session-lifecycle

Session Lifecycle (Android)

Manage session and stream state in DAT SDK integrations.

Create a Session with Wearables.createSession(...), start it, then attach capabilities such as camera streaming. Session lifecycle and stream lifecycle are related but distinct.

Session states

Observe session state

val session = Wearables.createSession(AutoDeviceSelector()).getOrElse { error ->
    throw IllegalStateException(error.description)
}
session.start()

lifecycleScope.launch {
    session.state.collect { state ->
        when (state) {
            DeviceSessionState.STARTED -> onStarted()
            DeviceSessionState.PAUSED -> onPaused()
            DeviceSessionState.STOPPED -> onStopped()
            else -> Unit
        }
    }
}

Stream state

Camera streaming has its own state flow after you attach a stream:

STOPPED -> STARTING -> STARTED -> STREAMING -> STOPPING -> STOPPED -> CLOSED

lifecycleScope.launch {
    stream.state.collect { state ->
        // React to camera capability state changes
    }
}

Common transitions

The SDK may pause or stop a session when:

• Another experience takes over the device
• The user removes or folds the glasses
• Bluetooth connectivity drops
• The user unregisters the app or revokes needed access

Pause and resume

When a session is paused:

• The device connection may remain active
• Attached capabilities stop doing useful work
• Your app should wait for the next observed session state instead of trying to force a restart

Device availability

lifecycleScope.launch {
    Wearables.devices.collect { devices ->
        // Update the list of available devices
    }
}

Use Wearables.devices and device metadata to decide when it is sensible to create a new session after a stop.

Checklist

• Handle all DeviceSessionState values you care about
• Observe stream state separately from session state
• Release resources only after stop or close
• Recreate sessions after terminal stops instead of reusing dead ones
• Surface typed SessionError and StreamError failures

Links

• Session lifecycle documentation
• Android API reference