Merge overscrolling from gingerbread.

Change-Id: I3eb4413261b38ddd8c609d6153bdfd4ae46c6a0f
diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index e6eb46e..011ad77 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -1627,6 +1627,40 @@
     static final int ACTIVATED                    = 0x40000000;
 
     /**
+     * Always allow a user to over-scroll this view, provided it is a
+     * view that can scroll.
+     *
+     * @see #getOverScrollMode()
+     * @see #setOverScrollMode(int)
+     */
+    public static final int OVER_SCROLL_ALWAYS = 0;
+
+    /**
+     * Allow a user to over-scroll this view only if the content is large
+     * enough to meaningfully scroll, provided it is a view that can scroll.
+     *
+     * @see #getOverScrollMode()
+     * @see #setOverScrollMode(int)
+     */
+    public static final int OVER_SCROLL_IF_CONTENT_SCROLLS = 1;
+
+    /**
+     * Never allow a user to over-scroll this view.
+     *
+     * @see #getOverScrollMode()
+     * @see #setOverScrollMode(int)
+     */
+    public static final int OVER_SCROLL_NEVER = 2;
+
+    /**
+     * Controls the over-scroll mode for this view.
+     * See {@link #overScrollBy(int, int, int, int, int, int, int, int, boolean)},
+     * {@link #OVER_SCROLL_ALWAYS}, {@link #OVER_SCROLL_IF_CONTENT_SCROLLS},
+     * and {@link #OVER_SCROLL_NEVER}.
+     */
+    private int mOverScrollMode;
+
+    /**
      * The parent this view is attached to.
      * {@hide}
      *
@@ -2057,6 +2091,7 @@
         mResources = context != null ? context.getResources() : null;
         mViewFlags = SOUND_EFFECTS_ENABLED | HAPTIC_FEEDBACK_ENABLED;
         mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
+        setOverScrollMode(OVER_SCROLL_IF_CONTENT_SCROLLS);
     }
 
     /**
@@ -2122,6 +2157,7 @@
 
         int scrollbarStyle = SCROLLBARS_INSIDE_OVERLAY;
 
+        int overScrollMode = mOverScrollMode;
         final int N = a.getIndexCount();
         for (int i = 0; i < N; i++) {
             int attr = a.getIndex(i);
@@ -2327,9 +2363,14 @@
                         });
                     }
                     break;
+                case R.styleable.View_overScrollMode:
+                    overScrollMode = a.getInt(attr, OVER_SCROLL_IF_CONTENT_SCROLLS);
+                    break;
             }
         }
 
+        setOverScrollMode(overScrollMode);
+
         if (background != null) {
             setBackgroundDrawable(background);
         }
@@ -10131,6 +10172,128 @@
     }
 
     /**
+     * Scroll the view with standard behavior for scrolling beyond the normal
+     * content boundaries. Views that call this method should override
+     * {@link #onOverScrolled(int, int, boolean, boolean)} to respond to the
+     * results of an over-scroll operation.
+     *
+     * Views can use this method to handle any touch or fling-based scrolling.
+     *
+     * @param deltaX Change in X in pixels
+     * @param deltaY Change in Y in pixels
+     * @param scrollX Current X scroll value in pixels before applying deltaX
+     * @param scrollY Current Y scroll value in pixels before applying deltaY
+     * @param scrollRangeX Maximum content scroll range along the X axis
+     * @param scrollRangeY Maximum content scroll range along the Y axis
+     * @param maxOverScrollX Number of pixels to overscroll by in either direction
+     *          along the X axis.
+     * @param maxOverScrollY Number of pixels to overscroll by in either direction
+     *          along the Y axis.
+     * @param isTouchEvent true if this scroll operation is the result of a touch event.
+     * @return true if scrolling was clamped to an over-scroll boundary along either
+     *          axis, false otherwise.
+     */
+    protected boolean overScrollBy(int deltaX, int deltaY,
+            int scrollX, int scrollY,
+            int scrollRangeX, int scrollRangeY,
+            int maxOverScrollX, int maxOverScrollY,
+            boolean isTouchEvent) {
+        final int overScrollMode = mOverScrollMode;
+        final boolean canScrollHorizontal =
+                computeHorizontalScrollRange() > computeHorizontalScrollExtent();
+        final boolean canScrollVertical =
+                computeVerticalScrollRange() > computeVerticalScrollExtent();
+        final boolean overScrollHorizontal = overScrollMode == OVER_SCROLL_ALWAYS ||
+                (overScrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && canScrollHorizontal);
+        final boolean overScrollVertical = overScrollMode == OVER_SCROLL_ALWAYS ||
+                (overScrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && canScrollVertical);
+
+        int newScrollX = scrollX + deltaX;
+        if (!overScrollHorizontal) {
+            maxOverScrollX = 0;
+        }
+
+        int newScrollY = scrollY + deltaY;
+        if (!overScrollVertical) {
+            maxOverScrollY = 0;
+        }
+
+        // Clamp values if at the limits and record
+        final int left = -maxOverScrollX;
+        final int right = maxOverScrollX + scrollRangeX;
+        final int top = -maxOverScrollY;
+        final int bottom = maxOverScrollY + scrollRangeY;
+
+        boolean clampedX = false;
+        if (newScrollX > right) {
+            newScrollX = right;
+            clampedX = true;
+        } else if (newScrollX < left) {
+            newScrollX = left;
+            clampedX = true;
+        }
+
+        boolean clampedY = false;
+        if (newScrollY > bottom) {
+            newScrollY = bottom;
+            clampedY = true;
+        } else if (newScrollY < top) {
+            newScrollY = top;
+            clampedY = true;
+        }
+
+        onOverScrolled(newScrollX, newScrollY, clampedX, clampedY);
+
+        return clampedX || clampedY;
+    }
+
+    /**
+     * Called by {@link #overScrollBy(int, int, int, int, int, int, int, int, boolean)} to
+     * respond to the results of an over-scroll operation.
+     *
+     * @param scrollX New X scroll value in pixels
+     * @param scrollY New Y scroll value in pixels
+     * @param clampedX True if scrollX was clamped to an over-scroll boundary
+     * @param clampedY True if scrollY was clamped to an over-scroll boundary
+     */
+    protected void onOverScrolled(int scrollX, int scrollY,
+            boolean clampedX, boolean clampedY) {
+        // Intentionally empty.
+    }
+
+    /**
+     * Returns the over-scroll mode for this view. The result will be
+     * one of {@link #OVER_SCROLL_ALWAYS} (default), {@link #OVER_SCROLL_IF_CONTENT_SCROLLS}
+     * (allow over-scrolling only if the view content is larger than the container),
+     * or {@link #OVER_SCROLL_NEVER}.
+     *
+     * @return This view's over-scroll mode.
+     */
+    public int getOverScrollMode() {
+        return mOverScrollMode;
+    }
+
+    /**
+     * Set the over-scroll mode for this view. Valid over-scroll modes are
+     * {@link #OVER_SCROLL_ALWAYS} (default), {@link #OVER_SCROLL_IF_CONTENT_SCROLLS}
+     * (allow over-scrolling only if the view content is larger than the container),
+     * or {@link #OVER_SCROLL_NEVER}.
+     *
+     * Setting the over-scroll mode of a view will have an effect only if the
+     * view is capable of scrolling.
+     *
+     * @param overScrollMode The new over-scroll mode for this view.
+     */
+    public void setOverScrollMode(int overScrollMode) {
+        if (overScrollMode != OVER_SCROLL_ALWAYS &&
+                overScrollMode != OVER_SCROLL_IF_CONTENT_SCROLLS &&
+                overScrollMode != OVER_SCROLL_NEVER) {
+            throw new IllegalArgumentException("Invalid overscroll mode " + overScrollMode);
+        }
+        mOverScrollMode = overScrollMode;
+    }
+
+    /**
      * A MeasureSpec encapsulates the layout requirements passed from parent to child.
      * Each MeasureSpec represents a requirement for either the width or the height.
      * A MeasureSpec is comprised of a size and a mode. There are three possible
diff --git a/core/java/android/view/ViewConfiguration.java b/core/java/android/view/ViewConfiguration.java
index 85981d2..bb85894 100644
--- a/core/java/android/view/ViewConfiguration.java
+++ b/core/java/android/view/ViewConfiguration.java
@@ -144,7 +144,7 @@
     /**
      * Maximum velocity to initiate a fling, as measured in pixels per second
      */
-    private static final int MAXIMUM_FLING_VELOCITY = 4000;
+    private static final int MAXIMUM_FLING_VELOCITY = 8000;
 
     /**
      * The maximum size of View's drawing cache, expressed in bytes. This size
@@ -158,6 +158,16 @@
      */
     private static float SCROLL_FRICTION = 0.015f;
 
+    /**
+     * Max distance to overscroll for edge effects
+     */
+    private static final int OVERSCROLL_DISTANCE = 0;
+
+    /**
+     * Max distance to overfling for edge effects
+     */
+    private static final int OVERFLING_DISTANCE = 4;
+
     private final int mEdgeSlop;
     private final int mFadingEdgeLength;
     private final int mMinimumFlingVelocity;
@@ -168,6 +178,8 @@
     private final int mDoubleTapSlop;
     private final int mWindowTouchSlop;
     private final int mMaximumDrawingCacheSize;
+    private final int mOverscrollDistance;
+    private final int mOverflingDistance;
 
     private static final SparseArray<ViewConfiguration> sConfigurations =
             new SparseArray<ViewConfiguration>(2);
@@ -188,6 +200,8 @@
         mWindowTouchSlop = WINDOW_TOUCH_SLOP;
         //noinspection deprecation
         mMaximumDrawingCacheSize = MAXIMUM_DRAWING_CACHE_SIZE;
+        mOverscrollDistance = OVERSCROLL_DISTANCE;
+        mOverflingDistance = OVERFLING_DISTANCE;
     }
 
     /**
@@ -216,6 +230,9 @@
 
         // Size of the screen in bytes, in ARGB_8888 format
         mMaximumDrawingCacheSize = 4 * metrics.widthPixels * metrics.heightPixels;
+
+        mOverscrollDistance = (int) (density * OVERSCROLL_DISTANCE + 0.5f);
+        mOverflingDistance = (int) (density * OVERFLING_DISTANCE + 0.5f);
     }
 
