How to make the date change simultaneously in all views? - swift

Question

Date not change simultaneously in all views.
I want to link two calendars. Standard and custom. But they don't connect.
When I change the date in one, it doesn't change in the other.
I made Published:
import Combine
import Foundation
class CustomCalendar: ObservableObject {
#Published var currentDate = Date()
var currentThreeWeek: [Date] = []
init() {
fetchCurrentThreeWeek()
}
func fetchCurrentThreeWeek() {
let calendar = Calendar.current
var todayDay = DateInterval(start: Date(), duration: 1814400).start
let lastDay = DateInterval(start: Date(), duration: 1814400).end
currentThreeWeek.append(todayDay)
while todayDay < lastDay {
todayDay = calendar.date(byAdding: .day, value: 1, to: todayDay)!
currentThreeWeek.append(todayDay)
}
}
func extractDate(date: Date, format: String) -> String {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = format
dateFormatter.locale = Locale(identifier: "rus")
return dateFormatter.string(from: date)
}
func isToday(date: Date) -> Bool {
let calendar = Calendar.current
return calendar.isDate(currentDate, inSameDayAs: date)
}
}
When I select a date it doesn't change in other views.
import SwiftUI
struct FilterView: View {
#StateObject private var calendar = CustomCalendar()
#Binding var filterViewIsPresented: Bool
let todayDay = DateInterval(start: Date(), duration: 1814400).start
let lastDay = DateInterval(start: Date(), duration: 1814400).end
var body: some View {
VStack {
DatePicker("", selection: $calendar.currentDate, in: todayDay...lastDay, displayedComponents: .date)
.labelsHidden()
.environment(\.locale, Locale.init(identifier: "ru"))
HorizontalCalendarView()
HorizontalCalendarView()
}
}
}
struct FilterView_Previews: PreviewProvider {
static var previews: some View {
FilterView(filterViewIsPresented: .constant(false))
}
}
Custom calendar. On tap Gesture I change currentDate
import SwiftUI
struct HorizontalCalendarView: View {
#StateObject private var calendar = CustomCalendar()
var body: some View {
ScrollViewReader { value in
ScrollView(.horizontal, showsIndicators: false) {
HStack(spacing: 0) {
ForEach(calendar.currentThreeWeek, id: \.self) { day in
VStack(spacing: 0) {
Text(calendar.extractDate(date: day, format: "dd"))
.font(.title3)
.fontWeight(.bold)
Text(calendar.extractDate(date: day, format: "EEE"))
RoundedRectangle(cornerRadius: 10, style: .continuous)
.frame(width: calendar.isToday(date: day) ? 40 : 0, height: 5)
.opacity(calendar.isToday(date: day) ? 1 : 0)
.padding(4)
}
.frame(width: 45, height: 45)
.foregroundStyle(calendar.isToday(date: day) ? .primary : .secondary )
.foregroundColor(calendar.isToday(date: day) ? .white : .black)
.padding(8)
.background(
ZStack {
if calendar.isToday(date: day) {
RoundedRectangle(cornerRadius: 10, style: .continuous)
}
}
)
.onTapGesture {
withAnimation(.easeIn(duration: 0.2)) {
calendar.currentDate = day
value.scrollTo(calendar.currentDate, anchor: .leading)
}
}
}
.padding(9)
}
}
Text(calendar.currentDate.formatted())
}
}
}
struct HorizontalCalendarView_Previews: PreviewProvider {
static var previews: some View {
HorizontalCalendarView()
}
}
How can I do this?

Answer 1

You have two options:
Pass calendar in HorizontalCalendarView constructor and use #ObservedObject property wrapper instead of #StateObject:
struct HorizontalCalendarView: View {
#ObservedObject private var calendar: CustomCalendar
init(_ calendar: CustomCalendar) {
self.calendar = calendar
}
...
and just pass it in FilterView
HorizontalCalendarView(calendar)
Another option is to use #EnvironmentObject (it's preferred method for deeply nested views in your example option 1 is better):
struct HorizontalCalendarView: View {
#EnvironmentObject private var calendar: CustomCalendar = CustomCalendar()
...
then you have to pass calendar with environmentObject modifier:
HorizontalCalendarView().environmentObject(calendar)
Note: in order to #EnvironmentObject works as expected it is not necessary to use environmentObject modifier on actual view, you can use this modifier in any of parent views. That makes it perfect for deep nested views