core/res/res/layout/notification_material_action_list.xml

<?xml version="1.0" encoding="utf-8"?><!-- Copyright (C) 2014 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/actions_container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="@dimen/notification_action_list_margin_top"
    android:layout_gravity="bottom"
    >

    <LinearLayout
        android:id="@+id/actions_container_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="end"
        android:layout_gravity="bottom"
        android:orientation="horizontal"
        android:background="@color/notification_action_list_background_color"
        >

        <com.android.internal.widget.NotificationActionListLayout
            android:id="@+id/actions"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:minHeight="@dimen/notification_action_list_height"
            android:orientation="horizontal"
            android:gravity="center_vertical"
            android:visibility="gone"
            >
            <!-- actions will be added here -->
        </com.android.internal.widget.NotificationActionListLayout>

        <!--
        This nested linear layout exists to ensure that if the neither of the contained
        actions is visible we have some minimum padding at the end of the actions is present,
        then there will be 12dp of padding at the end of the actions list.
        -->
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:orientation="horizontal"
            android:minWidth="@dimen/snooze_and_bubble_gone_padding_end"
            >
            <ImageView
                android:id="@+id/snooze_button"
                android:layout_width="@dimen/notification_actions_icon_size"
                android:layout_height="@dimen/notification_actions_icon_size"
                android:layout_gravity="center_vertical|end"
                android:visibility="gone"
                android:scaleType="centerInside"
                />

            <ImageView
                android:id="@+id/bubble_button"
                android:layout_width="@dimen/notification_actions_icon_size"
                android:layout_height="@dimen/notification_actions_icon_size"
                android:layout_gravity="center_vertical|end"
                android:visibility="gone"
                android:scaleType="centerInside"
                />
        </LinearLayout>
    </LinearLayout>
</FrameLayout>