diff --git a/core/java/android/widget/StackView.java b/core/java/android/widget/StackView.java
index 7a74241e1bdf1..6a09d3548e797 100644
--- a/core/java/android/widget/StackView.java
+++ b/core/java/android/widget/StackView.java
@@ -546,12 +546,16 @@ public class StackView extends AdapterViewAnimator {
 
     private void onLayout() {
         if (!mFirstLayoutHappened) {
-            mSlideAmount = Math.round(SLIDE_UP_RATIO * getMeasuredHeight());
-            mSwipeThreshold = Math.round(SWIPE_THRESHOLD_RATIO * mSlideAmount);
             mFirstLayoutHappened = true;
             updateChildTransforms();
         }
 
+        final int newSlideAmount = Math.round(SLIDE_UP_RATIO * getMeasuredHeight());
+        if (mSlideAmount != newSlideAmount) {
+            mSlideAmount = newSlideAmount;
+            mSwipeThreshold = Math.round(SWIPE_THRESHOLD_RATIO * newSlideAmount);
+        }
+
         if (Float.compare(mPerspectiveShiftY, mNewPerspectiveShiftY) != 0 ||
                 Float.compare(mPerspectiveShiftX, mNewPerspectiveShiftX) != 0) {