comaps/android/app/src/main/res/layout/fragment_phone.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    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
        style="@style/MwmWidget.FrameLayout.Elevation"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/frameLayout"
        android:background="?cardBackground">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/phones_recycler"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="?cardBackground"
            android:scrollbars="vertical" />

    </FrameLayout>

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/tv__append_phone"
        style="@style/MwmWidget.M3.FAB.Primary"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/margin_base"
        android:clickable="true"
        android:contentDescription="@string/editor_add_phone"
        android:focusable="true"
        app:fabSize="normal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:srcCompat="@drawable/ic_plus" />

</androidx.constraintlayout.widget.ConstraintLayout>