Perform null check in animation complete

Bug 17561235

Change-Id: I280dca9e03eed3f4e1edd97f2f8efac0b5e4b29d
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index 1b95c2b..2094b07 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -3632,9 +3632,11 @@
                     }
 
                     // Reset page transforms
-                    page.setTranslationX(0);
-                    page.setTranslationY(0);
-                    page.setAlpha(1);
+                    if (page != null) {
+                        page.setTranslationX(0);
+                        page.setTranslationY(0);
+                        page.setAlpha(1);
+                    }
                     content.setCurrentPage(content.getNextPage());
 
                     mAppsCustomizeContent.updateCurrentPageScroll();