Panduan Mengelola Tipe Data di Database Swift

15min
Mengurai tipe data di Swift
Pendahuluan
Saat menyimpan data di Database Back4App, setiap entitas disimpan dalam format pasangan kunci-nilai. Tipe data untuk bidang nilai berkisar dari yang fundamental (seperti String, Int, Double, Float, dan Bool) hingga struktur yang lebih kompleks. Persyaratan utama untuk menyimpan data di Database Back4App adalah bahwa entitas harus mematuhi ParseSwift protokol. Pada gilirannya, protokol ini menyediakan serangkaian metode untuk menyimpan, memperbarui, dan menghapus setiap instance dari entitas.
Dalam panduan ini, Anda akan belajar bagaimana cara membuat dan mengatur entitas untuk menyimpannya di Database Back4App Anda. Dalam contoh proyek, entitas yang kami simpan mencakup informasi tentang sebuah Resep.
Tutorial ini menggunakan aplikasi dasar yang dibuat di Xcode 12 dan iOS 14.
Kapan saja, Anda dapat mengakses Proyek lengkap melalui repositori GitHub kami.
﻿Repositori Contoh iOS﻿
Tujuan
Untuk memahami bagaimana objek diparsing dan disimpan di Database Back4App.
Prasyarat
Untuk menyelesaikan quickstart ini, Anda memerlukan:
Xcode.
Sebuah aplikasi yang dibuat di Back4App.
Ikuti tutorial Aplikasi Parse Baru untuk belajar cara membuat aplikasi Parse di Back4App.
Catatan: Ikuti Tutorial Instalasi Parse SDK (Swift) untuk membuat Proyek Xcode yang terhubung ke Back4App.
Memahami Aplikasi Resep Kami
Fungsi aplikasi ini berdasarkan pada sebuah formulir di mana seseorang dapat memasukkan informasi tentang sebuah resep. Tergantung pada informasi tersebut, jenis data dapat bervariasi. Dalam contoh kami, resep ini memiliki fitur-fitur berikut:
Lapangan
Tipe Data
Deskripsi
Nama
String
Nama resep
Porsi
Int
Jumlah porsi
Tersedia
Bool
Menentukan apakah resep tersedia atau tidak
Kategori
Kategori
Sebuah enumerasi kustom yang mengklasifikasikan resep dalam tiga kategori: Sarapan, Makan Siang, dan Makan Malam
Bahan-bahan
[Bahan-bahan]
Sekumpulan bahan yang terkurung dalam struktur customIngredient** **
Opsi samping
[String]
Nama opsi tambahan yang disertakan dalam resep
Informasi nutrisi
[String:String]
Sebuah kamus yang berisi informasi tentang kandungan nutrisi resep tersebut
Tanggal rilis
Tanggal
Tanggal yang menunjukkan kapan resep tersebut tersedia
Selain itu, ada lebih banyak tipe data yang digunakan untuk mengimplementasikan fungsionalitas Database seperti hubungan antara objek. Tipe data ini tidak dibahas dalam tutorial ini.
Referensi cepat perintah yang akan kita gunakan
Diberikan sebuah objek, katakanlah Resep, jika Anda ingin menyimpannya di Database Back4App, Anda harus terlebih dahulu membuat objek ini sesuai dengan protokol ParseSwift (tersedia melalui SDK ParseSwift).
Swift
 import Foundation
 import ParseSwift
3
 struct Recipe: ParseObject {
     /// Enumeration for the recipe category
     enum Category: Int, CaseIterable, Codable {
         case breakfast = 0, lunch = 1, dinner = 2
      
         var title: String {
            switch self {
            case .breakfast: return "Breakfast"
            case .lunch: return "Lunch"
            case .dinner: return "Dinner"
            }
        }
    }
17
    ...
19
    /// A *String* type property
    var name: String?
  
    /// An *Integer* type property
    var servings: Int?
  
