Integrate your app to modern world in Niigata

2594ac7ce91fd7d9a3ce71ca7cc2d0c0?s=47 d_date
October 11, 2019

Integrate your app to modern world in Niigata

2019/10/11 Mobile Crew Niigata

2594ac7ce91fd7d9a3ce71ca7cc2d0c0?s=128

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October 11, 2019
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  1. 2.

    Daiki Matsudate • Tokyo • iOS Developer from iOS 4

    • Google Developers Expert for Firebase • Independent Developer • Sushi • Book: ʮiOSΞϓϦઃܭύλʔϯೖ໳ʯ
  2. 3.

    Daiki Matsudate • Tokyo • iOS Developer from iOS 4

    • Google Developers Expert for Firebase • Independent Developer • Sushi • Book: ʮiOSΞϓϦઃܭύλʔϯೖ໳ʯ
  3. 4.

    Daiki Matsudate • Tokyo • iOS Developer from iOS 4

    • Google Developers Expert for Firebase • Independent Developer • Sushi • Book: ʮiOSΞϓϦઃܭύλʔϯೖ໳ʯ
  4. 5.
  5. 11.
  6. 12.
  7. 13.
  8. 16.

    The Age of Declarative UI • iOS: SwiftUI • Android:

    Jetpack Compose • ReactNative / Flutter
  9. 17.

    SwiftUI • UI Framework with declarative Syntax • Live Preview

    in Xcode • Available for iOS, iPadOS, macOS, watchOS and tvOS • Using newest Swift features • Property wrapper • Function Builder • Opaque Result Type • Goodbye Storyboard / Xib
  10. 18.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif
  11. 19.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif
  12. 20.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif public protocol View { associatedtype Body : View var body: Self.Body { get } }
  13. 21.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif
  14. 22.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif
  15. 23.

    import SwiftUI struct SpeakerList: View { var body: View {

    NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif
  16. 24.

    import SwiftUI struct SpeakerList: View { var body: NavigationView<List<Speaker.ID, NavigationLink<SpeakerRow,

    SpeakerDetail>>> { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif
  17. 25.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif Opaque Result Type
  18. 26.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif
  19. 27.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif
  20. 28.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif No Comma!
  21. 29.

    import SwiftUI struct SpeakerList: View { var body: some View

    { NavigationView { List(speakersData, id: \.id) { speaker in NavigationLink(destination: SpeakerDetail(speaker: speaker)) { SpeakerRow(speaker: speaker) } } .navigationBarTitle(Text("Speakers"), displayMode: .automatic) } } } #if DEBUG struct SpeakerList_Previews : PreviewProvider { static var previews: some View { Group { SpeakerList() .environment(\.colorScheme, .light) SpeakerList() .environment(\.colorScheme, .dark) } } } #endif Function Builders
  22. 30.

    struct ContentView: View { @State var selectedIndex: Int = 0

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) TabView(selection: $selectedIndex) { SpeakerList().tabItem { Text("Speaker").tag(0) } ScheduleList().tabItem { Text("Schedule").tag(1) } SponsorList().tabItem { Text("Sponsor").tag(2) } Text("Other").tabItem { Text("Other").tag(3) } } } } }
  23. 31.

    struct ContentView: View { @State var selectedIndex: Int = 0

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) TabView(selection: $selectedIndex) { SpeakerList().tabItem { Text("Speaker").tag(0) } ScheduleList().tabItem { Text("Schedule").tag(1) } SponsorList().tabItem { Text("Sponsor").tag(2) } Text("Other").tabItem { Text("Other").tag(3) } } } } }
  24. 32.

    struct ContentView: View { @State var selectedIndex: Int = 0

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) TabView(selection: $selectedIndex) { SpeakerList().tabItem { Text("Speaker").tag(0) } ScheduleList().tabItem { Text("Schedule").tag(1) } SponsorList().tabItem { Text("Sponsor").tag(2) } Text("Other").tabItem { Text("Other").tag(3) } } } } } Property Wrapper wrappedValue: Value projectedValue: Wrapped<Value> Without $ With $
  25. 33.

    struct ContentView: View { @State var selectedIndex: Int = 0

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) TabView(selection: $selectedIndex) { SpeakerList().tabItem { Text("Speaker").tag(0) } ScheduleList().tabItem { Text("Schedule").tag(1) } SponsorList().tabItem { Text("Sponsor").tag(2) } Text("Other").tabItem { Text("Other").tag(3) } } } } } Property Wrapper Value Binding<Value> Without $ With $ cf. RxSwift.BehaviorRelay
  26. 34.