     /**
@@ -473,6 +490,20 @@
     }
 
     /**
+     * @return The maximum distance a View should overscroll by when showing edge effects.
+     */
+    public int getScaledOverscrollDistance() {
+        return mOverscrollDistance;
+    }
+
+    /**
+     * @return The maximum distance a View should overfling by when showing edge effects.
+     */
+    public int getScaledOverflingDistance() {
+        return mOverflingDistance;
+    }
+
+    /**
      * The amount of time that the zoom controls should be
      * displayed on the screen expressed in milliseconds.
      * 
diff --git a/core/java/android/webkit/OverScrollGlow.java b/core/java/android/webkit/OverScrollGlow.java
new file mode 100644
index 0000000..53600f6
--- /dev/null
+++ b/core/java/android/webkit/OverScrollGlow.java
@@ -0,0 +1,223 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.webkit;
+
+import com.android.internal.R;
+
+import android.content.res.Resources;
+import android.graphics.Canvas;
+import android.graphics.drawable.Drawable;
+import android.view.View;
+import android.widget.EdgeGlow;
+
+/**
+ * This class manages the edge glow effect when a WebView is flung or pulled beyond the edges.
+ * @hide
+ */
+public class OverScrollGlow {
+    private WebView mHostView;
+
+    private EdgeGlow mEdgeGlowTop;
+    private EdgeGlow mEdgeGlowBottom;
+    private EdgeGlow mEdgeGlowLeft;
+    private EdgeGlow mEdgeGlowRight;
+
+    private int mOverScrollDeltaX;
+    private int mOverScrollDeltaY;
+
+    public OverScrollGlow(WebView host) {
+        mHostView = host;
+        final Resources res = host.getContext().getResources();
+        final Drawable edge = res.getDrawable(R.drawable.overscroll_edge);
+        final Drawable glow = res.getDrawable(R.drawable.overscroll_glow);
+        mEdgeGlowTop = new EdgeGlow(edge, glow);
+        mEdgeGlowBottom = new EdgeGlow(edge, glow);
+        mEdgeGlowLeft = new EdgeGlow(edge, glow);
+        mEdgeGlowRight = new EdgeGlow(edge, glow);
+    }
+
+    /**
+     * Pull leftover touch scroll distance into one of the edge glows as appropriate.
+     *
+     * @param x Current X scroll offset
+     * @param y Current Y scroll offset
+     * @param oldX Old X scroll offset
+     * @param oldY Old Y scroll offset
+     * @param maxX Maximum range for horizontal scrolling
+     * @param maxY Maximum range for vertical scrolling
+     */
+    public void pullGlow(int x, int y, int oldX, int oldY, int maxX, int maxY) {
+        // Only show overscroll bars if there was no movement in any direction
+        // as a result of scrolling.
+        if (oldX == mHostView.getScrollX() && oldY == mHostView.getScrollY()) {
+            // Don't show left/right glows if we fit the whole content.
+            // Also don't show if there was vertical movement.
+            if (maxX > 0) {
+                final int pulledToX = oldX + mOverScrollDeltaX;
+                if (pulledToX < 0) {
+                    mEdgeGlowLeft.onPull((float) mOverScrollDeltaX / mHostView.getWidth());
+                    if (!mEdgeGlowRight.isFinished()) {
+                        mEdgeGlowRight.onRelease();
+                    }
+                } else if (pulledToX > maxX) {
+                    mEdgeGlowRight.onPull((float) mOverScrollDeltaX / mHostView.getWidth());
+                    if (!mEdgeGlowLeft.isFinished()) {
+                        mEdgeGlowLeft.onRelease();
+                    }
+                }
+                mOverScrollDeltaX = 0;
+            }
+
+            if (maxY > 0 || mHostView.getOverScrollMode() == View.OVER_SCROLL_ALWAYS) {
+                final int pulledToY = oldY + mOverScrollDeltaY;
+                if (pulledToY < 0) {
+                    mEdgeGlowTop.onPull((float) mOverScrollDeltaY / mHostView.getHeight());
+                    if (!mEdgeGlowBottom.isFinished()) {
+                        mEdgeGlowBottom.onRelease();
+                    }
+                } else if (pulledToY > maxY) {
+                    mEdgeGlowBottom.onPull((float) mOverScrollDeltaY / mHostView.getHeight());
+                    if (!mEdgeGlowTop.isFinished()) {
+                        mEdgeGlowTop.onRelease();
+                    }
+                }
+                mOverScrollDeltaY = 0;
+            }
+        }
+    }
+
+    /**
+     * Set touch delta values indicating the current amount of overscroll.
+     *
+     * @param deltaX
+     * @param deltaY
+     */
+    public void setOverScrollDeltas(int deltaX, int deltaY) {
+        mOverScrollDeltaX = deltaX;
+        mOverScrollDeltaY = deltaY;
+    }
+
+    /**
+     * Absorb leftover fling velocity into one of the edge glows as appropriate.
+     *
+     * @param x Current X scroll offset
+     * @param y Current Y scroll offset
+     * @param oldX Old X scroll offset
+     * @param oldY Old Y scroll offset
+     * @param rangeX Maximum range for horizontal scrolling
+     * @param rangeY Maximum range for vertical scrolling
+     */
+    public void absorbGlow(int x, int y, int oldX, int oldY, int rangeX, int rangeY) {
+        if (rangeY > 0 || mHostView.getOverScrollMode() == View.OVER_SCROLL_ALWAYS) {
+            if (y < 0 && oldY >= 0) {
+                mEdgeGlowTop.onAbsorb((int) mHostView.mScroller.getCurrVelocity());
+                if (!mEdgeGlowBottom.isFinished()) {
+                    mEdgeGlowBottom.onRelease();
+                }
+            } else if (y > rangeY && oldY <= rangeY) {
+                mEdgeGlowBottom.onAbsorb((int) mHostView.mScroller.getCurrVelocity());
+                if (!mEdgeGlowTop.isFinished()) {
+                    mEdgeGlowTop.onRelease();
+                }
+            }
+        }
+
+        if (rangeX > 0) {
+            if (x < 0 && oldX >= 0) {
+                mEdgeGlowLeft.onAbsorb((int) mHostView.mScroller.getCurrVelocity());
+                if (!mEdgeGlowRight.isFinished()) {
+                    mEdgeGlowRight.onRelease();
+                }
+            } else if (x > rangeX && oldX <= rangeX) {
+                mEdgeGlowRight.onAbsorb((int) mHostView.mScroller.getCurrVelocity());
+                if (!mEdgeGlowLeft.isFinished()) {
+                    mEdgeGlowLeft.onRelease();
+                }
+            }
+        }
+    }
+
+    /**
+     * Draw the glow effect along the sides of the widget. mEdgeGlow* must be non-null.
+     *
+     * @param canvas Canvas to draw into, transformed into view coordinates.
+     * @return true if glow effects are still animating and the view should invalidate again.
+     */
+    public boolean drawEdgeGlows(Canvas canvas) {
+        final int scrollX = mHostView.getScrollX();
+        final int scrollY = mHostView.getScrollY();
+        final int width = mHostView.getWidth();
+        int height = mHostView.getHeight();
+
+        boolean invalidateForGlow = false;
+        if (!mEdgeGlowTop.isFinished()) {
+            final int restoreCount = canvas.save();
+
+            canvas.translate(-width / 2 + scrollX, Math.min(0, scrollY));
+            mEdgeGlowTop.setSize(width * 2, height);
+            invalidateForGlow |= mEdgeGlowTop.draw(canvas);
+            canvas.restoreToCount(restoreCount);
+        }
+        if (!mEdgeGlowBottom.isFinished()) {
+            final int restoreCount = canvas.save();
+
+            canvas.translate(-width / 2 + scrollX,
+                    Math.max(mHostView.computeMaxScrollY(), scrollY) + height);
+            canvas.rotate(180, width, 0);
+            mEdgeGlowBottom.setSize(width * 2, height);
+            invalidateForGlow |= mEdgeGlowBottom.draw(canvas);
+            canvas.restoreToCount(restoreCount);
+        }
+        if (!mEdgeGlowLeft.isFinished()) {
+            final int restoreCount = canvas.save();
+
+            canvas.rotate(270);
+            canvas.translate(-height * 1.5f - scrollY, Math.min(0, scrollX));
+            mEdgeGlowLeft.setSize(height * 2, width);
+            invalidateForGlow |= mEdgeGlowLeft.draw(canvas);
+            canvas.restoreToCount(restoreCount);
+        }
+        if (!mEdgeGlowRight.isFinished()) {
+            final int restoreCount = canvas.save();
+
+            canvas.rotate(90);
+            canvas.translate(-height / 2 + scrollY,
+                    -(Math.max(mHostView.computeMaxScrollX(), scrollX) + width));
+            mEdgeGlowRight.setSize(height * 2, width);
+            invalidateForGlow |= mEdgeGlowRight.draw(canvas);
+            canvas.restoreToCount(restoreCount);
+        }
+        return invalidateForGlow;
+    }
+
+    /**
+     * @return True if any glow is still animating
+     */
+    public boolean isAnimating() {
+        return (!mEdgeGlowTop.isFinished() || !mEdgeGlowBottom.isFinished() ||
+                !mEdgeGlowLeft.isFinished() || !mEdgeGlowRight.isFinished());
+    }
+
+    /**
+     * Release all glows from any touch pulls in progress.
+     */
+    public void releaseAll() {
+        mEdgeGlowTop.onRelease();
+        mEdgeGlowBottom.onRelease();
+        mEdgeGlowLeft.onRelease();
+        mEdgeGlowRight.onRelease();
+    }
+}
diff --git a/core/java/android/webkit/WebSettings.java b/core/java/android/webkit/WebSettings.java
index 98e6ab8..2e69d99 100644
--- a/core/java/android/webkit/WebSettings.java
+++ b/core/java/android/webkit/WebSettings.java
@@ -268,6 +268,8 @@
 
     private AutoFillProfile mAutoFillProfile;
 
+    private boolean         mUseWebViewBackgroundForOverscroll = true;
+
     // private WebSettings, not accessible by the host activity
     static private int      mDoubleTapToastCount = 3;
 
