【问题标题】：UITableView Cell with dynamic height and width not getting reused properly具有动态高度和宽度的 UITableView Cell 未正确重用
【发布时间】：2021-01-13 13:24:15
【问题描述】：

我有一个具有动态高度和宽度的 UITableView 单元格。最初，它可以正常工作，但是在重用旧单元格时，约束设置不正确。我正在停用所有旧约束并再次激活它们。我还打电话给setNeedsLayout() 和layoutIfNeeded()。但这无济于事。

自动高度设置：（我认为这会导致问题）

discussionTableView.rowHeight = UITableViewAutomaticDimension
discussionTableView.estimatedRowHeight = 10

我的表格视图单元格：

class DiscussionChatMessageCell: UITableViewCell {
    
    private let messageLabel: UILabel
    private let senderNameLabel: UILabel
    private let messageBubble: UIView
    
    let screenWidth: CGFloat
    
    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        messageLabel = UILabel()
        senderNameLabel = UILabel()
        screenWidth = UIScreen.main.bounds.size.width
        messageBubble = UIView()
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        
        //        self.contentView.backgroundColor = .clear
        
        self.contentView.addSubview(messageBubble)
        messageBubble.translatesAutoresizingMaskIntoConstraints = false
        
        messageBubble.addSubview(senderNameLabel)
        senderNameLabel.translatesAutoresizingMaskIntoConstraints = false
        senderNameLabel.numberOfLines = 0
        senderNameLabel.lineBreakMode = .byCharWrapping
        senderNameLabel.font = UIFont.boldSystemFont(ofSize: 15)
        senderNameLabel.textColor = .white
        
        messageBubble.addSubview(messageLabel)
        messageLabel.translatesAutoresizingMaskIntoConstraints = false
        messageLabel.numberOfLines = 0
        messageLabel.lineBreakMode = .byWordWrapping
        messageLabel.font = UIFont.systemFont(ofSize: 13)
        messageLabel.textColor = .white
        
        NSLayoutConstraint.activate([
            messageBubble.topAnchor.constraint(equalTo: self.contentView.topAnchor, constant: 10),
            messageBubble.bottomAnchor.constraint(equalTo:  self.contentView.bottomAnchor, constant: -10),
            messageBubble.widthAnchor.constraint(lessThanOrEqualToConstant: screenWidth - 100),
            
            senderNameLabel.topAnchor.constraint(equalTo: messageBubble.topAnchor, constant: 10),
            senderNameLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            senderNameLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            
            messageLabel.topAnchor.constraint(equalTo: senderNameLabel.bottomAnchor, constant: 10),
            messageLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            messageLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            messageLabel.bottomAnchor.constraint(equalTo: messageBubble.bottomAnchor, constant: -10),
        ])
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func configureCell(message: String, isSender: Bool) {
        senderNameLabel.text = "Default Sender"
        messageLabel.text = message
        
        for constraint in messageBubble.constraints {
            //            messageBubble.removeConstraint(constraint)
            constraint.isActive = false
        }
        for constraint in messageLabel.constraints {
            //            messageLabel.removeConstraint(constraint)
            constraint.isActive = false
        }
        for constraint in senderNameLabel.constraints {
            //senderNameLabel.removeConstraint(constraint)
            constraint.isActive = false
        }
        
        NSLayoutConstraint.deactivate([
            messageBubble.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor, constant: -10),
            messageBubble.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor, constant: 10)
        ])
        NSLayoutConstraint.activate([
            messageBubble.topAnchor.constraint(equalTo: self.contentView.topAnchor, constant: 10),
            messageBubble.bottomAnchor.constraint(equalTo:  self.contentView.bottomAnchor, constant: -10),
            messageBubble.widthAnchor.constraint(lessThanOrEqualToConstant: screenWidth - 100),
            
            senderNameLabel.topAnchor.constraint(equalTo: messageBubble.topAnchor, constant: 10),
            senderNameLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            senderNameLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            
            messageLabel.topAnchor.constraint(equalTo: senderNameLabel.bottomAnchor, constant: 10),
            messageLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            messageLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            messageLabel.bottomAnchor.constraint(equalTo: messageBubble.bottomAnchor, constant: -10),
        ])
        
        messageBubble.backgroundColor = isSender ? accentColor : .gray
        if isSender {
            
