samples/sample3/rro/res/layout/car_bottom_system_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2020 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.
  -->

<com.android.systemui.car.systembar.CarSystemBarView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:systemui="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/system_bar_background"
    android:gravity="center"
    android:orientation="horizontal">

    <RelativeLayout
        android:id="@+id/nav_buttons"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layoutDirection="ltr">

        <com.android.systemui.car.hvac.AdjustableTemperatureView
            android:id="@+id/driver_hvac"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:gravity="center_vertical"
            systemui:hvacAreaId="49"
            systemui:hvacTempFormat="%.0f\u00B0" />

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_centerInParent="true"
            android:layout_weight="1"
            android:gravity="center"
            android:layoutDirection="ltr"
            android:paddingEnd="@dimen/system_bar_button_group_padding"
            android:paddingStart="@dimen/system_bar_button_group_padding">

            <Space
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_weight="1"/>

            <com.android.systemui.car.systembar.CarSystemBarButton
                android:id="@+id/home"
                android:contentDescription="@string/system_bar_home_label"
                style="@style/SystemBarButton"
                systemui:componentNames="com.android.car.carlauncher/.CarLauncher"
                systemui:highlightWhenSelected="true"
                systemui:icon="@drawable/car_ic_home"
                systemui:intent="intent:#Intent;action=android.intent.action.MAIN;category=android.intent.category.HOME;launchFlags=0x14000000;end"/>

            <com.android.systemui.car.systembar.CarSystemBarButton
                android:id="@+id/phone_nav"
                style="@style/SystemBarButton"
                systemui:highlightWhenSelected="true"
                systemui:icon="@drawable/car_ic_phone"
                systemui:intent="intent:#Intent;action=android.intent.action.MAIN;category=android.intent.category.LAUNCHER;package=com.android.car.dialer;launchFlags=0x10000000;end"
                systemui:packages="com.android.car.dialer"/>

            <com.android.systemui.car.systembar.CarSystemBarButton
                android:id="@+id/grid_nav"
                android:contentDescription="@string/system_bar_applications_label"
                style="@style/SystemBarButton"
                systemui:componentNames="@string/config_appGridComponentName"
                systemui:highlightWhenSelected="true"
                systemui:icon="@drawable/car_ic_apps"
                systemui:intent="intent:#Intent;action=com.android.car.carlauncher.ACTION_APP_GRID;package=com.android.car.carlauncher;launchFlags=0x24000000;end"/>

            <com.android.systemui.car.systembar.HvacButton
                android:id="@+id/hvac"
                android:contentDescription="@string/system_bar_climate_control_label"
                style="@style/SystemBarButton"
                systemui:highlightWhenSelected="true"
                systemui:icon="@drawable/car_ic_hvac"
                systemui:broadcast="true"/>

            <com.android.systemui.car.systembar.CarSystemBarButton
                android:id="@+id/notifications"
                android:contentDescription="@string/system_bar_notifications_label"
                style="@style/SystemBarButton"
                systemui:highlightWhenSelected="true"
                systemui:icon="@drawable/car_ic_notification"
                systemui:longIntent="intent:#Intent;action=com.android.car.bugreport.action.START_AUDIO_FIRST;component=com.android.car.bugreport/.BugReportActivity;end"/>

            <Space
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_weight="1"/>
        </LinearLayout>

        <com.android.systemui.car.hvac.AdjustableTemperatureView
            android:id="@+id/passenger_hvac"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_alignParentEnd="true"
            android:gravity="center_vertical"
            systemui:hvacAreaId="68"
            systemui:hvacTempFormat="%.0f\u00B0"/>
    </RelativeLayout>

    <LinearLayout
        android:id="@+id/lock_screen_nav_buttons"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:gravity="center"
        android:layoutDirection="ltr"
        android:paddingEnd="@dimen/car_keyline_1"
        android:paddingStart="@dimen/car_keyline_1"
        android:visibility="gone"/>
</com.android.systemui.car.systembar.CarSystemBarView>