GroupActivities Reference

Signatures, availability, and deprecations for GroupActivities, the framework behind SharePlay. Every signature is checked against the iOS 27 SDK interface rather than Apple's web documentation, which truncates several of these pages.

When to Use This Reference

Use this reference when:

• You need an exact signature, and the rendered Apple page shows only a member list
• You're checking whether a symbol exists on a given platform or OS version
• You've inherited SharePlay code and need to know which APIs are deprecated
• You're auditing a switch over ActivityType or GroupSession.State
• You need to know which import an overlay symbol requires

Example Prompts

Questions you can ask your assistant that will draw from this reference:

• "What's the full list of GroupActivityMetadata.ActivityType values?"
• "Is GroupActivityTransferRepresentation available on tvOS?"
• "What replaced metadata.localizedTitle?"
• "What are the cases of GroupActivityActivationResult and what should each one do?"
• "Which import do I need for GroupActivitySharingController?"

What's Covered

Setup

Entitlement, Info.plist keys (none needed), allowed target types, platform support

Activity definition

GroupActivity, GroupActivityMetadata, ActivityType (all ten values), LifetimePolicy, SceneAssociationBehavior, BroadcastOptions, supportsContinuationOnTV

Activation and discovery

GroupStateObserver, GroupActivityActivationResult, prepareForActivation(), activate(), GroupActivitySharingController, GroupActivityTransferRepresentation

Session

GroupSession, GroupSession.State, GroupSession.Sessions, Participant, Participants

Distributed state

GroupSessionMessenger, DeliveryMode, Messages, MessageContext, GroupSessionJournal, Attachment, Attachments

Notices

GroupSessionEvent, Action, QueueChange

Migration

Full deprecation table, cross-import overlay requirements, visionOS additions (systemCoordinator, SpatialTemplatePreference, GroupActivityAssociationKind)

Documentation Scope

This page documents the shareplay-ref skill (in the axiom-integration suite), the API lookup half of Axiom's SharePlay coverage. Patterns, decisions, and the reasoning behind them live in the shareplay and shareplay-playback skills listed under Related.

Notes That Change How You Write the Code

A few facts in this reference deserve a callout, because the obvious reading of Apple's documentation produces code that looks right and is wrong.

ActivityType is a struct of static lets, not an enum. A switch over it needs default:. There are ten values; the deprecated Experience enum exposes only two of them.

GroupSession.State and GroupActivityActivationResult are non-frozen. In Swift 6 language mode, a switch without @unknown default is a compile error rather than a warning.

The journal has no pre-download validation hook. Attachments cap at 100 MB, and there is no point at which you can gate, moderate, or check entitlements before a participant downloads. Apple directs protected content to your own server.

activate() returns Bool, and false is not a failure — it means no session will be delivered to your app, so stop waiting rather than retrying or calling end(). An Apple TV handoff is one example, not the only one. Real failures throw.

GroupActivityTransferRepresentation is unavailable on tvOS, even though GroupActivities itself runs there, so the share sheet, ShareLink, and AirDrop can't start a session on that platform. GroupActivitySharingController is unavailable on tvOS too, which leaves no in-app way to start SharePlay there: sessions must begin on another device.

GroupSession is not Sendable, while GroupSessionMessenger and GroupSessionJournal are @unchecked Sendable. Observation is Combine-only — there is no AsyncSequence for state, activity, or activeParticipants.

GroupSessionJournal.Attachments.Element is an array, not a single attachment. Each iteration delivers the entire current set to everyone, including whoever uploaded it.

Nothing was added to GroupActivities in the 27 SDK line — the iOS and visionOS interfaces are identical between the 27.0 and 27.2 SDKs apart from their header lines. Guidance here is written against the 27.2 interface.

Related

• SharePlay overview – where to start with Axiom's SharePlay coverage, and which skill answers which question
• shareplay – session lifecycle, activation, distributed state, and the patterns these APIs require
• shareplay-playback – synchronized media playback, which AVFoundation coordinates rather than your messenger (in the axiom-media suite)
• swift-concurrency – isolating a GroupSession, which is not Sendable

Resources

WWDC: 2021-10183, 2021-10187, 2022-10140, 2023-10239, 2023-10241

Docs: /groupactivities, /groupactivities/groupsession, /groupactivities/groupsessionmessenger, /groupactivities/groupsessionjournal, /groupactivities/groupactivitymetadata, /xcode/configuring-group-activities