HxqFirst

.idea/encodings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" addBOMForNewFiles="with NO BOM" />
+</project>

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

@@ -2,17 +2,28 @@
 <androidx.constraintlayout.widget.ConstraintLayout 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:id="@+id/container"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
-    <TextView
-        android:layout_width="wrap_content"
+    <FrameLayout
+        android:id="@+id/content"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1"
+        tools:ignore="MissingConstraints" />
+
+    <com.google.android.material.bottomnavigation.BottomNavigationView
+        android:id="@+id/nav_view"
+        android:layout_width="0dp"
         android:layout_height="wrap_content"
-        android:text="Hello World!"
+        android:layout_marginStart="0dp"
+        android:layout_marginEnd="0dp"
+        android:background="?android:attr/windowBackground"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintLeft_toLeftOf="parent"
         app:layout_constraintRight_toRightOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        app:menu="@menu/bottom_nav_menu" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>