update

.config/Code/User/History/-2e064889/zkFb.dart

@@ -0,0 +1,96 @@
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
+void main(){
+  runApp(const MyApp());
+}
+
+class MyApp extends StatelessWidget{
+  const MyApp({super.key});
+  
+  @override
+  Widget build(BuildContext context){
+    return ChangeNotifierProvider(
+      create: (context) => MyAppState(),
+      child: MaterialApp(
+        title: 'First App',
+        theme: ThemeData(
+          useMaterial3: true,
+          colorScheme: ColorScheme.fromSeed(seedColor: Colors.green)
+        ),
+        home: const MyHomePage(),
+      ),
+    );
+  }
+}
+
+class MyAppState extends ChangeNotifier{
+  
+}
+
+class MyHomePage extends StatefulWidget{
+  const MyHomePage({super.key});
+
+  @override
+  State<MyHomePage> createState() => _MyHomePageState();
+}
+
+class _MyHomePageState extends State<MyHomePage>{
+
+  var counter = 0;
+  var selectedIndex = 0;
+
+
+  @override
+  Widget build(BuildContext context){
+    var sCount = counter.toString();
+
+    Widget page;
+    switch(selectedIndex){
+      case 0: page = MyHomePage();
+    }
+
+    return Scaffold(
+      body: Row(
+        children: [
+          SafeArea(
+            child: NavigationRail(
+              destinations: const [
+                NavigationRailDestination(
+                  icon: Icon(Icons.home),
+                  label: Text('Home'),
+                ),
+                NavigationRailDestination(
+                  icon: Icon(Icons.favorite),
+                  label: Text('Favorites'),
+                ),
+              ],
+              selectedIndex: selectedIndex,
+              onDestinationSelected: (value) => setState((){
+                selectedIndex = value;
+              }),
+            ),
+          ),
+          Expanded(
+            child: Center(
+              child: Column(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: [
+                  Text('count: $sCount'),
+                  ElevatedButton(
+                    onPressed: () => {
+                      setState((){
+                        counter++;
+                      })
+                    },
+                    child: const Text('Increment')
+                  ),
+                ],
+              ),
+            ),
+          )
+        ],
+      )
+    );
+  }
+}