feat(android): live dashboard screen (Phase 28.4)

android/app/src/main/java/com/yarisobd/app/DashboardScreen.kt

@@ -0,0 +1,305 @@
+package com.yarisobd.app
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.LocationOn
+import androidx.compose.material.icons.filled.Speed
+import androidx.compose.material.icons.filled.Warning
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.yarisobd.app.data.remote.dto.GpsStatus
+import com.yarisobd.app.data.remote.dto.ObdStatus
+import com.yarisobd.app.data.remote.dto.Stats
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+
+private val MIL_AMBER = Color(0xFFE6A817)
+
+@Composable
+fun DashboardScreen(
+    gps: GpsStatus?,
+    obd: ObdStatus?,
+    stats: Stats?,
+    piOnline: Boolean,
+    serverOnline: Boolean,
+    lastUpdate: Long,
+    onStartPolling: () -> Unit,
+    onStopPolling: () -> Unit,
+) {
+    // Poll while this screen is composed; stop when the user navigates away.
+    DisposableEffect(Unit) {
+        onStartPolling()
+        onDispose { onStopPolling() }
+    }
+
+    Column(modifier = Modifier.fillMaxSize()) {
+        com.yarisobd.app.ui.components.YarisHeader()
+
+        // Connection status bar
+        Row(
+            modifier = Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 6.dp),
+            horizontalArrangement = Arrangement.spacedBy(16.dp),
+            verticalAlignment = Alignment.CenterVertically
+        ) {
+            StatusDot(online = piOnline, label = "Pi WiFi", color = MaterialTheme.colorScheme.primary)
+            StatusDot(online = serverOnline, label = "Server", color = MaterialTheme.colorScheme.tertiary)
+            Spacer(Modifier.weight(1f))
+            if (lastUpdate > 0L) {
+                Text(
+                    "Updated ${SimpleDateFormat("HH:mm:ss", Locale.US).format(Date(lastUpdate))}",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
+                )
+            }
+        }
+
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .verticalScroll(rememberScrollState())
+                .padding(horizontal = 16.dp),
+            verticalArrangement = Arrangement.spacedBy(10.dp)
+        ) {
+            Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+                SpeedCard(obd, Modifier.weight(1f))
+                RpmCard(obd, Modifier.weight(1f))
+            }
+
+            EngineStatsCard(obd)
+            MilCard(obd, stats)
+            GpsCard(gps)
+            OverviewCard(stats)
+            Spacer(Modifier.height(8.dp))
+        }
+    }
+}
+
+@Composable
+private fun StatusDot(online: Boolean, label: String, color: Color) {
+    Row(verticalAlignment = Alignment.CenterVertically) {
+        Box(
+            Modifier
+                .size(10.dp)
+                .background(if (online) color else MaterialTheme.colorScheme.surfaceVariant, CircleShape)
+        )
+        Spacer(Modifier.width(6.dp))
+        Text(
+            label,
+            style = MaterialTheme.typography.bodySmall,
+            color = if (online) color else MaterialTheme.colorScheme.onSurfaceVariant
+        )
+    }
+}
+
+@Composable
+private fun SpeedCard(obd: ObdStatus?, modifier: Modifier = Modifier) {
+    val speed = obd?.speed
+    val connected = obd?.car_connected == true
+    Card(
+        modifier = modifier,
+        shape = RoundedCornerShape(16.dp),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerHigh)
+    ) {
+        Column(Modifier.fillMaxWidth().padding(16.dp), horizontalAlignment = Alignment.CenterHorizontally) {
+            Icon(Icons.Filled.Speed, null, tint = MaterialTheme.colorScheme.primary, modifier = Modifier.size(22.dp))
