Property wrappers like @Published aren't by default Codeable. We need to do some extra work.
class User: ObservableObject, Codable {
@Published var name = "Paul Hudson"
enum CodingKeys: CodingKey {
case name
}
required init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
name = try container.decode(String.self, forKey: .name)
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(name, forKey: .name)
}
}struct Response: Codable {
var results: [Result]
}
struct Result: Codable {
var trackId: Int
var trackName: String
var collectionName: String
}
struct ContentView: View {
@State private var results = [Result]()
var body: some View {
List(results, id: \.trackId) { item in
VStack(alignment: .leading) {
Text(item.trackName)
.font(.headline)
Text(item.collectionName)
}
}.onAppear(perform: loadData)
}
func loadData() {
guard let url = URL(string: "https://itunes.apple.com/search?term=Tron&entity=song") else {
print("Invalid URL")
return
}
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) { data, response, error in
if let data = data {
if let decodedResponse = try? JSONDecoder().decode(Response.self, from: data) {
// we have good data – go back to the main thread
DispatchQueue.main.async {
// update our UI
self.results = decodedResponse.results
}
// everything is good, so we can exit
return
}
}
}.resume()
}
}
Order.swift
final class Order: ObservableObject, Codable {
static let types = ["Vanilla", "Strawberry", "Chocolate", "Rainbow"]
@Published var type = 0
@Published var quantity = 3
@Published var specialRequestEnabled = false {
didSet {
if specialRequestEnabled == false {
extraFrosting = false
addSprinkles = false
}
}
}
@Published var extraFrosting = false
@Published var addSprinkles = false
@Published var name = ""
@Published var streetAddress = ""
@Published var city = ""
@Published var zip = ""
var hasValidAddress: Bool {
if name.isEmpty || streetAddress.isEmpty || city.isEmpty || zip.isEmpty {
return false
}
return true
}
var cost: Double {
// $2 per cake
var cost = Double(quantity) * 2
// complicated cakes cost more
cost += (Double(type) / 2)
// $1/cake for extra frosting
if extraFrosting {
cost += Double(quantity)
}
// $0.50/cake for sprinkles
if addSprinkles {
cost += Double(quantity) / 2
}
return cost
}
enum CodingKeys: CodingKey {
case type, quantity, extraFrosting, addSprinkles, name, streetAddress, city, zip
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(type, forKey: .type)
try container.encode(quantity, forKey: .quantity)
try container.encode(extraFrosting, forKey: .extraFrosting)
try container.encode(addSprinkles, forKey: .addSprinkles)
try container.encode(name, forKey: .name)
try container.encode(streetAddress, forKey: .streetAddress)
try container.encode(city, forKey: .city)
try container.encode(zip, forKey: .zip)
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
type = try container.decode(Int.self, forKey: .type)
quantity = try container.decode(Int.self, forKey: .quantity)
extraFrosting = try container.decode(Bool.self, forKey: .extraFrosting)
addSprinkles = try container.decode(Bool.self, forKey: .addSprinkles)
name = try container.decode(String.self, forKey: .name)
streetAddress = try container.decode(String.self, forKey: .streetAddress)
city = try container.decode(String.self, forKey: .city)
zip = try container.decode(String.self, forKey: .zip)
}
init() { }
}ContentView.swift
struct ContentView: View {
@ObservedObject var order = Order() // initialized
var body: some View {
NavigationView {
Form {
Section {
Picker("Select your cake type", selection: $order.type) {
ForEach(0..<Order.types.count) {
Text(Order.types[$0])
}
}
Stepper(value: $order.quantity, in: 3...20) {
Text("Number of cakes: \(order.quantity)")
}
}
Section {
Toggle(isOn: $order.specialRequestEnabled.animation()) {
Text("Any special requests?")
}
if order.specialRequestEnabled {
Toggle(isOn: $order.extraFrosting) {
Text("Add extra frosting")
}
Toggle(isOn: $order.addSprinkles) {
Text("Add extra sprinkles")
}
}
}
Section {
NavigationLink(destination: AddressView(order: order)) {
Text("Delivery details")
}
}
}
.navigationBarTitle("Cupcake Corner")
}
}
}AddressView.shift
struct AddressView: View {
@ObservedObject var order: Order // passed
var body: some View {
Form {
Section {
TextField("Name", text: $order.name)
TextField("Street Address", text: $order.streetAddress)
TextField("City", text: $order.city)
TextField("Zip", text: $order.zip)
}
Section {
NavigationLink(destination: CheckoutView(order: order)) {
Text("Check out")
}
}.disabled(order.hasValidAddress == false)
}
.navigationBarTitle("Delivery details", displayMode: .inline)
}
}
struct AddressView_Previews: PreviewProvider {
static var previews: some View {
AddressView(order: Order())
}
}
Checkout.swift
//
// CheckoutView.swift
// CupCake
//
// Created by jrasmusson on 2021-05-07.
//
import SwiftUI
struct CheckoutView: View {
@ObservedObject var order: Order // passed
@State private var confirmationMessage = ""
@State private var showingConfirmation = false
var body: some View {
GeometryReader { geo in
ScrollView {
VStack {
Image("cupcakes")
.resizable()
.scaledToFit()
.frame(width: geo.size.width)
Text("Your total is $\(self.order.cost, specifier: "%.2f")")
.font(.title)
Button("Place Order") {
placeOrder()
}
.padding()
}
}
}
.navigationBarTitle("Check out", displayMode: .inline)
.alert(isPresented: $showingConfirmation) {
Alert(title: Text("Thank you!"), message: Text(confirmationMessage), dismissButton: .default(Text("OK")))
}
}
func placeOrder() {
guard let encoded = try? JSONEncoder().encode(order) else {
print("Failed to encode order")
return
}
let url = URL(string: "https://reqres.in/api/cupcakes")!
var request = URLRequest(url: url)
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpMethod = "POST"
request.httpBody = encoded
URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data else {
print("No data in response: \(error?.localizedDescription ?? "Unknown error").")
return
}
if let decodedOrder = try? JSONDecoder().decode(Order.self, from: data) {
self.confirmationMessage = "Your order for \(decodedOrder.quantity)x \(Order.types[decodedOrder.type].lowercased()) cupcakes is on its way!"
self.showingConfirmation = true
} else {
print("Invalid response from server")
}
}.resume()
}
}
struct CheckoutView_Previews: PreviewProvider {
static var previews: some View {
CheckoutView(order: Order())
}
}