            NSLayoutConstraint.activate([
                messageBubble.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor, constant: -10)
            ])
            
            //            let corners: UIRectCorner  = [.topLeft, .topRight, .bottomLeft]
            //            roundCorners(corners: corners, isSender: isSender)
            
        } else {
            NSLayoutConstraint.activate([
                messageBubble.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor, constant: 10)
            ])
            
            //            let corners: UIRectCorner  = [.topLeft, .topRight, .bottomRight]
            //            roundCorners(corners: corners, isSender: isSender)
        }
    }

重用单元格：

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let discussionChatMessageCell = tableView.dequeueReusableCell(withIdentifier: discussionChatId, for: indexPath) as? DiscussionChatMessageCell else { return UITableViewCell()}
        
        discussionChatMessageCell.configureCell(message: messages[indexPath.row], isSender: isSender[indexPath.row])

        discussionChatMessageCell.setNeedsLayout()
        discussionChatMessageCell.layoutIfNeeded()
        
        return discussionChatMessageCell
    }

重用单元格之前：

重用单元格后：

编辑

当使用 UITextView 而不是 UILabel 作为 messageLabel 时，约束的工作方式非常不同，并且表格视图需要 2-3 秒才能加载。

更改了 textView 的设置

// messageLabel.numberOfLines = 0
// messageLabel.lineBreakMode = .byWordWrapping
messageLabel.isEditable = false
messageLabel.dataDetectorTypes = .all
messageLabel.textContainer.lineBreakMode = .byWordWrapping
messageLabel.setContentCompressionResistancePriority(.required, for: .vertical)
messageLabel.setContentHuggingPriority(.required, for: .vertical)

输出：

这是更新单元格的代码，我还添加了一个时间标签。所以需要的是 UILable、UITextView、UILabel。现在这是 UILabel，UILabel，UILabel。

class DiscussionChatMessageCell: UITableViewCell {
    
    private let messageLabel: UILabel
    private let senderNameLabel: UILabel
    private let messageSentTimeLabel: UILabel
    private let messageBubble: UIView
    
    private var bubbleLeadingConstraint: NSLayoutConstraint!
    private var bubbleTrailingConstraint: NSLayoutConstraint!
    
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        
        messageLabel = UILabel()
        senderNameLabel = UILabel()
        messageSentTimeLabel = UILabel()
        messageBubble = UIView()
        
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        
        self.contentView.addSubview(messageBubble)
        messageBubble.translatesAutoresizingMaskIntoConstraints = false
        
        messageBubble.addSubview(senderNameLabel)
        senderNameLabel.translatesAutoresizingMaskIntoConstraints = false
        senderNameLabel.numberOfLines = 0
        senderNameLabel.lineBreakMode = .byCharWrapping
        senderNameLabel.font = UIFont.boldSystemFont(ofSize: 15)
        senderNameLabel.textColor = .white
        
        messageBubble.addSubview(messageLabel)
        messageLabel.translatesAutoresizingMaskIntoConstraints = false
        
        //        messageLabel.isEditable = false
        //        messageLabel.dataDetectorTypes = .all
        //        messageLabel.textContainer.lineBreakMode = .byWordWrapping
        
        messageLabel.numberOfLines = 0
        messageLabel.lineBreakMode = .byWordWrapping
        messageLabel.font = UIFont(name: "Helvetica Neue", size: 13)!
        
        messageBubble.addSubview(messageSentTimeLabel)
        messageSentTimeLabel.translatesAutoresizingMaskIntoConstraints = false
        messageSentTimeLabel.lineBreakMode = .byCharWrapping
        messageSentTimeLabel.numberOfLines = 0
        messageSentTimeLabel.font = UIFont(name: "HelveticaNeue-Italic", size: 11)!
        
