自定义 tableviewcell 动态高度未根据约束更新（以编程方式自动布局）

Question

I have a custom uitableviewcell in app, I am trying to update its length dynamically based on its subviews (labels) contents.

but it's not working.

find related code as below.

class TransactionTableViewCell: UITableViewCell{


    private lazy var dateLabel: UILabel = {
        let datelabel = UILabel()
        datelabel.textColor = .label
        datelabel.backgroundColor = .red
        datelabel.lineBreakMode = .byTruncatingTail
        datelabel.numberOfLines = 0
        datelabel.translatesAutoresizingMaskIntoConstraints = false
        return datelabel
    }()

another method in same class:

 func setupDefaultUI(){
        self.contentView.addSubview(dateLabel)
}

 override func awakeFromNib() {
        super.awakeFromNib()
        setupDefaultUI()
        buildConstraints()
    }

 override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        setupDefaultUI()
        buildConstraints()
    }

 func buildConstraints(){

        let marginGuide = self.contentView

        NSLayoutConstraint.activate([
            dateLabel.topAnchor.constraint(equalTo: marginGuide.topAnchor)
            ,
            dateLabel.leadingAnchor.constraint(equalTo: marginGuide.leadingAnchor),
            dateLabel.trailingAnchor.constraint(equalTo: marginGuide.trailingAnchor),
            dateLabel.heightAnchor.constraint(greaterThanOrEqualToConstant: 1.0)
            ,

            dateLabel.bottomAnchor.constraint(equalTo: marginGuide.bottomAnchor)
  ])
    }

and inside viewcontroller file:

 private lazy var transactionTableView: UITableView = {
        let tableview = UITableView.init()
        tableview.backgroundView = nil
        tableview.backgroundColor = .clear
        tableview.rowHeight = UITableView.automaticDimension
        tableview.estimatedRowHeight = 300
        return tableview
    }()

and in viewdidload:

    transactionTableView.dataSource = Objdatasource 
        transactionTableView.delegate = Objdelegate

        transactionTableView.register(TransactionTableViewCell.self, forCellReuseIdentifier: CellIdentifiers.transactionCell)

Answer 1

删除这个

dateLabel.heightAnchor.constraint(greaterThanOrEqualToConstant: 1.0)

Answer 2

In this tutorial (which I recently followed and worked for me), there is a function you are missing there:

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
   return UITableView.automaticDimension
}