iOS Swift - 删除 tableViewCell 中 tableview 中的行

Question

所以我试图从 tableViewCell 内的 tableView 中删除项目。该应用程序几乎是一个待办事项列表类型的应用程序，用户可以在其中添加任务，然后可以将具有相同日期的任务分组在一起。

日期位于其自己的表格 View 中，并且在这些日期的单元格中包含属于其下的相应任务的表格 View 。

但是，每当我删除 tableViewCell 中的 tableView 中的任务时，应用程序就会崩溃。

我已经查找了每当删除一行但没有更改时收到的错误。它们仅适用于普通的 tableView。不是 tableViewCell 中的 tableView。

我尝试添加 tableView.beginUpdates() 和 tableView.endUpdates() 但问题仍然存在。我不确定接下来要做什么，因为我认为这应该可行，而且我真的找不到太多关于删除 tableViewCell 的 tableView 中的行的信息。

代码如下:

ToDoListTableViewController.swift(外部tableView)

class ToDoListTableViewController: UITableViewController {

    // MARK: - Properties
    var toDos = [ToDo]()
    var toDoDateGroup = [String]()
    var matchedToDoCount: Int = 0
    //var savedToDos = [ToDo]()

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.delegate = self
        tableView.dataSource = self

        // If there are saved ToDos, load them
        if let savedToDos = loadToDos() {
            toDos = savedToDos
        }
        groupToDosAccordingToDates()
        sortToDoGroupDates()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        //savedToDos = loadToDos()!

        groupToDosAccordingToDates()
        sortToDoGroupDates()
        reloadTableViewData()
    }

    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        return toDoDateGroup.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        // Table view cells are reused and should be dequeued using a cell identifier.
        let dateCellIdentifier = "ToDoTableViewCell"
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "M/d/yy"
        //dateFormatter.dateFormat = "M/d/yy, h:mm a"

        guard let cell = tableView.dequeueReusableCell(withIdentifier: dateCellIdentifier, for: indexPath) as? ToDoTableViewCell else {
            fatalError("The dequeued cell is not an instance of ToDoTableViewCell.")
        }

        // Fetches the appropriate toDo for the data source layout.
        let toDoDate = toDoDateGroup[indexPath.row]

        cell.toDoDate = dateFormatter.date(from: toDoDate)!
        cell.toDoDateWeekDayLabel.text = toDoDate
        cell.toDoDateWeekDayLabel.backgroundColor = UIColor.green
        for toDo in toDos {
            //print(dateFormatter.string(from: toDo.workDate))
            //print("cell.ToDoDate Below:")
            //print(toDoDate)
            if dateFormatter.string(from: toDo.workDate) == toDoDate {
                cell.toDos.append(toDo)
            }
        }

        matchedToDoCount = cell.toDos.count
        //cell.toDoTableView.reloadData()

        return cell
    }

    override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 150
    }

    // MARK: - Actions
    @IBAction func unwindToToDoList(sender: UIStoryboardSegue) {
        if let sourceViewController = sender.source as? ToDoItemTableViewController, let toDo = sourceViewController.toDo {

            if let selectedIndexPath = tableView.indexPathForSelectedRow {
                let dateFormatter = DateFormatter()
                dateFormatter.dateFormat = "M/d/yy"
                // Update an existing ToDo
                //toDos.append(toDo)
                toDoDateGroup[selectedIndexPath.row] = dateFormatter.string(from: toDo.workDate)
                tableView.reloadRows(at: [selectedIndexPath], with: .none)
            }

            else {
                // Add a new toDo
                toDos.append(toDo)

                var newIndexPath: IndexPath
                let dateFormatter = DateFormatter()
                dateFormatter.dateFormat = "M/d/yy"

                if (toDoDateGroup.isEmpty) {
                    newIndexPath = IndexPath(row: toDoDateGroup.count, section: 0)
                    toDoDateGroup.append(dateFormatter.string(from: toDo.workDate))
                    tableView.insertRows(at: [newIndexPath], with: .automatic)
                } else {
                    groupToDosAccordingToDates()
                }
            }