    SwiftUI • UI Framework with declarative Syntax • Live Preview

    in Xcode • Available for iOS, iPadOS, macOS, watchOS and tvOS • Using newest Swift features • Property wrapper • Function Builder • Opaque Result Type
  27. 41.

    Massive View Controller • Business logic in View Controller •

    Many UI Components in one View Controller
  28. 42.

    Small Components • Use StackView as possible • Use Xib

    as possible • Use UIViewController than UIView
  29. 43.

    Small Components • Use StackView as possible • Use Xib

    as possible • Use UIViewController than UIView super.init(nibName: nil, bundle: nil)
  30. 47.

    VStackViewController override open func viewDidLoad() { super.viewDidLoad() components.forEach { [weak

    self] in self?.addChild($0) } view.addSubview(scrollView, constraints: .allEdges()) scrollView.addSubview(stackView, constraints: .allEdges() + [equal(\.widthAnchor)]) components.forEach { [weak self] in guard let self = self else { return } self.stackView.addArrangedSubview($0.view) } components.forEach { [weak self] in guard let self = self else { return } $0.didMove(toParent: self) } }
  31. 48.

    VStackViewController import UIKit open class VStackViewController: UIViewController { public let

    scrollView: UIScrollView = .init() public let stackView: UIStackView = { let stackView: UIStackView = .init() stackView.axis = .vertical stackView.alignment = .fill stackView.distribution = .equalSpacing stackView.spacing = 0 return stackView }() var components: [UIViewController] public init(components: [UIViewController]) { self.components = components super.init(nibName: nil, bundle: nil) }
  32. 49.

    VStackViewController override open func viewDidLoad() { super.viewDidLoad() components.forEach { [weak

    self] in self?.addChild($0) } view.addSubview(scrollView, constraints: .allEdges()) scrollView.addSubview(stackView, constraints: .allEdges() + [equal(\.widthAnchor)]) components.forEach { [weak self] in guard let self = self else { return } self.stackView.addArrangedSubview($0.view) } components.forEach { [weak self] in guard let self = self else { return } $0.didMove(toParent: self) } } Set Constraints all edges of view and width anchor
  33. 50.

    import UIKit final class HomeViewController: VStackViewController { private let featuredComponent

    = HomeFeaturedCellViewController(dependencies: .init(onTap: { index in // transition logic })) private let rankingComponents = HomeRankingViewController() init() { super.init(components: [featuredComponent, rankingComponents]) } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } override func viewDidLoad() { super.viewDidLoad() title = "Home" }
  34. 51.

    import UIKit final class HomeViewController: VStackViewController { private let featuredComponent

    = HomeFeaturedCellViewController(dependencies: .init(onTap: { index in // transition logic })) private let rankingComponents = HomeRankingViewController() init() { super.init(components: [featuredComponent, rankingComponents]) } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } override func viewDidLoad() { super.viewDidLoad() title = "Home" } Override initializer with child components
  35. 52.

    Ex. User Registration • Each form need to be validate

    • Enable to tap “Done” when all form has valid • Show error below each form
  36. 54.

    FormViewController class FormViewController: UIViewController { struct Dependency { let title:

    String let placeholder: String let validation: (String) -> ValidationResult let textContentType: UITextContentType? let keyboardType: UIKeyboardType? let isSecureTextEntry: Bool init(title: String, placeholder: String, validation: @escaping (String) -> ValidationResult, textContentType: UITextContentType? = nil, keyboardType: UIKeyboardType? = nil, isSecureTextEntry: Bool = false) { self.title = title self.placeholder = placeholder self.validation = validation self.textContentType = textContentType self.keyboardType = keyboardType self.isSecureTextEntry = isSecureTextEntry } }
  37. 55.

    FormViewController @IBOutlet private var titleLabel: UILabel! @IBOutlet var textField: UITextField!

    @IBOutlet private var errorLabel: UILabel! private let dependency: Dependency private let disposeBag = DisposeBag() private lazy var viewModel: FormViewModel = .init(text: self.textField.rx.text.orEmpty.asDriver(), validation: self.dependency.validation) var isValid: Driver<Bool> { return viewModel.validatedValue.map { $0.isValid } } init(dependency: Dependency) { self.dependency = dependency super.init(nibName: nil, bundle: nil) }
  38. 56.

