ios – ‘*** – [__ NSArrayM insertObject：atIndex：]：执行UITableView动画重新加载时,对象不能为nil

问题摘要：当UITableViewCell的UITableViewCell的高度从UITextView编辑它的文本时,当UITableView中有很多单元格时,它会崩溃.使用iOS 8自定义单元格.

长问题：我已经成功实现,所以我可以动态地使用iOS 8自定义单元格进入单元格UITextView的文本,并改变单元格高度而不失去焦点(firstReponder).但是,如果tableView太大(行数太多),则会崩溃.这是我的堆栈跟踪：

Terminating app due to uncaught exception 'NSinvalidargumentexception',reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
*** First throw call stack:
(
0   CoreFoundation                      0x000000010b3b3d85 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x000000010b9cbdeb objc_exception_throw + 48
2   CoreFoundation                      0x000000010b274cc5 -[__NSArrayM insertObject:atIndex:] + 901
3   UIKit                               0x0000000108b05439 __46-[UITableView _updateWithItems:updateSupport:]_block_invoke1029 + 180
4   UIKit                               0x0000000108a7e838 +[UIView(UIViewAnimationWithBlocks) _setupAnimationWithDuration:delay:view:options:factory:animations:start:animationStateGenerator:completion:] + 582
5   UIKit                               0x0000000108a7ec6d +[UIView(UIViewAnimationWithBlocks) animateWithDuration:delay:options:animations:completion:] + 105
6   UIKit                               0x0000000108b05048 -[UITableView _updateWithItems:updateSupport:] + 4590
7   UIKit                               0x0000000108afd5a0 -[UITableView _endCellAnimationsWithContext:] + 15360
8   Test RYM                            0x0000000107e6a173 _TFE8Test_RYMCSo11UITableView31reloadDataAnimatedKeepingOffsetfT_T_ + 163
9   Test RYM                            0x0000000107e6a242 _TToFE8Test_RYMCSo11UITableView31reloadDataAnimatedKeepingOffsetfT_T_ + 34
10  Test RYM                            0x0000000107dcda90 _TFC8Test_RYM20AgendaViewController19cellHeightDidUpdatefTCSo11NSIndexPath6heightV12CoreGraphics7CGFloat_T_ + 144
11  Test RYM                            0x0000000107dcdb04 _TToFC8Test_RYM20AgendaViewController19cellHeightDidUpdatefTCSo11NSIndexPath6heightV12CoreGraphics7CGFloat_T_ + 68
12  Test RYM                            0x0000000107e725cb _TFC8Test_RYM27AgendaDecisionTableViewCell20updateTextViewHeightfT_T_ + 907
13  Test RYM                            0x0000000107e731fa _TFC8Test_RYM27AgendaDecisionTableViewCell17textViewDidChangefCSo10UITextViewT_ + 42

并导致它的代码：

// In UITableView extension
func reloadDataAnimatedKeepingOffset() {
    //let offset = contentOffset
    //UIView.setAnimationsEnabled(false)
    beginUpdates()
    endUpdates()
    //UIView.setAnimationsEnabled(true)
    //layoutIfNeeded()
    //contentOffset = offset
}

// In a self-sizing UITableViewCell subclass
func updateTextViewHeight() {
    let size = decisionTextView.bounds.size
    let newSize = decisionTextView.sizeThatFits(CGSize(width: size.width,height: CGFloat.max))
    let newHeight = newSize.height
    if size.height != newHeight {
        textViewHeightConstraint.constant = newHeight
        agendaViewController?.cellHeightDidUpdate(indexPath!,height: newSize.height)
    }
}

// In the ViewController managing the tableView
public func cellHeightDidUpdate(indexPath: NSIndexPath,height: CGFloat) {
    updateHelperAlphas()
    tableView?.reloadDataAnimatedKeepingOffset()
}

它在调用endUpdates()时崩溃.我已经尝试删除tableView：estimateHeightForRowAtIndexPath：方法在UITableView insertRowsAtIndexPaths throwing __NSArrayM insertObject:atIndex:’object cannot be nil’ error中没有成功.

