Spec: Status Bar (MVP)

Implementable contract for v0.1 Status Bar. Overview narrative: status-bars.md. Scope freeze: mvp.md.

Purpose

Glanceable vehicle/system status: connectivity, clock, battery/SOC, alerts. Honest unavailable/stale/fault presentation. Deep links gated by Restriction Engine.

Anatomy

┌──────────────────────────────────────────────────────────┐
│ 🕒  📶  🔋 80%  72°F                    ⚠ (alerts)       │
└──────────────────────────────────────────────────────────┘

Items are an ordered list; overflow policy is program-defined but must not drop active fault affordances.

States

State	Behavior
Normal	Items show live values
Warning / fault present	Semantic warning/error tokens; persistent until cleared
Charging	Charging accent recognizable
Signal unavailable / stale	Explicit degraded UI — never fake “off”
Restricted	Settings deep links Block/Substitute per matrix
Day / Night	Token schemes

Live warning / charging accents are selected via CabinStatusEmphasis on CabinStatusGlyph. Signal unavailable / stale / fault always override emphasis. Missing CabinComplianceHost is fail-closed (GateDisposition.Block) for activating deep links.

Sizes & type (from tokens)

Token (stub)	Role
cabin.component.statusBar.height	Bar height
cabin.component.statusBar.iconSize	Icons
cabin.component.statusBar.itemGap	Gap
cabin.type.role.status	Status typography
cabin.color.scheme.*.warning / error / charging	Feedback / domain (night contrast locked)
cabin.color.scheme.*.container / onContainer / outline	Bar chrome

Stub file: tokens/cabin.tokens.json. See token-schema for day/night role table.

Compliance gates

Interaction	Gating
Glance display	Always
StatusDeepLink informational	Substitute while Moving/Restricted
StatusDeepLink settings/setup	Block while Moving/Restricted
OpenKeyboard	Block outside Parked

Safety class: mostly Informational; fault presentation is safety-adjacent (safety-critical).

Planned Views API (MVP primary)

class CabinStatusBarView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
) : ViewGroup(context, attrs) {
    fun setItems(items: List<CabinStatusItem>) { /* … */ }
    fun setCompliance(host: CabinComplianceHost) { /* … */ }
}

Alpha implementation: dev.decoupled.cabin.views.CabinStatusBarView in cabin-views / CabinViews. Signal lives in cabin-compliance.

Compose API (Experimental parity)

@Composable
fun CabinStatusBar(
    items: List<CabinStatusItem>,
    modifier: Modifier = Modifier,
)

Experimental implementation: dev.decoupled.cabin.compose.CabinStatusBar in cabin-compose / CabinCompose. Same Signal / emphasis / deep-link gating as Views; wrap with CabinTheme. Not for SystemUI Soong adoption.

Acceptance criteria (MVP)

• Exhaustive unavailable/stale/fault rendering for signal-backed items
• Matrix behavior matches restriction-states for Status Bar
• Fault/warning contrast day/night
• Content descriptions present
• No dependency on cabin-compose

Related

• System Bar spec
• Restriction states
• Compose (Experimental parity)
• EV (SOC item semantics; full EV screens post-MVP)