    /// A *Double* (or *Float*) type property
    var price: Double?
  
    /// A *Boolean* type property
    var isAvailable: Bool?
  
    /// An *Enumeration* type property
    var category: Category?
  
    /// An array of *structs*
    var ingredients: [Ingredient]
  
    /// An array of *Strings*
    var sideOptions: [String]
  
    /// A dictionary property
    var nutritionalInfo: [String: String]
  
    /// A *Date* type property
    var releaseDate: Date?
}
 import Foundation
 import ParseSwift
3
 struct Recipe: ParseObject {
     /// Enumeration for the recipe category
     enum Category: Int, CaseIterable, Codable {
         case breakfast = 0, lunch = 1, dinner = 2
      
         var title: String {
            switch self {
            case .breakfast: return "Breakfast"
            case .lunch: return "Lunch"
            case .dinner: return "Dinner"
            }
        }
    }
17
    ...
19
    /// A *String* type property
    var name: String?
  
    /// An *Integer* type property
    var servings: Int?
  
    /// A *Double* (or *Float*) type property
    var price: Double?
  
    /// A *Boolean* type property
    var isAvailable: Bool?
  
    /// An *Enumeration* type property
    var category: Category?
  
    /// An array of *structs*
    var ingredients: [Ingredient]
  
    /// An array of *Strings*
    var sideOptions: [String]
  
    /// A dictionary property
    var nutritionalInfo: [String: String]
  
    /// A *Date* type property
    var releaseDate: Date?
}
﻿
Sebelum menyimpan instance dari objek ini di Database Back4App, semua propertinya harus sesuai dengan protokol Codable dan Hashable.
Kami menggunakan metode berikut untuk mengelola objek-objek ini di Database Back4App:
Create
Update
Read
Delete
//The procedure for reading and updating a Recipe object is similar since they rely on the save() method. How a Recipe is instantiated determines if we are creating or updating the object on the Back4App Database. When creating a new instance we use
 var newRecipe: Recipe
2
 // Setup newRecipe's properties
 newRecipe.name = "My recipe's name"
 newRecipe.servings = 4
 newRecipe.price = 3.99
 newRecipe.isAvailable = false
 newRecipe.category = .breakfast
 newRecipe.sideOptions = ["Juice"]
newRecipe.releaseDate = Date()
...
12
// Saves newRecipe on your Back4App Database synchronously and returns the new saved Item. It throws and error if something went wrong.
let savedRecipe = try? savedRecipe.save()
15
// Saves savedRecipe on your Back4App Database asynchronously, and passes a Result<ToDoListItem, ParseError> object to the completion block to handle the save proccess.
savedRecipe.save { result in
    // Handle the result to check the save was successfull or not
}
//The procedure for reading and updating a Recipe object is similar since they rely on the save() method. How a Recipe is instantiated determines if we are creating or updating the object on the Back4App Database. When creating a new instance we use
 var newRecipe: Recipe
2
 // Setup newRecipe's properties
 newRecipe.name = "My recipe's name"
 newRecipe.servings = 4
 newRecipe.price = 3.99
 newRecipe.isAvailable = false
 newRecipe.category = .breakfast
 newRecipe.sideOptions = ["Juice"]
newRecipe.releaseDate = Date()
...
12
// Saves newRecipe on your Back4App Database synchronously and returns the new saved Item. It throws and error if something went wrong.
let savedRecipe = try? savedRecipe.save()
15
// Saves savedRecipe on your Back4App Database asynchronously, and passes a Result<ToDoListItem, ParseError> object to the completion block to handle the save proccess.
savedRecipe.save { result in
    // Handle the result to check the save was successfull or not
}
﻿
- Buat Template Aplikasi Resep
Kita mulai dengan membuat proyek XCode baru. Dalam tutorial ini proyek harus terlihat seperti ini
﻿
Kapan saja, Anda dapat mengakses Proyek lengkap melalui repositori GitHub kami.
﻿Repositori Contoh iOS﻿
Buka Xcode, dan temukan file SceneDelegate.swift. Untuk menambahkan bilah navigasi di atas aplikasi, kami mengatur UINavigationController sebagai pengontrol tampilan root dengan cara berikut
Swift
 class SceneDelegate: UIResponder, UIWindowSceneDelegate {
2
     var window: UIWindow?
4
     func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
         guard let scene = (scene as? UIWindowScene) else { return }
      
