Date picker

Examples/Package.swift

@@ -76,11 +76,11 @@ let package = Package(
         .executableTarget(
             name: "HoverExample",
             dependencies: exampleDependencies
-		),
-		.executableTarget(
+        ),
+        .executableTarget(
             name: "ForEachExample",
             dependencies: exampleDependencies
-		),
+        ),
         .executableTarget(
             name: "AdvancedCustomizationExample",
             dependencies: exampleDependencies,

Examples/Sources/ControlsExample/ControlsApp.swift

@@ -1,4 +1,5 @@
 import DefaultBackend
+import Foundation
 import SwiftCrossUI
 
 #if canImport(SwiftBundlerRuntime)
@@ -16,10 +17,14 @@ struct ControlsApp: App {
     @State var text = ""
     @State var flavor: String? = nil
     @State var enabled = true
+    @State var date = Date()
+    @State var datePickerStyle: DatePickerStyle? = .automatic
     @State var menuToggleState = false
     @State var progressViewSize: Int = 10
     @State var isProgressViewResizable = true
 
+    @Environment(\.supportedDatePickerStyles) var supportedDatePickerStyles: [DatePickerStyle]
+
     var body: some Scene {
         WindowGroup("ControlsApp") {
             #hotReloadable {
@@ -94,15 +99,40 @@ struct ControlsApp: App {
                                 .frame(width: progressViewSize, height: progressViewSize)
                         }
 
-                        VStack {
-                            Text("Drop down")
-                            HStack {
-                                Text("Flavor: ")
-                                Picker(
-                                    of: ["Vanilla", "Chocolate", "Strawberry"], selection: $flavor)
+                        #if !canImport(Gtk3Backend)
+                            VStack {
+                                Text("Drop down")
+                                HStack {
+                                    Text("Flavor: ")
+                                    Picker(
+                                        of: ["Vanilla", "Chocolate", "Strawberry"],
+                                        selection: $flavor
+                                    )
+                                }
+                                Text("You chose: \(flavor ?? "Nothing yet!")")
                             }
-                            Text("You chose: \(flavor ?? "Nothing yet!")")
-                        }
+
+                            #if !os(tvOS)
+                                VStack {
+                                    Text("Selected date: \(date)")
+
+                                    HStack {
+                                        Text("Date picker style: ")
+                                        Picker(
+                                            of: supportedDatePickerStyles,
+                                            selection: $datePickerStyle
+                                        )
+                                    }
+
+                                    DatePicker(selection: $date) {}
+                                        .datePickerStyle(datePickerStyle ?? .automatic)
+
+                                    Button("Reset date to now") {
+                                        date = Date()
+                                    }
+                                }
+                            #endif
+                        #endif
                     }.padding().disabled(!enabled)
 
                     Toggle(enabled ? "Disable all" : "Enable all", isOn: $enabled)

Package.swift

@@ -112,15 +112,15 @@ let package = Package(
         ),
         .package(
             url: "https://github.com/stackotter/swift-windowsappsdk",
-            revision: "ba6f0ec377b70d8be835d253102ff665a0e47d99"
+            revision: "f1c50892f10c0f7f635d3c7a3d728fd634ad001a"
         ),
         .package(
             url: "https://github.com/stackotter/swift-windowsfoundation",
             revision: "4ad57d20553514bcb23724bdae9121569b19f172"
         ),
         .package(
             url: "https://github.com/stackotter/swift-winui",
-            revision: "1695ee3ea2b7a249f6504c7f1759e7ec7a38eb86"
+            revision: "42c47f4e4129c8b5a5d9912f05e1168c924ac180"
         ),
         .package(
             url: "https://github.com/apple/swift-collections.git",

Sources/AppKitBackend/AppKitBackend.swift

@@ -26,6 +26,7 @@ public final class AppKitBackend: AppBackend {
     public let menuImplementationStyle = MenuImplementationStyle.dynamicPopover
     public let canRevealFiles = true
     public let deviceClass = DeviceClass.desktop
+    public let supportedDatePickerStyles: [DatePickerStyle] = [.automatic, .graphical, .compact]
 
     public var scrollBarWidth: Int {
         // We assume that all scrollers have their controlSize set to `.regular` by default.
@@ -368,6 +369,14 @@ public final class AppKitBackend: AppBackend {
             // Self.scrollBarWidth has changed
             action()
         }
+
+        NotificationCenter.default.addObserver(
+            forName: .NSSystemTimeZoneDidChange,
+            object: nil,
+            queue: .main
+        ) { _ in
+            action()
+        }
     }
 
