res/layout/live_wallpaper_preview.xml

<!--
  ~ Copyright (C) 2016 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"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <FrameLayout
        android:id="@+id/loading"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#ff000000"
        android:forceHasOverlappingRendering="false">

        <ProgressBar
            style="@android:style/Widget.DeviceDefault.ProgressBar"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:indeterminate="true"/>

    </FrameLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="@dimen/preview_gradient_background_height"
        android:layout_gravity="top"
        android:background="@drawable/gradient_background"/>

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <androidx.coordinatorlayout.widget.CoordinatorLayout
            android:id="@+id/coordinator_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom"
            android:orientation="vertical">

            <LinearLayout
                android:id="@+id/bottom_pane"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@color/translucent_black"
                android:orientation="vertical"
                app:behavior_peekHeight="@dimen/preview_attribution_pane_collapsed_height"
                app:layout_behavior="com.google.android.material.bottomsheet.BottomSheetBehavior">

                <com.google.android.material.tabs.TabLayout
                    android:id="@+id/tablayout"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    style="@style/TabLayoutStyle"
                    android:visibility="gone"/>

                <com.android.wallpaper.livepicker.widget.ConstraintViewPager
                    android:id="@+id/viewpager"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"/>

            </LinearLayout>

        </androidx.coordinatorlayout.widget.CoordinatorLayout>

        <android.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="top"
            style="@style/TranslucentToolbarStyle"
            android:paddingStart="@dimen/preview_toolbar_start_padding"
            android:paddingEnd="@dimen/preview_toolbar_end_padding"/>

    </FrameLayout>

</FrameLayout>