         window = .init(windowScene: scene)
         window?.rootViewController = UINavigationController(rootViewController: RecipesController())
        window?.makeKeyAndVisible()
11
        // Additional logic
    }
14
    ...
}
 class SceneDelegate: UIResponder, UIWindowSceneDelegate {
2
     var window: UIWindow?
4
     func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
         guard let scene = (scene as? UIWindowScene) else { return }
      
         window = .init(windowScene: scene)
         window?.rootViewController = UINavigationController(rootViewController: RecipesController())
        window?.makeKeyAndVisible()
11
        // Additional logic
    }
14
    ...
}
﻿
Kelas pengontrol tampilan akar (RecipesController) untuk pengontrol navigasi adalah subclass dari UIViewController di mana kita akan menyusun formulir untuk membuat dan memperbarui objek Resep di Database Back4App.
- Siapkan objek Resep
Objek yang ingin Anda simpan di Database Back4App Anda harus mematuhi protokol ParseObject. Di aplikasi Resep kami, objek ini adalah Resep. Oleh karena itu, Anda perlu membuat objek ini terlebih dahulu. Buat file baru Recipe.swift dan tambahkan yang berikut ini
Swift
 import Foundation
 import ParseSwift
3
 struct Recipe: ParseObject {
     /// Enumeration for the recipe category
     enum Category: Int, CaseIterable, Codable {
         case breakfast = 0, lunch = 1, dinner = 2
      
         var title: String {
            switch self {
            case .breakfast: return "Breakfast"
            case .lunch: return "Lunch"
            case .dinner: return "Dinner"
            }
        }
    }
  
    // Required properties from ParseObject protocol
    var objectId: String?
    var createdAt: Date?
    var updatedAt: Date?
    var ACL: ParseACL?
  
    /// A *String* type property
    var name: String?
  
    /// An *Integer* type property
    var servings: Int?
  
    /// A *Double* (or *Float*) type property
    var price: Double?
  
    /// A *Boolean* type property
    var isAvailable: Bool?
  
    /// An *Enumeration* type property
    var category: Category?
  
    /// An array of *structs*
    var ingredients: [Ingredient]
  
    /// An array of *Strings*
    var sideOptions: [String]
44
    /// A dictionary property
    var nutritionalInfo: [String: String]
      
    /// A *Date* type property
    var releaseDate: Date?
  
    /// Maps the nutritionalInfo property into an array of tuples
    func nutritionalInfoArray() -> [(name: String, value: String)] {
        return nutritionalInfo.map { ($0.key, $0.value) }
    }
}
 import Foundation
 import ParseSwift
3
 struct Recipe: ParseObject {
     /// Enumeration for the recipe category
     enum Category: Int, CaseIterable, Codable {
         case breakfast = 0, lunch = 1, dinner = 2
      
         var title: String {
            switch self {
            case .breakfast: return "Breakfast"
            case .lunch: return "Lunch"
            case .dinner: return "Dinner"
            }
        }
    }
  
    // Required properties from ParseObject protocol
    var objectId: String?
    var createdAt: Date?
    var updatedAt: Date?
    var ACL: ParseACL?
  
    /// A *String* type property
    var name: String?
  
    /// An *Integer* type property
    var servings: Int?
  
    /// A *Double* (or *Float*) type property
    var price: Double?
  
    /// A *Boolean* type property
    var isAvailable: Bool?
  
    /// An *Enumeration* type property
    var category: Category?
  