+            Spacer(Modifier.height(6.dp))
+            Text(speedText(speed), fontSize = 44.sp, fontWeight = FontWeight.Bold, color = MaterialTheme.colorScheme.onSurface)
+            Text("km/h", style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
+            Spacer(Modifier.height(4.dp))
+            Text(
+                if (connected) "OBD speed" else "OBD offline",
+                style = MaterialTheme.typography.bodySmall,
+                color = if (connected) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.error
+            )
+        }
+    }
+}
+
+@Composable
+private fun RpmCard(obd: ObdStatus?, modifier: Modifier = Modifier) {
+    val rpm = obd?.rpm
+    Card(
+        modifier = modifier,
+        shape = RoundedCornerShape(16.dp),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerHigh)
+    ) {
+        Column(Modifier.fillMaxWidth().padding(16.dp), horizontalAlignment = Alignment.CenterHorizontally) {
+            Text("RPM", style = MaterialTheme.typography.labelMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+            Spacer(Modifier.height(6.dp))
+            Text(intText(rpm), fontSize = 44.sp, fontWeight = FontWeight.Bold, color = rpmColor(rpm))
+            Text("rev/min", style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
+        }
+    }
+}
+
+@Composable
+private fun EngineStatsCard(obd: ObdStatus?) {
+    Card(
+        modifier = Modifier.fillMaxWidth(),
+        shape = RoundedCornerShape(16.dp),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerHigh)
+    ) {
+        Row(Modifier.fillMaxWidth().padding(16.dp)) {
+            StatCell("Coolant", "${intText(obd?.coolant_temp)} °C", Modifier.weight(1f))
+            StatCell("Fuel", "${intText(obd?.fuel_level)} %", Modifier.weight(1f))
+            StatCell("Throttle", "${intText(obd?.throttle_position)} %", Modifier.weight(1f))
+        }
+    }
+}
+
+@Composable
+private fun StatCell(label: String, value: String, modifier: Modifier = Modifier) {
+    Column(modifier = modifier, horizontalAlignment = Alignment.CenterHorizontally) {
+        Text(label, style = MaterialTheme.typography.labelSmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
+        Spacer(Modifier.height(4.dp))
+        Text(value, style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+    }
+}
+
+@Composable
+private fun MilCard(obd: ObdStatus?, stats: Stats?) {
+    val mil = obd?.mil_on
+    val dtcCount = stats?.active_dtc ?: 0
+    val color = when {
+        mil == true -> MIL_AMBER
+        mil == false -> Color(0xFF2E7D32)
+        else -> MaterialTheme.colorScheme.onSurfaceVariant
+    }
+    val label = when {
+        mil == true -> "MIL ON — Check Engine"
+        mil == false -> "No MIL"
+        else -> "MIL unknown"
+    }
+    Card(
+        modifier = Modifier.fillMaxWidth(),
+        shape = RoundedCornerShape(16.dp),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerHigh)
+    ) {
+        Row(Modifier.fillMaxWidth().padding(16.dp), verticalAlignment = Alignment.CenterVertically) {
+            Icon(Icons.Filled.Warning, null, tint = color, modifier = Modifier.size(22.dp))
+            Spacer(Modifier.width(10.dp))
+            Column(Modifier.weight(1f)) {
+                Text(label, style = MaterialTheme.typography.titleSmall, color = color, fontWeight = FontWeight.SemiBold)
+                Text("DTCs stored: $dtcCount", style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
+            }
+            Text("DTC", style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
+        }
+    }
+}
+
+@Composable
+private fun GpsCard(gps: GpsStatus?) {
