如何显示两组不同数据之间的平衡？

Question

我想在不同的 tableviewcontroller 上创建一个新的 table view 单元格，它将显示收入和支出数据之间的平衡。如何获取收入数据和费用数据的总和，从收入中减去费用，然后将该余额连接到新单元格中的 UILabel？

这是我的项目的布局方式：

1. IncomeTableViewController - 列出收入的场景。
2. AddEditIncomeTableViewController - 允许用户创建新收入的场景。
3. IncomeTableViewCell - 有自定义单元格。一个 UILabel 为收入名称，另一个 UILabel 为收入金额。
4. ExpenseTableViewController - 列出费用的场景。
5. AddEditExpenseTableViewController - 允许用户创建新费用的场景。
6. ExpenseTableViewCell - 有自定义单元格。一个 UILabel 用于费用名称，另一个 UILabel 用于费用金额。

import Foundation

struct Expense: Codable {
    var name: String
    var amount: String

    init(name: String, amount: String) {
        self.name = name
        self.amount = amount

    }

    static let DocumentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!

       static let ArchiveURL = DocumentsDirectory.appendingPathComponent("expenses").appendingPathExtension("plist")

       static func loadSampleExpenses() -> [Expense] {
           return [
                Expense(name: "Rent/Mortgage", amount: "0"),
                Expense(name: "Electric", amount: "0"),
                Expense(name: "Gas", amount: "0"),
                Expense(name: "Cell Phone", amount: "0"),
                Expense(name: "Groceries", amount: "0"),
                Expense(name: "Car Payment", amount: "0"),
                Expense(name: "Auto Expenses", amount: "0"),
                Expense(name: "Auto Insurance", amount: "0"),
                Expense(name: "Personal Care", amount: "0"),
                Expense(name: "Entertainment", amount: "0"),
                Expense(name: "Miscellaneous", amount: "0")]
       }

       static func saveToFile(expenses: [Expense]) {
              let propertyListEncoder = PropertyListEncoder()
              let codedExpenses = try? propertyListEncoder.encode(expenses)

              try? codedExpenses?.write(to: ArchiveURL, options: .noFileProtection)

       }

       static func loadFromFile() -> [Expense]? {
               guard let codedExpenses = try? Data(contentsOf: ArchiveURL) else { return nil }

               let propertyListDecoder = PropertyListDecoder()

               return try? propertyListDecoder.decode(Array<Expense>.self, from: codedExpenses)
       }

   }

import Foundation

struct Income: Codable {
    var name: String
    var amount: String

    init(name: String, amount: String) {
        self.name = name
        self.amount = amount
    }



    static let DocumentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!

    static let ArchiveURL = DocumentsDirectory.appendingPathComponent("incomes").appendingPathExtension("plist")

    static func loadSampleIncomes() -> [Income] {
        return [
            Income(name: "Main Income", amount: "0"),
            Income(name: "Secondary Income", amount: "0"),
            Income(name: "Interest Income", amount: "0")]

    }

    static func saveToFile(incomes: [Income]) {
           let propertyListEncoder = PropertyListEncoder()
           let codedIncomes = try? propertyListEncoder.encode(incomes)

           try? codedIncomes?.write(to: ArchiveURL, options: .noFileProtection)

    }

    static func loadFromFile() -> [Income]? {
            guard let codedIncomes = try? Data(contentsOf: ArchiveURL) else { return nil }

            let propertyListDecoder = PropertyListDecoder()

            return try? propertyListDecoder.decode(Array<Income>.self, from: codedIncomes)
    }

}

我也有这两个文件来定义费用和收入。不确定需要显示什么代码。

Answer 1

如果我理解正确，您希望有一个共享模型来保存数据，这样您就可以从不同的 UIViewControllers 中读取和写入模型中的数据。

最简单的方法是使用单例。