Live Activities and the Dynamic Island

Before Live Activities, showing live progress outside your own app — a delivery, a live score, a timer — meant either the user keeping the app foregrounded or you spamming local notifications; nothing occupied the Lock Screen persistently and updated in place.

#The new way

import ActivityKit

struct DeliveryAttributes: ActivityAttributes {
    struct ContentState: Codable, Hashable {
        var driverName: String
        var minutesAway: Int
    }

    var orderNumber: String
}

func startDeliveryActivity(orderNumber: String) throws {
    let attributes = DeliveryAttributes(orderNumber: orderNumber)
    let initialState = DeliveryAttributes.ContentState(driverName: "Alex", minutesAway: 18)

    _ = try Activity<DeliveryAttributes>.request(
        attributes: attributes,
        content: .init(state: initialState, staleDate: nil)
    )
}

func updateDeliveryActivity(_ activity: Activity<DeliveryAttributes>, minutesAway: Int) async {
    let updatedState = DeliveryAttributes.ContentState(driverName: "Alex", minutesAway: minutesAway)
    await activity.update(.init(state: updatedState, staleDate: nil))
}

#Why it matters

• Updates push live content to the Lock Screen and Dynamic Island without the user reopening the app
• Activity.request and .update work locally from the app, or remotely via push updates for state changes that originate server-side
• One ActivityAttributes.ContentState type drives both the Lock Screen banner and the compact/expanded Dynamic Island layouts, defined together in a widget extension's ActivityConfiguration
• Removes the need for local-notification hacks or background polling just to keep a status visible

#Gotcha

Live Activities have a hard duration limit — they end automatically after several hours of inactivity regardless of whether you ever call end(), so a long-running process needs its own way to notify the user once the activity has been force-ended. ContentState also has to stay small and Codable; a payload that pushes past the system's size limit for a push update fails silently rather than throwing where you'd expect. Verify current duration and payload limits against Apple's docs, since both have shifted across iOS releases since the 16.1 launch.