector(switchWasPressed)))
        settingSwitchImageView.isUserInteractionEnabled = true
        let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(switchWasPressed(tapGestureRecognizer:)))
        settingSwitchImageView.addGestureRecognizer(tapGestureRecognizer)
    }
    

    @objc func switchWasPressed(tapGestureRecognizer: UITapGestureRecognizer) {
        delegate?.settingCellDidPress(settingText: settingTitle.text!)
    }
}

My ViewModel.updateSettings function:

    func updateSetting(settingTitle: String, completionHandler: @escaping (Int?, Int?) -> ()) {
    
    var sectionTitle: String? = nil
    var sectionIndex: Int? = nil
    if appSettings[Constants.AppSettingsSectionTitles.SEARCH]?.options[settingTitle] != nil {
        sectionTitle = Constants.AppSettingsSectionTitles.SEARCH
        sectionIndex = 0
    } else if appSettings[Constants.AppSettingsSectionTitles.PREFERENCES]?.options[settingTitle] != nil {
        sectionTitle = Constants.AppSettingsSectionTitles.PREFERENCES
        sectionIndex = 1
    }
    
    if let sectionTitle = sectionTitle {
        let currentStatus = appSettings[sectionTitle]?.options[settingTitle]?.status
        var newStatus: SwitchStatus = .off
        if currentStatus != .disabled {
            if currentStatus == .on {
                appSettings[sectionTitle]?.options[settingTitle]?.status = newStatus // update local array
            } else {
                newStatus = .on
                appSettings[sectionTitle]?.options[settingTitle]?.status = newStatus // update local array
            }
            
            let settingIndex = appSettings[sectionTitle]?.options[settingTitle]?.index
            
            repository.updateSavedSetting(settingTitle: settingTitle, newStatus: newStatus) {
                completionHandler(sectionIndex, settingIndex)
            }
        }
    }
}

and the repository function it leads to:

func updateSavedSetting(settingTitle: String, newStatus: SwitchStatus, completionHandler: @escaping () -> ()) {

    switch settingTitle {
    case Constants.AppSettings.SAVE_FILTERS:
        userDefaultsManager.setItemToUserDefaults(key: Constants.UserDefaults.SAVE_FILTERS, data: newStatus.rawValue)
    case Constants.AppSettings.SEARCH_RESULTS:
        userDefaultsManager.setItemToUserDefaults(key: Constants.UserDefaults.SAVE_SEARCH_RESULTS, data: newStatus.rawValue)
        if newStatus == .off {
            userDefaultsManager.clearSingleKeyValuePairFromUserDefaults(keyToRemove: Constants.UserDefaults.RECENT_SEARCHES)
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: Constants.NotificationCenter.RECENT_SEARCHES_EMPTIED), object: nil)
        }
    case Constants.AppSettings.NOTIFICATION:
        userDefaultsManager.setItemToUserDefaults(key: Constants.UserDefaults.SEND_NOTIFICATIONS, data: newStatus.rawValue)
    default:
        print("not valid option")
    }
    completionHandler()
}

When I print the appSettings data dictionary before and after the update - you can see that all the descriptions are still there:

CURRENT APP SETTINGS ARRAY:
["Search results": Dispatcher_Development.SettingModel(sectionTitle: "Search results", options: ["Save filters": Dispatcher_Development.SingleSetting(title: "Save filters", description: "Allow us to save filters when entering back to the app", status: Dispatcher_Development.SwitchStatus.on), "Save search results": Dispatcher_Development.SingleSetting(title: "Save search results", description: "Allow us to save your search result preferences for next search", status: Dispatcher_Development.SwitchStatus.on)]), "App preferences": Dispatcher_Development.SettingModel(sectionTitle: "App preferences", options: ["Notification": Dispatcher_Development.SingleSetting(title: "Notification", description: "", status: Dispatcher_Development.SwitchStatus.on)])]
UPDATED APP SETTINGS ARRAY:
["Search results": Dispatcher_Development.SettingModel(sectionTitle: "Search results", options: ["Save filters": Dispatcher_Development.SingleSetting(title: "Save filters", description: "Allow us to save filters when entering back to the app", status: Dispatcher_Development.SwitchStatus.off), "Save search results": Dispatcher_Development.SingleSetting(title: "Save search results", description: "Allow us to save your search result preferences for next search", status: Dispatcher_Development.SwitchStatus.on)]), "App preferences": Dispatcher_Development.SettingModel(sectionTitle: "App preferences", options: ["Notification": Dispatcher_Development.SingleSetting(title: "Notification", description: "", status: Dispatcher_Development.SwitchStatus.on)])]

EDIT - I updated my code to refresh only the relevant line (instead of the whole table) using the reloadRows(at:with:) function. It somewhat improved the situation but the weird disappearance still happens.

Here is how I do it (the right section and row numbers are passed back in the closure):

// MARK: - AppSettingCellDelegate
extension SettingsViewController: AppSettingCellDelegate {

    func settingCellDidPress(settingText: String) {
        viewModel.updateSetting(settingTitle: settingText) { sectionIndex, settingIndex in
            DispatchQueue.main.async {
                let indexPath = IndexPath(row: settingIndex ?? 0, section: sectionIndex ?? 0 )
                self.tableView.reloadRows(at: [indexPath], with: UITableView.RowAnimation.none)
            }
        }
    }
}

Here is a photo of how the page looks when you first enter it: enter image description here

Here is a photo of how the page looks after you start flipping the switches: enter image description here

CodePudding user response：

Managed to solve this by defining a row height in heightForRowAt function and re-arranging the constraints in my custom appSettingCell