android: correctly finish parent activity in navigation flow

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

@@ -65,6 +65,7 @@ fun LobstersApp(
   val coroutineScope = rememberCoroutineScope()
   val postActions = rememberPostActions(urlLauncher, navController, viewModel)
   val currentDestination by currentNavigationDestination(navController)
+  val context = LocalContext.current
 
   val hottestPosts = viewModel.hottestPosts.collectAsLazyPagingItems()
   val newestPosts = viewModel.newestPosts.collectAsLazyPagingItems()
@@ -128,7 +129,9 @@ fun LobstersApp(
           backgroundColor = systemBarsColor,
           navigationIcon = {
             if (navItems.none { it.route == currentDestination }) {
-              IconButton(onClick = { navController.popBackStack() }) {
+              IconButton(
+                onClick = { if (!navController.popBackStack()) context.getActivity()?.finish() }
+              ) {
                 Icon(
                   painter = ClawIcons.ArrowBack,
                   contentDescription = "Go back to previous screen",

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

@@ -1,7 +1,9 @@
 package dev.msfjarvis.claw.android.ui
 
 import android.content.Context
+import android.content.ContextWrapper
 import android.os.Build
+import androidx.activity.ComponentActivity
 import androidx.compose.animation.EnterTransition
 import androidx.compose.animation.ExitTransition
 import androidx.compose.animation.core.FastOutLinearInEasing
@@ -48,6 +50,14 @@ fun slideOutAnimation(): ExitTransition {
   )
 }
 
+fun Context.getActivity(): ComponentActivity? {
+  return when (this) {
+    is ComponentActivity -> this
+    is ContextWrapper -> baseContext.getActivity()
+    else -> null
+  }
+}
+
 /**
  * Parses a given [String] into a [LocalDateTime]. This method is only intended to be used for dates
  * in the format returned by the Lobsters API, and is not a general purpose parsing solution.