Merge pull request #765 from android/refactor/notification-dot-modifier

Notification dot improvements

app/src/main/java/com/google/samples/apps/nowinandroid/ui/NiaApp.kt

@@ -15,6 +15,7 @@
  */
 
 package com.google.samples.apps.nowinandroid.ui
+
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.ExperimentalLayoutApi
 import androidx.compose.foundation.layout.Row
@@ -46,6 +47,7 @@ import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.composed
 import androidx.compose.ui.draw.drawWithContent
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.graphics.Color
@@ -129,6 +131,8 @@ fun NiaApp(
                 )
             }
 
+            val unreadDestinations by appState.topLevelDestinationsWithUnreadResources.collectAsStateWithLifecycle()
+
             Scaffold(
                 modifier = Modifier.semantics {
                     testTagsAsResourceId = true
@@ -139,7 +143,6 @@ fun NiaApp(
                 snackbarHost = { SnackbarHost(snackbarHostState) },
                 bottomBar = {
                     if (appState.shouldShowBottomBar) {
-                        val unreadDestinations by appState.topLevelDestinationsWithUnreadResources.collectAsStateWithLifecycle()
                         NiaBottomBar(
                             destinations = appState.topLevelDestinations,
                             destinationsWithUnreadResources = unreadDestinations,
@@ -164,6 +167,7 @@ fun NiaApp(
                     if (appState.shouldShowNavRail) {
                         NiaNavRail(
                             destinations = appState.topLevelDestinations,
+                            destinationsWithUnreadResources = unreadDestinations,
                             onNavigateToDestination = appState::navigateToTopLevelDestination,
                             currentDestination = appState.currentDestination,
                             modifier = Modifier
@@ -208,6 +212,7 @@ fun NiaApp(
 @Composable
 private fun NiaNavRail(
     destinations: List<TopLevelDestination>,
+    destinationsWithUnreadResources: Set<TopLevelDestination>,
     onNavigateToDestination: (TopLevelDestination) -> Unit,
     currentDestination: NavDestination?,
     modifier: Modifier = Modifier,
@@ -215,6 +220,7 @@ private fun NiaNavRail(
     NiaNavigationRail(modifier = modifier) {
         destinations.forEach { destination ->
             val selected = currentDestination.isTopLevelDestinationInHierarchy(destination)
+            val hasUnread = destinationsWithUnreadResources.contains(destination)
             NiaNavigationRailItem(
                 selected = selected,
                 onClick = { onNavigateToDestination(destination) },
@@ -237,7 +243,7 @@ private fun NiaNavRail(
                     }
                 },
                 label = { Text(stringResource(destination.iconTextId)) },
-
+                modifier = if (hasUnread) Modifier.notificationDot() else Modifier,
             )
         }
     }
@@ -279,30 +285,30 @@ private fun NiaBottomBar(
                     }
                 },
                 label = { Text(stringResource(destination.iconTextId)) },
-                modifier = if (hasUnread) notificationDot() else Modifier,
+                modifier = if (hasUnread) Modifier.notificationDot() else Modifier,
             )
         }
     }
 }
 
-@Composable
+private fun Modifier.notificationDot(): Modifier =
-private fun notificationDot(): Modifier {
+    composed {
-    val tertiaryColor = MaterialTheme.colorScheme.tertiary
+        val tertiaryColor = MaterialTheme.colorScheme.tertiary
-    return Modifier.drawWithContent {
+        drawWithContent {
-        drawContent()
+            drawContent()
-        drawCircle(
+            drawCircle(
-            tertiaryColor,
+                tertiaryColor,
-            radius = 5.dp.toPx(),
+                radius = 5.dp.toPx(),
-            // This is based on the dimensions of the NavigationBar's "indicator pill";
+                // This is based on the dimensions of the NavigationBar's "indicator pill";
-            // however, its parameters are private, so we must depend on them implicitly
+                // however, its parameters are private, so we must depend on them implicitly
-            // (NavigationBarTokens.ActiveIndicatorWidth = 64.dp)
+                // (NavigationBarTokens.ActiveIndicatorWidth = 64.dp)
-            center = center + Offset(
+                center = center + Offset(
-                64.dp.toPx() * .45f,
+                    64.dp.toPx() * .45f,
-                32.dp.toPx() * -.45f - 6.dp.toPx(),
+                    32.dp.toPx() * -.45f - 6.dp.toPx(),
-            ),
+                ),
-        )
+            )
+        }
     }
-}
 
 private fun NavDestination?.isTopLevelDestinationInHierarchy(destination: TopLevelDestination) =
     this?.hierarchy?.any {