Merge pull request #11 from iscle/feature/host-toasts

Show app toasts on the projected car display

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarToastOverlay.kt

@@ -0,0 +1,55 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.platform.LocalAccessibilityManager
+import androidx.compose.ui.semantics.LiveRegionMode
+import androidx.compose.ui.semantics.liveRegion
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.delay
+
+/** Draw inside the encoded car display; a normal Android Toast would appear on the phone. */
+@Composable
+internal fun CarToastOverlay(modifier: Modifier = Modifier) {
+    val current by CarToasts.message.collectAsState()
+    val message = current ?: return
+    val accessibility = LocalAccessibilityManager.current
+    LaunchedEffect(message, accessibility) {
+        val timeout = accessibility?.calculateRecommendedTimeoutMillis(
+            message.durationMs, containsIcons = false, containsText = true, containsControls = false,
+        ) ?: message.durationMs
+        delay(timeout)
+        CarToasts.dismiss(message)
+    }
+
+    // A non-interactive overlay leaves the map's touch handling and focus intact.
+    Box(
+        modifier
+            .padding(horizontal = 24.dp, vertical = 16.dp)
+            .widthIn(max = 560.dp)
+            .clip(MaterialTheme.shapes.medium)
+            .background(MaterialTheme.colorScheme.inverseSurface)
+            .semantics { liveRegion = LiveRegionMode.Polite },
+    ) {
+        Text(
+            message.text,
+            modifier = Modifier.padding(horizontal = 20.dp, vertical = 12.dp),
+            color = MaterialTheme.colorScheme.inverseOnSurface,
+            style = MaterialTheme.typography.bodyLarge,
+            maxLines = 3,
+            overflow = TextOverflow.Ellipsis,
+        )
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarToasts.kt

@@ -0,0 +1,33 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.annotation.MainThread
+import androidx.car.app.CarToast
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+/** One toast across navigation and browse apps; newer requests replace stale messages. */
+@MainThread
+internal object CarToasts {
+    // Identity matters: repeating identical text must restart its display timer.
+    class Message(val owner: Any, val text: String, val durationMs: Long)
+
+    private val current = MutableStateFlow<Message?>(null)
+    val message: StateFlow<Message?> = current.asStateFlow()
+
+    fun show(owner: Any, text: String, duration: Int) {
+        if (text.isBlank()) return
+        val durationMs = if (duration == CarToast.LENGTH_LONG) 3_500L else 2_000L
+        current.value = Message(owner, text, durationMs)
+    }
+
+    fun dismiss(message: Message) {
+        // An old timer must not dismiss a newer toast, even if its text is identical.
+        if (current.value === message) current.value = null
+    }
+
+    fun clear(owner: Any) {
+        // Disconnecting the map must not clear a toast belonging to the browse app.
+        if (current.value?.owner === owner) current.value = null
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarUi.kt

@@ -226,6 +226,7 @@ fun CarUi() {
                                 }
                             }
                         }
+                        CarToastOverlay(Modifier.align(Alignment.BottomCenter))
                         PopupTimer()
                         // The dashboard is already listing them, so it needs no popup.
                         NotificationPopup(

gearslip/src/main/java/app/seb3thehacker/gearslip/host/CarAppConnection.kt

@@ -1,6 +1,7 @@
 package app.seb3thehacker.gearslip.host
 
 import app.seb3thehacker.gearslip.car.CarEnvironment
+import app.seb3thehacker.gearslip.car.CarToasts
 import android.content.ComponentName
 import android.content.Context
 import android.content.Intent
@@ -80,6 +81,8 @@ class CarAppConnection(private val context: Context) {
     val template: StateFlow<Template?> = _template.asStateFlow()
 
     private val main = Handler(Looper.getMainLooper())
+    /** Captured by each host Binder so callbacks queued by a replaced app cannot show a toast. */
+    private var toastOwner = Any()
 
     private var carApp: ICarApp? = null
     private var appManager: IAppManager? = null
@@ -215,6 +218,7 @@ class CarAppConnection(private val context: Context) {
     fun disconnect() = disconnect(keepLocation = false)
 
     private fun disconnect(keepLocation: Boolean) {
+        clearToasts()
         lent?.let { sendSurfaceDestroyed(it) }
         lent = null
         val carApp = this.carApp
@@ -285,7 +289,7 @@ class CarAppConnection(private val context: Context) {
             ?: Intent(Intent.ACTION_MAIN).setComponent(component)
         pendingDestination = null
         call("onAppCreate", onValue = { onCreated() }) {
-            app.onAppCreate(carHost, intent, carConfiguration(), it)
+            app.onAppCreate(createCarHost(toastOwner), intent, carConfiguration(), it)
         }
     }
 
@@ -558,14 +562,19 @@ class CarAppConnection(private val context: Context) {
 
     // --- host interfaces the app calls back into -----------------------------------------
 
-    private val appHost = object : IAppHost.Stub() {
+    private fun createAppHost(owner: Any) = object : IAppHost.Stub() {
         override fun invalidate() {
             GearslipLog.i("host: app invalidated its template")
             main.post { requestTemplate() }
         }
 
         override fun showToast(text: CharSequence?, duration: Int) {
-            GearslipLog.i("host: toast \"$text\"")
+            val message = text?.toString() ?: return
+            main.post {
+                if (toastOwner !== owner) return@post
+                GearslipLog.i("host: toast \"$message\"")
+                CarToasts.show(owner, message, duration)
+            }
         }
 
         /**
@@ -665,7 +674,9 @@ class CarAppConnection(private val context: Context) {
         override fun updateSuggestions(suggestions: Bundleable?) = Unit
     }
 
-    private val carHost = object : ICarHost.Stub() {
+    private fun createCarHost(owner: Any) = object : ICarHost.Stub() {
+        private val appHost = createAppHost(owner)
+
         override fun getHost(type: String?): IBinder? = when (type) {
             CarContext.APP_SERVICE -> appHost.asBinder()
             CarContext.NAVIGATION_SERVICE -> navigationHost.asBinder()
@@ -754,10 +765,16 @@ class CarAppConnection(private val context: Context) {
     }
 
     private fun fail(phase: Phase, detail: String) {
+        clearToasts()
         GearslipLog.e("host: $detail")
         update { it.copy(phase = phase, detail = detail) }
     }
 
+    private fun clearToasts() {
+        CarToasts.clear(toastOwner)
+        toastOwner = Any()
+    }
+
     private fun update(block: (Status) -> Status) {
         _status.value = block(_status.value)
     }