#27 利用 Codable 儲存過年紅包

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#27 利用 Codable 儲存過年紅包

目的: 學習將自訂型別的資料存檔，存在 Documents 下，運用 Codable, PropertyListEncoder，PropertyListDecoder。

製作過年紅包 App，記錄別人給的紅包，和發給別人的紅包，方便未來研究分析，決定明年要包給對方多大的紅包。

參考資料

App Development with Swift 的 4.1 Protocols，4.7 Saving Data

App Development with Swift by Apple Education on iBooks
Read a free sample or buy App Development with Swift by Apple Education. You can read this book with iBooks on your…itunes.apple.com

4.7 的 Lab 範例，Emoji App

import Foundation

struct Emoji: Codable {

   var symbol: String

   var name: String

   var detailDescription: String

   var usage: String

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

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

   static func loadFromFile() -> [Emoji]?  {

      guard let codedEmojis = try? Data(contentsOf: ArchiveURL) else {return nil}

      let decoder = PropertyListDecoder()

      return try? decoder.decode(Array<Emoji>.self, from: codedEmojis)

   }

   static func saveToFile(emojis: [Emoji]) {

      let encoder = PropertyListEncoder()

      let codedEmojis = try? encoder.encode(emojis)

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

   }

}