@@ -631,6 +633,23 @@
     }
 
     /**
+     * Set whether the WebView uses its background for over scroll background.
+     * If true, it will use the WebView's background. If false, it will use an
+     * internal pattern. Default is true.
+     */
+    public void setUseWebViewBackgroundForOverscrollBackground(boolean view) {
+        mUseWebViewBackgroundForOverscroll = view;
+    }
+
+    /**
+     * Returns true if this WebView uses WebView's background instead of
+     * internal pattern for over scroll background.
+     */
+    public boolean getUseWebViewBackgroundForOverscrollBackground() {
+        return mUseWebViewBackgroundForOverscroll;
+    }
+
+    /**
      * Store whether the WebView is saving form data.
      */
     public void setSaveFormData(boolean save) {
diff --git a/core/java/android/webkit/WebView.java b/core/java/android/webkit/WebView.java
index 376b1d0..3cb9084 100644
--- a/core/java/android/webkit/WebView.java
+++ b/core/java/android/webkit/WebView.java
@@ -16,19 +16,24 @@
 
 package android.webkit;
 
+import com.android.internal.R;
+
 import android.annotation.Widget;
 import android.app.AlertDialog;
 import android.content.BroadcastReceiver;
 import android.content.ClipboardManager;
 import android.content.Context;
 import android.content.DialogInterface;
-import android.content.IntentFilter;
 import android.content.DialogInterface.OnCancelListener;
+import android.content.Intent;
+import android.content.IntentFilter;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
-import android.content.Intent;
+import android.content.res.Resources;
 import android.database.DataSetObserver;
 import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.BitmapShader;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.CornerPathEffect;
@@ -40,6 +45,7 @@
 import android.graphics.Rect;
 import android.graphics.RectF;
 import android.graphics.Region;
+import android.graphics.Shader;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.net.http.SslCertificate;
@@ -81,13 +87,12 @@
 import android.widget.AdapterView.OnItemClickListener;
 import android.widget.ArrayAdapter;
 import android.widget.CheckedTextView;
+import android.widget.EdgeGlow;
 import android.widget.LinearLayout;
 import android.widget.ListView;
-import android.widget.Scroller;
+import android.widget.OverScroller;
 import android.widget.Toast;
 
-import junit.framework.Assert;
-
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
@@ -102,6 +107,8 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import junit.framework.Assert;
+
 /**
  * <p>A View that displays web pages. This class is the basis upon which you
  * can roll your own web browser or simply display some online content within your Activity.
@@ -529,7 +536,13 @@
     // time for the longest scroll animation
     private static final int MAX_DURATION = 750;   // milliseconds
     private static final int SLIDE_TITLE_DURATION = 500;   // milliseconds
-    private Scroller mScroller;
+
+    // Used by OverScrollGlow
+    OverScroller mScroller;
+
+    private boolean mInOverScrollMode = false;
+    private static Paint mOverScrollBackground;
+    private static Paint mOverScrollBorder;
 
     private boolean mWrapContent;
     private static final int MOTIONLESS_FALSE           = 0;
@@ -734,6 +747,20 @@
     // variable to cache the above pattern in case accessibility is enabled.
     private Pattern mMatchAxsUrlParameterPattern;
 
+    /**
+     * Max distance to overscroll by in pixels.
+     * This how far content can be pulled beyond its normal bounds by the user.
+     */
+    private int mOverscrollDistance;
+
+    /**
+     * Max distance to overfling by in pixels.
+     * This is how far flinged content can move beyond the end of its normal bounds.
+     */
+    private int mOverflingDistance;
+
+    private OverScrollGlow mOverScrollGlow;
+
     // Used to match key downs and key ups
     private boolean mGotKeyDown;
 
@@ -909,7 +936,7 @@
         L10nUtils.loadStrings(context);
         mWebViewCore = new WebViewCore(context, this, mCallbackProxy, javascriptInterfaces);
         mDatabase = WebViewDatabase.getInstance(context);
-        mScroller = new Scroller(context);
+        mScroller = new OverScroller(context, null, 0, 0, false); //TODO Use OverScroller's flywheel
         mZoomManager = new ZoomManager(this, mCallbackProxy);
 
         /* The init method must follow the creation of certain member variables,
@@ -1044,6 +1071,9 @@
 
         // Compute the inverse of the density squared.
         DRAG_LAYER_INVERSE_DENSITY_SQUARED = 1 / (density * density);
+
+        mOverscrollDistance = configuration.getScaledOverscrollDistance();
+        mOverflingDistance = configuration.getScaledOverflingDistance();
     }
 
     /**
@@ -1066,6 +1096,18 @@
                 new TextToSpeech(getContext(), null));
     }
 
+    @Override
+    public void setOverScrollMode(int mode) {
+        super.setOverScrollMode(mode);
+        if (mode != OVER_SCROLL_NEVER) {
+            if (mOverScrollGlow == null) {
+                mOverScrollGlow = new OverScrollGlow(this);
+            }
+        } else {
+            mOverScrollGlow = null;
+        }
+    }
+
     /* package */void updateDefaultZoomDensity(int zoomDensity) {
         final float density = mContext.getResources().getDisplayMetrics().density
                 * 100 / zoomDensity;
@@ -1197,7 +1239,8 @@
      * @hide
      */
     public int getVisibleTitleHeight() {
-        return Math.max(getTitleHeight() - mScrollY, 0);
+        // need to restrict mScrollY due to over scroll
+        return Math.max(getTitleHeight() - Math.max(0, mScrollY), 0);
     }
 
     /*
@@ -1946,7 +1989,7 @@
         }
         nativeClearCursor(); // start next trackball movement from page edge
         if (bottom) {
-            return pinScrollTo(mScrollX, computeVerticalScrollRange(), true, 0);
+            return pinScrollTo(mScrollX, computeRealVerticalScrollRange(), true, 0);
         }
         // Page down.
         int h = getHeight();
@@ -2171,13 +2214,15 @@
 
     // Expects x in view coordinates
     int pinLocX(int x) {
-        return pinLoc(x, getViewWidth(), computeHorizontalScrollRange());
+        if (mInOverScrollMode) return x;
+        return pinLoc(x, getViewWidth(), computeRealHorizontalScrollRange());
     }
 
     // Expects y in view coordinates
     int pinLocY(int y) {
+        if (mInOverScrollMode) return y;
         return pinLoc(y, getViewHeightWithTitle(),
-                      computeVerticalScrollRange() + getTitleHeight());
+                      computeRealVerticalScrollRange() + getTitleHeight());
     }
 
     /**
@@ -2412,7 +2457,7 @@
     // Sets r to be our visible rectangle in content coordinates
     private void calcOurContentVisibleRect(Rect r) {
         calcOurVisibleRect(r);
-        // pin the rect to the bounds of the content
+        // since we might overscroll, pin the rect to the bounds of the content
         r.left = Math.max(viewToContentX(r.left), 0);
         // viewToContentY will remove the total height of the title bar.  Add
         // the visible height back in to account for the fact that if the title
@@ -2497,8 +2542,7 @@
         return false;
     }
 
-    @Override
-    protected int computeHorizontalScrollRange() {
+    private int computeRealHorizontalScrollRange() {
         if (mDrawHistory) {
             return mHistoryWidth;
         } else if (mHorizontalScrollBarMode == SCROLLBAR_ALWAYSOFF
@@ -2512,7 +2556,27 @@
     }
 
     @Override
-    protected int computeVerticalScrollRange() {
+    protected int computeHorizontalScrollRange() {
+        int range = computeRealHorizontalScrollRange();
+
+        // Adjust reported range if overscrolled to compress the scroll bars
+        final int scrollX = mScrollX;
+        final int overscrollRight = computeMaxScrollX();
+        if (scrollX < 0) {
+            range -= scrollX;
+        } else if (scrollX > overscrollRight) {
+            range += scrollX - overscrollRight;
+        }
+
+        return range;
+    }
+
+    @Override
+    protected int computeHorizontalScrollOffset() {
+        return Math.max(mScrollX, 0);
+    }
+
+    private int computeRealVerticalScrollRange() {
         if (mDrawHistory) {
             return mHistoryHeight;
         } else if (mVerticalScrollBarMode == SCROLLBAR_ALWAYSOFF
@@ -2526,6 +2590,22 @@
     }
 
     @Override
+    protected int computeVerticalScrollRange() {
+        int range = computeRealVerticalScrollRange();
+
+        // Adjust reported range if overscrolled to compress the scroll bars
+        final int scrollY = mScrollY;
+        final int overscrollBottom = computeMaxScrollY();
+        if (scrollY < 0) {
+            range -= scrollY;
+        } else if (scrollY > overscrollBottom) {
+            range += scrollY - overscrollBottom;
+        }
+
+        return range;
+    }
+
+    @Override
     protected int computeVerticalScrollOffset() {
         return Math.max(mScrollY - getTitleHeight(), 0);
     }
@@ -2540,10 +2620,39 @@
     protected void onDrawVerticalScrollBar(Canvas canvas,
                                            Drawable scrollBar,
                                            int l, int t, int r, int b) {
+        if (mScrollY < 0) {
+            t -= mScrollY;
+        }
         scrollBar.setBounds(l, t + getVisibleTitleHeight(), r, b);
         scrollBar.draw(canvas);
     }
 