    /// An array of *structs*
    var ingredients: [Ingredient]
  
    /// An array of *Strings*
    var sideOptions: [String]
44
    /// A dictionary property
    var nutritionalInfo: [String: String]
      
    /// A *Date* type property
    var releaseDate: Date?
  
    /// Maps the nutritionalInfo property into an array of tuples
    func nutritionalInfoArray() -> [(name: String, value: String)] {
        return nutritionalInfo.map { ($0.key, $0.value) }
    }
}
﻿
di mana kami sudah menambahkan semua properti yang diperlukan ke Resep sesuai dengan tabel fitur resep.
Tipe data Ingredient adalah sebuah struct yang menyimpan jumlah dan deskripsi dari bahan. Seperti yang disebutkan sebelumnya, tipe data ini harus mematuhi protokol Codable dan Hashable agar menjadi bagian dari properti Recipe.
Swift
 import Foundation
2
 struct Ingredient: Hashable, Codable {
     var quantity: Float
     var description: String
 }
 import Foundation
2
 struct Ingredient: Hashable, Codable {
     var quantity: Float
     var description: String
 }
﻿
Selain itu, properti kategori dalam Recipe memiliki enumerasi (Category) sebagai tipe data yang juga mematuhi protokol yang sesuai.
Swift
 struct Recipe: ParseObject {
     /// Enumeration for the recipe category
     enum Category: Int, CaseIterable, Codable {
         case breakfast = 0, lunch = 1, dinner = 2
      
         ...
     }
     ...   
 }
 struct Recipe: ParseObject {
     /// Enumeration for the recipe category
     enum Category: Int, CaseIterable, Codable {
         case breakfast = 0, lunch = 1, dinner = 2
      
         ...
     }
     ...   
 }
﻿
- Menyiapkan RecipesController
Dalam RecipesController kita harus mengimplementasikan semua konfigurasi yang diperlukan untuk navigationBar dan formulir yang digunakan untuk menangkap semua properti Recipe. Tutorial ini tidak membahas cara mengimplementasikan tata letak untuk formulir. Kita kemudian fokus pada logika yang terkait dengan pengelolaan tipe data menggunakan ParseSwift SDK. Di bawah ini kami menyoroti poin-poin kunci dalam RecipesController yang memungkinkan kita memahami bagaimana kita mengimplementasikan koneksi antara antarmuka pengguna dan data yang berasal dari Database Back4App Anda.
Swift
 class RecipesController: UIViewController {
     enum PreviousNext: Int { case previous = 0, next = 1 }
  
     ...
  
     var recipes: [Recipe] = [] // 1: An array of recipes fetched from your Back4App Database
  
     // Section header labels
     private let recipeLabel: UILabel = .titleLabel(title: "Recipe overview")
    private let ingredientsLabel: UILabel = .titleLabel(title: "Ingredients")
    private let nutritionalInfoLabel: UILabel = .titleLabel(title: "Nutritional information")
  
    // 2: A custom view containing input fields to enter the recipe's information (except nutritional info. and ingredients)
    let recipeOverviewView: RecipeInfoView
  
    // 3: A  stack view containig the fields to enter the recipe's ingredients
    let ingredientsStackView: UIStackView
   
    // 4: A  stack view containig the fields to enter the nutritional information
    let nutritionalInfoStackView: UIStackView
  
    // 5: Buttons to handle the CRUD logic for the Recipe object currently displayed
    private var saveButton: UIButton = UIButton(title: "Save")
    private var updateButton: UIButton = UIButton(title: "Update")
    private var reloadButton: UIButton = UIButton(title: "Reload")
  
    var currentRecipeIndex: Int? // 6: An integer containing the index of the current recipe presenten from the recipes property
  
    override func viewDidLoad() {
        super.viewDidLoad()
        setupNavigationBar()
        setupViews()
    }
  
