twoway-view-rotation-fix

diff --git a/library/src/main/java/org/lucasr/twowayview/TWSpannableGridLayoutManager.java b/library/src/main/java/org/lucasr/twowayview/TWSpannableGridLayoutManager.java
index e631060..d6956ff 100644
--- a/library/src/main/java/org/lucasr/twowayview/TWSpannableGridLayoutManager.java
+++ b/library/src/main/java/org/lucasr/twowayview/TWSpannableGridLayoutManager.java
@@ -218,6 +218,8 @@ public class TWSpannableGridLayoutManager extends TWGridLayoutManager {
         int childCount = 0, i = 0;
         while (i < itemCount && i < laneCount) {
             SpannableItemEntry entry = (SpannableItemEntry) getItemEntryForPosition(i);
+            if (entry == null)
+                break;
             i += (isVertical ? entry.colSpan : entry.rowSpan);
             childCount++;
         }