app/src/main/res/xml/pref_connection.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
	<EditTextPreference
	  android:key="server_address"
	  android:title="Server address"
	  android:hint="10.1.1.1"
	  android:singleLine="true"/>
	<EditTextPreference
	  android:key="server_port"
	  android:title="Server port"
	  android:numeric="integer"
	  android:defaultValue="3446"
	  android:singleLine="true"/>
	<PreferenceScreen
	android:title="Client key"/>

</PreferenceScreen>