如何防止UITableview向下滚动时刷新单元格数据？

问题描述 投票：0回答：1

我正在开发一个 iOS 项目，我的 

UITableView
遇到了问题。我无法阻止表格视图在向下滚动时刷新单元格数据。我使用 Core Data 来管理和获取我的数据。

在表格视图中，每个单元格都有一个用于添加项目的 (+) 按钮。点击此按钮也会更改单元格的颜色。然而，当我向下滚动时，单元格刷新并且它们的状态重置，这意味着颜色变化和其他动态状态丢失。

添加ShoppingItemTableViewCell：

import UIKit

// MARK: - PantryTableViewCellDelegate
protocol AddShoppingItemTableViewCellDelegate: AnyObject {
    func addButtonTapped(shoppingSubItem: Shopping_Sub_List)
    func editButtonTapped(shoppingSubItem: Shopping_Sub_List)
}

class AddShoppingItemTableViewCell: UITableViewCell {
    @IBOutlet weak var addToListButton: UIButton!
    @IBOutlet weak var itemNameLabel: UILabel!
    @IBOutlet weak var categoryLabel: UILabel!
    @IBOutlet weak var editButton: UIButton!
    
    weak var delegate: AddShoppingItemTableViewCellDelegate?
    var shoppingSubItem: Shopping_Sub_List?
    
    override func awakeFromNib() {
        super.awakeFromNib()
        itemNameLabel.font = UIFont(name: Global.Inter_Medium_500, size: 17.0)
        categoryLabel.font = UIFont(name: Global.Inter_Medium_500, size: 17.0)
    }
    
    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
    }
    
    // MARK: - Action
    // add To List Button Action
    @IBAction func addToListButtonAction(_ sender: UIButton) {
        guard let shoppingSubItem = shoppingSubItem else { return }
        addToListButton.setImage(UIImage(named: "Added"), for: .normal)
        delegate?.addButtonTapped(shoppingSubItem: shoppingSubItem)
    }
    
    // edit Button Action
    @IBAction func editButtonAction(_ sender: UIButton) {
        guard let shoppingSubItem = shoppingSubItem else { return }
        delegate?.editButtonTapped(shoppingSubItem: shoppingSubItem)
    }
    
    // MARK: Cell Configuration
    // configure The Cell
    func configureTheCell(_ shoppingSubList: Shopping_Sub_List) {
        self.shoppingSubItem = shoppingSubList
        itemNameLabel.text = shoppingSubList.name
        categoryLabel.text = "in \(shoppingSubList.category ?? "Uncategorized")"
    }
}

添加购物项目VC：

import UIKit
import CoreData

class AddShoppingItemsVC: UIViewController {
    // MARK: - IBOutlet
    @IBOutlet weak var addItemSearchBar: UISearchBar!
    @IBOutlet weak var microphoneButton: UIButton!
    @IBOutlet weak var addShoppingItemTableView: UITableView!
    
    var shoppingList: Shopping_List?
    let coreDataHelper = CoreDataHelper()
    var allShoppingSubLists: [Shopping_Sub_List]?
    var filteredShoppingSubLists: [Shopping_Sub_List]?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        addItemSearchBar.delegate = self
        addShoppingItemTableView.delegate = self
        addShoppingItemTableView.dataSource = self
        
        addShoppingItemTableView.register(UINib(nibName: "AddShoppingItemTableViewCell", bundle: nil),
                                          forCellReuseIdentifier: Global.AddShoppingItemTableViewCellIdentifier)
        
        addShoppingItemTableView.register(UINib(nibName: "AddItemTableViewCell", bundle: nil),
                                          forCellReuseIdentifier: Global.AddItemTableViewCellIdentifier)
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        self.navigationController?.isNavigationBarHidden = false
        self.navigationController?.navigationBar.prefersLargeTitles = false
        
        fetchAllShoppingSubLists()
        addItemSearchBar.text = ""
        addShoppingItemTableView.reloadData()
    }
    
    // MARK: - Function
    
    // Function to fetch all shopping sub-lists
    func fetchAllShoppingSubLists() {
        if let shoppingSubLists = coreDataHelper.fetchAllShoppingSubListData() {
            self.allShoppingSubLists = shoppingSubLists.sorted { $0.name ?? "" < $1.name ?? "" }
            self.filteredShoppingSubLists = shoppingSubLists.sorted { $0.name ?? "" < $1.name ?? "" }
        } else {
            print("Error fetching shopping sub-lists")
        }
    }
    
    // MARK: - Action
    // microphone Button Action
    @IBAction func microphoneButtonAction(_ sender: UIButton) {
        print("microphoneButtonAction")
    }
    
