app/src/main/res/layout/activity_settings.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

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

    <FrameLayout
        android:id="@+id/settings"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>