Manage a Group Activity Session with a Deterministic Finite State Machine
summary
Claims that a deterministic finite state machine reliably manages Apple Group Activities / SharePlay sessions by separating flow from operations and encoding all transitions in a state table. Uses GroupActivities API: activity types, prepareForActivation vs activate, group session messenger with reliable/unreliable messages (64k → 256k in iOS16), participant join/leave events, and activation pop‑up quirks that can disrupt shared flows. Implements transitions as events-only returns, logs every transition; demo mostly works but table size and iOS16 audio restrictions are real limits.
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chapters (11)
- 0:00Welcome
- 1:08Introduction
- 2:12Group Activities API
- 7:01Setting up API
- 13:25API quirks
- 16:56Why a deterministic finite state machine
- 19:37State transition diagram
- 23:30Implementing FSM core
- 26:25Advantages of the state machine approach
- 26:47Live demo & UI
- 30:57Concluding remarks
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