+    @Override
+    protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX,
+            boolean clampedY) {
+        mInOverScrollMode = false;
+        int maxX = computeMaxScrollX();
+        int maxY = computeMaxScrollY();
+        if (maxX == 0) {
+            // do not over scroll x if the page just fits the screen
+            scrollX = pinLocX(scrollX);
+        } else if (scrollX < 0 || scrollX > maxX) {
+            mInOverScrollMode = true;
+        }
+        if (scrollY < 0 || scrollY > maxY) {
+            mInOverScrollMode = true;
+        }
+
+        int oldX = mScrollX;
+        int oldY = mScrollY;
+
+        super.scrollTo(scrollX, scrollY);
+
+        if (mOverScrollGlow != null) {
+            mOverScrollGlow.pullGlow(mScrollX, mScrollY, oldX, oldY, maxX, maxY);
+        }
+    }
+
     /**
      * Get the url for the current page. This is not always the same as the url
      * passed to WebViewClient.onPageStarted because although the load for
@@ -2923,17 +3032,29 @@
         if (mScroller.computeScrollOffset()) {
             int oldX = mScrollX;
             int oldY = mScrollY;
-            mScrollX = mScroller.getCurrX();
-            mScrollY = mScroller.getCurrY();
-            postInvalidate();  // So we draw again
-            if (oldX != mScrollX || oldY != mScrollY) {
-                onScrollChanged(mScrollX, mScrollY, oldX, oldY);
-            } else if (mScroller.getStartX() != mScrollX
-                    || mScroller.getStartY() != mScrollY) {
-                abortAnimation();
-                mPrivateHandler.removeMessages(RESUME_WEBCORE_PRIORITY);
-                WebViewCore.resumePriority();
-                WebViewCore.resumeUpdatePicture(mWebViewCore);
+            int x = mScroller.getCurrX();
+            int y = mScroller.getCurrY();
+            invalidate();  // So we draw again
+
+            if (!mScroller.isFinished()) {
+                final int rangeX = computeMaxScrollX();
+                final int rangeY = computeMaxScrollY();
+                overScrollBy(x - oldX, y - oldY, oldX, oldY,
+                        rangeX, rangeY,
+                        mOverflingDistance, mOverflingDistance, false);
+
+                if (mOverScrollGlow != null) {
+                    mOverScrollGlow.absorbGlow(x, y, oldX, oldY, rangeX, rangeY);
+                }
+            } else {
+                mScrollX = x;
+                mScrollY = y;
+                if (mScroller.getStartX() != mScrollX || mScroller.getStartY() != mScrollY) {
+                    abortAnimation();
+                    mPrivateHandler.removeMessages(RESUME_WEBCORE_PRIORITY);
+                    WebViewCore.resumePriority();
+                    WebViewCore.resumeUpdatePicture(mWebViewCore);
+                }
             }
         } else {
             super.computeScroll();
@@ -3436,6 +3557,40 @@
         drawCoreAndCursorRing(canvas, mBackgroundColor, mDrawCursorRing);
     }
 
+    /**
+     * Draw the background when beyond bounds
+     * @param canvas Canvas to draw into
+     */
+    private void drawOverScrollBackground(Canvas canvas) {
+        if (mOverScrollBackground == null) {
+            mOverScrollBackground = new Paint();
+            Bitmap bm = BitmapFactory.decodeResource(
+                    mContext.getResources(),
+                    com.android.internal.R.drawable.status_bar_background);
+            mOverScrollBackground.setShader(new BitmapShader(bm,
+                    Shader.TileMode.REPEAT, Shader.TileMode.REPEAT));
+            mOverScrollBorder = new Paint();
+            mOverScrollBorder.setStyle(Paint.Style.STROKE);
+            mOverScrollBorder.setStrokeWidth(0);
+            mOverScrollBorder.setColor(0xffbbbbbb);
+        }
+
+        int top = 0;
+        int right = computeRealHorizontalScrollRange();
+        int bottom = top + computeRealVerticalScrollRange();
+        // first draw the background and anchor to the top of the view
+        canvas.save();
+        canvas.translate(mScrollX, mScrollY);
+        canvas.clipRect(-mScrollX, top - mScrollY, right - mScrollX, bottom
+                - mScrollY, Region.Op.DIFFERENCE);
+        canvas.drawPaint(mOverScrollBackground);
+        canvas.restore();
+        // then draw the border
+        canvas.drawRect(-1, top - 1, right, bottom, mOverScrollBorder);
+        // next clip the region for the content
+        canvas.clipRect(0, top, right, bottom);
+    }
+
     @Override
     protected void onDraw(Canvas canvas) {
         // if mNativeClass is 0, the WebView has been destroyed. Do nothing.
@@ -3452,6 +3607,10 @@
         }
 
         int saveCount = canvas.save();
+        if (mInOverScrollMode && !getSettings()
+                .getUseWebViewBackgroundForOverscrollBackground()) {
+            drawOverScrollBackground(canvas);
+        }
         if (mTitleBar != null) {
             canvas.translate(0, (int) mTitleBar.getHeight());
         }
@@ -3466,6 +3625,10 @@
         }
         mWebViewCore.signalRepaintDone();
 
+        if (mOverScrollGlow != null && mOverScrollGlow.drawEdgeGlows(canvas)) {
+            invalidate();
+        }
+
         // paint the highlight in the end
         if (!mTouchHighlightRegion.isEmpty()) {
             if (mTouchHightlightPaint == null) {
@@ -4707,12 +4870,14 @@
     @Override
     protected void onScrollChanged(int l, int t, int oldl, int oldt) {
         super.onScrollChanged(l, t, oldl, oldt);
-        sendOurVisibleRect();
-        // update WebKit if visible title bar height changed. The logic is same
-        // as getVisibleTitleHeight.
-        int titleHeight = getTitleHeight();
-        if (Math.max(titleHeight - t, 0) != Math.max(titleHeight - oldt, 0)) {
-            sendViewSizeZoom(false);
+        if (!mInOverScrollMode) {
+            sendOurVisibleRect();
+            // update WebKit if visible title bar height changed. The logic is same
+            // as getVisibleTitleHeight.
+            int titleHeight = getTitleHeight();
+            if (Math.max(titleHeight - t, 0) != Math.max(titleHeight - oldt, 0)) {
+                sendViewSizeZoom(false);
+            }
         }
     }
 
@@ -5167,20 +5332,6 @@
                 }
 
                 // do pan
-                if (mTouchMode != TOUCH_DRAG_LAYER_MODE) {
-                    int newScrollX = pinLocX(mScrollX + deltaX);
-                    int newDeltaX = newScrollX - mScrollX;
-                    if (deltaX != newDeltaX) {
-                        deltaX = newDeltaX;
-                        fDeltaX = (float) newDeltaX;
-                    }
-                    int newScrollY = pinLocY(mScrollY + deltaY);
-                    int newDeltaY = newScrollY - mScrollY;
-                    if (deltaY != newDeltaY) {
-                        deltaY = newDeltaY;
-                        fDeltaY = (float) newDeltaY;
-                    }
-                }
                 boolean done = false;
                 boolean keepScrollBarsVisible = false;
                 if (Math.abs(fDeltaX) < 1.0f && Math.abs(fDeltaY) < 1.0f) {
@@ -5370,6 +5521,12 @@
                             mHeldMotionless = MOTIONLESS_IGNORE;
                             doFling();
                             break;
+                        } else {
+                            if (mScroller.springBack(mScrollX, mScrollY, 0,
+                                    computeMaxScrollX(), 0,
+                                    computeMaxScrollY())) {
+                                invalidate();
+                            }
                         }
                         // redraw in high-quality, as we're done dragging
                         mHeldMotionless = MOTIONLESS_TRUE;
@@ -5390,6 +5547,8 @@
             }
             case MotionEvent.ACTION_CANCEL: {
                 if (mTouchMode == TOUCH_DRAG_MODE) {
+                    mScroller.springBack(mScrollX, mScrollY, 0,
+                            computeMaxScrollX(), 0, computeMaxScrollY());
                     invalidate();
                 }
                 cancelWebCoreTouchEvent(contentX, contentY, false);
@@ -5465,7 +5624,22 @@
                 }
                 return;
             }
-            scrollBy(deltaX, deltaY);
+
+            final int oldX = mScrollX;
+            final int oldY = mScrollY;
+            final int rangeX = computeMaxScrollX();
+            final int rangeY = computeMaxScrollY();
+
+            if (mOverScrollGlow != null) {
+                mOverScrollGlow.setOverScrollDeltas(deltaX, deltaY);
+            }
+
+            overScrollBy(deltaX, deltaY, oldX, oldY,
+                    rangeX, rangeY,
+                    mOverscrollDistance, mOverscrollDistance, true);
+            if (mOverScrollGlow != null && mOverScrollGlow.isAnimating()) {
+                invalidate();
+            }
         }
         mZoomManager.keepZoomPickerVisible();
     }
@@ -5478,6 +5652,11 @@
             mVelocityTracker.recycle();
             mVelocityTracker = null;
         }
+
+        // Release any pulled glows
+        if (mOverScrollGlow != null) {
+            mOverScrollGlow.releaseAll();
+        }
     }
 
     private void cancelTouch() {
@@ -5488,6 +5667,7 @@
             mVelocityTracker.recycle();
             mVelocityTracker = null;
         }
+
         if (mTouchMode == TOUCH_DRAG_MODE ||
                 mTouchMode == TOUCH_DRAG_LAYER_MODE) {
             WebViewCore.resumePriority();
@@ -5799,12 +5979,20 @@
         }
     }
 
-    private int computeMaxScrollX() {
-        return Math.max(computeHorizontalScrollRange() - getViewWidth(), 0);
+    /**
+     * Compute the maximum horizontal scroll position. Used by {@link OverScrollGlow}.
+     * @return Maximum horizontal scroll position within real content
+     */
+    int computeMaxScrollX() {
+        return Math.max(computeRealHorizontalScrollRange() - getViewWidth(), 0);
     }
 
-    private int computeMaxScrollY() {
-        return Math.max(computeVerticalScrollRange() + getTitleHeight()
+    /**
+     * Compute the maximum vertical scroll position. Used by {@link OverScrollGlow}.
+     * @return Maximum vertical scroll position within real content
+     */
+    int computeMaxScrollY() {
+        return Math.max(computeRealVerticalScrollRange() + getTitleHeight()
                 - getViewHeightWithTitle(), 0);
     }
 
@@ -5823,7 +6011,7 @@
 
     public void flingScroll(int vx, int vy) {
         mScroller.fling(mScrollX, mScrollY, vx, vy, 0, computeMaxScrollX(), 0,
-                computeMaxScrollY());
+                computeMaxScrollY(), mOverflingDistance, mOverflingDistance);
         invalidate();
     }
 
@@ -5853,6 +6041,10 @@
         if ((maxX == 0 && vy == 0) || (maxY == 0 && vx == 0)) {
             WebViewCore.resumePriority();
             WebViewCore.resumeUpdatePicture(mWebViewCore);
+            if (mScroller.springBack(mScrollX, mScrollY, 0, computeMaxScrollX(),
+                    0, computeMaxScrollY())) {
+                invalidate();
+            }
             return;
         }
         float currentVelocity = mScroller.getCurrVelocity();
@@ -5879,13 +6071,37 @@
                     + " maxX=" + maxX + " maxY=" + maxY
                     + " mScrollX=" + mScrollX + " mScrollY=" + mScrollY);
         }
+
+        // Allow sloppy flings without overscrolling at the edges.
+        if ((mScrollX == 0 || mScrollX == maxX) && Math.abs(vx) < Math.abs(vy)) {
+            vx = 0;
+        }
+        if ((mScrollY == 0 || mScrollY == maxY) && Math.abs(vy) < Math.abs(vx)) {
+            vy = 0;
+        }
+
+        if (mOverscrollDistance < mOverflingDistance) {
+            if (mScrollX == -mOverscrollDistance || mScrollX == maxX + mOverscrollDistance) {
+                vx = 0;
+            }
+            if (mScrollY == -mOverscrollDistance || mScrollY == maxY + mOverscrollDistance) {
+                vy = 0;
+            }
+        }
+
         mLastVelX = vx;
         mLastVelY = vy;
         mLastVelocity = velocity;
 