            // Save the ToDos
            saveToDos()
        }
    }


    // Override to support conditional editing of the table view.
    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }


    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        super.prepare(for: segue, sender: sender)

        switch(segue.identifier ?? "") {
        case "AddToDoItem":
            os_log("Adding a new ToDo item.", log: OSLog.default, type: .debug)
        case "ShowToDoItemDetails":
            guard let toDoItemDetailViewController = segue.destination as? ToDoItemTableViewController else {
                fatalError("Unexpected destination: \(segue.destination)")
            }

            guard let selectedToDoItemCell = sender as? ToDoGroupTableViewCell else {
                fatalError("Unexpected sender: \(sender)")
            }

            guard let indexPath = tableView.indexPath(for: selectedToDoItemCell) else {
                fatalError("The selected cell is not being displayed by the table")
            }

            let selectedToDoItem = toDos[indexPath.row]
            toDoItemDetailViewController.toDo = selectedToDoItem
        default:
            fatalError("Unexpected Segue Identifier; \(segue.identifier)")
        }
    }

    // MARK: - Private Methods
    private func saveToDos() {
        //sortToDosByWorkDate()
        let isSuccessfulSave = NSKeyedArchiver.archiveRootObject(toDos, toFile: ToDo.ArchiveURL.path)
        if isSuccessfulSave {
            os_log("ToDos successfully saved.", log: OSLog.default, type: .debug)
        } else {
            os_log("Failed to save toDos...", log: OSLog.default, type: .error)
        }
    }

    private func loadToDos() -> [ToDo]? {
        return NSKeyedUnarchiver.unarchiveObject(withFile: ToDo.ArchiveURL.path) as? [ToDo]
    }

    private func groupToDosAccordingToDates() {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "M/d/yy"
        //dateFormatter.dateFormat = "M/d/yy, h:mm a"

        var newIndexPath: IndexPath

        for toDo in toDos {
            print(toDo.taskName)
            let chosenWorkDate = dateFormatter.string(from: toDo.workDate)
            if !toDoDateGroup.contains(chosenWorkDate) {
                print(chosenWorkDate)
                newIndexPath = IndexPath(row: toDoDateGroup.count, section: 0)
                toDoDateGroup.append(chosenWorkDate)
                tableView.insertRows(at: [newIndexPath], with: .automatic)
            }
        }
    }

    private func sortToDoGroupDates() {
        toDoDateGroup = toDoDateGroup.sorted(by: {
            $1 > $0
        })
    }

    private func reloadTableViewData() {
        DispatchQueue.main.async {
            self.tableView.reloadData()
        }
    }

}

ToDoTableViewCell.swift(内部tableView)

class ToDoTableViewCell: UITableViewCell, UITableViewDataSource, UITableViewDelegate {

    // MARK: - Properties

    @IBOutlet weak var toDoDateWeekDayLabel: UILabel!
    @IBOutlet weak var toDoTableView: UITableView!

    var toDos = [ToDo]()
    let dateFormatter = DateFormatter()
    var toDoDate = Date()

    let cellIdentifier = "ToDoGroupTableViewCell"

    override var intrinsicContentSize: CGSize {
        return self.intrinsicContentSize
    }

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code

        dateFormatter.dateFormat = "M/d/yy, h:mm a"
        sortToDosByWorkDate()
        //reloadTableViewData()
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
        toDoTableView.delegate = self
        toDoTableView.dataSource = self
    }

    // MARK: - Table view data source

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        //print("Inner Cell Data");
        return toDos.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cellIdentifier = "ToDoGroupTableViewCell"
        let dueDateFormatter = DateFormatter()
        let workDateFormatter = DateFormatter()
        dueDateFormatter.dateFormat = "M/d/yy, h:mm a"
        workDateFormatter.dateFormat = "h:mm a"

        guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as? ToDoGroupTableViewCell  else {
            fatalError("The dequeued cell is not an instance of ToDoGroupTableViewCell.")
        }

