ios - fatal error : Index out of range tableview

Question

谁能看出我错在哪里？ tableView Controller 应显示 1 或 4 个部分(取决于来自先前 View Controller 的输入)以及来自数组的动态行数。

该程序应该用不同的数组填充每个部分，但是我在 Switch 语句的第三种情况下收到索引超出范围错误。部分和行在 viewdidLoad() 方法中设置，selectPic() 方法相应地更改 houseImg 变量。

我正在使用 Swift 4。

 override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        if checkData == 0 {
            //Inserting one section and filling the cells with the array
            saveCount = pupilNames.count
                if saveCount > counter{
                    cell.imageView?.image = houseImg
                    cell.textLabel?.text = "Pupil Name:  \(pupilNames[indexPath.row])"
                    cell.detailTextLabel?.text = "Score:  \(pupilScores[indexPath.row])"
                    counter = counter+1
                }
            checkData = 2
            return cell
        }
        else if checkData == 1 {
            //Inserting four sections and populate 4 arrays for each section
            var countIf: Int = 0
            var secondCount: Int = 0
            houseCount = 4
                if checkCount > houseCont {
                    switch houseCont {
                        case 0:
                            chosenHouse = 1
                            selectPic()
                            countIf = pupilNames.count
                            repeat {
                                cell.imageView?.image = houseImg
                                cell.textLabel?.text = "Pupil Name:  \(pupilNames[indexPath.row])"
                                cell.detailTextLabel?.text = "Score:   \(pupilScores[indexPath.row])"
                                secondCount = secondCount+1
                            } while countIf > secondCount
                        case 1:
                            chosenHouse = 2
                            selectPic()
                            countIf = secondNames.count
                            secondCount = 0
                            repeat {
                                cell.imageView?.image = houseImg
                                cell.textLabel?.text = "Pupil Name:  \(secondNames[indexPath.row])"
                                cell.detailTextLabel?.text = "Score:   \(secondScores[indexPath.row])"
                                secondCount = secondCount+1
                            } while countIf > secondCount
                        case 2:
                            chosenHouse = 3
                            selectPic()
                            countIf = thirdNames.count
                            secondCount = 0
                            repeat {
                                cell.imageView?.image = houseImg
                                //*******Error occurring on Pupil Name line *********
                                cell.textLabel?.text = "Pupil Name:  \(thirdNames[indexPath.row])"
                                cell.detailTextLabel?.text = "Score:   \(thirdScores[indexPath.row])"
                                secondCount = secondCount+1
                            } while countIf > secondCount
                        case 3:
                            chosenHouse = 4
                            selectPic()
                            repeat {
                                cell.imageView?.image = houseImg
                                cell.textLabel?.text = "Pupil Name:  \(fourNames[indexPath.row])"
                                cell.detailTextLabel?.text = "Score:   \(fourScores[indexPath.row])"
                                secondCount = secondCount+1
                            }while countIf > secondCount
                    default:
                            houseCont = 5
                            checkData = 2
                    }
                    houseCont = houseCont+1
                }
        }
    return cell
}

编辑:'houseCount' 是从前一个 View Controller 发送的，包含值 1 或 4。 “saveCount”包含一个通过将所有数组的计数相加而创建的数字，这是在填充数组的方法中完成的。

saveCount = pupilNames.count+secondNames.count+thirdNames.count+fourNames.count

override func numberOfSections(in tableView: UITableView) -> Int{
    return houseCount
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
    return saveCount
}

最终编辑:感谢大家的帮助，这两个答案的结合帮助我解决了我的错误。这是我解决问题的最终代码，我删除了 if 语句和重复循环，并更改了一些代码以解决我的问题。

else if checkData == 1 {
            houseCount = 4
                    switch indexPath.section {
                        case 0:
                            chosenHouse = 1
                            selectPic()
                                cell.imageView?.image = houseImg
                                cell.textLabel?.text = "Pupil Name:  \(pupilNames[indexPath.row])"
                                cell.detailTextLabel?.text = "Score:   \(pupilScores[indexPath.row])"
                        case 1:
                            chosenHouse = 2
                            selectPic()
                                cell.imageView?.image = houseImg
                                cell.textLabel?.text = "Pupil Name:  \(secondNames[indexPath.row])"
                                cell.detailTextLabel?.text = "Score:   \(secondScores[indexPath.row])"
                        case 2:
                            chosenHouse = 3
                            selectPic()
                                cell.imageView?.image = houseImg
                                cell.textLabel?.text = "Pupil Name:  \(thirdNames[indexPath.row])"
                                cell.detailTextLabel?.text = "Score:   \(thirdScores[indexPath.row])"
                        case 3:
                            chosenHouse = 4
                            selectPic()
                            //saveCount = fourNames.count
                                cell.imageView?.image = houseImg
                                cell.textLabel?.text = "Pupil Name:  \(fourNames[indexPath.row])"
                                cell.detailTextLabel?.text = "Score:   \(fourScores[indexPath.row])"
                    default:
                            houseCont = 5
                            checkData = 2
                    }
                    houseCont = houseCont+1
        }

Answer 1

看看下面的代码，几个警钟响了:

                       chosenHouse = 3
                       selectPic()
                       countIf = thirdNames.count
                       secondCount = 0
                       repeat {
                            cell.imageView?.image = houseImg
                            //*******Error occurring on Pupil Name line *********
                            cell.textLabel?.text = "Pupil Name:  \(thirdNames[indexPath.row])"
                            cell.detailTextLabel?.text = "Score:   \(thirdScores[indexPath.row])"
                            secondCount = secondCount+1
                        } while countIf > secondCount

首先使用repeat。里面的代码总是至少执行一次。我认为在 thirdNames.count == 0

的情况下这将是一个错误

然而，更奇怪的是，repeat 循环的内容在迭代之间并没有改变。您不会做任何依赖于唯一变化的事情 - secondCount。如果 countIf 为 10，您只需将相同的名称和分数分配给相同的两个控件 10 次。