Hide back arrow in supporting pane when 2 panes shown

Jetcaster/app/src/main/java/com/example/jetcaster/ui/JetcasterApp.kt

@@ -113,7 +113,8 @@ fun JetcasterApp(
                     navigateToPlayer = { episodePlayer ->
                         appState.navigateToPlayer(episodePlayer.uri, backStackEntry)
                     },
-                    navigateBack = appState::navigateBack
+                    navigateBack = appState::navigateBack,
+                    showBackButton = true,
                 )
             }
         }

Jetcaster/app/src/main/java/com/example/jetcaster/ui/home/Home.kt

@@ -66,8 +66,10 @@ import androidx.compose.material3.TabRowDefaults.tabIndicatorOffset
 import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBar
 import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
+import androidx.compose.material3.adaptive.layout.PaneAdaptedValue
 import androidx.compose.material3.adaptive.layout.SupportingPaneScaffold
 import androidx.compose.material3.adaptive.layout.SupportingPaneScaffoldRole
+import androidx.compose.material3.adaptive.navigation.ThreePaneScaffoldNavigator
 import androidx.compose.material3.adaptive.navigation.rememberSupportingPaneScaffoldNavigator
 import androidx.compose.material3.windowsizeclass.ExperimentalMaterial3WindowSizeClassApi
 import androidx.compose.material3.windowsizeclass.WindowSizeClass
@@ -118,6 +120,11 @@ import kotlinx.collections.immutable.PersistentList
 import kotlinx.collections.immutable.toPersistentList
 import kotlinx.coroutines.launch
 
+@OptIn(ExperimentalMaterial3AdaptiveApi::class)
+private fun <T> ThreePaneScaffoldNavigator<T>.isMainPaneHidden(): Boolean {
+    return scaffoldValue[SupportingPaneScaffoldRole.Main] == PaneAdaptedValue.Hidden
+}
+
 @OptIn(ExperimentalMaterial3AdaptiveApi::class)
 @Composable
 fun MainScreen(
@@ -154,7 +161,8 @@ fun MainScreen(
                             if (navigator.canNavigateBack()) {
                                 navigator.navigateBack()
                             }
-                        }
+                        },
+                        showBackButton = navigator.isMainPaneHidden(),
                     )
                 }
             },

Jetcaster/app/src/main/java/com/example/jetcaster/ui/podcast/PodcastDetailsScreen.kt

@@ -80,6 +80,7 @@ fun PodcastDetailsScreen(
     viewModel: PodcastDetailsViewModel,
     navigateToPlayer: (EpisodeInfo) -> Unit,
     navigateBack: () -> Unit,
+    showBackButton: Boolean,
     modifier: Modifier = Modifier
 ) {
     val state by viewModel.state.collectAsStateWithLifecycle()
@@ -97,6 +98,7 @@ fun PodcastDetailsScreen(
                 onQueueEpisode = viewModel::onQueueEpisode,
                 navigateToPlayer = navigateToPlayer,
                 navigateBack = navigateBack,
+                showBackButton = showBackButton,
                 modifier = modifier,
             )
         }
@@ -118,6 +120,7 @@ fun PodcastDetailsScreen(
     onQueueEpisode: (PlayerEpisode) -> Unit,
     navigateToPlayer: (EpisodeInfo) -> Unit,
     navigateBack: () -> Unit,
+    showBackButton: Boolean,
     modifier: Modifier = Modifier
 ) {
     val coroutineScope = rememberCoroutineScope()
@@ -126,10 +129,12 @@ fun PodcastDetailsScreen(
     Scaffold(
         modifier = modifier.fillMaxSize(),
         topBar = {
-            PodcastDetailsTopAppBar(
-                navigateBack = navigateBack,
-                modifier = Modifier.fillMaxWidth()
-            )
+            if (showBackButton) {
+                PodcastDetailsTopAppBar(
+                    navigateBack = navigateBack,
+                    modifier = Modifier.fillMaxWidth()
+                )
+            }
         },
         snackbarHost = {
             SnackbarHost(hostState = snackbarHostState)
@@ -352,6 +357,7 @@ fun PodcastDetailsScreenPreview() {
         toggleSubscribe = { },
         onQueueEpisode = { },
         navigateToPlayer = { },
-        navigateBack = { }
+        navigateBack = { },
+        showBackButton = true,
     )
 }