car_product/car_ui_portrait/apps/CarUiPortraitSystemUI/res/drawable/status_icon_background.xml

<?xml version="1.0" encoding="UTF-8" ?>
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  ~ Copyright (C) 2022 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
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  ~ distributed under the License is distributed on an "AS IS" BASIS,
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  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->

<selector
    xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:state_focused="true"
        android:state_selected="true">
        <layer-list>
            <item>
                <shape>
                    <solid android:color="@color/status_icon_selected_button_color"/>
                    <corners android:radius="@dimen/top_system_bar_icon_selected_corner" />
                    <size android:width="@dimen/top_system_bar_icon_size"
                          android:height="@dimen/top_system_bar_icon_size"/>
                </shape>
            </item>
        </layer-list>
    </item>
    <item
        android:state_focused="true"
        android:state_selected="false">
        <layer-list>
            <item>
                <shape android:shape="oval">
                    <solid android:color="@color/system_bar_background_pill_color"/>
                    <size android:width="@dimen/top_system_bar_icon_size"
                          android:height="@dimen/top_system_bar_icon_size"/>
                </shape>
            </item>
        </layer-list>
    </item>
    <item android:state_selected="true">
        <layer-list>
            <item>
                <shape>
                    <solid android:color="@color/status_icon_selected_button_color"/>
                    <corners android:radius="@dimen/top_system_bar_icon_selected_corner" />
                    <size android:width="@dimen/top_system_bar_icon_size"
                          android:height="@dimen/top_system_bar_icon_size"/>
                </shape>
            </item>
        </layer-list>
    </item>
    <item android:drawable="@drawable/system_bar_background_pill"/>
</selector>