FossifyGallery/app/src/main/res/layout/activity_medium.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/fragment_holder"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.simplemobiletools.commons.views.MyViewPager
        android:id="@+id/view_pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <include
        android:id="@+id/bottom_actions"
        layout="@layout/bottom_actions" />

    <ImageView
        android:id="@+id/top_shadow"
        android:layout_width="match_parent"
        android:layout_height="@dimen/default_status_action_height"
        android:background="@drawable/gradient_background_flipped"
        android:contentDescription="@null" />

    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/medium_viewer_appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:background="@android:color/transparent"
        android:elevation="0dp"
        app:elevation="0dp">

        <com.google.android.material.appbar.MaterialToolbar
            android:id="@+id/medium_viewer_toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:menu="@menu/menu_viewpager"
            app:navigationIcon="@drawable/ic_arrow_left_vector" />

    </com.google.android.material.appbar.AppBarLayout>
</RelativeLayout>