实例成员“____”不能用于“ScoreHistory”类型

Question

我有以下来自“ScoreHistory.swift”的变量：

// ScoreHistory.swift

var datePlayed: NSDate
var totalScore: Int
var totalAnswered: Int
var totalDuration: Int
var gameStatus: String

我正在尝试将数据显示到“ScoreHistoryViewController.swift”

// ScoreHistory.swift

navigationItem.title = ScoreHistory.datePlayed
datePlayedLabel.text = ScoreHistory.datePlayed
totalScoreLabel.text = ScoreHistory.totalScore
totalAnsweredLabel.text = ScoreHistory.totalAnswered
totalDurationLabel.text  = ScoreHistory.totalDuration
gameStatusLabel.text  = ScoreHistory.gameStatus

但他们都错了： 实例成员“____”不能用于“ScoreHistory”类型

这是什么意思？

我的 ScoreHistory.swift 的完整代码如下所示：

class ScoreHistory: NSObject, NSCoding {

// MARK: Properties

var datePlayed: NSDate
var totalScore: Int
var totalAnswered: Int
var totalDuration: Int
var gameStatus: String

// MARK: Archiving Paths

static let DocumentsDirectory = NSFileManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask).first!
static let ArchiveURL = DocumentsDirectory.URLByAppendingPathComponent("scores")

// MARK: Types

struct PropertyKey {
    static let datePlayedKey = "datePlayed"
    static let totalScoreKey = "totalScore"
    static let totalAnsweredKey = "totalAnswered"
    static let totalDurationKey = "totalDuration"
    static let gameStatusKey = "gameStatus"
}

// MARK: Initialization

init?(datePlayed: NSDate, totalScore: Int, totalAnswered: Int, totalDuration: Int, gameStatus: String) {
    // Initialize stored properties.

    self.datePlayed = datePlayed
    self.totalScore = totalScore
    self.totalAnswered = totalAnswered
    self.totalDuration = totalDuration
    self.gameStatus = gameStatus


    super.init()

    // Initialization should fail if there is no name or if the rating is negative.
    if gameStatus.isEmpty {
        return nil
    }
}

// MARK: NSCoding

func encodeWithCoder(aCoder: NSCoder) {

    aCoder.encodeObject(datePlayed, forKey: PropertyKey.datePlayedKey)
    aCoder.encodeInteger(totalScore, forKey: PropertyKey.totalScoreKey)
    aCoder.encodeInteger(totalAnswered, forKey: PropertyKey.totalAnsweredKey)
    aCoder.encodeInteger(totalDuration, forKey: PropertyKey.totalDurationKey)
    aCoder.encodeObject(gameStatus, forKey: PropertyKey.gameStatusKey)
}

required convenience init?(coder aDecoder: NSCoder) {

    let datePlayed = aDecoder.decodeObjectForKey(PropertyKey.datePlayedKey) as! NSDate
    let totalScore = aDecoder.decodeIntegerForKey(PropertyKey.totalScoreKey)
    let totalAnswered = aDecoder.decodeIntegerForKey(PropertyKey.totalAnsweredKey)
    let totalDuration = aDecoder.decodeIntegerForKey(PropertyKey.totalDurationKey)
    let gameStatus = aDecoder.decodeObjectForKey(PropertyKey.gameStatusKey) as! String

    // Must call designated initializer.
    self.init(datePlayed: datePlayed, totalScore: totalScore, totalAnswered: totalAnswered, totalDuration: totalDuration, gameStatus: gameStatus)
}

Answer 1

根据您的模型设计，您无法访问类上的属性，例如 ScoreHistory.datePlayed

你必须创建一个实例。

let history = ScoreHistory(datePlayed: NSDate(), totalScore: 0, totalAnswered: 0, totalDuration: 0, gameStatus: "started")

并调用一个属性

navigationItem.title = history.datePlayed