它似乎只发生在列表很长时间.

编辑：我使用的更多方法：

public func tableView(tableView: UITableView,estimatedHeightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return 48.0
}

public func tableView(tableView: UITableView,heightForHeaderInSection section: Int) -> CGFloat {
    if (section == 0) {
        return 0
    }
    else {
        let currentSectionIsEmpty = sectionIsEmpty(section)
        if ((!isInEditProtocolMode && isProtocolMode) || isPrevIoUsProtocolMode) && currentSectionIsEmpty {
            return 0
        }
        let subSection = sectionHelper.subSectionForSection(section)
        let isProtocolTopSection = isProtocolMode && subSection == 0
        if (isProtocolTopSection) {
            return UITableViewAutomaticDimension
        }
        else {
            return agendaHeaderHeight
        }
    }
}

public func tableView(tableView: UITableView,estimatedHeightForHeaderInSection section: Int) -> CGFloat {
    if (section == 0) {
        return 0
    }
    else {
        let subSection = sectionHelper.subSectionForSection(section)
        let isProtocolTopSection = isProtocolMode && subSection == 0
        if (isProtocolTopSection) {
            return protocolAgendaHeaderHeight
        }
        else {
            return agendaHeaderHeight
        }
    }
}

public override func viewDidLoad() {
    super.viewDidLoad()
    tableView.rowHeight = UITableViewAutomaticDimension
}

EDIT2：
这几乎是同样的问题. tableView crashes on end up with more than 16 items然而,我无法消除细胞高度的估计,因为这破坏了我的自动调整细胞图的动态高度.

编辑3：
尝试(从下面的评论)使用CATransaction.setdisableActions(_)和setContentOffset(_：动画:)没有任何帮助.这似乎与此无关,除了beginUpdates()和endUpdates()都没有帮助. reloadDataAnimatedKeepingOffset()似乎只被调用一次,没有其他reloadData似乎被调用在同一时间.将估计高度设置为1而不是0也没有帮助.它奇怪地显示零标题而不是高度1.

编辑4：
根据请求,我的numberOrRowsInSection和cellForRowAtIndexPath方法(有点复杂)：

public func tableView(tableView: UITableView,numberOfRowsInSection section: Int) -> Int
{
    let mainSection = sectionHelper.mainSectionForSection(section)
    let subSection = sectionHelper.subSectionForSection(section)


    let isHeaderSection = subSection <= 0
    if isHeaderSection {
        return isProtocolMode ? 0 : cellIdSectionList[0].count
    }

    let rowType = sectionHelper.rowTypeForSection(section)

    let agenda = agendaForSection(section)

    switch rowType {
    case .NoteRow:
        return mainSectionShowingPlaceholderNewNoteCell == mainSection || !agenda.protocolString.isEmpty ? 1 : 0
    case .ActionRow:
        let count = max(0,agenda.actionListCount())
        return count
    case .DecisionRow:
        var count = agenda.decisions.count ?? 0
        count = max(0,count)
        count = indexPathShowingPlaceholderNewDecisionCell?.section == section ? count+1 : count
        return count
    default:
        return 0
    }
}

public func tableView(tableView: UITableView,cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
    let row = indexPath.row
    let section = indexPath.section
    let cellId = cellIdForIndexPath(indexPath)

    let cell = tableView.dequeueReusableCellWithIdentifier(cellId,forIndexPath: indexPath)
    let allowEditing = (isInEditProtocolMode || !isProtocolMode) && !isPrevIoUsProtocolMode

