SwiftUIを使ったTODOアプリのサンプル

	import SwiftUI

	struct CalendarView: UIViewRepresentable {
	let didSelectDate: (_ dateComponents: DateComponents) -> Void

	final public class Coordinator: NSObject, UICalendarSelectionSingleDateDelegate {
	let didSelectDate: (_ dateComponents: DateComponents) -> Void

	init(
	didSelectDate: @escaping (_ dateComponents: DateComponents) -> Void
	) {
	self.didSelectDate = didSelectDate
	}

	public func dateSelection(_ selection: UICalendarSelectionSingleDate, didSelectDate dateComponents: DateComponents?) {
	guard let dateComponents = dateComponents else {
	return
	}
	didSelectDate(dateComponents)
	}
	}

	public func makeCoordinator() -> Coordinator {
	Coordinator(didSelectDate: didSelectDate)
	}

	func makeUIView(context: Context) -> some UIView {
	let selection = UICalendarSelectionSingleDate(delegate: context.coordinator)

	let calendarView = UICalendarView()
	calendarView.selectionBehavior = selection
	return calendarView
	}

	func updateUIView(_ uiView: UIViewType, context: Context) {}
	}

view raw CalendarView.swift hosted with ❤ by GitHub

	import SwiftUI

	struct ContentView: View {
	@State var showingSheet: ContentViewSheetItem?

	var body: some View {
	VStack {
	CalendarView { dateComponents in
	guard let year = dateComponents.year,
	let month = dateComponents.month,
	let day = dateComponents.day else {
	return
	}
	showingSheet = .showScheduleList(year: year, month: month, day: day)
	}
	.padding()
	.navigationTitle("UICalendarView")

	Button {
	showingSheet = .showInputSchedule
	} label: {
	Text("Add Schedule")
	.font(Font.system(size: 20))
	.fontWeight(.bold)
	.padding(16)
	.border(Color.black, width: 1)
	}
	}
	.sheet(item: $showingSheet, content: { item in
	switch item {
	case .showScheduleList(let year, let month, let day):
	ScheduleList(year: year, month: month, day: day)
	case .showInputSchedule:
	InputScheduleView()
	}
	})
	}
	}

view raw ContentView.swift hosted with ❤ by GitHub

	import Foundation

	enum ContentViewSheetItem: Hashable, Identifiable {
	var id: Self {
	return self
	}
	case showInputSchedule
	case showScheduleList(year: Int, month: Int, day: Int)
	}

	import SwiftUI

	struct InputScheduleView: View {
	@Environment(\.dismiss) private var dismiss

	@State var schedule = ""
	@State var date = Date()

	var body: some View {
	VStack {
	TextField("Schedule", text: $schedule)
	.textFieldStyle(RoundedBorderTextFieldStyle())

	DatePicker(selection: $date, label: { Text("") })
	.environment(\.locale, Locale(identifier: "ja_JP"))

	Button {
	let calendar = Calendar.current
	let components = calendar.dateComponents([.year, .month, .day], from: date)
	guard let year = components.year, let month = components.month, let day = components.day else {
	return
	}

	// Add Schedules
	var schedules = UserDefaultsManager.getSchedules(year: year, month: month, day: day)
	schedules.append(schedule)

	UserDefaultsManager.setSchedules(year: year, month: month, day: day, schedules: schedules)

	dismiss()
	} label: {
	Text("Add")
	.font(Font.system(size: 20))
	.fontWeight(.bold)
	.padding(16)
	.border(Color.black, width: 1)
	}
	}
	.padding()
	}
	}

	import SwiftUI

	struct ScheduleList: View {
	@State var year: Int
	@State var month: Int
	@State var day: Int
	@State var schedules: [String] = []

	var body: some View {
	List(schedules, id: \.self) { schedule in
	Text(schedule)
	}
	.onAppear {
	schedules = UserDefaultsManager.getSchedules(year: year, month: month, day: day)
	}
	}
	}

view raw ScheduleList.swift hosted with ❤ by GitHub

	import Foundation

	struct UserDefaultsManager {
	static func getSchedules(year: Int, month: Int, day: Int) -> [String] {
	if let schedules = UserDefaults.standard.object(forKey: "\(year)-\(month)-\(day)") as? [String] {
	return schedules
	}
	return []
	}
	static func setSchedules(year: Int, month: Int, day: Int, schedules: [String]) {
	UserDefaults.standard.set(schedules, forKey: "\(year)-\(month)-\(day)")
	}
	}