-        mScroller.fling(mScrollX, mScrollY, -vx, -vy, 0, maxX, 0, maxY);
+        // no horizontal overscroll if the content just fits
+        mScroller.fling(mScrollX, mScrollY, -vx, -vy, 0, maxX, 0, maxY,
+                maxX == 0 ? 0 : mOverflingDistance, mOverflingDistance);
+        // Duration is calculated based on velocity. With range boundaries and overscroll
+        // we may not know how long the final animation will take. (Hence the deprecation
+        // warning on the call below.) It's not a big deal for scroll bars but if webcore
+        // resumes during this effect we will take a performance hit. See computeScroll;
+        // we resume webcore there when the animation is finished.
         final int time = mScroller.getDuration();
-        mPrivateHandler.sendEmptyMessageDelayed(RESUME_WEBCORE_PRIORITY, time);
         awakenScrollBars(time);
         invalidate();
     }
@@ -6684,6 +6900,10 @@
                             case MotionEvent.ACTION_CANCEL:
                                 if (mDeferTouchMode == TOUCH_DRAG_MODE) {
                                     // no fling in defer process
+                                    mScroller.springBack(mScrollX, mScrollY, 0,
+                                            computeMaxScrollX(), 0,
+                                            computeMaxScrollY());
+                                    invalidate();
                                     WebViewCore.resumePriority();
                                     WebViewCore.resumeUpdatePicture(mWebViewCore);
                                 }
diff --git a/core/java/android/widget/AbsListView.java b/core/java/android/widget/AbsListView.java
index 70cfee9..eb8e2de 100644
--- a/core/java/android/widget/AbsListView.java
+++ b/core/java/android/widget/AbsListView.java
@@ -20,6 +20,7 @@
 
 import android.content.Context;
 import android.content.Intent;
+import android.content.res.Resources;
 import android.content.res.TypedArray;
 import android.graphics.Canvas;
 import android.graphics.Rect;
@@ -39,6 +40,7 @@
 import android.util.SparseBooleanArray;
 import android.util.StateSet;
 import android.view.ActionMode;
+import android.view.ContextMenu.ContextMenuInfo;
 import android.view.Gravity;
 import android.view.HapticFeedbackConstants;
 import android.view.KeyEvent;
@@ -52,7 +54,6 @@
 import android.view.ViewDebug;
 import android.view.ViewGroup;
 import android.view.ViewTreeObserver;
-import android.view.ContextMenu.ContextMenuInfo;
 import android.view.inputmethod.BaseInputConnection;
 import android.view.inputmethod.EditorInfo;
 import android.view.inputmethod.InputConnection;
@@ -138,6 +139,17 @@
     static final int TOUCH_MODE_FLING = 4;
 
     /**
+     * Indicates the touch gesture is an overscroll - a scroll beyond the beginning or end.
+     */
+    static final int TOUCH_MODE_OVERSCROLL = 5;
+
+    /**
+     * Indicates the view is being flung outside of normal content bounds
+     * and will spring back.
+     */
+    static final int TOUCH_MODE_OVERFLING = 6;
+
+    /**
      * Regular layout - usually an unsolicited layout from the view system
      */
     static final int LAYOUT_NORMAL = 0;
@@ -446,6 +458,16 @@
     private ContextMenuInfo mContextMenuInfo = null;
     
     /**
+     * Maximum distance to record overscroll
+     */
+    int mOverscrollMax;
+
+    /**
+     * Content height divided by this is the overscroll limit.
+     */
+    static final int OVERSCROLL_LIMIT_DIVISOR = 3;
+
+    /**
      * Used to request a layout when we changed touch mode
      */
     private static final int TOUCH_MODE_UNKNOWN = -1;
@@ -548,6 +570,48 @@
     private static final int INVALID_POINTER = -1;
 
     /**
+     * Maximum distance to overscroll by during edge effects
+     */
+    int mOverscrollDistance;
+
+    /**
+     * Maximum distance to overfling during edge effects
+     */
+    int mOverflingDistance;
+
+    // These two EdgeGlows are always set and used together.
+    // Checking one for null is as good as checking both.
+
+    /**
+     * Tracks the state of the top edge glow.
+     */
+    private EdgeGlow mEdgeGlowTop;
+
+    /**
+     * Tracks the state of the bottom edge glow.
+     */
+    private EdgeGlow mEdgeGlowBottom;
+
+    /**
+     * An estimate of how many pixels are between the top of the list and
+     * the top of the first position in the adapter, based on the last time
+     * we saw it. Used to hint where to draw edge glows.
+     */
+    private int mFirstPositionDistanceGuess;
+
+    /**
+     * An estimate of how many pixels are between the bottom of the list and
+     * the bottom of the last position in the adapter, based on the last time
+     * we saw it. Used to hint where to draw edge glows.
+     */
+    private int mLastPositionDistanceGuess;
+
+    /**
+     * Used for determining when to cancel out of overscroll.
+     */
+    private int mDirection = 0;
+
+    /**
      * Interface definition for a callback to be invoked when the list or grid
      * has been scrolled.
      */
@@ -690,9 +754,29 @@
         mTouchSlop = configuration.getScaledTouchSlop();
         mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
         mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
+        mOverscrollDistance = configuration.getScaledOverscrollDistance();
+        mOverflingDistance = configuration.getScaledOverflingDistance();
+
         mDensityScale = getContext().getResources().getDisplayMetrics().density;
     }
 
+    @Override
+    public void setOverScrollMode(int mode) {
+        if (mode != OVER_SCROLL_NEVER) {
+            if (mEdgeGlowTop == null) {
+                final Resources res = getContext().getResources();
+                final Drawable edge = res.getDrawable(R.drawable.overscroll_edge);
+                final Drawable glow = res.getDrawable(R.drawable.overscroll_glow);
+                mEdgeGlowTop = new EdgeGlow(edge, glow);
+                mEdgeGlowBottom = new EdgeGlow(edge, glow);
+            }
+        } else {
+            mEdgeGlowTop = null;
+            mEdgeGlowBottom = null;
+        }
+        super.setOverScrollMode(mode);
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -1003,6 +1087,18 @@
     }
 
     /**
+     * @return true if all list content currently fits within the view boundaries
+     */
+    private boolean contentFits() {
+        final int childCount = getChildCount();
+        if (childCount != mItemCount) {
+            return false;
+        }
+
+        return getChildAt(0).getTop() >= 0 && getChildAt(childCount - 1).getBottom() <= mBottom;
+    }
+
+    /**
      * Enables fast scrolling by letting the user quickly scroll through lists by
      * dragging the fast scroll thumb. The adapter attached to the list may want
      * to implement {@link SectionIndexer} if it wishes to display alphabet preview and
@@ -1540,6 +1636,10 @@
         int result;
         if (mSmoothScrollbarEnabled) {
             result = Math.max(mItemCount * 100, 0);
+            if (mScrollY != 0) {
+                // Compensate for overscroll
+                result += Math.abs((int) ((float) mScrollY / getHeight() * mItemCount * 100));
+            }
         } else {
             result = mItemCount;
         }
@@ -1612,6 +1712,8 @@
 
         layoutChildren();
         mInLayout = false;
+
+        mOverscrollMax = (b - t) / OVERSCROLL_LIMIT_DIVISOR;
     }
 
     /**
@@ -2126,6 +2228,7 @@
                 mFlingRunnable.endFling();
                 if (mScrollY != 0) {
                     mScrollY = 0;
+                    finishGlows();
                     invalidate();
                 }
             }
@@ -2445,9 +2548,10 @@
         // Check if we have moved far enough that it looks more like a
         // scroll than a tap
         final int distance = Math.abs(deltaY);
-        if (distance > mTouchSlop) {
+        final boolean overscroll = mScrollY != 0;
+        if (overscroll || distance > mTouchSlop) {
             createScrollingCache();
-            mTouchMode = TOUCH_MODE_SCROLL;
+            mTouchMode = overscroll ? TOUCH_MODE_OVERSCROLL : TOUCH_MODE_SCROLL;
             mMotionCorrection = deltaY;
             final Handler handler = getHandler();
             // Handler should not be null unless the AbsListView is not attached to a
@@ -2483,6 +2587,19 @@
                 // touch mode). Force an initial layout to get rid of the selection.
                 layoutChildren();
             }
+        } else {
+            int touchMode = mTouchMode;
+            if (touchMode == TOUCH_MODE_OVERSCROLL || touchMode == TOUCH_MODE_OVERFLING) {
+                if (mFlingRunnable != null) {
+                    mFlingRunnable.endFling();
+                }
+
+                if (mScrollY != 0) {
+                    mScrollY = 0;
+                    finishGlows();
+                    invalidate();
+                }
+            }
         }
     }
 
@@ -2513,49 +2630,63 @@
 
         switch (action & MotionEvent.ACTION_MASK) {
         case MotionEvent.ACTION_DOWN: {
-            mActivePointerId = ev.getPointerId(0);
-            final int x = (int) ev.getX();
-            final int y = (int) ev.getY();
-            int motionPosition = pointToPosition(x, y);
-            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
-                    mTouchMode = TOUCH_MODE_DOWN;
-                    // FIXME Debounce
-                    if (mPendingCheckForTap == null) {
-                        mPendingCheckForTap = new CheckForTap();
-                    }
-                    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
-                        return false;
-                    }
+            switch (mTouchMode) {
+            case TOUCH_MODE_OVERFLING: {
+                mFlingRunnable.endFling();
+                mTouchMode = TOUCH_MODE_OVERSCROLL;
+                mMotionY = mLastY = (int) ev.getY();
+                mMotionCorrection = 0;
+                mActivePointerId = ev.getPointerId(0);
+                break;
+            }
 
