Live Activity — что это такое, виджеты на экране блокировки

import ActivityKit

struct DeliveryAttributes: ActivityAttributes {
    public struct ContentState: Codable & Hashable {
        var status: DeliveryStatus
        var estimatedMinutes: Int
    }
    var orderNumber: String
    var restaurantName: String
}

let attributes = DeliveryAttributes(
    orderNumber: "A-1234",
    restaurantName: "Pizza House"
)

let initialState = DeliveryAttributes.ContentState(
    status: DeliveryStatus.preparing,
    estimatedMinutes: 30
)

do {
    let activity = try await Activity<DeliveryAttributes>.request(
        attributes: attributes,
        content: ActivityContent(state: initialState, staleDate: nil),
        pushType: .token
    )
    print("Activity started: \(activity.id)")
} catch {
    print("Failed: \(error)")
}

let updatedState = DeliveryAttributes.ContentState(
    status: DeliveryStatus.outForDelivery,
    estimatedMinutes: 10
)

await activity.update(
    ActivityContent<DeliveryAttributes.ContentState>(
        state: updatedState,
        staleDate: Date().addingTimeInterval(60)
    ),
    alertConfiguration: AlertConfiguration(
        title: "Order out for delivery",
        body: "Arriving in 10 min"
    )
)

struct DeliveryLiveActivity: Widget {
    var body: some WidgetConfiguration {
        ActivityConfiguration(for: DeliveryAttributes.self) { context in
            LockScreenView(context: context)
        } dynamicIsland: { context in
            DynamicIsland {
                DynamicIslandExpandedContent {
                    ExpandedView(context: context)
                }
            } compactLeading: {
                CompactLeadingView(context: context)
            } compactTrailing: {
                CompactTrailingView(context: context)
            } minimal: {
                MinimalView(context: context)
            }
        }
    }
}