res/layout/option_container.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2015 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
  ~
  ~      http://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.
  -->

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/side_panel"
    android:layout_width="@dimen/side_panel_width"
    android:layout_height="match_parent"
    android:layout_gravity="end"
    android:elevation="@dimen/side_panel_elevation"
    android:background="@color/side_panel_background"
    android:translationX="@dimen/side_panel_enter_offset_x"
    android:alpha="0.0"
    android:visibility="gone">

    <!-- Background for header -->
    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="@dimen/side_panel_header_height"
        android:elevation="@dimen/side_panel_header_elevation"
        android:background="@color/side_panel_header_background" />

    <!-- This fragment container needs to have at least the same elevation as the above FrameLayout
         for the header background. Otherwise, header text in the fragment won't be drawn, as it's
         under the above FrameLayout. This container won't draw any shadow though, as it have
         transparent background. -->
    <FrameLayout
        android:id="@+id/side_fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:elevation="@dimen/side_panel_header_elevation" />

</FrameLayout>