+    val hasFix = gps?.has_fix == true
+    Card(
+        modifier = Modifier.fillMaxWidth(),
+        shape = RoundedCornerShape(16.dp),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerHigh)
+    ) {
+        Column(Modifier.fillMaxWidth().padding(16.dp)) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Icon(
+                    Icons.Filled.LocationOn,
+                    null,
+                    tint = if (hasFix) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.error,
+                    modifier = Modifier.size(20.dp)
+                )
+                Spacer(Modifier.width(8.dp))
+                Text(
+                    if (hasFix) "GPS fix" else "No GPS fix",
+                    style = MaterialTheme.typography.titleSmall,
+                    color = if (hasFix) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.error,
+                    fontWeight = FontWeight.SemiBold
+                )
+                Spacer(Modifier.weight(1f))
+                Text(
+                    "age ${ageText(gps?.fix_age_seconds)}",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
+                )
+            }
+            Spacer(Modifier.height(8.dp))
+            HorizontalDivider(color = MaterialTheme.colorScheme.surfaceVariant)
+            Spacer(Modifier.height(8.dp))
+            Row(Modifier.fillMaxWidth()) {
+                StatCell("Lat", coordText(gps?.latitude), Modifier.weight(1f))
+                StatCell("Lon", coordText(gps?.longitude), Modifier.weight(1f))
+                StatCell("Thread", if (gps?.thread_alive == true) "alive" else "—", Modifier.weight(1f))
+            }
+        }
+    }
+}
+
+@Composable
+private fun OverviewCard(stats: Stats?) {
+    Card(
+        modifier = Modifier.fillMaxWidth(),
+        shape = RoundedCornerShape(16.dp),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerHigh)
+    ) {
+        Column(Modifier.fillMaxWidth().padding(16.dp)) {
+            Text("Overview", style = MaterialTheme.typography.titleSmall, color = MaterialTheme.colorScheme.primary)
+            Spacer(Modifier.height(10.dp))
+            Row(Modifier.fillMaxWidth()) {
+                StatCell("Trips", "${stats?.trip_count ?: 0}", Modifier.weight(1f))
+                StatCell("Total km", oneDecimal(stats?.total_km), Modifier.weight(1f))
+                StatCell("Max speed", "${intText(stats?.all_time_max_speed)} km/h", Modifier.weight(1f))
+            }
+            Spacer(Modifier.height(10.dp))
+            Row(Modifier.fillMaxWidth()) {
+                StatCell("Videos", "${stats?.video_count ?: 0}", Modifier.weight(1f))
+                StatCell("DTCs", "${stats?.active_dtc ?: 0}", Modifier.weight(1f))
+                StatCell("Odometer", odoText(stats), Modifier.weight(1f))
+            }
+        }
+    }
+}
+
+// --- formatting helpers ---
+
+private fun speedText(v: Double?): String = v?.let { "%.0f".format(it) } ?: "—"
+private fun intText(v: Double?): String = v?.let { "%.0f".format(it) } ?: "—"
+private fun oneDecimal(v: Double?): String = v?.let { "%.1f".format(it) } ?: "—"
+private fun coordText(v: Double?): String = v?.let { "%.4f".format(it) } ?: "—"
+private fun ageText(v: Double?): String = v?.let { "%.0fs".format(it) } ?: "—"
+
+private fun odoText(stats: Stats?): String {
+    val v = stats?.odometer_km ?: return "—"
+    return "%.0f".format(v)
+}
+
+@Composable
+private fun rpmColor(rpm: Double?): Color = when {
+    rpm == null -> MaterialTheme.colorScheme.onSurface
+    rpm < 3000 -> Color(0xFF2E7D32)
+    rpm < 5000 -> MIL_AMBER
+    else -> MaterialTheme.colorScheme.error
+}