        // set hugging and compression resistance for Name label
        senderNameLabel.setContentCompressionResistancePriority(.required, for: .vertical)
        senderNameLabel.setContentHuggingPriority(.required, for: .vertical)
        
        //        messageLabel.setContentCompressionResistancePriority(.required, for: .vertical)
        //        messageLabel.setContentHuggingPriority(.required, for: .vertical)
        
        // create bubble Leading and Trailing constraints
        bubbleLeadingConstraint = messageBubble.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor, constant: 10)
        bubbleTrailingConstraint = messageBubble.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor, constant: -10)
        
        // priority will be changed in configureCell()
        bubbleLeadingConstraint.priority = .defaultHigh
        bubbleTrailingConstraint.priority = .defaultLow
        
        NSLayoutConstraint.activate([
            
            bubbleLeadingConstraint,
            bubbleTrailingConstraint,
            
            messageBubble.topAnchor.constraint(equalTo: self.contentView.topAnchor, constant: 10),
            messageBubble.bottomAnchor.constraint(equalTo:  self.contentView.bottomAnchor, constant: -10),
            
            messageBubble.widthAnchor.constraint(lessThanOrEqualTo: self.contentView.widthAnchor, constant: -100),
            
            senderNameLabel.topAnchor.constraint(equalTo: messageBubble.topAnchor, constant: 10),
            senderNameLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            senderNameLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            
            messageLabel.topAnchor.constraint(equalTo: senderNameLabel.bottomAnchor, constant: 10),
            messageLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            messageLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            messageLabel.bottomAnchor.constraint(equalTo: messageSentTimeLabel.topAnchor, constant: -10),
            
            messageSentTimeLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            messageSentTimeLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            messageSentTimeLabel.bottomAnchor.constraint(equalTo: messageBubble.bottomAnchor, constant: -10),
            
        ])
        
        // corners will have radius: 10
        messageBubble.layer.cornerRadius = 10
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func configureCell(message: DiscussionMessage, isSender: Bool) {
        senderNameLabel.text = message.userName + " " + message.userCountryEmoji
        
        let date = Date(timeIntervalSince1970: message.messageTimestamp)
        
        let dayTimePeriodFormatter = DateFormatter()
        dayTimePeriodFormatter.timeZone = .current
        
        dayTimePeriodFormatter.dateFormat = "hh:mm a"
        let dateString = dayTimePeriodFormatter.string(from: date)
        
        messageLabel.text = message.message
        
        messageSentTimeLabel.text = dateString
        
        messageLabel.textColor = isSender ? .black : .white
        senderNameLabel.textColor = isSender ? .black : .white
        messageSentTimeLabel.textColor = isSender ? .black : .white
        messageSentTimeLabel.textAlignment = isSender ? .right : .left
        
        bubbleLeadingConstraint.priority = isSender ? .defaultLow : .defaultHigh
        bubbleTrailingConstraint.priority = isSender ? .defaultHigh : .defaultLow
        
        messageBubble.backgroundColor = isSender ? accentColor : .gray
        
        let senderCorners: CACornerMask = [.layerMinXMinYCorner, .layerMaxXMinYCorner, .layerMinXMaxYCorner]
        let nonSenderCorners: CACornerMask =  [.layerMinXMinYCorner, .layerMaxXMinYCorner, .layerMaxXMaxYCorner]
        
        if #available(iOS 11.0, *) {
            messageBubble.layer.maskedCorners = isSender ?
                // topLeft, topRight, bottomRight
                senderCorners
                :
                // topLeft, topRight, bottomLeft
                nonSenderCorners
        } else {
            // Fallback on earlier versions
            // All corners will be rounded
        }
    }
}

