diff --git a/src/com/google/doclava/DocFile.java b/src/com/google/doclava/DocFile.java
index 24bcbb6..a71b884 100644
--- a/src/com/google/doclava/DocFile.java
+++ b/src/com/google/doclava/DocFile.java
@@ -246,6 +246,7 @@
         hdf.setValue("wear", "true");
       } else if (filename.indexOf("preview") == 0) {
         hdf.setValue("preview", "true");
+        hdf.setValue("page.type", "preview");
       } else if (filename.indexOf("auto") == 0) {
         hdf.setValue("auto", "true");
       } else if (filename.indexOf("tv") == 0) {