ios - Swift UITableViewCell 显示默认隐藏的数据

Question

我有一个看似随机的问题，我的 UITableView 中的一些单元格显示了默认情况下应该隐藏的数据。

解释隐藏的数据。

这是一个股票投资组合，您可以点击其中的一个单元格将其展开(并查看此数据)。当它关闭时，数据再次被隐藏。

这是我遇到的导致随机单元格默认显示此数据的问题的屏幕截图。

在上面的屏幕截图中，显示隐藏数据的是“RUS.TO”和“CUB”单元格。

下面是应该隐藏的 View 和标签的设置方式:

// #Advanced data

    stockNameView.setTranslatesAutoresizingMaskIntoConstraints(false)
    stockNameView.hidden = true
    self.addSubview(stockNameView)

    purchasePriceView.setTranslatesAutoresizingMaskIntoConstraints(false)
    purchasePriceView.hidden = true
    self.addSubview(purchasePriceView)

    lastPriceView.setTranslatesAutoresizingMaskIntoConstraints(false)
    lastPriceView.hidden = true
    self.addSubview(lastPriceView)

    daysHeldView.setTranslatesAutoresizingMaskIntoConstraints(false)
    daysHeldView.hidden = true
    self.addSubview(daysHeldView)

重叠的 8 个标签是上述 4 个 View 的 subview 。

如您所见，这 4 个 View 默认设置为隐藏。所以我认为问题不在于我的单元格类？

我的代码中只有一处将这 4 个 UIView 的隐藏值设置为 false。

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("com.Stocks.portfolioCell", forIndexPath: indexPath) as! portfolioCell


    if indexPath.row % 2 == 0 {
        cell.backgroundColor = UIColor.whiteColor()
    } else {
        cell.backgroundColor = UIColor.formulaWhiteColor()
    }

    if selectedCellIndexPath == indexPath {
        cell.tickerLabel.textColor = UIColor.formulaBlueColor()
        cell.heightSeperator.hidden = false
        cell.stockNameView.hidden = false
        cell.purchasePriceView.hidden = false
        cell.lastPriceView.hidden = false
        cell.daysHeldView.hidden = false
        cell.endSeperator.hidden = false
        tableHeight.constant = tableHeight.constant+250
        self.scrollView.contentSize = CGSize(width:self.view.bounds.width, height: self.contentView.frame.height)
    }

    if lastCollapsing == true || currentCollapsing == true {
        cell.tickerLabel.textColor = UIColor.formulaDarkGrayColor()
        cell.heightSeperator.hidden = true
        cell.stockNameView.hidden = true
        cell.purchasePriceView.hidden = true
        cell.lastPriceView.hidden = true
        cell.daysHeldView.hidden = true
        cell.endSeperator.hidden = true
        lastCollapsing = false
        currentCollapsing = false
        tableHeight.constant = tableHeight.constant-250
        self.scrollView.contentSize = CGSize(width:self.view.bounds.width, height: self.contentView.frame.height)
    }

    if stocks.count > 0 {
        let formulaStock = stocks[indexPath.row]

        ticker = formulaStock.valueForKey("ticker") as! String!

        let fontAwesomeBlueAttribute = [NSForegroundColorAttributeName: UIColor.formulaBlueColor(), NSFontAttributeName: UIFont(name: "FontAwesome", size: 12)!]
        let fontAwesomeGreenAttribute = [NSForegroundColorAttributeName: UIColor.formulaGreenColor(), NSFontAttributeName: UIFont(name: "FontAwesome", size: 12)!]
        let latoBoldDarkGrayAttribute = [NSForegroundColorAttributeName: UIColor.formulaDarkGrayColor(), NSFontAttributeName: UIFont(name: "Lato-Bold", size: 12)!]
        if ticker != "CASH" {
            let tickerString = "  \(ticker)" as NSString
            var tickerAttributedString = NSMutableAttributedString(string: tickerString as String)
            tickerAttributedString.addAttributes(fontAwesomeBlueAttribute, range: tickerString.rangeOfString(""))
            tickerAttributedString.addAttributes(latoBoldDarkGrayAttribute, range: tickerString.rangeOfString("  \(ticker)"))
            cell.tickerLabel.attributedText = tickerAttributedString
        } else {
            let tickerString = "  \(ticker)" as NSString
            var tickerAttributedString = NSMutableAttributedString(string: tickerString as String)
            tickerAttributedString.addAttributes(fontAwesomeGreenAttribute, range: tickerString.rangeOfString(""))
            tickerAttributedString.addAttributes(latoBoldDarkGrayAttribute, range: tickerString.rangeOfString("  \(ticker)"))
            cell.tickerLabel.attributedText = tickerAttributedString
        }