android/app/src/main/java/com/yarisobd/app/DashboardViewModel.kt

@@ -0,0 +1,128 @@
+package com.yarisobd.app
+
+import android.app.Application
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import com.yarisobd.app.data.CredentialStore
+import com.yarisobd.app.data.remote.PiApi
+import com.yarisobd.app.data.remote.ServerApi
+import com.yarisobd.app.data.remote.dto.GpsStatus
+import com.yarisobd.app.data.remote.dto.ObdStatus
+import com.yarisobd.app.data.remote.dto.Stats
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlinx.serialization.json.Json
+import okhttp3.MediaType.Companion.toMediaType
+import okhttp3.OkHttpClient
+import retrofit2.Retrofit
+import retrofit2.converter.kotlinx.serialization.asConverterFactory
+import java.util.concurrent.TimeUnit
+
+class DashboardViewModel(application: Application) : AndroidViewModel(application) {
+
+    private val baseUrl = "http://10.42.0.1"
+    private val json = Json { ignoreUnknownKeys = true; coerceInputValues = true }
+
+    private val okHttp = OkHttpClient.Builder()
+        .connectTimeout(3, TimeUnit.SECONDS)
+        .readTimeout(5, TimeUnit.SECONDS)
+        .build()
+
+    private val api: PiApi = Retrofit.Builder()
+        .baseUrl("$baseUrl/")
+        .client(okHttp)
+        .addConverterFactory(json.asConverterFactory("application/json".toMediaType()))
+        .build()
+        .create(PiApi::class.java)
+
+    private val _gps = MutableStateFlow<GpsStatus?>(null)
+    val gps: StateFlow<GpsStatus?> = _gps.asStateFlow()
+
+    private val _obd = MutableStateFlow<ObdStatus?>(null)
+    val obd: StateFlow<ObdStatus?> = _obd.asStateFlow()
+
+    private val _stats = MutableStateFlow<Stats?>(null)
+    val stats: StateFlow<Stats?> = _stats.asStateFlow()
+
+    private val _piOnline = MutableStateFlow(false)
+    val piOnline: StateFlow<Boolean> = _piOnline.asStateFlow()
+
+    private val _serverOnline = MutableStateFlow(false)
+    val serverOnline: StateFlow<Boolean> = _serverOnline.asStateFlow()
+
+    private val _lastUpdate = MutableStateFlow(0L)
+    val lastUpdate: StateFlow<Long> = _lastUpdate.asStateFlow()
+
+    private var pollJob: Job? = null
+    private var serverApi: ServerApi? = null
+
+    /** Begin the 2s poll loop. Fetches immediately, then every 2s. */
+    fun startPolling() {
+        if (pollJob?.isActive == true) return
+        pollJob = viewModelScope.launch {
+            while (isActive) {
+                fetch()
+                delay(2000)
+            }
+        }
+    }
+
+    fun stopPolling() {
+        pollJob?.cancel()
+        pollJob = null
+    }
+
+    fun refreshNow() {
+        viewModelScope.launch { fetch() }
+    }
+
+    private suspend fun fetch() {
+        // Pi (hotspot WiFi) — GPS + OBD + overview stats, all on 10.42.0.1
+        try {
+            val g = api.getGpsStatus()
+            val o = api.getObdStatus()
+            val s = api.getStats()
+            _gps.value = g
+            _obd.value = o
+            _stats.value = s
+            _piOnline.value = true
+            _lastUpdate.value = System.currentTimeMillis()
+        } catch (e: Exception) {
+            _piOnline.value = false
+        }
+
+        // Server (cellular) — lightweight /health check when credentials are set
+        val srv = serverApi()
+        if (srv != null) {
+            try {
+                srv.health()
+                _serverOnline.value = true
+            } catch (e: Exception) {
+                _serverOnline.value = false
+            }
+        } else {
+            _serverOnline.value = false
+        }
+    }
+
+    /** Lazily build the ServerApi from the stored server URL (built once). */
+    private fun serverApi(): ServerApi? {
+        val ctx = getApplication<Application>().applicationContext
+        val serverUrl = CredentialStore.getServerUrl(ctx)
+        if (!CredentialStore.isConfigured(ctx) || serverUrl.isBlank()) return null
+        serverApi?.let { return it }
+        val built = Retrofit.Builder()
+            .baseUrl(serverUrl.trimEnd('/') + "/")
+            .client(okHttp)
+            .addConverterFactory(json.asConverterFactory("application/json".toMediaType()))
+            .build()
+            .create(ServerApi::class.java)
+        serverApi = built
+        return built
+    }
+}

