diff --git a/app/src/main/res/values/attrs.xml b/app/src/main/res/values/attrs.xml
index 216e6afe5..570ccb408 100644
--- a/app/src/main/res/values/attrs.xml
+++ b/app/src/main/res/values/attrs.xml
@@ -244,6 +244,10 @@
         <attr name="title" />
         <attr name="max" />
         <attr name="min" format="integer" />
+        <attr name="orientation" format="enum">
+            <enum name="horizontal" value="0" />
+            <enum name="vertical" value="1" />
+        </attr>
     </declare-styleable>
 
     <declare-styleable name="TipPreference">