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SwiftUI Calendar view using LazyVGrid
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import SwiftUI | |
extension Calendar { | |
func generateDates( | |
inside interval: DateInterval, | |
matching components: DateComponents | |
) -> [Date] { | |
var dates: [Date] = [] | |
dates.append(interval.start) | |
enumerateDates( | |
startingAfter: interval.start, | |
matching: components, | |
matchingPolicy: .nextTime | |
) { date, _, stop in | |
if let date = date { | |
if date < interval.end { | |
dates.append(date) | |
} else { | |
stop = true | |
} | |
} | |
} | |
return dates | |
} | |
} | |
extension DateFormatter { | |
static let monthAndYear: DateFormatter = { | |
let formatter = DateFormatter() | |
formatter.setLocalizedDateFormatFromTemplate("MMMM yyyy") | |
return formatter | |
}() | |
} | |
struct EquatableCalendarView<DateView: View, Value: Equatable>: View, Equatable { | |
static func == ( | |
lhs: EquatableCalendarView<DateView, Value>, | |
rhs: EquatableCalendarView<DateView, Value> | |
) -> Bool { | |
lhs.interval == rhs.interval && lhs.value == rhs.value && lhs.showHeaders == rhs.showHeaders | |
} | |
let interval: DateInterval | |
let value: Value | |
let showHeaders: Bool | |
let onHeaderAppear: (Date) -> Void | |
let content: (Date) -> DateView | |
init( | |
interval: DateInterval, | |
value: Value, | |
showHeaders: Bool = true, | |
onHeaderAppear: @escaping (Date) -> Void = { _ in }, | |
@ViewBuilder content: @escaping (Date) -> DateView | |
) { | |
self.interval = interval | |
self.value = value | |
self.showHeaders = showHeaders | |
self.onHeaderAppear = onHeaderAppear | |
self.content = content | |
} | |
var body: some View { | |
CalendarView( | |
interval: interval, | |
showHeaders: showHeaders, | |
onHeaderAppear: onHeaderAppear | |
) { date in | |
content(date) | |
} | |
} | |
} | |
struct CalendarView<DateView>: View where DateView: View { | |
let interval: DateInterval | |
let showHeaders: Bool | |
let onHeaderAppear: (Date) -> Void | |
let content: (Date) -> DateView | |
@Environment(\.sizeCategory) private var contentSize | |
@Environment(\.calendar) private var calendar | |
@State private var months: [Date] = [] | |
@State private var days: [Date: [Date]] = [:] | |
private var columns: [GridItem] { | |
let spacing: CGFloat = contentSize.isAccessibilityCategory ? 2 : 8 | |
return Array(repeating: GridItem(spacing: spacing), count: 7) | |
} | |
var body: some View { | |
LazyVGrid(columns: columns) { | |
ForEach(months, id: \.self) { month in | |
Section(header: header(for: month)) { | |
ForEach(days[month, default: []], id: \.self) { date in | |
if calendar.isDate(date, equalTo: month, toGranularity: .month) { | |
content(date).id(date) | |
} else { | |
content(date).hidden() | |
} | |
} | |
} | |
} | |
} | |
.onAppear { | |
months = calendar.generateDates( | |
inside: interval, | |
matching: DateComponents(day: 1, hour: 0, minute: 0, second: 0) | |
) | |
days = months.reduce(into: [:]) { current, month in | |
guard | |
let monthInterval = calendar.dateInterval(of: .month, for: month), | |
let monthFirstWeek = calendar.dateInterval(of: .weekOfMonth, for: monthInterval.start), | |
let monthLastWeek = calendar.dateInterval(of: .weekOfMonth, for: monthInterval.end) | |
else { return } | |
current[month] = calendar.generateDates( | |
inside: DateInterval(start: monthFirstWeek.start, end: monthLastWeek.end), | |
matching: DateComponents(hour: 0, minute: 0, second: 0) | |
) | |
} | |
} | |
} | |
private func header(for month: Date) -> some View { | |
Group { | |
if showHeaders { | |
Text(DateFormatter.monthAndYear.string(from: month)) | |
.font(.title) | |
.padding() | |
} | |
} | |
.onAppear { onHeaderAppear(month) } | |
} | |
} |
@AbdullohBahromjonov, it depends on your calendar preferences. So, if in your phone settings, the week starts on Monday, then it will be the same here.
thank you!
But I have another issue here. I am using EnvironmentObject to make changes on the view but the calendar is not displaying changes instantly, it displays changes after I some random day on the calendar.
Can someone help me with this?
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@AbdullohBahromjonov, it depends on your calendar preferences. So, if in your phone settings, the week starts on Monday, then it will be the same here.