ios - 为什么要减去数组中的某个项目而不是添加它？

Question

我有一个包含 4 个项目的默认数组。当我尝试从第二个 View 添加新项目时，一项会被删除，但应该添加。每当 saveNewScore 被触发时，我应该向数组添加一个新项目。

第一次查看我有这个数组

var playerData: [Player] = Player.createDefaultData()

前面的数组有 4 个默认值。后来我有一个 un Wind segue IBAction

@IBAction func newPlayerData(segue: UIStoryboardSegue) {
        let editor = segue.source as! playerEditor
        if let newData = editor.playerData {
            playerData = newData
        }
        displayPlayerLeaderboard()
    }

前面的代码从playerEditor View 获取一个新数组，这是我的第二个 View Controller 。

对于名为 playerEditor 的第二个 View ，我有以下代码

// Player Array
    var playerData: [Player]?
// Func to add new player to playerData
    @IBAction func saveNewScore() {
            if let name = nameField.text, let hometown = hometownField.text, let state = stateField.text, let score = scoreField.text, let date = dateField.text {
                if name.isEmpty == false && hometown.isEmpty == false && state.isEmpty == false && score.isEmpty == false && date.isEmpty == false {
                    let thisScore = Int(score) ?? 300
                    if thisScore >= 300 || thisScore < 0 {
                        let alert = UIAlertController(title: "Invalid Score", message: "A Player score must between the values of 0 and 300.", preferredStyle: .alert)
                        let okButton = UIAlertAction(title: "OK", style: .default, handler: nil)
                        alert.addAction(okButton)
                        present(alert, animated: true)
                    } else if let savedPlayer = playerID, let savedData = playerData {
                        for (offset,player) in savedData.enumerated() {
                            if player.uniqueID == savedplayer {
                                player.name = name
                                player.town = hometown
                                player.state = state
                                player.score = thisScore
                                player.date = date
                                player.Data?[offset] = player
                            }
                        }
                        dismiss(animated: true, completion: nil)
                    } else {
                        let newPlayer = Player(name: name, town: hometown, state: state, score: thisScore, date: date, uniqueID: largestID + 1)
                        playerData?.append(newPlayer)
                        dismiss(animated: true, completion: nil)
                    }
                } else {
                    let alert = UIAlertController(title: "Invalid Data", message: "Ensure that all text fields have data in them before proceeding.", preferredStyle: .alert)
                    let okButton = UIAlertAction(title: "OK", style: .default, handler: nil)
                    // add action to alert controller 
                    alert.addAction(okButton)
                    present(alert, animated: true)
                }
            }
        }

前面的代码将一个新的 Player 添加到 Player 类型的playerData 数组中，该数组从多个 UITextField 获取信息。

排序功能

func sortData(data: [Player]) -> [Player] {
        var newData: [Player] = []
        for (offset,player) in data.enumerated() {
            if offset == 1 {
                newData += [player]
            } else {
                for (offset,newPlayer) in newData.enumerated() {
                    if player.score >= newPlayer.score {
                        newData.insert(player, at: offset)
                        break
                    } else if offset == (newData.count - 1) {
                        newData.append(player)
                    }
                }
            }

        }
        return newData
    }

Answer 1

在下面的方法中检查 newData 的计数。看起来您要更新到的 playerData 数组有所不同:-

@IBAction func newPlayerData(segue: UIStoryboardSegue) {
        let editor = segue.source as! playerEditor
        if let newData = editor.playerData {
        //Check the count of newData here
            playerData = newData
        }
        displayPlayerLeaderboard()
    }