-                    if (mTouchMode == TOUCH_MODE_FLING) {
-                        // Stopped a fling. It is a scroll.
-                        createScrollingCache();
-                        mTouchMode = TOUCH_MODE_SCROLL;
-                        mMotionCorrection = 0;
-                        motionPosition = findMotionRow(y);
-                        mFlingRunnable.flywheelTouch();
+            default: {
+                mActivePointerId = ev.getPointerId(0);
+                final int x = (int) ev.getX();
+                final int y = (int) ev.getY();
+                int motionPosition = pointToPosition(x, y);
+                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
+                        mTouchMode = TOUCH_MODE_DOWN;
+                        // FIXME Debounce
+                        if (mPendingCheckForTap == null) {
+                            mPendingCheckForTap = new CheckForTap();
+                        }
+                        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
+                            return false;
+                        }
+
+                        if (mTouchMode == TOUCH_MODE_FLING) {
+                            // Stopped a fling. It is a scroll.
+                            createScrollingCache();
+                            mTouchMode = TOUCH_MODE_SCROLL;
+                            mMotionCorrection = 0;
+                            motionPosition = findMotionRow(y);
+                            mFlingRunnable.flywheelTouch();
+                        }
                     }
                 }
-            }
 
-            if (motionPosition >= 0) {
-                // Remember where the motion event started
-                v = getChildAt(motionPosition - mFirstPosition);
-                mMotionViewOriginalTop = v.getTop();
+                if (motionPosition >= 0) {
+                    // Remember where the motion event started
+                    v = getChildAt(motionPosition - mFirstPosition);
+                    mMotionViewOriginalTop = v.getTop();
+                }
+                mMotionX = x;
+                mMotionY = y;
+                mMotionPosition = motionPosition;
+                mLastY = Integer.MIN_VALUE;
+                break;
             }
-            mMotionX = x;
-            mMotionY = y;
-            mMotionPosition = motionPosition;
-            mLastY = Integer.MIN_VALUE;
+            }
             break;
         }
 
@@ -2593,9 +2724,25 @@
                         requestDisallowInterceptTouchEvent(true);
                     }
 
+                    final int rawDeltaY = deltaY;
                     deltaY -= mMotionCorrection;
                     int incrementalDeltaY = mLastY != Integer.MIN_VALUE ? y - mLastY : deltaY;
 
+                    final int motionIndex;
+                    if (mMotionPosition >= 0) {
+                        motionIndex = mMotionPosition - mFirstPosition;
+                    } else {
+                        // If we don't have a motion position that we can reliably track,
+                        // pick something in the middle to make a best guess at things below.
+                        motionIndex = getChildCount() / 2;
+                    }
+
+                    int motionViewPrevTop = 0;
+                    View motionView = this.getChildAt(motionIndex);
+                    if (motionView != null) {
+                        motionViewPrevTop = motionView.getTop();
+                    }
+
                     // No need to do all this work if we're not going to move anyway
                     boolean atEdge = false;
                     if (incrementalDeltaY != 0) {
@@ -2603,23 +2750,117 @@
                     }
 
                     // Check to see if we have bumped into the scroll limit
-                    if (atEdge && getChildCount() > 0) {
-                        // Treat this like we're starting a new scroll from the current
-                        // position. This will let the user start scrolling back into
-                        // content immediately rather than needing to scroll back to the
-                        // point where they hit the limit first.
-                        int motionPosition = findMotionRow(y);
-                        if (motionPosition >= 0) {
-                            final View motionView = getChildAt(motionPosition - mFirstPosition);
-                            mMotionViewOriginalTop = motionView.getTop();
+                    motionView = this.getChildAt(motionIndex);
+                    if (motionView != null) {
+                        // Check if the top of the motion view is where it is
+                        // supposed to be
+                        final int motionViewRealTop = motionView.getTop();
+                        if (atEdge) {
+                            // Apply overscroll
+
+                            int overscroll = -incrementalDeltaY -
+                                    (motionViewRealTop - motionViewPrevTop);
+                            overScrollBy(0, overscroll, 0, mScrollY, 0, 0,
+                                    0, mOverscrollDistance, true);
+                            if (Math.abs(mOverscrollDistance) == Math.abs(mScrollY)) {
+                                // Don't allow overfling if we're at the edge.
+                                mVelocityTracker.clear();
+                            }
+
+                            final int overscrollMode = getOverScrollMode();
+                            if (overscrollMode == OVER_SCROLL_ALWAYS ||
+                                    (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS &&
+                                            !contentFits())) {
+                                mDirection = 0; // Reset when entering overscroll.
+                                mTouchMode = TOUCH_MODE_OVERSCROLL;
+                                if (rawDeltaY > 0) {
+                                    mEdgeGlowTop.onPull((float) overscroll / getHeight());
+                                    if (!mEdgeGlowBottom.isFinished()) {
+                                        mEdgeGlowBottom.onRelease();
+                                    }
+                                } else if (rawDeltaY < 0) {
+                                    mEdgeGlowBottom.onPull((float) overscroll / getHeight());
+                                    if (!mEdgeGlowTop.isFinished()) {
+                                        mEdgeGlowTop.onRelease();
+                                    }
+                                }
+                            }
                         }
                         mMotionY = y;
-                        mMotionPosition = motionPosition;
                         invalidate();
                     }
                     mLastY = y;
                 }
                 break;
+
+            case TOUCH_MODE_OVERSCROLL:
+                if (y != mLastY) {
+                    final int rawDeltaY = deltaY;
+                    deltaY -= mMotionCorrection;
+                    int incrementalDeltaY = mLastY != Integer.MIN_VALUE ? y - mLastY : deltaY;
+
+                    final int oldScroll = mScrollY;
+                    final int newScroll = oldScroll - incrementalDeltaY;
+                    int newDirection = y > mLastY ? 1 : -1;
+
+                    if (mDirection == 0) {
+                        mDirection = newDirection;
+                    }
+
+                    if (mDirection != newDirection) {
+                        // Coming back to 'real' list scrolling
+                        incrementalDeltaY = -newScroll;
+                        mScrollY = 0;
+
+                        // No need to do all this work if we're not going to move anyway
+                        if (incrementalDeltaY != 0) {
+                            trackMotionScroll(incrementalDeltaY, incrementalDeltaY);
+                        }
+
+                        // Check to see if we are back in
+                        View motionView = this.getChildAt(mMotionPosition - mFirstPosition);
+                        if (motionView != null) {
+                            mTouchMode = TOUCH_MODE_SCROLL;
+
+                            // We did not scroll the full amount. Treat this essentially like the
+                            // start of a new touch scroll
+                            final int motionPosition = findClosestMotionRow(y);
+
+                            mMotionCorrection = 0;
+                            motionView = getChildAt(motionPosition - mFirstPosition);
+                            mMotionViewOriginalTop = motionView.getTop();
+                            mMotionY = y;
+                            mMotionPosition = motionPosition;
+                        }
+                    } else {
+                        overScrollBy(0, -incrementalDeltaY, 0, mScrollY, 0, 0,
+                                0, mOverscrollDistance, true);
+                        final int overscrollMode = getOverScrollMode();
+                        if (overscrollMode == OVER_SCROLL_ALWAYS ||
+                                (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS &&
+                                        !contentFits())) {
+                            if (rawDeltaY > 0) {
+                                mEdgeGlowTop.onPull((float) -incrementalDeltaY / getHeight());
+                                if (!mEdgeGlowBottom.isFinished()) {
+                                    mEdgeGlowBottom.onRelease();
+                                }
+                            } else if (rawDeltaY < 0) {
+                                mEdgeGlowBottom.onPull((float) -incrementalDeltaY / getHeight());
+                                if (!mEdgeGlowTop.isFinished()) {
+                                    mEdgeGlowTop.onRelease();
+                                }
+                            }
+                            invalidate();
+                        }
+                        if (Math.abs(mOverscrollDistance) == Math.abs(mScrollY)) {
+                            // Don't allow overfling if we're at the edge.
+                            mVelocityTracker.clear();
+                        }
+                    }
+                    mLastY = y;
+                    mDirection = newDirection;
+                }
+                break;
             }
 
             break;
@@ -2693,19 +2934,30 @@
             case TOUCH_MODE_SCROLL:
                 final int childCount = getChildCount();
                 if (childCount > 0) {
-                    if (mFirstPosition == 0 && getChildAt(0).getTop() >= mListPadding.top &&
+                    final int firstChildTop = getChildAt(0).getTop();
+                    final int lastChildBottom = getChildAt(childCount - 1).getBottom();
+                    final int contentTop = mListPadding.top;
+                    final int contentBottom = getHeight() - mListPadding.bottom;
+                    if (mFirstPosition == 0 && firstChildTop >= contentTop &&
                             mFirstPosition + childCount < mItemCount &&
-                            getChildAt(childCount - 1).getBottom() <=
-                                    getHeight() - mListPadding.bottom) {
+                            lastChildBottom <= getHeight() - contentBottom) {
                         mTouchMode = TOUCH_MODE_REST;
                         reportScrollStateChange(OnScrollListener.SCROLL_STATE_IDLE);
                     } else {
                         final VelocityTracker velocityTracker = mVelocityTracker;
                         velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
+
                         final int initialVelocity = (int)
                                 (velocityTracker.getYVelocity(mActivePointerId) * mVelocityScale);
-    
-                        if (Math.abs(initialVelocity) > mMinimumVelocity) {
+                        // Fling if we have enough velocity and we aren't at a boundary.
+                        // Since we can potentially overfling more than we can overscroll, don't
+                        // allow the weird behavior where you can scroll to a boundary then
+                        // fling further.
+                        if (Math.abs(initialVelocity) > mMinimumVelocity &&
+                                !((mFirstPosition == 0 &&
+                                        firstChildTop == contentTop - mOverscrollDistance) ||
+                                  (mFirstPosition + childCount == mItemCount &&
+                                        lastChildBottom == contentBottom + mOverscrollDistance))) {
                             if (mFlingRunnable == null) {
                                 mFlingRunnable = new FlingRunnable();
                             }
@@ -2725,10 +2977,32 @@
                     reportScrollStateChange(OnScrollListener.SCROLL_STATE_IDLE);
                 }
                 break;
+
+            case TOUCH_MODE_OVERSCROLL:
+                if (mFlingRunnable == null) {
+                    mFlingRunnable = new FlingRunnable();
+                }
+                final VelocityTracker velocityTracker = mVelocityTracker;
+                velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
+                final int initialVelocity = (int) velocityTracker.getYVelocity(mActivePointerId);
+
+                reportScrollStateChange(OnScrollListener.SCROLL_STATE_FLING);
+                if (Math.abs(initialVelocity) > mMinimumVelocity) {
+                    mFlingRunnable.startOverfling(-initialVelocity);
+                } else {
+                    mFlingRunnable.startSpringback();
+                }
+
+                break;
             }
 
             setPressed(false);
 
