ios - 向 UITableView 添加行时更新无效

Question

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 (1), plus or minus the number of rows inserted or deleted from that section (1 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).

我正在尝试在用户点击一行时将行添加到 TableView ，以创建一个可扩展部分，但是在 Xcode 尝试添加它们之前不会计算额外的行，因此会导致此错误(我认为)。谁能指出我正确的方向？

// sectionExpanded is set to false in viewDidLoad. It is set to true when
// the user taps on the expandable section (section 0 in this case)

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    if section == 0 && sectionExpanded {
        return 5
    } else {
        return 1
    }
}

// This should recount the rows, add the new ones to a temporary array and then add
// them to the table causing the section to 'expand'.

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    let selectedItem = menu[indexPath.row]
    let cell = tableView.cellForRowAtIndexPath(indexPath) as MenuCell
    if indexPath.section == 0 {
        var rows: Int
        var tmpArray: NSMutableArray = NSMutableArray()

        sectionExpanded = !sectionExpanded
        rows = tableView.numberOfRowsInSection(0)

        for i in 1...rows {
            var tmpIndexPath: NSIndexPath
            tmpIndexPath = NSIndexPath(forRow: i, inSection: 0)

            tmpArray.addObject(tmpIndexPath)
        }

        if !sectionExpanded {
            tableView.deleteRowsAtIndexPaths(tmpArray, withRowAnimation: UITableViewRowAnimation.Top)
        } else {
            tableView.insertRowsAtIndexPaths(tmpArray, withRowAnimation: UITableViewRowAnimation.Top)
        }
    } else {
        delegate?.rightItemSelected(selectedItem)
    }
}

Answer 1

它告诉您您正在尝试插入 1 个新行，但是 numberofrows 应该是 5，之前是 1，而您正在尝试插入 1 个新行，那是 2。这就是您的问题。

rows = tableView.numberOfRowsInSection(0) //this returns 1
for i in 1...rows { //
    var tmpIndexPath: NSIndexPath
    tmpIndexPath = NSIndexPath(forRow: i, inSection: 0)

    tmpArray.addObject(tmpIndexPath)//this will contain only 1 object, because the loop will run only for 1 cycle
}

编辑

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    let selectedItem = menu[indexPath.row]
    let cell = tableView.cellForRowAtIndexPath(indexPath) as MenuCell
    if indexPath.section == 0 {
        var rows: Int
        var tmpArray: NSMutableArray = NSMutableArray()

        sectionExpanded = !sectionExpanded
        rows = 1
        if sectionExpanded {
            rows = 5
        }

        for i in 1...rows {
            var tmpIndexPath: NSIndexPath
            tmpIndexPath = NSIndexPath(forRow: i, inSection: 0)

            tmpArray.addObject(tmpIndexPath)
        }

        if !sectionExpanded {
            tableView.deleteRowsAtIndexPaths(tmpArray, withRowAnimation: UITableViewRowAnimation.Top)
        } else {
            tableView.insertRowsAtIndexPaths(tmpArray, withRowAnimation: UITableViewRowAnimation.Top)
        }
    } else {
        delegate?.rightItemSelected(selectedItem)
    }
}

既然你知道行数总是 5 或 1，你可以尝试这样的事情。但是，这不是标准方法，我建议更改您的数据源数组。
以下是一些如何操作的示例:http://www.nsprogrammer.com/2013/07/updating-uitableview-with-dynamic-data.html它是针对 Objective-C 的，但您会了解它的要点。