ScrollView and HorizontalScrollView now will spring back if smoothScrollBy scrolls out of bounds. Tweaked bounce physics for OverScroller.

1 files changed, 8 insertions, 1 deletions

diff --git a/core/java/android/widget/ScrollView.java b/core/java/android/widget/ScrollView.java
index 62797f3c384a..1a50f8589eb9 100644
--- a/core/java/android/widget/ScrollView.java
+++ b/core/java/android/widget/ScrollView.java
@@ -817,9 +817,16 @@ public class ScrollView extends FrameLayout {
      * @param dy the number of pixels to scroll by on the Y axis
      */
     public final void smoothScrollBy(int dx, int dy) {
+        if (getChildCount() == 0) {
+            // Nothing to do.
+            return;
+        }
         long duration = AnimationUtils.currentAnimationTimeMillis() - mLastScroll;
         if (duration > ANIMATED_SCROLL_GAP) {
-            mScroller.startScroll(mScrollX, mScrollY, dx, dy);
+            int height = getHeight() - mPaddingBottom - mPaddingTop;
+            int bottom = getChildAt(0).getHeight();
+            mScroller.startScroll(mScrollX, mScrollY, dx, dy,
+                    0, 0, 0, Math.max(0, bottom - height));
             awakenScrollBars(mScroller.getDuration());
             invalidate();
         } else {