How to reference custom resource-file in xml
<p>How does you register a custom xml-resource-file with android studio so that you can reference it from other xml files?</p>

<p>I understand that its possible to call values from new resource values programmatically using R but I was wondering if there was a way to do that statically from another XML file.</p>

<p>For example, referencing that new file (in this case called keys.xml) in another xml file</p>

<pre><code>&lt;meta-data
        android:name="com.google.android.maps.v2.API_KEY"
        android:value="@keys/MAPS_API_KEY" /&gt;
</code></pre>

<p>as opposed to using strings.xml</p>

<p><strong>Edit:</strong> It turns out that @string does <em>NOT</em> specifically reference strings.xml. I was originally under the impression that it did and knowing that know makes my question seem a tad silly.</p>