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        handleReloadRecipes()
    }
  
    private func setupNavigationBar() {
        navigationController?.navigationBar.barTintColor = .primary
        navigationController?.navigationBar.titleTextAttributes = [.foregroundColor: UIColor.white]
        navigationController?.navigationBar.isTranslucent = false
        navigationController?.navigationBar.barStyle = .black
        navigationItem.title = "Parse data types".uppercased()
    }
  
    private func setupViews() {
        ... // See the project example for more details
50
        saveButton.addTarget(self, action: #selector(handleSaveRecipe), for: .touchUpInside)
        updateButton.addTarget(self, action: #selector(handleUpdateRecipe), for: .touchUpInside)
        reloadButton.addTarget(self, action: #selector(handleReloadRecipes), for: .touchUpInside)
    }
  
    ...
}
 class RecipesController: UIViewController {
     enum PreviousNext: Int { case previous = 0, next = 1 }
  
     ...
  
     var recipes: [Recipe] = [] // 1: An array of recipes fetched from your Back4App Database
  
     // Section header labels
     private let recipeLabel: UILabel = .titleLabel(title: "Recipe overview")
    private let ingredientsLabel: UILabel = .titleLabel(title: "Ingredients")
    private let nutritionalInfoLabel: UILabel = .titleLabel(title: "Nutritional information")
  
    // 2: A custom view containing input fields to enter the recipe's information (except nutritional info. and ingredients)
    let recipeOverviewView: RecipeInfoView
  
    // 3: A  stack view containig the fields to enter the recipe's ingredients
    let ingredientsStackView: UIStackView
   
    // 4: A  stack view containig the fields to enter the nutritional information
    let nutritionalInfoStackView: UIStackView
  
    // 5: Buttons to handle the CRUD logic for the Recipe object currently displayed
    private var saveButton: UIButton = UIButton(title: "Save")
    private var updateButton: UIButton = UIButton(title: "Update")
    private var reloadButton: UIButton = UIButton(title: "Reload")
  
    var currentRecipeIndex: Int? // 6: An integer containing the index of the current recipe presenten from the recipes property
  
    override func viewDidLoad() {
        super.viewDidLoad()
        setupNavigationBar()
        setupViews()
    }
  
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        handleReloadRecipes()
    }
  
    private func setupNavigationBar() {
        navigationController?.navigationBar.barTintColor = .primary
        navigationController?.navigationBar.titleTextAttributes = [.foregroundColor: UIColor.white]
        navigationController?.navigationBar.isTranslucent = false
        navigationController?.navigationBar.barStyle = .black
        navigationItem.title = "Parse data types".uppercased()
    }
  
    private func setupViews() {
        ... // See the project example for more details
50
        saveButton.addTarget(self, action: #selector(handleSaveRecipe), for: .touchUpInside)
        updateButton.addTarget(self, action: #selector(handleUpdateRecipe), for: .touchUpInside)
        reloadButton.addTarget(self, action: #selector(handleReloadRecipes), for: .touchUpInside)
    }
  
    ...
}
﻿
- Menangani input pengguna dan mengurai objek Resep
Dalam file terpisah (disebut RecipesController+ParseSwiftLogic.swift), menggunakan ekstensi kami sekarang mengimplementasikan metode handleSaveRecipe(), handleUpdateRecipe() dan handleUpdateRecipe() untuk menangani data input
Swift
 import UIKit
 import ParseSwift
3
 extension RecipesController {
     /// Retrieves all the recipes stored on your Back4App Database
     @objc func handleReloadRecipes() {
         view.endEditing(true)
         let query = Recipe.query()
         query.find { [weak self] result in // Retrieves all the recipes stored on your Back4App Database and refreshes the UI acordingly
            guard let self = self else { return }
            switch result {
            case .success(let recipes):
                self.recipes = recipes
                self.currentRecipeIndex = recipes.isEmpty ? nil : 0
                self.setupRecipeNavigation()
              
