car-ui-lib/res/layout/car_ui_base_layout_toolbar_legacy.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.
  -->
<!-- This layout is used on Q or earlier, to support OEMs that shipped
     on Q and only customized the non-baselayout version of the toolbar -->
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!-- When the user finishes searching, we call clearFocus() on the editText in the search bar.
         clearFocus() will actually send the focus to the first focusable thing in the layout.
         If that focusable thing is still the search bar it will just reselect it, and the user won't
         be able to deselect. So make a focusable view here to guarantee that we can clear the focus -->
    <View
        android:layout_width="1dp"
        android:layout_height="1dp"
        android:focusable="true"
        android:focusableInTouchMode="true"/>

    <FrameLayout
        android:id="@+id/car_ui_base_layout_content_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <com.android.car.ui.toolbar.Toolbar
        android:id="@+id/car_ui_toolbar"
        android:tag="car_ui_top_inset"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>