将时间标签添加到发件人姓名标签和消息标签的当前输出：

【问题讨论】：

你试过discussionChatMessageCell.messageBubble.layoutIfNeeded() 吗？
我应该在哪里称呼它？
我也会尝试在 tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) 中使用 messageLabel 类似 discussionChatMessageCell.messageLabel.layoutIfNeeded() 我会尝试两者
我认为这就是告诉单元格它需要多少空间
没有帮助。 layoutIfNeeded 也将处理整个子树布局

标签： ios swift uitableview uitableviewautomaticdimension

【解决方案1】：

您对约束的修改超出了您的需要。

更好的方法是为您的“气泡”创建前导和尾随约束 --- 并更改它们的优先级以确定使用哪个。

因此，如果是“已接收”消息，我们将前导约束优先级设置为高，将尾随约束优先级设置为低。如果是“已发送”消息，我们会反其道而行之。

试试这个：

class DiscussionChatMessageCell: UITableViewCell {
    
    let accentColor: UIColor = .systemYellow
    
    private let messageLabel: UILabel
    private let senderNameLabel: UILabel
    private let messageBubble: UIView
    
    private var bubbleLeadingConstraint: NSLayoutConstraint!
    private var bubbleTrailingConstraint: NSLayoutConstraint!

    // not needed
    //let screenWidth: CGFloat

    // wrong signature
    //override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        
        messageLabel = UILabel()
        senderNameLabel = UILabel()
        messageBubble = UIView()

        super.init(style: style, reuseIdentifier: reuseIdentifier)
        
        //        self.contentView.backgroundColor = .clear
        
        self.contentView.addSubview(messageBubble)
        messageBubble.translatesAutoresizingMaskIntoConstraints = false
        
        messageBubble.addSubview(senderNameLabel)
        senderNameLabel.translatesAutoresizingMaskIntoConstraints = false
        senderNameLabel.numberOfLines = 0
        senderNameLabel.lineBreakMode = .byCharWrapping
        senderNameLabel.font = UIFont.boldSystemFont(ofSize: 15)
        senderNameLabel.textColor = .white
        
        messageBubble.addSubview(messageLabel)
        messageLabel.translatesAutoresizingMaskIntoConstraints = false
        messageLabel.numberOfLines = 0
        messageLabel.lineBreakMode = .byWordWrapping
        messageLabel.font = UIFont.systemFont(ofSize: 13)
        messageLabel.textColor = .white
        
        // set hugging and compression resistance for Name label
        senderNameLabel.setContentCompressionResistancePriority(.required, for: .vertical)
        senderNameLabel.setContentHuggingPriority(.required, for: .vertical)
        
        // create bubble Leading and Trailing constraints
        bubbleLeadingConstraint = messageBubble.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor, constant: 10)
        bubbleTrailingConstraint = messageBubble.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor, constant: -10)

        // priority will be changed in configureCell()
        bubbleLeadingConstraint.priority = .defaultHigh
        bubbleTrailingConstraint.priority = .defaultLow
        
        NSLayoutConstraint.activate([
            
            bubbleLeadingConstraint,
            bubbleTrailingConstraint,
            
            messageBubble.topAnchor.constraint(equalTo: self.contentView.topAnchor, constant: 10),
            messageBubble.bottomAnchor.constraint(equalTo:  self.contentView.bottomAnchor, constant: -10),
            
            messageBubble.widthAnchor.constraint(lessThanOrEqualTo: self.contentView.widthAnchor, constant: -100),
            
            senderNameLabel.topAnchor.constraint(equalTo: messageBubble.topAnchor, constant: 10),
            senderNameLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            senderNameLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            
            messageLabel.topAnchor.constraint(equalTo: senderNameLabel.bottomAnchor, constant: 10),
            messageLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            messageLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            messageLabel.bottomAnchor.constraint(equalTo: messageBubble.bottomAnchor, constant: -10),
            
        ])
        