                DispatchQueue.main.async { self.presentCurrentRecipe() }
            case .failure(let error):
                DispatchQueue.main.async { self.showAlert(title: "Error", message: error.message) }
            }
        }
    }
  
    /// Called when the user wants to update the information of the currently displayed recipe
    @objc func handleUpdateRecipe() {
        view.endEditing(true)
        guard let recipe = prepareRecipeMetadata(), recipe.objectId != nil else { // Prepares the Recipe object for updating
            return showAlert(title: "Error", message: "Recipe not found.")
        }
      
        recipe.save { [weak self] result in
            switch result {
            case .success(let newRecipe):
                self?.recipes.append(newRecipe)
                self?.showAlert(title: "Success", message: "Recipe saved on your Back4App Database! (objectId: \(newRecipe.id)")
            case .failure(let error):
                self?.showAlert(title: "Error", message: "Failedto save recipe: \(error.message)")
            }
        }
    }
  
    /// Saves the currently displayed recipe on your Back4App Database
    @objc func handleSaveRecipe() {
        view.endEditing(true)
        guard var recipe = prepareRecipeMetadata() else { // Prepares the Recipe object for storing
            return showAlert(title: "Error", message: "Failed to retrieve all the recipe fields.")
        }
      
        recipe.objectId = nil // When saving a Recipe object, we ensure it will be a new instance of it.
        recipe.save { [weak self] result in
            switch result {
            case .success(let newRecipe):
                if let index = self?.currentRecipeIndex { self?.recipes[index] = newRecipe }
                self?.showAlert(title: "Success", message: "Recipe saved on your Back4App Database! (objectId: \(newRecipe.id))")
            case .failure(let error):
                self?.showAlert(title: "Error", message: "Failed to save recipe: \(error.message)")
            }
        }
    }
  
    /// When called it refreshes the UI according to the content of *recipes* and *currentRecipeIndex* properties
    private func presentCurrentRecipe() {
        ...
    }
  
    /// Adds the 'Next recipe' and 'Previous recipe' button on the navigation bar. These are used to iterate over all the recipes retreived from your Back4App Database
    private func setupRecipeNavigation() {
        ...
    }
  
    /// Reads the information the user entered via the form and returns it as a *Recipe* object
    private func prepareRecipeMetadata() -> Recipe? {
        let ingredientsCount = ingredientsStackView.arrangedSubviews.count
        let nutritionalInfoCount = nutritionalInfoStackView.arrangedSubviews.count
      
        let ingredients: [Ingredient] = (0..<ingredientsCount).compactMap { row in
            guard let textFields = ingredientsStackView.arrangedSubviews[row] as? DoubleTextField,
                  let quantityString = textFields.primaryText,
                  let quantity = Float(quantityString),
                  let description = textFields.secondaryText
            else {
                return nil
            }
            return Ingredient(quantity: quantity, description: description)
        }
      
        var nutritionalInfo: [String: String] = [:]
        
        (0..<nutritionalInfoCount).forEach { row in
            guard let textFields = nutritionalInfoStackView.arrangedSubviews[row] as? DoubleTextField,
                  let content = textFields.primaryText, !content.isEmpty,
                  let value = textFields.secondaryText, !value.isEmpty
            else {
                return
            }
            nutritionalInfo[content] = value
        }
       
        let recipeInfo = recipeOverviewView.parseInputToRecipe() // Reads all the remaining fields from the form (name, category, price, serving, etc) and returns them as a tuple