        weight = formulaStock.valueForKey("weight") as! Float
        cell.weightLabel.text = "\(weight.roundTo(2))%"

        cell.filledWeightWidth.constant = CGFloat(weight/2)

        lastPrice = formulaStock.valueForKey("lastPrice") as! Float
        purchasePrice  = formulaStock.valueForKey("purchasePrice") as! Float
        percentDifference = ((lastPrice/purchasePrice)*100.00)-100


        if ticker == "CASH" {
            cell.changeLabel.text = ""
        } else if percentDifference > 0 {
            cell.changeLabel.text = ("+\(percentDifference.roundTo(2))%")
            cell.changeLabel.textColor = UIColor.formulaGreenColor()
        } else if percentDifference < 0 && percentDifference > -100 {
            cell.changeLabel.text = ("\(percentDifference.roundTo(2))%")
            cell.changeLabel.textColor = UIColor.formulaRedColor()
        } else if percentDifference == 0 {
            cell.changeLabel.text = ("\(percentDifference.roundTo(2))%")
            cell.changeLabel.textColor = UIColor.formulaGreenColor()
        } else {
            cell.changeLabel.text = "N/A"
            cell.changeLabel.textColor = UIColor.formulaDarkGrayColor()
        }

        cell.stockNameLabel.text = formulaStock.valueForKey("name") as! String!
        cell.purchasePriceLabel.text = "$\(purchasePrice)"
        cell.lastPriceLabel.text = "$\(lastPrice)"
        daysHeld = formulaStock.valueForKey("daysHeld") as! Int
        cell.daysHeldLabel.text = "\(daysHeld)"
    }

    cell.selectionStyle = UITableViewCellSelectionStyle.None
    return cell
}

但是将单元格的隐藏值设置为假的代码部分。要求我的 selectedCellIndexPath 等于 cellForRowAtIndexPath 正在经历的当前 indexPath。

这是我设置 selectedCellIndexPath 的地方:

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    let cell = tableView.dequeueReusableCellWithIdentifier("com.Stocks.portfolioCell", forIndexPath: indexPath) as! portfolioCell
    if let selectedCellIndexPath = selectedCellIndexPath {
        if selectedCellIndexPath == indexPath {
            self.selectedCellIndexPath = nil
            currentCollapsing = true
            tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: .None)
        } else {
            lastCollapsing = true
            self.selectedCellIndexPath = indexPath
            tableView.reloadRowsAtIndexPaths([lastIndexPath], withRowAnimation: .None)
            tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: .None)
            self.lastIndexPath = indexPath
        }
    } else {
        selectedCellIndexPath = indexPath
        self.lastIndexPath = indexPath
        tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.None)
    }
    tableView.beginUpdates()
    tableView.endUpdates()
}

只有当我点击一个单元格时，它才应该是任何东西。

每次我为 UITableView 提供一组新数据时，我还要确保运行以下代码行:

(menuTabBarController.viewControllers as! [Portfolio_ViewController])[1].selectedCellIndexPath = nil

这会将 selectedCellIndexPath 设置为 nil，以避免任何潜在问题。

那么，为什么一些随机单元格会显示本应默认隐藏的信息？

当我测试这个错误时，我没有点击任何单元格。所以 selectedCellIndex 此时甚至不应该有值。

Answer 1

这很可能是由单元格重用引起的 - 如果以前选择的单元格用作未选择的单元格，则其 subview 的隐藏值不会改变。

您可以通过添加 else 分支来解决这个问题:

if selectedCellIndexPath == indexPath {
    ...
} else {
    // reset cell to non-selected state
    ...
}