android: hide NavigationBar in comments screen

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/LobstersApp.kt

@@ -106,6 +106,7 @@ fun LobstersApp(
           ClawNavigationBar(
             navController = navController,
             items = navItems,
+            isVisible = navItems.any { it.route == currentDestination },
           )
         },
       ) {

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/decorations/ClawFab.kt

@@ -15,10 +15,9 @@ import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.painterResource
 import dev.msfjarvis.claw.android.R
+import dev.msfjarvis.claw.android.ui.AnimationDuration
 import kotlinx.coroutines.launch
 
-private const val AnimationDuration = 100
-
 @OptIn(ExperimentalAnimationApi::class)
 @Composable
 fun ClawFab(

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/decorations/ClawNavigationBar.kt

@@ -1,5 +1,11 @@
 package dev.msfjarvis.claw.android.ui.decorations
 
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.core.FastOutLinearInEasing
+import androidx.compose.animation.core.LinearOutSlowInEasing
+import androidx.compose.animation.core.tween
+import androidx.compose.animation.slideInVertically
+import androidx.compose.animation.slideOutVertically
 import androidx.compose.material3.Icon
 import androidx.compose.material3.NavigationBar
 import androidx.compose.material3.NavigationBarItem
@@ -12,26 +18,45 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.painter.Painter
 import androidx.navigation.NavController
+import dev.msfjarvis.claw.android.ui.AnimationDuration
 
 @Composable
 fun ClawNavigationBar(
   navController: NavController,
   items: List<NavigationItem>,
+  isVisible: Boolean,
   modifier: Modifier = Modifier,
 ) {
   var selectedIndex by remember { mutableStateOf(0) }
 
-  NavigationBar(modifier = modifier) {
+  AnimatedVisibility(
-    items.forEachIndexed { index, navItem ->
+    visible = isVisible,
-      NavigationBarItem(
+    enter =
-        icon = { Icon(painter = navItem.icon, contentDescription = navItem.label) },
+      slideInVertically(
-        label = { Text(text = navItem.label) },
+        // Enters by sliding up from offset 0 to fullHeight.
-        selected = selectedIndex == index,
+        initialOffsetY = { fullHeight -> fullHeight },
-        onClick = {
+        animationSpec = tween(durationMillis = AnimationDuration, easing = LinearOutSlowInEasing),
-          selectedIndex = index
+      ),
-          navController.navigate(navItem.route)
+    exit =
-        }
+      slideOutVertically(
-      )
+        // Exits by sliding up from offset 0 to -fullHeight.
+        targetOffsetY = { fullHeight -> fullHeight },
+        animationSpec = tween(durationMillis = AnimationDuration, easing = FastOutLinearInEasing),
+      ),
+    modifier = Modifier,
+  ) {
+    NavigationBar(modifier = modifier) {
+      items.forEachIndexed { index, navItem ->
+        NavigationBarItem(
+          icon = { Icon(painter = navItem.icon, contentDescription = navItem.label) },
+          label = { Text(text = navItem.label) },
+          selected = selectedIndex == index,
+          onClick = {
+            selectedIndex = index
+            navController.navigate(navItem.route)
+          }
+        )
+      }
     }
   }
 }

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/ext.kt

@@ -27,6 +27,8 @@ import dev.msfjarvis.claw.common.urllauncher.UrlLauncher
 import dev.msfjarvis.claw.database.local.SavedPost
 import kotlin.math.ln
 
+const val AnimationDuration = 100
+
 // The destination needs to be tracked like this rather than used directly since
 // `NavController#currentDestination` is not a Composable state.
 @Composable