       // we collect all the information the user entered and create an instance of Recipe.
       // The recipeInfo.objectId will be nil if the currently displayed information does not correspond to a recipe already saved on your Back4App Database
       let newRecipe: Recipe = Recipe(
           objectId: recipeInfo.objectId,
           name: recipeInfo.name,
           servings: recipeInfo.servings,
           price: recipeInfo.price,
           isAvailable: recipeInfo.isAvailable,
           category: recipeInfo.category,
           ingredients: ingredients,
           sideOptions: recipeInfo.sideOptions,
           nutritionalInfo: nutritionalInfo,
           releaseDate: recipeInfo.releaseDate
       )
      
       return newRecipe
   }
  
   /// Called when the user presses the 'Previous recipe' or 'Next recipe' button
   @objc private func handleSwitchRecipe(button: UIBarButtonItem) {
       ...
   }
}
 import UIKit
 import ParseSwift
3
 extension RecipesController {
     /// Retrieves all the recipes stored on your Back4App Database
     @objc func handleReloadRecipes() {
         view.endEditing(true)
         let query = Recipe.query()
         query.find { [weak self] result in // Retrieves all the recipes stored on your Back4App Database and refreshes the UI acordingly
            guard let self = self else { return }
            switch result {
            case .success(let recipes):
                self.recipes = recipes
                self.currentRecipeIndex = recipes.isEmpty ? nil : 0
                self.setupRecipeNavigation()
              
                DispatchQueue.main.async { self.presentCurrentRecipe() }
            case .failure(let error):
                DispatchQueue.main.async { self.showAlert(title: "Error", message: error.message) }
            }
        }
    }
  
    /// Called when the user wants to update the information of the currently displayed recipe
    @objc func handleUpdateRecipe() {
        view.endEditing(true)
        guard let recipe = prepareRecipeMetadata(), recipe.objectId != nil else { // Prepares the Recipe object for updating
            return showAlert(title: "Error", message: "Recipe not found.")
        }
      
        recipe.save { [weak self] result in
            switch result {
            case .success(let newRecipe):
                self?.recipes.append(newRecipe)
                self?.showAlert(title: "Success", message: "Recipe saved on your Back4App Database! (objectId: \(newRecipe.id)")
            case .failure(let error):
                self?.showAlert(title: "Error", message: "Failedto save recipe: \(error.message)")
            }
        }
    }
  
    /// Saves the currently displayed recipe on your Back4App Database
    @objc func handleSaveRecipe() {
        view.endEditing(true)
        guard var recipe = prepareRecipeMetadata() else { // Prepares the Recipe object for storing
            return showAlert(title: "Error", message: "Failed to retrieve all the recipe fields.")
        }
      
        recipe.objectId = nil // When saving a Recipe object, we ensure it will be a new instance of it.
        recipe.save { [weak self] result in
            switch result {
            case .success(let newRecipe):
                if let index = self?.currentRecipeIndex { self?.recipes[index] = newRecipe }
                self?.showAlert(title: "Success", message: "Recipe saved on your Back4App Database! (objectId: \(newRecipe.id))")
            case .failure(let error):
                self?.showAlert(title: "Error", message: "Failed to save recipe: \(error.message)")
            }
        }
    }
  
    /// When called it refreshes the UI according to the content of *recipes* and *currentRecipeIndex* properties
    private func presentCurrentRecipe() {
        ...
    }
  
    /// Adds the 'Next recipe' and 'Previous recipe' button on the navigation bar. These are used to iterate over all the recipes retreived from your Back4App Database
    private func setupRecipeNavigation() {
        ...
    }
  
    /// Reads the information the user entered via the form and returns it as a *Recipe* object
    private func prepareRecipeMetadata() -> Recipe? {
        let ingredientsCount = ingredientsStackView.arrangedSubviews.count
        let nutritionalInfoCount = nutritionalInfoStackView.arrangedSubviews.count
      
        let ingredients: [Ingredient] = (0..<ingredientsCount).compactMap { row in
            guard let textFields = ingredientsStackView.arrangedSubviews[row] as? DoubleTextField,
                  let quantityString = textFields.primaryText,
                  let quantity = Float(quantityString),
                  let description = textFields.secondaryText
            else {
                return nil
            }
            return Ingredient(quantity: quantity, description: description)
        }
      
        var nutritionalInfo: [String: String] = [:]
        
