| name | live-activities |
| description | Live Activities and Dynamic Island: ActivityKit, ActivityAttributes, real-time updates on Lock Screen and Dynamic Island. Use when showing live-updating content, delivery tracking, sports scores, or timers on the Lock Screen. Triggers: Live Activity, Dynamic Island, ActivityKit, ActivityAttributes, Lock Screen update. |
Live Activities
LIVE ACTIVITIES (ActivityKit + Dynamic Island):
FRAMEWORK: import ActivityKit
SETUP:
- Requires separate extension target (kind: "live_activity" in plan extensions array)
- NSSupportsLiveActivities: YES is auto-configured on the main app target in project.yml
- AppGroup entitlements are auto-configured for data sharing between app and extension
ATTRIBUTES (define in Shared/ directory so both app and extension compile it):
struct DeliveryAttributes: ActivityAttributes {
public struct ContentState: Codable, Hashable {
var status: String // Mutable: changes during the activity
var progress: Double
}
var orderID: String // Static: set at start, cannot change
}
STARTING AN ACTIVITY (in app):
let attributes = DeliveryAttributes(orderID: "123")
let initialState = DeliveryAttributes.ContentState(status: "Preparing", progress: 0.0)
let content = ActivityContent(state: initialState, staleDate: nil)
let activity = try Activity.request(attributes: attributes, content: content)
UPDATING AN ACTIVITY:
let updatedState = DeliveryAttributes.ContentState(status: "On the way", progress: 0.6)
let updatedContent = ActivityContent(state: updatedState, staleDate: nil)
await activity.update(updatedContent)
ENDING AN ACTIVITY:
await activity.end(nil, dismissalPolicy: .immediate)
LOCK SCREEN / DYNAMIC ISLAND UI (in extension):
struct DeliveryLiveActivityView: View {
let context: ActivityViewContext
var body: some View {
HStack { Text(context.state.status); ProgressView(value: context.state.progress) }
}
}
struct DeliveryWidget: Widget {
var body: some WidgetConfiguration {
ActivityConfiguration(for: DeliveryAttributes.self) { context in
DeliveryLiveActivityView(context: context) // Lock Screen
} dynamicIsland: { context in
DynamicIsland {
DynamicIslandExpandedRegion(.leading) { Text(context.state.status) }
DynamicIslandExpandedRegion(.trailing) { ProgressView(value: context.state.progress) }
} compactLeading: {
Image(systemName: "bicycle")
} compactTrailing: {
Text("(Int(context.state.progress * 100))%")
} minimal: {
ProgressView(value: context.state.progress)
}
}
}
}
MANDATORY FILES (every live activity extension MUST have ALL of these):
- {Name}Bundle.swift — @main WidgetBundle entry point. Without this, the extension has no entry point → linker error "undefined symbol: _main" → CodeSign failure.
- LiveActivityWidget.swift — Widget struct with ActivityConfiguration(for: Attributes.self) for Lock Screen and Dynamic Island UI.
- (Optional) Intents.swift — AppIntents for interactive buttons (complete, skip, etc.).
SHARED TYPES (CRITICAL):
- ActivityAttributes struct MUST be defined in Shared/ directory (NOT in main app's Models/). Both the main app and the live activity extension compile Shared/, so the type is visible to both. Defining it only in the main app causes "Cannot find type in scope" in the extension.
SWIFT 6 CONCURRENCY:
- AppIntent static properties MUST use "static let" (not "static var"). Mutable global state violates Swift 6 concurrency rules.
- LiveActivityService (if @MainActor) → all ViewModels calling it must also be @MainActor.
PUSH-TO-START: Use APNs with activity-update payload to start activities remotely (advanced, requires server).