    if let titleCell = cell as? StandardTitleTableViewCell {
        titleCell.setup(agendaForSection(section),meeting:selectedMeeting!,indexPath:indexPath)
        titleCell.delegate = self
    }
    if let descriptionCell = cell as? StandardDescriptionTableViewCell {
        descriptionCell.setup(agendaForSection(section),indexPath: indexPath,forceExpand: hasExpandedDescriptionCellView)
        descriptionCell.delegate = self
    }

    if let noteCell = cell as? AgendaNotesTableViewCell {
        noteCell.setup(agendaForSection(section),allowEditing:allowEditing)
        noteCell.agendaViewController = self
    }

    if let decisionCell = cell as? AgendaDecisionTableViewCell {
        let decisionList = agendaForSection(section).decisions
        let isNewDecisionCell = row >= decisionList.count
        if !isNewDecisionCell {
            let decision = decisionList[row]
            decisionCell.setup(decision,allowEditing: allowEditing)
        }
        else {
            decisionCell.setup(newDecisionToAdd!,allowEditing: allowEditing)
        }
        decisionCell.agendaViewController = self
    }

    if let actionCell = cell as? StandardTableViewCell,let actionList = agendaForSection(section).actionList {
            let action = actionList.actions[row]
            actionCell.setupAsActionListCell(action:action,delegate: self)
    }

    if let textCell = cell as? MeetingTextTableViewCell {
        var placeholderText = ""
        if indexPathIsActionTextPlaceholderCell(indexPath) {
            placeholderText = __("agenda.noActions.text")
        }
        else if indexPathIsDecisionTextPlaceholderCell(indexPath) {
            placeholderText = __("agenda.noDecisions.text")
        }
        textCell.setup(placeholderText)
    }

    return cell
}

public func tableView(tableView: UITableView,viewForHeaderInSection section: Int) -> UIView?
{
    if (section == 0) {
        return nil
    }
    let subSection = sectionHelper.subSectionForSection(section)
    let cellId = isProtocolMode && subSection == 0 ? protocolHeaderCellId : headerCellId
    let cell = tableView.dequeueReusableheaderfooterViewWithIdentifier(cellId)
    let agenda = agendaForSection(section)

    if let standardHeaderCell = cell as? StandardTableViewHeaderCell {
        let subSection = sectionHelper.subSectionForSection(section)

        let currentSectionIsEmpty = sectionIsEmpty(section)
        let protocolIsLocked = selectedMeeting!.protocolIsLocked
        if (isPrevIoUsProtocolMode && currentSectionIsEmpty) {
            return nil
        }
        let allowEditing = (isInEditProtocolMode || !isProtocolMode) && !isPrevIoUsProtocolMode && !protocolIsLocked
        let showRightAddButton = ((subSection == 1 && currentSectionIsEmpty) || subSection == 2 || (subSection == 3 && indexPathShowingPlaceholderNewDecisionCell?.section != section)) && allowEditing

        let headerTitle = headerTitleList[subSection]
        standardHeaderCell.setupWithText(headerTitle,section:section,showAddButton: showRightAddButton,delegate: self)
    }
    else if let protocolHeaderCell = cell as? ProtocolTableViewHeaderCell {
        let showSeparator = section > 1
        let onlyShowAttachmentIfItHaveAttachments = isPrevIoUsProtocolMode || (isProtocolMode && !isInEditProtocolMode)
        let showAttachmentIcon = !onlyShowAttachmentIfItHaveAttachments || agenda.attachments.count > 0
        protocolHeaderCell.setup(showSeparator: showSeparator,agenda: agenda,section: section,showProtocolIcon: false,showAttachmentIcon: showAttachmentIcon,delegate: self)
    }

    return cell!.wrappedInNewView()
}

// In UIView extension
func wrappedInNewView() -> UIView
{
    let view = UIView(frame: frame)
    autoresizingMask = [.FlexibleHeight,.FlexibleWidth]
    view.addSubview(self)
    return view
}

public func tableView(tableView: UITableView,estimatedHeightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return 48.0
}

tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 48.0