How do I reference android:gravity values in a resource file?

I have a layout with a TextView and I want the android:gravity attribute value to be pulled from another resource file, android:gravity="@???/item_align", where item_align is the name of a resource in another xml file. The typical values used in a layout, center or bottom or bottom|center_horizontal don't work. What type goes in the @???, integer works, if I replace the strings with the actual integer value ("center" replaced with 0x011). But, that's not a good solution.

So, the question(s): How do I refer to the value in the layout file, and what does the item look like in the resource file?

<TextView
   android:id="@+id/item_text"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_alignParentTop="true"
   android:layout_alignParentBottom="true"
   android:layout_alignParentLeft="true"
   android:layout_alignParentRight="true"
   android:layout_margin="1dp"
   android:layout_centerHorizontal="true"
   android:gravity="@???/item_align"
   android:text="65"
   android:textSize="20sp"
   android:typeface="sans"
   android:textStyle="bold"
   android:textColor="#000000" />