    FormViewController override func viewDidLoad() { super.viewDidLoad() errorLabel.isHidden = true titleLabel.text

    = dependency.title textField.placeholder = dependency.placeholder textField.textContentType = dependency.textContentType if let keyboardType = dependency.keyboardType { textField.keyboardType = keyboardType } viewModel.validatedValue .drive(errorLabel.rx.validationResult) .disposed(by: disposeBag) }
  39. 58.

    HStackViewController import UIKit open class HStackViewController: UIViewController { public let

    scrollView: UIScrollView = .init() public let stackView: UIStackView = { let stackView: UIStackView = .init() stackView.axis = .horizontal stackView.alignment = .fill stackView.distribution = .equalSpacing stackView.spacing = 0 return stackView }() var components: [UIViewController] public init(components: [UIViewController]) { self.components = components super.init(nibName: nil, bundle: nil) }
  40. 59.

    HStackViewController import UIKit open class HStackViewController: UIViewController { public let

    scrollView: UIScrollView = .init() public let stackView: UIStackView = { let stackView: UIStackView = .init() stackView.axis = .horizontal stackView.alignment = .fill stackView.distribution = .equalSpacing stackView.spacing = 0 return stackView }() var components: [UIViewController] public init(components: [UIViewController]) { self.components = components super.init(nibName: nil, bundle: nil) } Set to horizontal Scroll View Own child view controllers
  41. 60.

    HStackViewController override open func viewDidLoad() { super.viewDidLoad() components.forEach { [weak

    self] in self?.addChild($0) } view.addSubview(scrollView, constraints: .allEdges()) scrollView.addSubview(stackView, constraints: .allEdges() + [equal(\.heightAnchor)]) components.forEach { [weak self] in guard let self = self else { return } self.stackView.addArrangedSubview($0.view) } components.forEach { [weak self] in guard let self = self else { return } $0.didMove(toParent: self) } }
  42. 61.

    HStackViewController override open func viewDidLoad() { super.viewDidLoad() components.forEach { [weak

    self] in self?.addChild($0) } view.addSubview(scrollView, constraints: .allEdges()) scrollView.addSubview(stackView, constraints: .allEdges() + [equal(\.heightAnchor)]) components.forEach { [weak self] in guard let self = self else { return } self.stackView.addArrangedSubview($0.view) } components.forEach { [weak self] in guard let self = self else { return } $0.didMove(toParent: self) } } Set Constraints all edges of view and height anchor
  43. 62.

    final class RegisterContentViewController: VStackViewController { private let userNameComponent = FormViewController(

    dependency: .init( title: "Nickname", placeholder: "Nickname", validation: FormValidationService.shared.validate(nickName:), textContentType: .givenName ) ) private let emailComponent = FormViewController( dependency: .init( title: "Email", placeholder: "Email", validation: FormValidationService.shared.validate(email:), textContentType: .emailAddress ) ) Initialize components
  44. 65.

    lazy var isValidateForms: Driver<Bool> = Driver.combineLatest( userNameComponent.isValid, emailComponent.isValid, creditCardComponent.isValid, securityCodeComponent.isValid,

    expirationComponent.isValid ) { $0 && $1 && $2 && $3 && $4 } .distinctUntilChanged() Passing results isValidateForms .drive(onNext: { [weak self] in guard let self = self else { return } self.confirmViewController.set(isValid: $0) }) .disposed(by: disposeBag)
  45. 68.
  46. 69.
  47. 70.

    final class RegisterContentViewController: VStackViewController { private let userNameComponent = FormViewController(

    dependency: .init( title: "Nickname", placeholder: "Nickname", validation: FormValidationService.shared.validate(nickName:), textContentType: .givenName ) ) private let emailComponent = FormViewController( dependency: .init( title: "Email", placeholder: "Email", validation: FormValidationService.shared.validate(email:), textContentType: .emailAddress ) ) Initialize components in UIKit
  48. 71.

    final class RegisterContentViewController: VStackViewController { private let userNameView = UIHostingController(

    rootView: FormView( dependency: .init( title: "Nickname", placeholder: "Nickname", validation: FormValidationService.shared.validate(nickName:), textContentType: .givenName ) )) private let emailView = UIHostingController( rootView: FormView( dependency: .init( title: "Email", placeholder: "Email", validation: FormValidationService.shared.validate(email:), textContentType: .emailAddress ) )) Initialize components in SwiftUI
  49. 72.

    init() { super.init( components: [ userNameComponent, emailComponent, creditCardComponent, HStackViewController( components:

    [expirationComponent, securityCodeComponent] ) ] ) } Initialize components in UIKit
  50. 73.

    init() { super.init( components: [ userNameView, emailView, creditCardView, HStackViewController( components:

    [expirationView, securityCodeView] ) ] ) } Initialize components in SwiftUI
  51. 76.