+            if (mEdgeGlowTop != null) {
+                mEdgeGlowTop.onRelease();
+                mEdgeGlowBottom.onRelease();
+            }
+
             // Need to redraw since we probably aren't drawing the selector anymore
             invalidate();
 
@@ -2759,24 +3033,42 @@
         }
 
         case MotionEvent.ACTION_CANCEL: {
-            mTouchMode = TOUCH_MODE_REST;
-            setPressed(false);
-            View motionView = getChildAt(mMotionPosition - mFirstPosition);
-            if (motionView != null) {
-                motionView.setPressed(false);
-            }
-            clearScrollingCache();
+            switch (mTouchMode) {
+            case TOUCH_MODE_OVERSCROLL:
+                if (mFlingRunnable == null) {
+                    mFlingRunnable = new FlingRunnable();
+                }
+                mFlingRunnable.startSpringback();
+                break;
 
-            final Handler handler = getHandler();
-            if (handler != null) {
-                handler.removeCallbacks(mPendingCheckForLongPress);
-            }
+            case TOUCH_MODE_OVERFLING:
+                // Do nothing - let it play out.
+                break;
 
-            if (mVelocityTracker != null) {
-                mVelocityTracker.recycle();
-                mVelocityTracker = null;
+            default:
+                mTouchMode = TOUCH_MODE_REST;
+                setPressed(false);
+                View motionView = this.getChildAt(mMotionPosition - mFirstPosition);
+                if (motionView != null) {
+                    motionView.setPressed(false);
+                }
+                clearScrollingCache();
+
+                final Handler handler = getHandler();
+                if (handler != null) {
+                    handler.removeCallbacks(mPendingCheckForLongPress);
+                }
+
+                if (mVelocityTracker != null) {
+                    mVelocityTracker.recycle();
+                    mVelocityTracker = null;
+                }
             }
             
+            if (mEdgeGlowTop != null) {
+                mEdgeGlowTop.onRelease();
+                mEdgeGlowBottom.onRelease();
+            }
             mActivePointerId = INVALID_POINTER;
             break;
         }
@@ -2801,10 +3093,61 @@
     }
 
     @Override
+    protected void onOverScrolled(int scrollX, int scrollY,
+            boolean clampedX, boolean clampedY) {
+        mScrollY = scrollY;
+
+        if (clampedY) {
+            // Velocity is broken by hitting the limit; don't start a fling off of this.
+            if (mVelocityTracker != null) {
+                mVelocityTracker.clear();
+            }
+        }
+        awakenScrollBars();
+    }
+
+    @Override
     public void draw(Canvas canvas) {
         super.draw(canvas);
+        if (mEdgeGlowTop != null) {
+            final int scrollY = mScrollY;
+            if (!mEdgeGlowTop.isFinished()) {
+                final int restoreCount = canvas.save();
+                final int width = getWidth();
+
+                canvas.translate(-width / 2, Math.min(0, scrollY + mFirstPositionDistanceGuess));
+                mEdgeGlowTop.setSize(width * 2, getHeight());
+                if (mEdgeGlowTop.draw(canvas)) {
+                    invalidate();
+                }
+                canvas.restoreToCount(restoreCount);
+            }
+            if (!mEdgeGlowBottom.isFinished()) {
+                final int restoreCount = canvas.save();
+                final int width = getWidth();
+                final int height = getHeight();
+
+                canvas.translate(-width / 2,
+                        Math.max(height, scrollY + mLastPositionDistanceGuess));
+                canvas.rotate(180, width, 0);
+                mEdgeGlowBottom.setSize(width * 2, height);
+                if (mEdgeGlowBottom.draw(canvas)) {
+                    invalidate();
+                }
+                canvas.restoreToCount(restoreCount);
+            }
+        }
         if (mFastScroller != null) {
-            mFastScroller.draw(canvas);
+            final int scrollY = mScrollY;
+            if (scrollY != 0) {
+                // Pin to the top/bottom during overscroll
+                int restoreCount = canvas.save();
+                canvas.translate(0, (float) scrollY);
+                mFastScroller.draw(canvas);
+                canvas.restoreToCount(restoreCount);
+            } else {
+                mFastScroller.draw(canvas);
+            }
         }
     }
 
@@ -2823,6 +3166,10 @@
         switch (action & MotionEvent.ACTION_MASK) {
         case MotionEvent.ACTION_DOWN: {
             int touchMode = mTouchMode;
+            if (touchMode == TOUCH_MODE_OVERFLING || touchMode == TOUCH_MODE_OVERSCROLL) {
+                mMotionCorrection = 0;
+                return true;
+            }
             
             final int x = (int) ev.getX();
             final int y = (int) ev.getY();
@@ -2887,6 +3234,7 @@
             final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
             mMotionX = (int) ev.getX(newPointerIndex);
             mMotionY = (int) ev.getY(newPointerIndex);
+            mMotionCorrection = 0;
             mActivePointerId = ev.getPointerId(newPointerIndex);
             if (mVelocityTracker != null) {
                 mVelocityTracker.clear();
@@ -2942,7 +3290,7 @@
         /**
          * Tracks the decay of a fling scroll
          */
-        private final Scroller mScroller;
+        private final OverScroller mScroller;
 
         /**
          * Y value reported by mScroller on the previous fling
@@ -2953,7 +3301,7 @@
             public void run() {
                 final int activeId = mActivePointerId;
                 final VelocityTracker vt = mVelocityTracker;
-                final Scroller scroller = mScroller;
+                final OverScroller scroller = mScroller;
                 if (vt == null || activeId == INVALID_POINTER) {
                     return;
                 }
@@ -2975,7 +3323,7 @@
         private static final int FLYWHEEL_TIMEOUT = 40; // milliseconds
 
         FlingRunnable() {
-            mScroller = new Scroller(getContext());
+            mScroller = new OverScroller(getContext());
         }
 
         void start(int initialVelocity) {
@@ -2998,6 +3346,42 @@
             }
         }
 
+        void startSpringback() {
+            if (mScroller.springBack(0, mScrollY, 0, 0, 0, 0)) {
+                mTouchMode = TOUCH_MODE_OVERFLING;
+                invalidate();
+                post(this);
+            } else {
+                mTouchMode = TOUCH_MODE_REST;
+            }
+        }
+
+        void startOverfling(int initialVelocity) {
+            final int min = mScrollY > 0 ? Integer.MIN_VALUE : 0;
+            final int max = mScrollY > 0 ? 0 : Integer.MAX_VALUE;
+            mScroller.fling(0, mScrollY, 0, initialVelocity, 0, 0, min, max, 0, getHeight());
+            mTouchMode = TOUCH_MODE_OVERFLING;
+            invalidate();
+            post(this);
+        }
+
+        void edgeReached(int delta) {
+            mScroller.notifyVerticalEdgeReached(mScrollY, 0, mOverflingDistance);
+            final int overscrollMode = getOverScrollMode();
+            if (overscrollMode == OVER_SCROLL_ALWAYS ||
+                    (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && !contentFits())) {
+                mTouchMode = TOUCH_MODE_OVERFLING;
+                final int vel = (int) mScroller.getCurrVelocity();
+                if (delta > 0) {
+                    mEdgeGlowTop.onAbsorb(vel);
+                } else {
+                    mEdgeGlowBottom.onAbsorb(vel);
+                }
+            }
+            invalidate();
+            post(this);
+        }
+
         void startScroll(int distance, int duration) {
             int initialY = distance < 0 ? Integer.MAX_VALUE : 0;
             mLastFlingY = initialY;
@@ -3040,58 +3424,100 @@
                     return;
                 }
                 // Fall through
-            case TOUCH_MODE_FLING:
+            case TOUCH_MODE_FLING: {
                 if (mItemCount == 0 || getChildCount() == 0) {
                     endFling();
                     return;
                 }
-                break;
-            }
-            final Scroller scroller = mScroller;
-            boolean more = scroller.computeScrollOffset();
-            final int y = scroller.getCurrY();
 
-            // Flip sign to convert finger direction to list items direction
-            // (e.g. finger moving down means list is moving towards the top)
-            int delta = mLastFlingY - y;
+                final OverScroller scroller = mScroller;
+                boolean more = scroller.computeScrollOffset();
+                final int y = scroller.getCurrY();
 
-            // Pretend that each frame of a fling scroll is a touch scroll
-            if (delta > 0) {
-                // List is moving towards the top. Use first view as mMotionPosition
-                mMotionPosition = mFirstPosition;
-                final View firstView = getChildAt(0);
-                mMotionViewOriginalTop = firstView.getTop();
+                // Flip sign to convert finger direction to list items direction
+                // (e.g. finger moving down means list is moving towards the top)
+                int delta = mLastFlingY - y;
 
-                // Don't fling more than 1 screen
-                delta = Math.min(getHeight() - mPaddingBottom - mPaddingTop - 1, delta);
-            } else {
-                // List is moving towards the bottom. Use last view as mMotionPosition
-                int offsetToLast = getChildCount() - 1;
-                mMotionPosition = mFirstPosition + offsetToLast;
+                // Pretend that each frame of a fling scroll is a touch scroll
+                if (delta > 0) {
+                    // List is moving towards the top. Use first view as mMotionPosition
+                    mMotionPosition = mFirstPosition;
+                    final View firstView = getChildAt(0);
+                    mMotionViewOriginalTop = firstView.getTop();
 
-                final View lastView = getChildAt(offsetToLast);
-                mMotionViewOriginalTop = lastView.getTop();
+                    // Don't fling more than 1 screen
+                    delta = Math.min(getHeight() - mPaddingBottom - mPaddingTop - 1, delta);
+                } else {
+                    // List is moving towards the bottom. Use last view as mMotionPosition
+                    int offsetToLast = getChildCount() - 1;
+                    mMotionPosition = mFirstPosition + offsetToLast;
 
