增加平板界面配置，更新主页面

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

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/navigation_rail_fab"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:layout_gravity="top|start"
+    android:clipChildren="false"
+    android:clipToPadding="false"
+    android:orientation="vertical">
+
+    <ImageView
+        android:id="@+id/nav_botton"
+        android:layout_width="56dp"
+        android:layout_height="56dp"
+        android:scaleType="center"
+        android:src="@drawable/ic_menu" />
+
+    <com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton
+        android:id="@+id/nav_fab"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/search"
+        app:icon="@drawable/ic_search" />
+
+</LinearLayout>