        // Fetches the appropriate toDo for the data source layout.
        let toDo = toDos[indexPath.row]

        cell.taskNameLabel.text = toDo.taskName
        cell.workDateLabel.text = workDateFormatter.string(from: toDo.workDate)
        cell.estTimeLabel.text = toDo.estTime
        cell.dueDateLabel.text = dueDateFormatter.string(from: toDo.dueDate)

        return cell
    }

    func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }

    func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            // Delete the row from the data source of the current tableViewCell
            let toDoToBeDeleted = toDos[indexPath.row]
            tableView.beginUpdates()
            toDos.remove(at: indexPath.row)
            saveToDos(toDoToBeDeleted: toDoToBeDeleted)
            tableView.deleteRows(at: [indexPath], with: .fade)
            tableView.endUpdates()
        } else if editingStyle == .insert {
            // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
        }
    }

    // MARK: - Private Methods

    private func saveToDos(toDoToBeDeleted: ToDo?) {
        // TODO: Refactor the deletion part of this function to be its own delete function
        // If there are existing toDos, load them
        if var savedToDos = loadToDos() {
            // If a there is a specific toDo to be deleted after save
            if toDoToBeDeleted != nil {
                print("toDoToBeDeleted is not nil")
                print(savedToDos)
                /*while let toDoIdToDelete = savedToDos.index(of: toDoToBeDeleted!) {
                    print("Index Exists in savedToDos")
                    savedToDos.remove(at: toDoIdToDelete)
                }*/
                savedToDos.removeAll{$0 == toDoToBeDeleted}
                let isSuccessfulSave = NSKeyedArchiver.archiveRootObject(savedToDos, toFile: ToDo.ArchiveURL.path)
                if isSuccessfulSave {
                    os_log("A ToDo was deleted and ToDos is successfully saved.", log: OSLog.default, type: .debug)
                }
            // If there is no specific toDo to be deleted
            } else {
                let lastToDosItem: Int = toDos.count - 1
                savedToDos.append(toDos[lastToDosItem])
                let isSuccessfulSave = NSKeyedArchiver.archiveRootObject(savedToDos, toFile: ToDo.ArchiveURL.path)
                if isSuccessfulSave {
                    os_log("A ToDo was added and ToDos is successfully saved.", log: OSLog.default, type: .debug)
                }
            }
        // If this is the initial save and no other toDos exists
        } else {
            let isSuccessfulSave = NSKeyedArchiver.archiveRootObject(toDos, toFile: ToDo.ArchiveURL.path)
            if isSuccessfulSave {
                os_log("The initial ToDo is successfully saved.", log: OSLog.default, type: .debug)
            }
        }
    }

    private func loadToDos() -> [ToDo]? {
        print("loadToDos()")
        return NSKeyedUnarchiver.unarchiveObject(withFile: ToDo.ArchiveURL.path) as? [ToDo]
    }

    private func registerCell() {
        toDoTableView.register(ToDoTableViewCell.self, forCellReuseIdentifier: "ToDoTableViewCell")
    }

    private func sortToDosByWorkDate() {
        toDos = toDos.sorted(by: {
            $1.workDate > $0.workDate
        })
     }
}

在 tableViewCell 中删除 tableView 中的行时出现错误输出:

