[BottomNavigationBar] Update catalog demo to demonstrate adaptive bottom navigation bar

PiperOrigin-RevId: 723671728

Author: imhappi

catalog/java/io/material/catalog/bottomnav/res/layout-sw600dp/cat_bottom_nav.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2025 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     https://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<com.google.android.material.bottomnavigation.BottomNavigationView
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto"
+  android:id="@+id/cat_bottom_nav"
+  android:layout_width="match_parent"
+  android:layout_height="wrap_content"
+  android:layout_gravity="bottom"
+  app:itemIconGravity="start"
+  app:itemGravity="center"
+  app:menu="@menu/bottom_nav_menu"/>

docs/components/BottomNavigation.md

@@ -336,6 +336,28 @@ See the full list of
 and
 [bottom navigation attributes](https://github.com/material-components/material-components-android/tree/master/lib/java/com/google/android/material/bottomnavigation/res/values/attrs.xml).
 
+### Bottom Navigation on larger screens
+
+On medium screen sizes and larger, bottom navigation bars are recommended to be
+a horizontal item configuration, by setting `app:itemIconGravity` to be `start`
+instead of `top`. You can do this by
+[setting alternative layouts identified by resource qualifiers](https://developer.android.com/develop/ui/views/layout/responsive-adaptive-design-with-views#alternative_layout_resources).
+
+Here's an example:
+
+```xml
+<com.google.android.material.bottomnavigation.BottomNavigationView
+  android:id="@+id/bottom_navigation_bar"
+  android:layout_width="match_parent"
+  android:layout_height="wrap_content"
+  android:layout_gravity="bottom"
+  app:itemIconGravity="start"
+  app:itemGravity="center"
+  app:menu="@menu/bottom_navigation_menu"/>
+```
+
+!["Horizontal bottom navigation bar"](assets/bottomnav/bottomnav_horizontal.png)
+
 ## Theming a bottom navigation bar
 
 Bottom navigation supports