        (0..<nutritionalInfoCount).forEach { row in
            guard let textFields = nutritionalInfoStackView.arrangedSubviews[row] as? DoubleTextField,
                  let content = textFields.primaryText, !content.isEmpty,
                  let value = textFields.secondaryText, !value.isEmpty
            else {
                return
            }
            nutritionalInfo[content] = value
        }
       
        let recipeInfo = recipeOverviewView.parseInputToRecipe() // Reads all the remaining fields from the form (name, category, price, serving, etc) and returns them as a tuple

       // we collect all the information the user entered and create an instance of Recipe.
       // The recipeInfo.objectId will be nil if the currently displayed information does not correspond to a recipe already saved on your Back4App Database
       let newRecipe: Recipe = Recipe(
           objectId: recipeInfo.objectId,
           name: recipeInfo.name,
           servings: recipeInfo.servings,
           price: recipeInfo.price,
           isAvailable: recipeInfo.isAvailable,
           category: recipeInfo.category,
           ingredients: ingredients,
           sideOptions: recipeInfo.sideOptions,
           nutritionalInfo: nutritionalInfo,
           releaseDate: recipeInfo.releaseDate
       )
      
       return newRecipe
   }
  
   /// Called when the user presses the 'Previous recipe' or 'Next recipe' button
   @objc private func handleSwitchRecipe(button: UIBarButtonItem) {
       ...
   }
}
﻿
- Jalankan aplikasi!
Sebelum menekan tombol jalankan di XCode, jangan lupa untuk mengonfigurasi aplikasi Back4App Anda di kelas AppDelegate!
Pertama kali Anda menjalankan proyek, Anda harus melihat sesuatu seperti ini di simulator (dengan semua kolom kosong)
﻿
Sekarang Anda dapat mulai memasukkan resep untuk kemudian menyimpannya di Database Back4App Anda. Setelah Anda menyimpan satu resep, pergi ke dasbor Back4App dan pergi ke aplikasi Anda, di bagian Database Anda akan menemukan kelas Resep di mana semua resep yang dibuat oleh Aplikasi iOS.
Secara khusus, perlu dicatat bagaimana tipe data non-fundamental seperti Bahan, Resep.Kategori atau kamus disimpan. Jika Anda menavigasi melalui data yang disimpan di bawah kelas Resep, Anda akan menemukan bahwa
Kamus nutritionalInformation disimpan sebagai objek JSON.
Array [Bahan] disimpan sebagai array objek JSON.
Enumerasi Resep.Kategori, karena memiliki tipe data integer sebagai RawValue, diubah menjadi tipe nilai Number.
Properti releaseDate, nilai tipe Date di Swift, juga disimpan sebagai nilai tipe Date.
Sebagai kesimpulan, saat mengambil data dari Database Back4App Anda, Anda tidak perlu mendekode semua kolom ini secara manual, ParseSwift SDK akan mendekode mereka secara otomatis. Itu berarti, saat membuat kueri (Query<Recipe> dalam hal ini) untuk mengambil data, metode query.find() akan mengurai semua tipe data dan objek JSON untuk mengembalikan array Resep, tidak ada prosedur penguraian tambahan yang perlu diterapkan.
Lapangan	Tipe Data	Deskripsi
Nama	String	Nama resep
Porsi	Int	Jumlah porsi
Tersedia	Bool	Menentukan apakah resep tersedia atau tidak
Kategori	Kategori	Sebuah enumerasi kustom yang mengklasifikasikan resep dalam tiga kategori: Sarapan, Makan Siang, dan Makan Malam
Bahan-bahan	[Bahan-bahan]	Sekumpulan bahan yang terkurung dalam struktur customIngredient
Opsi samping	[String]	Nama opsi tambahan yang disertakan dalam resep
Informasi nutrisi	[String:String]	Sebuah kamus yang berisi informasi tentang kandungan nutrisi resep tersebut
Tanggal rilis	Tanggal	Tanggal yang menunjukkan kapan resep tersebut tersedia