2019-08-05 00:35:03.610047-0400 Focus-N-Do[1957:40199] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0.  The number of rows contained in an existing section after the update (5) must be equal to the number of rows contained in that section before the update (3), plus or minus the number of rows inserted or deleted from that section (0 inserted, 1 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).'
*** First throw call stack:
(
    0   CoreFoundation                      0x00000001095501bb __exceptionPreprocess + 331
    1   libobjc.A.dylib                     0x0000000107b66735 objc_exception_throw + 48
    2   CoreFoundation                      0x000000010954ff42 +[NSException raise:format:arguments:] + 98
    3   Foundation                          0x0000000107569877 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 194
    4   UIKitCore                           0x000000010c0e2e2d -[UITableView _endCellAnimationsWithContext:] + 18990
    5   UIKitCore                           0x000000010c0fc711 -[UITableView endUpdates] + 75
    6   Focus-N-Do                          0x00000001071201ac $S10Focus_N_Do02ToB13TableViewCellC05tableE0_6commit8forRowAtySo07UITableE0C_So0leF12EditingStyleV10Foundation9IndexPathVtF + 1036
    7   Focus-N-Do                          0x000000010712029b $S10Focus_N_Do02ToB13TableViewCellC05tableE0_6commit8forRowAtySo07UITableE0C_So0leF12EditingStyleV10Foundation9IndexPathVtFTo + 123
    8   UIKitCore                           0x000000010c120d90 __48-[UITableView _animateDeletionOfRowAtIndexPath:]_block_invoke + 71
    9   UIKitCore                           0x000000010c3b6235 +[UIView(Animation) performWithoutAnimation:] + 90
    10  UIKitCore                           0x000000010c120bdb -[UITableView _animateDeletionOfRowAtIndexPath:] + 219
    11  UIKitCore                           0x000000010c129739 __82-[UITableView _contextualActionForDeletingRowAtIndexPath:usingPresentationValues:]_block_invoke + 59
    12  UIKitCore                           0x000000010c07ef5e -[UIContextualAction executeHandlerWithView:completionHandler:] + 154
    13  UIKitCore                           0x000000010c084884 -[UISwipeOccurrence _performSwipeAction:inPullview:swipeInfo:] + 725
    14  UIKitCore                           0x000000010c086128 -[UISwipeOccurrence swipeActionPullView:tappedAction:] + 92
    15  UIKitCore                           0x000000010c08ad33 -[UISwipeActionPullView _tappedButton:] + 138
    16  UIKitCore                           0x000000010bedbecb -[UIApplication sendAction:to:from:forEvent:] + 83
    17  UIKitCore                           0x000000010b9170bd -[UIControl sendAction:to:forEvent:] + 67
    18  UIKitCore                           0x000000010b9173da -[UIControl _sendActionsForEvents:withEvent:] + 450
    19  UIKitCore                           0x000000010b91631e -[UIControl touchesEnded:withEvent:] + 583
    20  UIKitCore                           0x000000010bf170a4 -[UIWindow _sendTouchesForEvent:] + 2729
    21  UIKitCore                           0x000000010bf187a0 -[UIWindow sendEvent:] + 4080
    22  UIKitCore                           0x000000010bef6394 -[UIApplication sendEvent:] + 352
    23  UIKitCore                           0x000000010bfcb5a9 __dispatchPreprocessedEventFromEventQueue + 3054
    24  UIKitCore                           0x000000010bfce1cb __handleEventQueueInternal + 5948
    25  CoreFoundation                      0x00000001094b5721 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    26  CoreFoundation                      0x00000001094b4f93 __CFRunLoopDoSources0 + 243
    27  CoreFoundation                      0x00000001094af63f __CFRunLoopRun + 1263
    28  CoreFoundation                      0x00000001094aee11 CFRunLoopRunSpecific + 625
    29  GraphicsServices                    0x000000011166b1dd GSEventRunModal + 62
    30  UIKitCore                           0x000000010beda81d UIApplicationMain + 140
    31  Focus-N-Do                          0x00000001071230b7 main + 71
    32  libdyld.dylib                       0x000000010a9e9575 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

如有任何帮助，我们将不胜感激。

Answer 1

问题不在于 beginUpdates、endUpdates 等，而在于 ToDoTableViewCell 逻辑。

正如错误文本提示的那样，您删除和/或插入的行数不正确。

考虑这个例子:您从数据源中删除 1 个对象(即 toDos)，您为一个 indexPath 调用 tableView.deleteRows(at: [indexPath], with: .fade) 。

既然如此，那就万事大吉了。但错误表明更新前有 3 行，现在更新后有 5 行。请记住，您删除了 1 行，因此应该有 2 行。怎么会发生这种情况？...应用程序崩溃。

问题是您正在将对象插入到数据源中的某处，但没有调用tableView.inserRows(...)。你需要弄清楚这一点。