        // corners will have radius: 10
        messageBubble.layer.cornerRadius = 10
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func configureCell(message: String, isSender: Bool) {
        senderNameLabel.text = "Default Sender"
        messageLabel.text = message

        bubbleLeadingConstraint.priority = isSender ? .defaultHigh : .defaultLow
        bubbleTrailingConstraint.priority = isSender ? .defaultLow : .defaultHigh

        messageBubble.backgroundColor = isSender ? accentColor : .gray
        
        messageBubble.layer.maskedCorners = isSender ?
            // topLeft, topRight, bottomRight
            [.layerMinXMinYCorner, .layerMaxXMinYCorner, .layerMaxXMaxYCorner]
            :
            // topLeft, topRight, bottomLeft
            [.layerMinXMinYCorner, .layerMaxXMinYCorner, .layerMinXMaxYCorner]

    }

}

旁注：cellForRowAt 中不需要这两行：

    //discussionChatMessageCell.setNeedsLayout()
    //discussionChatMessageCell.layoutIfNeeded()

编辑 - 如果你真的想在 11 之前支持 iOS...

我建议你像这样子类化你的“BubbleView”：

class BubbleView: UIView {
    var radius: CGFloat = 0
    var corners: UIRectCorner = []
    var color: UIColor = .clear
    
    lazy var shapeLayer: CAShapeLayer = self.layer as! CAShapeLayer
    
    override class var layerClass: AnyClass {
        return CAShapeLayer.self
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
        shapeLayer.path = path.cgPath
        shapeLayer.fillColor = color.cgColor
    }
}

然后像这样使用它：

class DiscussionChatMessageCell: UITableViewCell {
    
    let accentColor: UIColor = .systemYellow
    
    private let messageLabel: UILabel
    private let senderNameLabel: UILabel
    
    // use custom BubbleView class instead of standard UIView
    private let messageBubble: BubbleView
    
    private var bubbleLeadingConstraint: NSLayoutConstraint!
    private var bubbleTrailingConstraint: NSLayoutConstraint!
    
    // wrong signature - I beliee as of Swift 4.2
    // 'UITableViewCellStyle' has been renamed to 'UITableViewCell.CellStyle'
    //override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        
        messageLabel = UILabel()
        senderNameLabel = UILabel()
        messageBubble = BubbleView()
        
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        
        self.contentView.addSubview(messageBubble)
        messageBubble.translatesAutoresizingMaskIntoConstraints = false
        
        messageBubble.addSubview(senderNameLabel)
        senderNameLabel.translatesAutoresizingMaskIntoConstraints = false
        senderNameLabel.numberOfLines = 0
        senderNameLabel.lineBreakMode = .byCharWrapping
        senderNameLabel.font = UIFont.boldSystemFont(ofSize: 15)
        senderNameLabel.textColor = .white
        
        messageBubble.addSubview(messageLabel)
        messageLabel.translatesAutoresizingMaskIntoConstraints = false
        messageLabel.numberOfLines = 0
        messageLabel.lineBreakMode = .byWordWrapping
        messageLabel.font = UIFont.systemFont(ofSize: 13)
        messageLabel.textColor = .white
        
        // set hugging and compression resistance for Name label
        senderNameLabel.setContentCompressionResistancePriority(.required, for: .vertical)
        senderNameLabel.setContentHuggingPriority(.required, for: .vertical)
        
        // create bubble Leading and Trailing constraints
        bubbleLeadingConstraint = messageBubble.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor, constant: 10)
        bubbleTrailingConstraint = messageBubble.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor, constant: -10)
        
        // priority will be changed in configureCell()
        bubbleLeadingConstraint.priority = .defaultHigh
        bubbleTrailingConstraint.priority = .defaultLow
        
