TableView重新加載后，元素從CustomCell視覺上消失-有解無憂

我有一個UITableView用于顯示我的應用程式設定的部分。該表的資料是dictionary. 表中的每個都cell包含一個title,description和一個switch來表示設定狀態。

每當用戶與其中一個開關互動時——至少一個表格單元格中的描述會在視覺上消失——即使相關字串仍然存在于資料字典中。

這幾天我一直在琢磨它。我錯過了什么或做錯了什么？

這是我的資料字典：

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
            )
        ]
    )
]

這是我的 UITableView 代碼：

設定表格視圖 -

   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
}

我的 TableView 委托功能 -

// 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
    }
}

而我的細胞委托功能 -

// 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()
            }
        }
    }
}

我的 AppSettingsCell 代碼 -

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!)
    }
}

我的 ViewModel.updateSettings 功能：

    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)
            }
        }
    }
}

以及它導致的存盤庫功能：

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()
}

當我在更新前后列印 appSettings 資料字典時 - 您可以看到所有描述仍然存在：

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)])]

編輯 -reloadRows(at:with:)我更新了我的代碼以使用該函式僅重繪相關行（而不是整個表）。它在一定程度上改善了情況，但奇怪的消失仍然發生。

這是我的做法（正確的部分和行號在閉包中傳回）：

// 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)
            }
        }
    }
}

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uj5u.com熱心網友回復：

設法通過在函式中定義行高heightForRowAt并在我的自定義中重新安排約束來解決這個問題appSettingCell

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