android/app/src/main/java/com/yarisobd/app/MainActivity.kt

@@ -18,6 +18,7 @@ import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Videocam
+import androidx.compose.material.icons.filled.Dashboard
 import androidx.compose.material.icons.filled.FileDownload
 import androidx.compose.material.icons.filled.Settings
 import androidx.compose.runtime.Composable
@@ -52,6 +53,13 @@ class MainActivity : ComponentActivity() {
 @Composable
 fun YarisMainScreen(client: OkHttpClient) {
     val dashcamVm: DashcamViewModel = viewModel()
+    val dashboardVm: DashboardViewModel = viewModel()
+    val gps by dashboardVm.gps.collectAsState()
+    val obd by dashboardVm.obd.collectAsState()
+    val stats by dashboardVm.stats.collectAsState()
+    val piOnline by dashboardVm.piOnline.collectAsState()
+    val serverOnline by dashboardVm.serverOnline.collectAsState()
+    val lastUpdate by dashboardVm.lastUpdate.collectAsState()
     val videos by dashcamVm.videos.collectAsState()
     val totalSize by dashcamVm.totalSize.collectAsState()
     val retentionDays by dashcamVm.retentionDays.collectAsState()
@@ -88,18 +96,24 @@ fun YarisMainScreen(client: OkHttpClient) {
                 NavigationBarItem(
                     selected = selectedTab == 0,
                     onClick = { selectedTab = 0 },
-                    icon = { Icon(Icons.Filled.Videocam, contentDescription = "Dashcam") },
-                    label = { Text("Dashcam") }
+                    icon = { Icon(Icons.Filled.Dashboard, contentDescription = "Dashboard") },
+                    label = { Text("Dashboard") }
                 )
                 NavigationBarItem(
                     selected = selectedTab == 1,
                     onClick = { selectedTab = 1 },
-                    icon = { Icon(Icons.Filled.FileDownload, contentDescription = "Downloads") },
-                    label = { Text("Downloads") }
+                    icon = { Icon(Icons.Filled.Videocam, contentDescription = "Dashcam") },
+                    label = { Text("Dashcam") }
                 )
                 NavigationBarItem(
                     selected = selectedTab == 2,
                     onClick = { selectedTab = 2 },
+                    icon = { Icon(Icons.Filled.FileDownload, contentDescription = "Downloads") },
+                    label = { Text("Downloads") }
+                )
+                NavigationBarItem(
+                    selected = selectedTab == 3,
+                    onClick = { selectedTab = 3 },
                     icon = { Icon(Icons.Filled.Settings, contentDescription = "Settings") },
                     label = { Text("Settings") }
                 )
@@ -108,7 +122,17 @@ fun YarisMainScreen(client: OkHttpClient) {
     ) { padding ->
         Column(modifier = Modifier.padding(padding)) {
             when (selectedTab) {
-                0 -> DashcamScreen(
+                0 -> DashboardScreen(
+                    gps = gps,
+                    obd = obd,
+                    stats = stats,
+                    piOnline = piOnline,
+                    serverOnline = serverOnline,
+                    lastUpdate = lastUpdate,
+                    onStartPolling = { dashboardVm.startPolling() },
+                    onStopPolling = { dashboardVm.stopPolling() },
+                )
+                1 -> DashcamScreen(
                     videos = videos,
                     totalSize = totalSize,
                     retentionDays = retentionDays,
@@ -125,7 +149,7 @@ fun YarisMainScreen(client: OkHttpClient) {
                     onDeleteDashcam = { dashcamVm.deleteDashcamFile(it) },
                     onImport = { dashcamVm.importDashcamFiles(it) },
                 )
-                1 -> DownloadsScreen(
+                2 -> DownloadsScreen(
                     files = downloadedFiles,
                     activeDownloads = activeDownloads,
                     activeUploads = uploadProgress,
@@ -141,7 +165,7 @@ fun YarisMainScreen(client: OkHttpClient) {
                     onGenerateTestFile = { dashcamVm.generateTestFile() },
                     onRefresh = { dashcamVm.scanDownloads() },
                 )
-                2 -> SettingsScreen(client = client)
+                3 -> SettingsScreen(client = client)
             }
         }
     }

android/app/src/main/java/com/yarisobd/app/data/remote/PiApi.kt

@@ -2,6 +2,8 @@ package com.yarisobd.app.data.remote
 
 import com.yarisobd.app.data.remote.dto.DashcamFilesResponse
 import com.yarisobd.app.data.remote.dto.GpsStatus
+import com.yarisobd.app.data.remote.dto.ObdStatus
+import com.yarisobd.app.data.remote.dto.Stats
 import com.yarisobd.app.data.remote.dto.VideoListResponse
 import kotlinx.serialization.json.JsonObject
 import okhttp3.ResponseBody
@@ -21,6 +23,14 @@ interface PiApi {
     @GET("/api/gps/status")
     suspend fun getGpsStatus(): GpsStatus
 
+    /** Live OBD values (speed, rpm, coolant, fuel, throttle, MIL) */
+    @GET("/api/obd/status")
+    suspend fun getObdStatus(): ObdStatus
+
+    /** Overview stats (trips, odometer, DTC count, video count) */
+    @GET("/api/stats")
+    suspend fun getStats(): Stats
+
     /** List imported dashcam videos (Phase 17) */
     @GET("/api/local-videos")
     suspend fun listVideos(): VideoListResponse

android/app/src/main/java/com/yarisobd/app/data/remote/dto/ObdStatus.kt

@@ -0,0 +1,23 @@
+package com.yarisobd.app.data.remote.dto
+
+import kotlinx.serialization.Serializable
+
+/**
+ * Response from Pi's GET /api/obd/status.
+ *
+ * Live OBD values — numeric fields are null while the Pi hasn't received a
+ * fresh value from the car yet.
+ */
+@Serializable
+data class ObdStatus(
+    val adapter_present: Boolean = false,
+    val port: String? = null,
+    val car_connected: Boolean = false,
+    val status_label: String = "",
+    val speed: Double? = null,
+    val rpm: Double? = null,
+    val coolant_temp: Double? = null,
+    val fuel_level: Double? = null,
+    val throttle_position: Double? = null,
+    val mil_on: Boolean? = null,
+)

