app/src/main/res/layout/fragment_map.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragment_map"
android:layout_width="match_parent"
android:layout_height="match_parent">
<fragment
android:id="@+id/google_map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>