res/layout/notification_history_app_layout.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.
    -->

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <RelativeLayout
        android:id="@+id/app_header"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:background="@drawable/button_ripple_radius"
        android:paddingTop="12dp"
        android:paddingBottom="12dp"
        android:paddingStart="16dp">
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical">
            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal">
                <ImageView
                    android:id="@+id/icon"
                    android:layout_height="24dp"
                    android:layout_width="24dp"
                    android:layout_gravity="center_vertical"
                    android:scaleType="centerInside"/>
                <TextView
                    android:id="@+id/label"
                    android:layout_height="wrap_content"
                    android:layout_width="wrap_content"
                    android:layout_gravity="center_vertical"
                    android:textAppearance="@*android:style/TextAppearance.DeviceDefault.Notification"
                    android:paddingStart="8dp" />
            </LinearLayout>
            <TextView
                android:id="@+id/count"
                android:layout_height="wrap_content"
                android:layout_width="wrap_content"
                android:paddingStart="6dp"
                android:layout_gravity="start|center_vertical"
                android:textDirection="locale"
                android:paddingTop="8dp"
                android:textAppearance="@*android:style/TextAppearance.DeviceDefault.Notification.Title"/>
        </LinearLayout>
        <ImageView
            android:id="@+id/expand"
            android:layout_alignParentEnd="true"
            android:layout_centerVertical="true"
            android:layout_height="48dp"
            android:layout_width="48dp"
            android:scaleType="center"
            android:contentDescription="@null"
            android:src="@*android:drawable/ic_expand_more"/>
    </RelativeLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="?android:attr/listDivider"/>

        <com.android.settings.notification.history.NotificationHistoryRecyclerView
            android:id="@+id/notification_list"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:clipChildren="true"
            android:clipToPadding="true"
            android:importantForAccessibility="yes"
            android:scrollbars="none"/>

</LinearLayout>