上传Android项目

app/src/main/res/layout/activity_main.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.coordinatorlayout.widget.CoordinatorLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".MainActivity">
+
+    <!-- 页面内容区域：用于切换 Fragment -->
+    <androidx.fragment.app.FragmentContainerView
+        android:id="@+id/nav_host_fragment"
+        android:name="androidx.navigation.fragment.NavHostFragment"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        app:navGraph="@navigation/nav_graph"
+        app:defaultNavHost="true" />
+
+    <!-- 底部导航栏 -->
+    <com.google.android.material.bottomnavigation.BottomNavigationView
+        android:id="@+id/bottom_nav"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_gravity="bottom"
+        android:background="@android:color/white"
+        app:menu="@menu/menu_bottom_nav"
+        app:itemIconTint="@null"
+        app:itemTextColor="@color/nav_text_color"/>
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>