ring-android/app/src/main/res/xml/preferences.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

    <PreferenceCategory android:title="@string/pref_category_network">
        <android.support.v14.preference.SwitchPreference
            android:defaultValue="false"
            android:icon="@drawable/ic_perm_data_setting_black_24dp"
            android:key="pref_mobileData"
            android:summary="@string/pref_mobileData_summary"
            android:title="@string/pref_mobileData_title" />
    </PreferenceCategory>

    <PreferenceCategory android:title="@string/pref_category_contacts">
        <android.support.v14.preference.SwitchPreference
            android:defaultValue="true"
            android:icon="@drawable/ic_group_black_24dp"
            android:key="pref_systemContacts"
            android:summary="@string/pref_systemContacts_summary"
            android:title="@string/pref_systemContacts_title" />

    </PreferenceCategory>

</PreferenceScreen>