Codex/background task

[tifroz]

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• AI was used to generate or assist with generating this PR. Please specify below how you used AI to help you, and what steps you have taken to manually verify the changes.

Codex generated the code, manually validate from a sandbox native app

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Summary

Adds three dual-platform device/app-shell capabilities to SkipDevice:

• ApplicationRuntimeProvider for app lifecycle and memory pressure events
• BackgroundActivity for finite user-visible background work
• DeviceIdentity.current for basic platform device metadata

Changes

Application runtime events

Adds ApplicationRuntimeProvider, which exposes:

• currentLifecyclePhase
• monitorLifecycle() -> AsyncStream<ApplicationLifecycleEvent>
• monitorMemoryPressure() -> AsyncStream<MemoryPressureEvent>
• stop()

On Apple platforms this uses UIApplication notifications for lifecycle and memory warnings.

On Android this uses:

• Application.ActivityLifecycleCallbacks for lifecycle
• ComponentCallbacks2 for memory pressure

Android memory pressure maps onLowMemory, TRIM_MEMORY_RUNNING_CRITICAL, and TRIM_MEMORY_COMPLETE to .critical; other trim callbacks map to .warning.

Lifecycle events expose both:

• kind, preserving iOS-style event names where possible
• phase, a normalized app phase

Background activity

Adds BackgroundActivity.begin(_:) / BackgroundActivity.end(_:) for finite background work.

On iOS/tvOS this wraps UIApplication.beginBackgroundTask and endBackgroundTask.

On Android this adds a generic BackgroundActivityService foreground service with a registry of active activity IDs. The service stops when no activities remain.

Android foreground-service type mapping:

Reason	Android foreground service type
localNetworkTransfer	dataSync
mediaProcessing	mediaProcessing on Android 15+, dataSync fallback
connectedDeviceTransfer	connectedDevice
shortCriticalWork	shortService when available, dataSync fallback

The Android service implements foreground-service timeout handling and stops promptly when Android reports a timeout.

Device identity

Adds DeviceIdentity.current, exposing low-level device metadata:

• name
• model
• localizedModel
• systemName
• systemVersion
• vendorIdentifier
• manufacturer
• brand
• device
• product

On Apple platforms this wraps UIDevice. On Android this reads from Build, Settings.Global, and Settings.Secure.

vendorIdentifier maps to UIDevice.identifierForVendor on Apple platforms and Settings.Secure.ANDROID_ID on Android.

Android setup

Adds an androidx.core:core dependency for NotificationCompat, ServiceCompat, and ContextCompat.

Updates README documentation with required Android manifest entries for apps using BackgroundActivity, including foreground-service permissions and service declaration.

Background task example usage

import SkipDevice

func runTransfer() async throws {
    let activityID = try await BackgroundActivity.begin(BackgroundActivityRequest(
        name: "Streaming to receiver",
        reason: .connectedDeviceTransfer,
        detail: "Maintaining the local transfer"
    ))

    do {
        try await streamToReceiver()
        await BackgroundActivity.end(activityID)
    } catch {
        await BackgroundActivity.end(activityID)
        throw error
    }
}

Background task in the sandbox

Notice the number of ticks executed in the background, from the UI report + logs

video-capture-20260610-143302-stream.mp4

[marcprux]

This looks useful overall! It does look like there's a concurrency issue in CI that we'll need to get fixed.

[marcprux]

Is there any reason to not use the latest (1.9.0) version of the dependency?

[tifroz]

Android’s foreground-service docs say the ServiceCompat overload that accepts foreground-service types is available in androidx-core 1.12+

• minimum defensible version: androidx.core:core:1.12.0
• conservative current choice: androidx.core:core:1.13.1
• latest stable if the Skip Android toolchain supports it: androidx.core:core:1.17.0

I picked 1.13.1 as a conservative stable version above that minimum. AndroidX’s release notes say 1.17.0 requires Kotlin Gradle Plugin 2.0.0+, so I’d prefer to only bump that far if skip-device’s Android build/toolchain is already aligned with that requirement.

Happy to update the PR to whichever version you prefer.

[tifroz]

@marcprux pinging your because it feels like PR that have a request change are falling off the radar? no rush