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) VStack

    { HStack { Text(dependency.title) .font(Font.system(size: 12, weight: .medium, design: .default)) .foregroundColor(Color(UIColor.label)) Spacer() } TextField(dependency.placeholder, text: $viewModel.value) .font(.system(size: 14, weight: .medium, design: .default)) .textFieldStyle(RoundedBorderTextFieldStyle()) .textContentType(dependency.textContentType) .keyboardType(dependency.keyboardType ?? .default) if !viewModel.isValid && !viewModel.isEmpty { HStack { Text(viewModel.errorMessage) .foregroundColor(.red) .font(Font.system(size: 12, weight: .medium, design: .default)) Spacer() } } } .padding() } } FormView in SwiftUI
  52. 77.

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) VStack

    { HStack { Text(dependency.title) .font(Font.system(size: 12, weight: .medium, design: .default)) .foregroundColor(Color(UIColor.label)) Spacer() } TextField(dependency.placeholder, text: $viewModel.value) .font(.system(size: 14, weight: .medium, design: .default)) .textFieldStyle(RoundedBorderTextFieldStyle()) .textContentType(dependency.textContentType) .keyboardType(dependency.keyboardType ?? .default) if !viewModel.isValid && !viewModel.isEmpty { HStack { Text(viewModel.errorMessage) .foregroundColor(.red) .font(Font.system(size: 12, weight: .medium, design: .default)) Spacer() } } } .padding() } } FormView in SwiftUI For Light / Dark mode
  53. 78.

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) VStack

    { HStack { Text(dependency.title) .font(Font.system(size: 12, weight: .medium, design: .default)) .foregroundColor(Color(UIColor.label)) Spacer() } TextField(dependency.placeholder, text: $viewModel.value) .font(.system(size: 14, weight: .medium, design: .default)) .textFieldStyle(RoundedBorderTextFieldStyle()) .textContentType(dependency.textContentType) .keyboardType(dependency.keyboardType ?? .default) if !viewModel.isValid && !viewModel.isEmpty { HStack { Text(viewModel.errorMessage) .foregroundColor(.red) .font(Font.system(size: 12, weight: .medium, design: .default)) Spacer() } } } .padding() } } FormView in SwiftUI Stack
  54. 79.

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) VStack

    { HStack { Text(dependency.title) .font(Font.system(size: 12, weight: .medium, design: .default)) .foregroundColor(Color(UIColor.label)) Spacer() } TextField(dependency.placeholder, text: $viewModel.value) .font(.system(size: 14, weight: .medium, design: .default)) .textFieldStyle(RoundedBorderTextFieldStyle()) .textContentType(dependency.textContentType) .keyboardType(dependency.keyboardType ?? .default) if !viewModel.isValid && !viewModel.isEmpty { HStack { Text(viewModel.errorMessage) .foregroundColor(.red) .font(Font.system(size: 12, weight: .medium, design: .default)) Spacer() } } } .padding() } } FormView in SwiftUI Title Label
  55. 80.

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) VStack

    { HStack { Text(dependency.title) .font(Font.system(size: 12, weight: .medium, design: .default)) .foregroundColor(Color(UIColor.label)) Spacer() } TextField(dependency.placeholder, text: $viewModel.value) .font(.system(size: 14, weight: .medium, design: .default)) .textFieldStyle(RoundedBorderTextFieldStyle()) .textContentType(dependency.textContentType) .keyboardType(dependency.keyboardType ?? .default) if !viewModel.isValid && !viewModel.isEmpty { HStack { Text(viewModel.errorMessage) .foregroundColor(.red) .font(Font.system(size: 12, weight: .medium, design: .default)) Spacer() } } } .padding() } } FormView in SwiftUI Text Field
  56. 81.

    var body: some View { ZStack { Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) VStack

    { HStack { Text(dependency.title) .font(Font.system(size: 12, weight: .medium, design: .default)) .foregroundColor(Color(UIColor.label)) Spacer() } TextField(dependency.placeholder, text: $viewModel.value) .font(.system(size: 14, weight: .medium, design: .default)) .textFieldStyle(RoundedBorderTextFieldStyle()) .textContentType(dependency.textContentType) .keyboardType(dependency.keyboardType ?? .default) if !viewModel.isValid && !viewModel.isEmpty { HStack { Text(viewModel.errorMessage) .foregroundColor(.red) .font(Font.system(size: 12, weight: .medium, design: .default)) Spacer() } } } .padding() } } FormView in SwiftUI Error label
  57. 82.