android/app/src/main/java/com/yarisobd/app/data/remote/dto/Stats.kt

@@ -0,0 +1,18 @@
+package com.yarisobd.app.data.remote.dto
+
+import kotlinx.serialization.Serializable
+
+/**
+ * Response from Pi's GET /api/stats (Phase 23 overview stats).
+ */
+@Serializable
+data class Stats(
+    val trip_count: Int = 0,
+    val total_km: Double = 0.0,
+    val total_duration_s: Double = 0.0,
+    val all_time_max_speed: Double = 0.0,
+    val active_dtc: Int = 0,
+    val video_count: Int = 0,
+    val odometer_km: Double? = null,
+    val odometer_source: String = "",
+)

android/plan.md

@@ -154,27 +154,29 @@ android/
 - [x] Retry button per failed file (tracks failed uploads via `failedUploads` StateFlow)
 - [x] Commit: `feat: upload queue screen — upload all + per-file retry`
 
-### 28.4 — Live dashboard ⬜ NOT STARTED
+### 28.4 — Live dashboard ✅ DONE (2026-08-15) — MapLibre map deferred
 **Depends on: 28.1 (networking layer). Independent of 28.2/28.3.**
 
-#### 28.4.1 — Data layer
-- [ ] Retrofit interface additions to `PiApi`:
+#### 28.4.1 — Data layer ✅
+- [x] Retrofit interface additions to `PiApi`:
   - `GET /api/gps/status` → `GpsStatus` (has_fix, lat, lon, fix_age_seconds, thread_alive)
-  - `GET /api/obd/status` → `ObdStatus` (adapter_present, port, car_connected)
-  - `GET /api/stats` → `Stats` (speed, rpm, coolant_temp, fuel_level, throttle_pos, mil_on, dtc_count, odometer_km)
-- [ ] Polling scheduler: coroutine `while(true) { delay(2000); fetch() }` scoped to ViewModel
-- [ ] Commit: `feat: dashboard data polling`
+  - `GET /api/obd/status` → `ObdStatus` (adapter_present, port, car_connected, speed, rpm,
+    coolant_temp, fuel_level, throttle_position, mil_on)
+  - `GET /api/stats` → `Stats` (trip_count, total_km, active_dtc, video_count, odometer_km)
+- [x] Polling scheduler: `DashboardViewModel` with `startPolling()`/`stopPolling()` — fetches
+  immediately then every 2s; stopped via `DisposableEffect` when the tab loses focus.
+- [x] Server `/health` check (cellular) alongside Pi polling for the connection bar.
 
-#### 28.4.2 — Dashboard UI
-- [ ] GPS card: MapLibre MapView centered on last fix with car marker
-- [ ] Speed card: large number (km/h), OBD or GPS source label
-- [ ] RPM card: gauge or number with color scale (green → yellow → red)
-- [ ] Engine stats row: coolant temp (°C), fuel level (%), throttle (%)
-- [ ] MIL/DTC indicator: check-engine icon (green/grey = no MIL, yellow/red = MIL on)
-  with DTC code count badge
-- [ ] Connection status bar: Pi WiFi icon (green = connected), cellular icon (green = online)
-- [ ] Auto-refresh every 2s, pause when app is backgrounded
-- [ ] Commit: `feat: live dashboard screen`
+#### 28.4.2 — Dashboard UI ✅ (map deferred)
+- [x] Speed card: large number (km/h), "OBD speed"/"OBD offline" source label
+- [x] RPM card: number with color scale (green < 3000, amber < 5000, red ≥ 5000)
+- [x] Engine stats row: coolant temp (°C), fuel level (%), throttle (%)
+- [x] MIL/DTC card: check-engine warning (amber = MIL on, green = no MIL) + stored DTC count
+- [x] GPS card: fix status, lat/lon, fix age, thread alive (text — MapLibre map deferred)
+- [x] Overview card: trips, total km, all-time max speed, videos, DTCs, odometer
+- [x] Connection status bar: Pi WiFi dot + Server dot (green = online), last-update timestamp
+- [x] Auto-refresh every 2s; polling stops when navigating away from the tab
+- [ ] GPS map (MapLibre) — deferred: needs the MapLibre dep + basemap over hotspot (no internet).
 
 ### 28.5 — Trip history ⬜ NOT STARTED
 **Depends on: 28.1. Independent of 28.2–28.4.**