}

extension AddShoppingItemsVC: UITableViewDelegate, UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return (filteredShoppingSubLists?.count ?? 0) + 1
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        if indexPath.row == (filteredShoppingSubLists?.count ?? 0) {
            // This is the last cell
            if let cell = tableView.dequeueReusableCell(withIdentifier: Global.AddItemTableViewCellIdentifier,
                                                        for: indexPath) as? AddItemTableViewCell {
                cell.delegate = self
                return cell
            }
        } else {
            // Regular cells for shopping sub lists
            if let cell = tableView.dequeueReusableCell(withIdentifier: Global.AddShoppingItemTableViewCellIdentifier,
                                                        for: indexPath) as? AddShoppingItemTableViewCell {
                
                guard let shoppingSubLists = filteredShoppingSubLists?[indexPath.row] else { return cell}
                
                cell.configureTheCell(shoppingSubLists)
                cell.delegate = self
                return cell
            }
        }
        return UITableViewCell()
    }
    
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 56
    }
    
    func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
        
        let editAction = UIContextualAction(style: .normal, title: "Remove") { [weak self] (_, _, completionHandler) in
            self?.deleteActionForRow(at: indexPath)
            completionHandler(true)
        }
        
        editAction.backgroundColor = UIColor(named: "DeleteAction")
        return UISwipeActionsConfiguration(actions: [editAction])
    }
    
    // edit Action For Row
    private func deleteActionForRow(at indexPath: IndexPath) {
        print(indexPath)
    }
}

// MARK: - AddShoppingItemTableViewCellDelegate
extension AddShoppingItemsVC: AddShoppingItemTableViewCellDelegate {
    func editButtonTapped(shoppingSubItem: Shopping_Sub_List) {
        let vc = storyboard?.instantiateViewController(identifier: Global.EditItemViewControllerIdentifier) as! EditItemViewController
        vc.selectedShoppingSubList = shoppingSubItem
        vc.parentList = shoppingList
        vc.isSavaItem = false
        self.navigationController?.pushViewController(vc, animated: true)
    }
    
    func addButtonTapped(shoppingSubItem: Shopping_Sub_List) {
        guard let shoppingLists = shoppingList else { return }
        coreDataHelper.addShoppingSubListToItemsList(subList: shoppingSubItem, parentList: shoppingLists)
    }
}

// MARK: - UISearchBarDelegate
extension AddShoppingItemsVC: UISearchBarDelegate {
    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        if searchText.isEmpty {
            filteredShoppingSubLists = allShoppingSubLists
        } else {
            filteredShoppingSubLists = allShoppingSubLists?.filter { $0.name?.lowercased().contains(searchText.lowercased()) ?? false }
        }
        addShoppingItemTableView.reloadData()
    }
}

// MARK: - AddItemTableViewCellDelegate
extension AddShoppingItemsVC: AddItemTableViewCellDelegate {
    func addButtonTapped() {
        let vc = storyboard?.instantiateViewController(identifier: Global.EditItemViewControllerIdentifier) as! EditItemViewController
        vc.isSavaItem = true
        self.navigationController?.pushViewController(vc, animated: true)
    }
}

向下滚动时，我无法阻止 

UITableView
刷新单元格数据。我使用核心数据来获取并显示所有购物清单（名称）。当我点击 
addButtonTapped
 时，所有单元格都有一个 (+) 按钮来添加项目。点击此按钮也会更改单元格的颜色。但是，当我向下滚动时，单元格会自动刷新。我想阻止这种事发生。

swift uitableview scroll
1个回答
1
投票

根据您从模型中获得的详细信息，我假设了模型并创建了一个模型。在模型中，你必须传递你的密钥，正如我下面提到的。

struct Shopping_Sub_List {
    var name,category: String?
    //Here you need to add bool in your model to track button updated value.
    var isAdded = false
} 


AddShoppingItemTableViewCell
：

func configureTheCell(_ shoppingSubList: Shopping_Sub_List) {
        self.shoppingSubItem = shoppingSubList
        itemNameLabel.text = shoppingSubList.name
        categoryLabel.text = "in \(shoppingSubList.category ?? "Uncategorized")"
    //Here you get dynamic state and based button image based on your value get.
    addToListButton.setImage(shoppingSubList.isAdded ? UIImage(named: "Added") : UIImage(named: "Add"), for: .normal)
    }


// add To List Button Action
@IBAction func addToListButtonAction(_ sender: UIButton) {
    guard let shoppingSubItem = shoppingSubItem else { return }
    //Here you update your value and passed to the delegate.
    shoppingSubItem.isAdded = true
    addToListButton.setImage(UIImage(named: "Added"), for: .normal)
    delegate?.addButtonTapped(shoppingSubItem: shoppingSubItem)
}

使用此功能，您可以获得动态状态并相应地进行管理。

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