From c72dff9971c66b28a2828c36a3b7932774e830b5 Mon Sep 17 00:00:00 2001
From: jhg3410 <80373033+jhg3410@users.noreply.github.com>
Date: Thu, 23 Feb 2023 20:54:45 +0900
Subject: [PATCH] #8 - Integrate RallyTabRow with navigation

---
 .../example/compose/rally/RallyActivity.kt    | 29 +++++++++++++++----
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/NavigationCodelab/app/src/main/java/com/example/compose/rally/RallyActivity.kt b/NavigationCodelab/app/src/main/java/com/example/compose/rally/RallyActivity.kt
index 60fad89..1e5ccb4 100644
--- a/NavigationCodelab/app/src/main/java/com/example/compose/rally/RallyActivity.kt
+++ b/NavigationCodelab/app/src/main/java/com/example/compose/rally/RallyActivity.kt
@@ -19,17 +19,16 @@ package com.example.compose.rally
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
-import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material.Scaffold
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.navigation.NavGraph.Companion.findStartDestination
+import androidx.navigation.NavHostController
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
+import androidx.navigation.compose.currentBackStackEntryAsState
 import androidx.navigation.compose.rememberNavController
 import com.example.compose.rally.ui.components.RallyTabRow
 import com.example.compose.rally.ui.theme.RallyTheme
@@ -50,13 +49,19 @@ class RallyActivity : ComponentActivity() {
 @Composable
 fun RallyApp() {
     RallyTheme {
-        var currentScreen: RallyDestination by remember { mutableStateOf(Overview) }
         val navController = rememberNavController()
+
+        val currentBackStack by navController.currentBackStackEntryAsState()
+        val currentDestination = currentBackStack?.destination
+
+        val currentScreen = rallyTabRowScreens.find { it.route == currentDestination?.route } ?: Overview
         Scaffold(
             topBar = {
                 RallyTabRow(
                     allScreens = rallyTabRowScreens,
-                    onTabSelected = { screen -> currentScreen = screen },
+                    onTabSelected = { newScreen ->
+                        navController.navigateSingleTopTo(newScreen.route)
+                    },
                     currentScreen = currentScreen
                 )
             }
@@ -79,3 +84,15 @@ fun RallyApp() {
         }
     }
 }
+
+
+fun NavHostController.navigateSingleTopTo(route: String) =
+    this.navigate(route) {
+        popUpTo(
+            this@navigateSingleTopTo.graph.findStartDestination().id
+        ) {
+            saveState = true
+        }
+        launchSingleTop = true
+        restoreState = true
+    }
\ No newline at end of file