MainActivity.axml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <com.google.android.gms.maps.MapView
        android:id="@+id/mainactivity_mapView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        map:uiZoomControls="true" />
</LinearLayout>