Show back button in appbar when current destination is not in nav items (#301)

* Add navigation icon support in `ClawAppBar`

* Show back icon in app bar when current destination is not in nav items

* Add title support in `ClawAppBar`

* Show title in app bar only if the current destination is present in nav items

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

@@ -2,9 +2,14 @@ package dev.msfjarvis.claw.android.ui
 
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.ArrowBack
 import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
@@ -19,6 +24,8 @@ import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalUriHandler
 import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
@@ -107,6 +114,21 @@ fun LobstersApp(
             modifier = Modifier.statusBarsPadding(),
             backgroundColor = systemBarsColor,
             scrollBehavior = scrollBehavior,
+            navigationIcon = {
+              if (navItems.none { it.route == currentDestination }) {
+                IconButton(onClick = { navController.popBackStack() }) {
+                  Icon(
+                    imageVector = Icons.Filled.ArrowBack,
+                    contentDescription = "Go back to previous screen"
+                  )
+                }
+              }
+            },
+            title = {
+              if (navItems.any { it.route == currentDestination }) {
+                Text(text = stringResource(R.string.app_name), fontWeight = FontWeight.Bold)
+              }
+            }
           )
         },
         bottomBar = {

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

@@ -1,31 +1,25 @@
 package dev.msfjarvis.claw.android.ui.decorations
 
 import androidx.compose.material3.SmallTopAppBar
-import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.material3.TopAppBarScrollBehavior
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.res.stringResource
-import androidx.compose.ui.text.font.FontWeight
-import dev.msfjarvis.claw.android.R
 
 @Composable
 fun ClawAppBar(
   backgroundColor: Color,
   scrollBehavior: TopAppBarScrollBehavior? = null,
+  navigationIcon: @Composable () -> Unit = {},
+  title: @Composable () -> Unit = {},
   modifier: Modifier = Modifier,
 ) {
   SmallTopAppBar(
-    title = {
+    title = title,
-      Text(
-        text = stringResource(R.string.app_name),
-        fontWeight = FontWeight.Bold,
-      )
-    },
     modifier = modifier,
     colors = TopAppBarDefaults.smallTopAppBarColors(containerColor = backgroundColor),
     scrollBehavior = scrollBehavior,
+    navigationIcon = navigationIcon
   )
 }