在 Swift 5 中保存天数

Question

所以我为一天和一杯饮料创建了一个课程。我正在尝试追踪你一天喝了多少酒，但我正在努力保存好几天。我目前正在设法保存当天（当天喝了多少酒），但我不知道如何保存超过一天。

我想保存一个包含所有天数的 Day 类型的数组。我该怎么做？

这是我的日课：

public class Day: NSObject {
var date: Date
var goalAmount: Drink
var consumedAmount: Drink

func saveDay() {
    let formatting = DateFormatter()
    formatting.dateFormat = "EEEE - dd/mm/yy"
    UserDefaults.standard.set(formatting.string(from: date), forKey: "date")
    UserDefaults.standard.set(goalAmount.amountOfDrink, forKey: "goal")
    UserDefaults.standard.set(consumedAmount.amountOfDrink, forKey: "consumed")
}

func loadDay() {
    let rawDate = UserDefaults.standard.value(forKey: "date") as? String ?? ""
    let formatter = DateFormatter()
    formatter.dateFormat = "EEEE - dd/mm/yy"
    date = formatter.date(from: rawDate)!
    goalAmount.amountOfDrink = UserDefaults.standard.float(forKey: "goal")
    consumedAmount.amountOfDrink = UserDefaults.standard.float(forKey: "consumed")
}
}

这是我的饮料课：

class Drink: NSObject {
   var typeOfDrink: String
   var amountOfDrink: Float

}

我在当天有任何更改时调用 saveDay()，然后在应用程序打开时调用 loadDay()。

Answer 1

更好的方法是将类的对象存储在 userDefaults 中，而不是存储该类的特定属性。并使用[Date] 而不是Date 来节省多天

首先，您需要序列化对象以存储在 userDefaults 中，并反序列化以从 userDefaults 中获取数据。

import Foundation

class Day: Codable {

    var date = Date()
    var goalAmount: Drink
    var consumedAmount: Drink

    init(date: Date, goalAmount: Drink,consumedAmount: Drink ) {
        self.date = date
        self.goalAmount = goalAmount
        self.consumedAmount = consumedAmount

    }


  static func saveDay(_ day : [Day]) {
        do {
            let object = try JSONEncoder().encode(day)
            UserDefaults.standard.set(object, forKey: "days")
        } catch {
            print(error)
        }


    }

  static func loadDay() {
        let decoder = JSONDecoder()
        if  let object = UserDefaults.standard.value(forKey: "days") as? Data {
            do {
                let days = try decoder.decode([Day].self, from: object)

                for day in days {
                    print("Date - ", day.date)
                    print("Goal Amount - ", day.goalAmount)
                    print("Consumed Amount - ",day.consumedAmount)
                    print("----------------------------------------------")
                }


            } catch {
                print(error)
            }


        } else {
            print("unable to fetch the data from day key in user defaults")
        }
    }
}


class Drink: Codable {
    var typeOfDrink: String
    var amountOfDrink: Float

    init(typeOfDrink: String,amountOfDrink: Float ) {
        self.typeOfDrink = typeOfDrink
        self.amountOfDrink = amountOfDrink
    }

}

使用saveAndGet() 方法从userDefaults 存储和获取详细信息

func saveAndGet() {
 // use any formats to format the dates
        let date = Date()
        let goalAmount = Drink(typeOfDrink: "Water", amountOfDrink: 5.0)
        let consumedAmount = Drink(typeOfDrink: "Water", amountOfDrink: 3.0)

        let day1 = Day(date: date, goalAmount: goalAmount, consumedAmount: consumedAmount)
        let day2 = Day(date: date, goalAmount: goalAmount, consumedAmount: consumedAmount)
        let day3 = Day(date: date, goalAmount: goalAmount, consumedAmount: consumedAmount)
        let day4 = Day(date: date, goalAmount: goalAmount, consumedAmount: consumedAmount)

        let days = [day1, day2, day3, day4]
        Day.saveDay(days)

        Day.loadDay()
    }

Answer 2

1) 您需要为此创建对象数组：

goalAmount = [Drink]()
var date = [Date]()

并附加每个新元素。 您还可以在您的饮料类中添加日期变量。

2) 你也可以创建字典数组：

var userData = [String : Any]()

关键是你的日期和任何包含与饮料数据相关的任何你可以存储的任何东西。