AbsListView notifies scroll events to the ViewTreeObserver.

ViewTreeObserver OnScrollChangedListener will then get notified.

The scroll values are not specified, since they are passed to the
base View.onScrollChanged method that simply sets the flags.

No need to throw these from a Runnable (in case this happens during
a relayout) since the listeners will be notified later from ViewRoot.draw().

Calling View.onScrollChanged in invokeOnItemScrollListener for normal scroll and
in onOverScrolled to handle mScroller animation.

Change-Id: Ib41434e5cd82e5a45ca6653db576746e89ef072d

1 files changed, 25 insertions, 25 deletions

diff --git a/core/java/android/widget/AbsListView.java b/core/java/android/widget/AbsListView.java
index 1d05d0b..7b0739b 100644
--- a/core/java/android/widget/AbsListView.java
+++ b/core/java/android/widget/AbsListView.java
@@ -1251,6 +1251,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
         if (mOnScrollListener != null) {
             mOnScrollListener.onScroll(this, mFirstPosition, getChildCount(), mItemCount);
         }
+        onScrollChanged(0, 0, 0, 0); // dummy values, View's implementation does not use these.
     }
 
     /**
@@ -2793,8 +2794,9 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
                 if (!mDataChanged) {
                     if ((mTouchMode != TOUCH_MODE_FLING) && (motionPosition >= 0)
                             && (getAdapter().isEnabled(motionPosition))) {
-                        // User clicked on an actual view (and was not stopping a fling). It might be a
-                        // click or a scroll. Assume it is a click until proven otherwise
+                        // User clicked on an actual view (and was not stopping a fling).
+                        // It might be a click or a scroll. Assume it is a click until
+                        // proven otherwise
                         mTouchMode = TOUCH_MODE_DOWN;
                         // FIXME Debounce
                         if (mPendingCheckForTap == null) {
@@ -2803,9 +2805,10 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
                         postDelayed(mPendingCheckForTap, ViewConfiguration.getTapTimeout());
                     } else {
                         if (ev.getEdgeFlags() != 0 && motionPosition < 0) {
-                            // If we couldn't find a view to click on, but the down event was touching
-                            // the edge, we will bail out and try again. This allows the edge correcting
-                            // code in ViewRoot to try to find a nearby view to select
+                            // If we couldn't find a view to click on, but the down event
+                            // was touching the edge, we will bail out and try again.
+                            // This allows the edge correcting code in ViewRoot to try to
+                            // find a nearby view to select
                             return false;
                         }
 
@@ -3247,18 +3250,20 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
     }
 
     @Override
-    protected void onOverScrolled(int scrollX, int scrollY,
-            boolean clampedX, boolean clampedY) {
-        mScrollY = scrollY;
-        invalidateParentIfNeeded();
-
-        if (clampedY) {
-            // Velocity is broken by hitting the limit; don't start a fling off of this.
-            if (mVelocityTracker != null) {
-                mVelocityTracker.clear();
+    protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boolean clampedY) {
+        if (mScrollY != scrollY) {
+            onScrollChanged(mScrollX, scrollY, mScrollX, mScrollY);
+            mScrollY = scrollY;
+            invalidateParentIfNeeded();
+
+            if (clampedY) {
+                // Velocity is broken by hitting the limit; don't start a fling off of this.
+                if (mVelocityTracker != null) {
+                    mVelocityTracker.clear();
+                }
             }
+            awakenScrollBars();
         }
-        awakenScrollBars();
     }
 
     @Override
@@ -4279,17 +4284,12 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
             mLastPositionDistanceGuess += incrementalDeltaY;
         }
 
-        if (firstPosition == 0 && firstTop >= listPadding.top && incrementalDeltaY >= 0) {
-            // Don't need to move views down if the top of the first position
-            // is already visible
-            return incrementalDeltaY != 0;
-        }
+        final boolean cannotScrollDown = (firstPosition == 0 &&
+                firstTop >= listPadding.top && incrementalDeltaY >= 0);
+        final boolean cannotScrollUp = (firstPosition + childCount == mItemCount &&
+                lastBottom <= getHeight() - listPadding.bottom && incrementalDeltaY <= 0);
 
-        if (firstPosition + childCount == mItemCount &&
-                lastBottom <= getHeight() - listPadding.bottom &&
-                incrementalDeltaY <= 0) {
-            // Don't need to move views up if the bottom of the last position
-            // is already visible
+        if (cannotScrollDown || cannotScrollUp) {
             return incrementalDeltaY != 0;
         }