ios - 在 scrollToRowAtIndexPath 之后动态计算 tableCells 中的 textWidth 变得错误

Question

当我尝试使用这种方式将表格滚动到底部时

  let ip = NSIndexPath(forItem: array.count - 1, inSection: 0)
  chatTableView.scrollToRowAtIndexPath(ip, atScrollPosition: .Top, animated: true)

单元格宽度计算:

private var leadingConstant: CGFloat = 30

@IBOutlet weak var leadingConstraint: NSLayoutConstraint! {
   didSet {
      leadingConstant = leadingConstraint!.constant
      }
   }

   private func resizeCell() {
     let labelTextWidth = chatTextLabel?.intrinsicContentSize().width
        guard labelTextWidth < lWidth else {
          return
        }
        leadingConstraint?.constant = leadingConstant + lWidth -  labelTextWidth!
   }

我会在单元格中得到错误的 textWidth 计算

Answer 1

我遇到了调整标签大小的问题，所以我只需要在设置文本后执行 chatTextLabel?.updateConstraints()

var chatMessage: ChatMessage! {
    didSet {
      setContent()
    }
}

func setContent() {
    chatTextLabel.text = chatMessage.message
    chatTextLabel?.updateConstraints()  // here

    let labelTextWidth = (chatTextLabel?.intrinsicContentSize().width) ?? 0
    let labelTextHeight = chatTextLabel?.intrinsicContentSize().height

    guard labelTextWidth < originWidth && labelTextHeight <= singleLineRowheight else {
      trailingConstraint?.constant = trailingConstant
      return
    }
    trailingConstraint?.constant = trailingConstant + (originWidth - labelTextWidth)

  }