        NSLayoutConstraint.activate([
            
            bubbleLeadingConstraint,
            bubbleTrailingConstraint,
            
            messageBubble.topAnchor.constraint(equalTo: self.contentView.topAnchor, constant: 10),
            messageBubble.bottomAnchor.constraint(equalTo:  self.contentView.bottomAnchor, constant: -10),
            
            messageBubble.widthAnchor.constraint(lessThanOrEqualTo: self.contentView.widthAnchor, constant: -100),
            
            senderNameLabel.topAnchor.constraint(equalTo: messageBubble.topAnchor, constant: 10),
            senderNameLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            senderNameLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            
            messageLabel.topAnchor.constraint(equalTo: senderNameLabel.bottomAnchor, constant: 10),
            messageLabel.leadingAnchor.constraint(equalTo: messageBubble.leadingAnchor, constant: 10),
            messageLabel.trailingAnchor.constraint(equalTo: messageBubble.trailingAnchor, constant: -10),
            messageLabel.bottomAnchor.constraint(equalTo: messageBubble.bottomAnchor, constant: -10),
            
        ])
        
        // corners will have radius: 10
        messageBubble.radius = 10
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func configureCell(message: String, isSender: Bool) {
        senderNameLabel.text = "Default Sender"
        messageLabel.text = message
        
        bubbleLeadingConstraint.priority = isSender ? .defaultHigh : .defaultLow
        bubbleTrailingConstraint.priority = isSender ? .defaultLow : .defaultHigh
        
        messageBubble.color = isSender ? accentColor : .gray

        let senderCorners: UIRectCorner = [.topLeft, .topRight, .bottomRight]
        let nonSenderCorners: UIRectCorner =  [.topLeft, .topRight, .bottomLeft]

        messageBubble.corners = isSender ? senderCorners : nonSenderCorners

    }
    
}

这将保持“气泡”视图的形状和大小，即使单元格发生变化（例如旋转设备时）。

【讨论】：

天啊！你是救生员。我做错了什么？您使用的init是更新版本吗？论据看起来一样。另外，基于gist.github.com/shaildyp/6cd1de39498ff7b3c22fa758f005f7cd，我正在修改掩码部分以在ios 11之前向后兼容。让我知道它是否正确。
@ParthTamane - 你真的需要支持 11 之前的 iOS 版本吗？
大声笑！我目前支持 iOS 9。我想我可以升级到 iOS 12，因为这是 iPhone 5s 支持的最新版本。你会推荐什么？
@ParthTamane - 如果这是一个现有的应用程序？如果是这样，您有多少用户仍在使用 iOS 9 或 10？如果它不是现有的应用程序...没有理由尝试支持那么久。当然，我只是提供一个意见——这完全是你的决定。
该应用程序已上线，但我不确定有多少用户在使用 iOS 9 或 10。但如果我要更新支持的版本，这些用户是否会无法访问以前版本的应用程序？他们的手机是否支持？

【解决方案2】：

我更改了您的代码设置 messageBuble 相对于单元格而不是内容视图的约束：

 messageBubble.topAnchor.constraint(equalTo: self.topAnchor, constant: 10),
 messageBubble.bottomAnchor.constraint(equalTo:  self.bottomAnchor, constant: -10)

刚刚打电话layoutIfNeeded()：

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let discussionChatMessageCell = tableView.dequeueReusableCell(withIdentifier: discussionChatId, for: indexPath) as? DiscussionChatMessageCell else { return UITableViewCell()}
        
discussionChatMessageCell.configureCell(message: messages[indexPath.row], isSender: isSender[indexPath.row])

discussionChatMessageCell.layoutIfNeeded()
        
return discussionChatMessageCell

}

【讨论】：

这并没有帮助发件人姓名标签消失并且单元格正在全屏显示
问题出在单元格约束中，而不是在 VC 中。让我看看。
在你的单元格中调用 messageBubble.layoutIfNeeded() 解决了第一个问题
你能分享单元格的完整代码吗？
给我一分钟我会更新答案

【解决方案3】：

您多次添加子视图，但它是可重复使用的。不要忘记它。在 .addSubview(....

之前添加下一个代码

contentView.subviews.forEach { $0.removeFromSuperview() }

或者只更改视图值，不要每次都添加

【讨论】：

我只在init方法中添加了子视图！