重新加载特定的 tableview 单元格并在本地更新数组模型

Question

我正在开发一个应用程序，其中电子邮件列表显示在表格视图中。每封电子邮件都包含来自三个状态的状态之一，例如已付款、待处理和争议。这些数据来自网络服务响应。如果电子邮件状态已支付，那么我可以通过单击待处理或争议按钮将状态更改为待处理或争议。如果状态已支付，则用户无法对已支付按钮执行任何操作。

现在假设我通过调用 web 服务将电子邮件状态从待处理更改为已付款，此时我想重新加载该特定单元格并在本地替换该模型的状态。

我怎样才能做到这一点。

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell : HomeTableViewCell = self.tableView.dequeueReusableCell(withIdentifier: cellReuseIdentifier) as! HomeTableViewCell
    if arrayData.count > 0 && arrayData.count > indexPath.row {
    var objemail = self.arrayData.object(at: indexPath.row) as? NewHomeModel
    if objemail?.unread == 1 {
        cell.lblEmailSender.textColor = UIColor.black
        cell.lblEmailDescription.textColor = UIColor.black
    }else{
        cell.lblEmailSender.textColor = UIColor.gray
        cell.lblEmailDescription.textColor = UIColor.gray
    }
    if objemail?.fileStatus == 1 {
        cell.imgAttachment.isHidden = false
    }else{
        cell.imgAttachment.isHidden = true
    }
    cell.lblEmailSender.text = objemail?.from
    cell.lblEmailHeading.text = objemail?.subject
    cell.lblEmailDescription.text = objemail?.body
    var pending = objemail?.pending
    if (pending == 0) {
        cell.btnPending.setBackgroundImage(UIImage(named: "pending_disable_icon"), for: UIControl.State.normal)
        cell.btnPending.addTarget(self, action: #selector(HomeViewController.penddingClick(_:)), for:.touchUpInside )
    }
    else
    {
        cell.btnPending.setBackgroundImage(UIImage(named: "pending_active_icon"), for: UIControl.State.normal)
    }
    if objemail?.dispute == 0 {
        cell.btnDispute.setBackgroundImage(UIImage(named: "dispute_disable_icon"), for: UIControl.State.normal)
        cell.btnDispute.addTarget(self, action: #selector(HomeViewController.disputeClick(_:)), for:.touchUpInside )
    }
    else
    {
        cell.btnDispute.setBackgroundImage(UIImage(named: "dispute_active_icon"), for: UIControl.State.normal)
    }
    if(objemail?.paid == 0)
    {
        cell.btnPaid.setBackgroundImage(UIImage(named: "paid_disable_icon"), for: UIControl.State.normal)
        cell.btnPaid.addTarget(self, action: #selector(HomeViewController.paidClick(_:)), for:.touchUpInside )
    }
    else
    {
        cell.btnPaid.setBackgroundImage(UIImage(named: "paid_active_icon"), for: UIControl.State.normal)

    }
    }
    return cell
}
struct NewHomeModel {
var body: String?
var date : String?
var dispute: Int?
var fileStatus: Int?
var from: String?
var msg_id: String?
var paid: Int?
var pending: Int?
var subject: String?
var thread_id: String?
var unread : Int?
var nextToken : String?

init(jsonData: [String: Any]) {
    body = jsonData["body"] as? String ?? ""
    date = jsonData["date"] as? String ?? ""
    dispute = jsonData["dispute"] as? Int ?? 0
    fileStatus = jsonData["fileStatus"] as? Int ?? 0
    from = jsonData["from"] as? String ?? ""
    msg_id = jsonData["msg_id"] as? String ?? ""
    paid = jsonData["paid"] as? Int ?? 0
    pending = jsonData["pending"] as? Int ?? 0
    subject = jsonData["subject"] as? String ?? ""
    thread_id = jsonData["thread_id"] as? String ?? ""
    unread = jsonData["unread"] as? Int ?? 0
}}

Answer 1

让我们假设您的 Email 模型看起来像，

class Email {
    var message: String
    var state: CellState

    init(message: String, state: CellState) {
        self.message = message
        self.state = state
    }
}

其中CellState 是一个enum，它代表states 的cell - paid, pending, dispute，即

enum CellState {
    case paid, pending, dispute
}

首先，你不能在tableView(_:cellForRowAt:)方法中写cell的配置代码。 cell's 配置必须写入cell 本身，即

class HomeTableViewCell: UITableViewCell {
    var buttonTapHandler: (()->())?
    private var email: Email?

    func configure(with email: Email) {
        self.email = email
        switch email.state {
        case .paid:
            self.backgroundColor = #colorLiteral(red: 0.3411764801, green: 0.6235294342, blue: 0.1686274558, alpha: 1)
        case .pending:
            self.backgroundColor = #colorLiteral(red: 0.9529411793, green: 0.6862745285, blue: 0.1333333403, alpha: 1)
        case .dispute:
            self.backgroundColor = #colorLiteral(red: 0.9254902005, green: 0.2352941185, blue: 0.1019607857, alpha: 1)
        }
    }

    @IBAction func onTapPendingButton(_ sender: UIButton) {
        if self.email?.state != .pending {
            self.email?.state = .pending
            self.buttonTapHandler?()
        }
    }

    @IBAction func onTapDisputeButton(_ sender: UIButton) {
        if self.email?.state != .dispute {
            self.email?.state = .dispute
            self.buttonTapHandler?()
        }
    }

    @IBAction func onTapPaidButton(_ sender: UIButton) {
        if self.email?.state != .paid {
            self.email?.state = .paid
            self.buttonTapHandler?()
        }
    }
}

在上面的代码中，

1. buttonTapHandler - 每当cell's state 在点击任何paid/pending/dispute buttons 后更改时，处理reload 的cell。我们将看看如何进一步使用它。

2. configure(with:) - 基于其current state 处理cell 的UI。

3. button tap actions - 更改cell's state，基于button 被窃听。还调用buttonTapHandler 来更新UI。

您的ViewController 看起来像，

class VC: UIViewController, UITableViewDataSource {
    var emails = [Email]()
    //rest of the code....

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.emails.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! HomeTableViewCell
        let email = self.emails[indexPath.row]
        cell.configure(with: email)
        cell.buttonTapHandler = {
            DispatchQueue.main.async {
                tableView.reloadRows(at: [indexPath], with: .none)
            }
        }
        return cell
    }
}

在上面的代码中，最重要的是我们设置cell'sbuttonTapHandler，即

cell.buttonTapHandler = {
    DispatchQueue.main.async {
        tableView.reloadRows(at: [indexPath], with: .none)
    }
}

每次您在cell 中点击button indexPath 时都会调用此handler，而特定的cell 将是reloaded。

Answer 2

您可以在本地重新加载模型数据，然后调用 tableView.reloadRows(at: IndexPath, with: UITableViewRowAnimation) 将使用您在模型对象上更新的新数据重新加载单元格。

Answer 3

你可以使用reloadRows(at:with:):

tableView.reloadRows(at: [indexPathOfTheCellToBeReloaded], with: .automatic)

这是 Swift 代码。不确定您需要什么，因为您在标签中同时指定了 Swift 和 Objective-C。