Fix nested prescrolling bug in ScrollView

mScrollOffset should not be applied to deltaY for the current
MotionEvent. Instead, it should be used to offset the y position
of the next motion event instead.

Change-Id: Iaed85083556d4606300d9a888662c32ab4dbf3ca

1 files changed, 2 insertions, 2 deletions

diff --git a/core/java/android/widget/ScrollView.java b/core/java/android/widget/ScrollView.java
index 8dfef25a..0fa75a6 100644
--- a/core/java/android/widget/ScrollView.java
+++ b/core/java/android/widget/ScrollView.java
@@ -628,7 +628,7 @@ public class ScrollView extends FrameLayout {
                 final int y = (int) ev.getY(activePointerIndex);
                 int deltaY = mLastMotionY - y;
                 if (dispatchNestedPreScroll(0, deltaY, mScrollConsumed, mScrollOffset)) {
-                    deltaY -= mScrollConsumed[1] + mScrollOffset[1];
+                    deltaY -= mScrollConsumed[1];
                     vtev.offsetLocation(0, mScrollOffset[1]);
                 }
                 if (!mIsBeingDragged && Math.abs(deltaY) > mTouchSlop) {
@@ -645,7 +645,7 @@ public class ScrollView extends FrameLayout {
                 }
                 if (mIsBeingDragged) {
                     // Scroll to follow the motion event
-                    mLastMotionY = y;
+                    mLastMotionY = y - mScrollOffset[1];
 
                     final int oldY = mScrollY;
                     final int range = getScrollRange();