Meshtastic-Android/app/src/main/res/layout/map_view.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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <org.osmdroid.views.MapView
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/fab_style_toggle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:backgroundTint="@color/design_default_color_secondary"
        android:contentDescription="@string/style_selection"
        android:orientation="vertical"
        android:src="@drawable/baseline_layers_white_24dp"
        app:layout_constraintBottom_toBottomOf="parent"
        android:visibility="visible"
        app:layout_constraintEnd_toEndOf="parent"
        tools:background="@color/design_default_color_secondary" />
</androidx.constraintlayout.widget.ConstraintLayout>