    FormView preview struct FormView_Previews: PreviewProvider { static var previews: some

    View { let form = FormView(dependency: .init( title: "Email", placeholder: "Email", validation: FormValidationService.shared.validate(email:), textContentType: .emailAddress)) return Group { form.environment(\.colorScheme, .light) form.environment(\.colorScheme, .dark) } .previewLayout(.fixed(width: 414, height: 129)) } }
  58. 83.

    FormView preview struct FormView_Previews: PreviewProvider { static var previews: some

    View { let form = FormView(dependency: .init( title: "Email", placeholder: "Email", validation: FormValidationService.shared.validate(email:), textContentType: .emailAddress)) return Group { form.environment(\.colorScheme, .light) form.environment(\.colorScheme, .dark) } .previewLayout(.fixed(width: 414, height: 129)) } } Light Mode Dark Mode
  59. 85.
  60. 86.
  61. 89.

    User Interaction SwiftUI Action State Mutation View Updates Render !

    " ⏰ Publisher https://developer.apple.com/videos/play/wwdc2019/226/
  62. 90.

    Dataflow in FormView struct FormView: View { let dependency: FormViewController.Dependency

    @ObservedObject var viewModel: FormViewSwiftUIModel init(dependency: FormViewController.Dependency) { self.dependency = dependency self.viewModel = .init(validation: dependency.validation) } var isValid: Bool { viewModel.isValid && !viewModel.isEmpty }
  63. 91.

    Dataflow in FormView struct FormView: View { let dependency: FormViewController.Dependency

    @ObservedObject var viewModel: FormViewSwiftUIModel init(dependency: FormViewController.Dependency) { self.dependency = dependency self.viewModel = .init(validation: dependency.validation) } var isValid: Bool { viewModel.isValid && !viewModel.isEmpty } ViewModel with ObservedObject
  64. 92.

    Dataflow in FormView import Foundation import SwiftUI class FormViewSwiftUIModel: ObservableObject

    { let validation: (String) -> ValidationResult var value: String = "" { willSet { if newValue != value { validationResult = self.validation(newValue) } } } var validationResult: ValidationResult = .empty { willSet { objectWillChange.send() } }
  65. 93.

    Dataflow in FormView var validationResult: ValidationResult = .empty { willSet

    { switch newValue { case .failed(let message): errorMessage = message case .ok: isValid = true isEmpty = false case .empty: isValid = false isEmpty = true default: errorMessage = "" } objectWillChange.send() } }
  66. 97.

    UIKit in SwiftUI extension FormViewController: UIViewControllerRepresentable { typealias UIViewControllerType =

    FormViewController func makeUIViewController( context: UIViewControllerRepresentableContext<FormViewController>) -> FormViewController { let formViewController = FormViewController(dependency: self.dependency) return formViewController } func updateUIViewController(_ uiViewController: FormViewController, context: UIViewControllerRepresentableContext<FormViewController>) { } func makeCoordinator() -> () { } }
  67. 98.

    UIKit in SwiftUI var body: some View { ZStack {

    Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) VStack { userNameComponent emailComponent creditCardComponent HStack { expirationComponent securityCodeComponent Spacer() } Spacer() } } }
  68. 99.

    UIKit in SwiftUI var body: some View { ZStack {

    Color(UIColor.systemBackground) .edgesIgnoringSafeArea(.all) VStack { userNameComponent emailComponent creditCardComponent HStack { expirationComponent securityCodeComponent Spacer() } Spacer() } } } super.init( components: [ userNameComponent, emailComponent, creditCardComponent, HStackViewController( components: [expirationComponent, securityCodeComponent] )] )
  69. 100.

    struct RegisterContentView_Previews: PreviewProvider { static var previews: some View {

    let content = RegisterContentView() return Group { NavigationView { content.environment(\.colorScheme, .light) } NavigationView { content.environment(\.colorScheme, .dark) } } } } UIKit in SwiftUI - Preview
  70. 105.

    let stackView = UIStackView(arrangedSubviews: [titleLabel, textField, errorLabel]) stackView.axis = .vertical

    stackView.spacing = 16 view.addSubview(stackView, constraints: .allEdges(margin: 16)) Use stack view instead of xib
  71. 107.

    Recap - UIKit to SwiftUI • Use stack view as

    possible • Some of SwiftUI feature still be broken • Sometime need to use UIKit instead • Keeping components small is key factor to migrate