     public func computeWindowEnvironment(
@@ -1835,6 +1844,80 @@ public final class AppKitBackend: AppBackend {
         parent.endSheet(sheet)
         parent.nestedSheet = nil
     }
+
+    public func createDatePicker() -> NSView {
+        let datePicker = CustomDatePicker()
+        datePicker.delegate = datePicker.strongDelegate
+        return datePicker
+    }
+
+    // Depending on the calendar, era is either necessary or must be omitted. Making the wrong
+    // choice for the current calendar means the cursor position is reset after every keystroke. I
+    // know of no simple way to tell whether NSDatePicker requires or forbids eras for a given
+    // calendar, so in lieu of that I have hardcoded the calendar identifiers.
+    private let calendarsRequiringEra: Set<Calendar.Identifier> = [
+        .buddhist, .coptic, .ethiopicAmeteAlem, .ethiopicAmeteMihret, .indian, .islamic,
+        .islamicCivil, .islamicTabular, .islamicUmmAlQura, .japanese, .persian, .republicOfChina,
+    ]
+
+    public func updateDatePicker(
+        _ datePicker: NSView,
+        environment: EnvironmentValues,
+        date: Date,
+        range: ClosedRange<Date>,
+        components: DatePickerComponents,
+        onChange: @escaping (Date) -> Void
+    ) {
+        let datePicker = datePicker as! CustomDatePicker
+
+        datePicker.isEnabled = environment.isEnabled
+        datePicker.textColor = environment.suggestedForegroundColor.nsColor
+
+        // If the time zone is set to autoupdatingCurrent, then the cursor position is reset after
+        // every keystroke. Thanks Apple
+        datePicker.timeZone =
+            environment.timeZone == .autoupdatingCurrent ? .current : environment.timeZone
+
+        // A couple properties cause infinite update loops if we assign to them on every update, so
+        // check their values first.
+        if datePicker.calendar != environment.calendar {
+            datePicker.calendar = environment.calendar
+        }
+
+        if datePicker.dateValue != date {
+            datePicker.dateValue = date
+        }
+
+        var elementFlags: NSDatePicker.ElementFlags = []
+        if components.contains(.date) {
+            elementFlags.insert(.yearMonthDay)
+            if calendarsRequiringEra.contains(environment.calendar.identifier) {
+                elementFlags.insert(.era)
+            }
+        }
+        if components.contains(.hourMinuteAndSecond) {
+            elementFlags.insert(.hourMinuteSecond)
+        } else if components.contains(.hourAndMinute) {
+            elementFlags.insert(.hourMinute)
+        }
+
+        if datePicker.datePickerElements != elementFlags {
+            datePicker.datePickerElements = elementFlags
+        }
+
+        datePicker.strongDelegate.onChange = onChange
+
+        datePicker.minDate = range.lowerBound
+        datePicker.maxDate = range.upperBound
+
+        datePicker.datePickerStyle =
+            switch environment.datePickerStyle {
+                case .automatic, .compact:
+                    .textFieldAndStepper
+                case .graphical:
+                    .clockAndCalendar
+            }
+    }
 }
 
 public final class NSCustomSheet: NSCustomWindow, NSWindowDelegate {
@@ -2367,3 +2450,19 @@ final class CustomWKNavigationDelegate: NSObject, WKNavigationDelegate {
         onNavigate?(url)
     }
 }
+
+final class CustomDatePicker: NSDatePicker {
+    var strongDelegate = CustomDatePickerDelegate()
+}
+
+final class CustomDatePickerDelegate: NSObject, NSDatePickerCellDelegate {
+    var onChange: ((Date) -> Void)?
+
+    func datePickerCell(
+        _: NSDatePickerCell,
+        validateProposedDateValue proposedDateValue: AutoreleasingUnsafeMutablePointer<NSDate>,
+        timeInterval _: UnsafeMutablePointer<TimeInterval>?
+    ) {
+        onChange?(proposedDateValue.pointee as Date)
+    }
+}

Sources/DummyBackend/DummyBackend.swift

@@ -247,6 +247,7 @@ public final class DummyBackend: AppBackend {
     public var menuImplementationStyle = MenuImplementationStyle.dynamicPopover
     public var deviceClass = DeviceClass.desktop
     public var canRevealFiles = false
+    public var supportedDatePickerStyles: [DatePickerStyle] = []
 
     public var incomingURLHandler: ((URL) -> Void)?