-                // Don't fling more than 1 screen
-                delta = Math.max(-(getHeight() - mPaddingBottom - mPaddingTop - 1), delta);
-            }
+                    final View lastView = getChildAt(offsetToLast);
+                    mMotionViewOriginalTop = lastView.getTop();
 
-            // Don't stop just because delta is zero (it could have been rounded)
-            final boolean atEnd = trackMotionScroll(delta, delta) && (delta != 0);
+                    // Don't fling more than 1 screen
+                    delta = Math.max(-(getHeight() - mPaddingBottom - mPaddingTop - 1), delta);
+                }
 
-            if (more && !atEnd) {
-                invalidate();
-                mLastFlingY = y;
-                post(this);
-            } else {
-                endFling();
+                // Check to see if we have bumped into the scroll limit
+                View motionView = getChildAt(mMotionPosition - mFirstPosition);
+                int oldTop = 0;
+                if (motionView != null) {
+                    oldTop = motionView.getTop();
+                }
 
-                if (PROFILE_FLINGING) {
-                    if (mFlingProfilingStarted) {
-                        Debug.stopMethodTracing();
-                        mFlingProfilingStarted = false;
+                // Don't stop just because delta is zero (it could have been rounded)
+                final boolean atEnd = trackMotionScroll(delta, delta) && (delta != 0);
+                if (atEnd) {
+                    if (motionView != null) {
+                        // Tweak the scroll for how far we overshot
+                        int overshoot = -(delta - (motionView.getTop() - oldTop));
+                        overScrollBy(0, overshoot, 0, mScrollY, 0, 0,
+                                0, mOverflingDistance, false);
+                    }
+                    edgeReached(delta);
+                    break;
+                }
+
+                if (more && !atEnd) {
+                    invalidate();
+                    mLastFlingY = y;
+                    post(this);
+                } else {
+                    endFling();
+
+                    if (PROFILE_FLINGING) {
+                        if (mFlingProfilingStarted) {
+                            Debug.stopMethodTracing();
+                            mFlingProfilingStarted = false;
+                        }
+
+                        if (mFlingStrictSpan != null) {
+                            mFlingStrictSpan.finish();
+                            mFlingStrictSpan = null;
+                        }
                     }
                 }
+                break;
+            }
+
+            case TOUCH_MODE_OVERFLING: {
+                final OverScroller scroller = mScroller;
+                if (scroller.computeScrollOffset()) {
+                    final int scrollY = mScrollY;
+                    final int deltaY = scroller.getCurrY() - scrollY;
+                    if (overScrollBy(0, deltaY, 0, scrollY, 0, 0,
+                            0, mOverflingDistance, false)) {
+                        startSpringback();
+                    } else {
+                        invalidate();
+                        post(this);
+                    }
+                } else {
+                    endFling();
+                }
+                break;
+            }
             }
         }
     }
@@ -3620,16 +4046,29 @@
 
         final int firstPosition = mFirstPosition;
 
-        if (firstPosition == 0 && firstTop >= listPadding.top && deltaY >= 0) {
-            // Don't need to move views down if the top of the first position
-            // is already visible
-            return true;
+        // Update our guesses for where the first and last views are
+        if (firstPosition == 0) {
+            mFirstPositionDistanceGuess = firstTop - mListPadding.top;
+        } else {
+            mFirstPositionDistanceGuess += incrementalDeltaY;
+        }
+        if (firstPosition + childCount == mItemCount) {
+            mLastPositionDistanceGuess = lastBottom + mListPadding.bottom;
+        } else {
+            mLastPositionDistanceGuess += incrementalDeltaY;
         }
 
-        if (firstPosition + childCount == mItemCount && lastBottom <= end && deltaY <= 0) {
+        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;
+        }
+
+        if (firstPosition + childCount == mItemCount && lastBottom <= end &&
+                incrementalDeltaY <= 0) {
             // Don't need to move views up if the bottom of the last position
             // is already visible
-            return true;
+            return incrementalDeltaY != 0;
         }
 
         final boolean down = incrementalDeltaY < 0;
@@ -3805,6 +4244,22 @@
     abstract int findMotionRow(int y);
 
     /**
+     * Find the row closest to y. This row will be used as the motion row when scrolling.
+     *
+     * @param y Where the user touched
+     * @return The position of the first (or only) item in the row closest to y
+     */
+    int findClosestMotionRow(int y) {
+        final int childCount = getChildCount();
+        if (childCount == 0) {
+            return INVALID_POSITION;
+        }
+
+        final int motionRow = findMotionRow(y);
+        return motionRow != INVALID_POSITION ? motionRow : mFirstPosition + childCount - 1;
+    }
+
+    /**
      * Causes all the views to be rebuilt and redrawn.
      */
     public void invalidateViews() {
@@ -4577,6 +5032,13 @@
         return result;
     }
 
+    private void finishGlows() {
+        if (mEdgeGlowTop != null) {
+            mEdgeGlowTop.finish();
+            mEdgeGlowBottom.finish();
+        }
+    }
+
     /**
      * Sets up this AbsListView to use a remote views adapter which connects to a RemoteViewsService
      * through the specified intent.
diff --git a/core/java/android/widget/EdgeGlow.java b/core/java/android/widget/EdgeGlow.java
new file mode 100644
index 0000000..416be86
--- /dev/null
+++ b/core/java/android/widget/EdgeGlow.java
@@ -0,0 +1,327 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.widget;
+
+import android.graphics.Canvas;
+import android.graphics.drawable.Drawable;
+import android.view.animation.AnimationUtils;
+import android.view.animation.DecelerateInterpolator;
+import android.view.animation.Interpolator;
+
+/**
+ * This class performs the glow effect used at the edges of scrollable widgets.
+ * @hide
+ */
+public class EdgeGlow {
+    private static final String TAG = "EdgeGlow";
+
+    // Time it will take the effect to fully recede in ms
+    private static final int RECEDE_TIME = 1000;
+
+    // Time it will take before a pulled glow begins receding
+    private static final int PULL_TIME = 167;
+
+    // Time it will take for a pulled glow to decay to partial strength before release
+    private static final int PULL_DECAY_TIME = 1000;
+
+    private static final float MAX_ALPHA = 0.8f;
+    private static final float HELD_EDGE_ALPHA = 0.7f;
+    private static final float HELD_EDGE_SCALE_Y = 0.5f;
+    private static final float HELD_GLOW_ALPHA = 0.5f;
+    private static final float HELD_GLOW_SCALE_Y = 0.5f;
+
+    private static final float MAX_GLOW_HEIGHT = 3.f;
+
+    private static final float PULL_GLOW_BEGIN = 1.f;
+    private static final float PULL_EDGE_BEGIN = 0.6f;
+
+    // Minimum velocity that will be absorbed
+    private static final int MIN_VELOCITY = 100;
+
+    private static final float EPSILON = 0.001f;
+
+    private final Drawable mEdge;
+    private final Drawable mGlow;
+    private int mWidth;
+    private int mHeight;
+
+    private float mEdgeAlpha;
+    private float mEdgeScaleY;
+    private float mGlowAlpha;
+    private float mGlowScaleY;
+
+    private float mEdgeAlphaStart;
+    private float mEdgeAlphaFinish;
+    private float mEdgeScaleYStart;
+    private float mEdgeScaleYFinish;
+    private float mGlowAlphaStart;
+    private float mGlowAlphaFinish;
+    private float mGlowScaleYStart;
+    private float mGlowScaleYFinish;
+
+    private long mStartTime;
+    private float mDuration;
+
+    private final Interpolator mInterpolator;
+
+    private static final int STATE_IDLE = 0;
+    private static final int STATE_PULL = 1;
+    private static final int STATE_ABSORB = 2;
+    private static final int STATE_RECEDE = 3;
+    private static final int STATE_PULL_DECAY = 4;
+
+    // How much dragging should effect the height of the edge image.
+    // Number determined by user testing.
+    private static final int PULL_DISTANCE_EDGE_FACTOR = 5;
+
+    // How much dragging should effect the height of the glow image.
+    // Number determined by user testing.
+    private static final int PULL_DISTANCE_GLOW_FACTOR = 5;
+    private static final float PULL_DISTANCE_ALPHA_GLOW_FACTOR = 0.8f;
+
+    private static final int VELOCITY_EDGE_FACTOR = 8;
+    private static final int VELOCITY_GLOW_FACTOR = 16;
+
+    private int mState = STATE_IDLE;
+
+    private float mPullDistance;
+
+    public EdgeGlow(Drawable edge, Drawable glow) {
+        mEdge = edge;
+        mGlow = glow;
+
+        mInterpolator = new DecelerateInterpolator();
+    }
+
+    public void setSize(int width, int height) {
+        mWidth = width;
+        mHeight = height;
+    }
+
+    public boolean isFinished() {
+        return mState == STATE_IDLE;
+    }
+
+    public void finish() {
+        mState = STATE_IDLE;
+    }
+
+    /**
+     * Call when the object is pulled by the user.
+     *
+     * @param deltaDistance Change in distance since the last call
+     */
+    public void onPull(float deltaDistance) {
+        final long now = AnimationUtils.currentAnimationTimeMillis();
+        if (mState == STATE_PULL_DECAY && now - mStartTime < mDuration) {
+            return;
+        }
+        if (mState != STATE_PULL) {
+            mGlowScaleY = PULL_GLOW_BEGIN;
+        }
+        mState = STATE_PULL;
+
+        mStartTime = now;
+        mDuration = PULL_TIME;
+
+        mPullDistance += deltaDistance;
+        float distance = Math.abs(mPullDistance);
+
+        mEdgeAlpha = mEdgeAlphaStart = Math.max(PULL_EDGE_BEGIN, Math.min(distance, MAX_ALPHA));
+        mEdgeScaleY = mEdgeScaleYStart = Math.max(
+                HELD_EDGE_SCALE_Y, Math.min(distance * PULL_DISTANCE_EDGE_FACTOR, 1.f));
+
+        mGlowAlpha = mGlowAlphaStart = Math.min(MAX_ALPHA,
+                mGlowAlpha +
+                (Math.abs(deltaDistance) * PULL_DISTANCE_ALPHA_GLOW_FACTOR));
+
+        float glowChange = Math.abs(deltaDistance);
+        if (deltaDistance > 0 && mPullDistance < 0) {
+            glowChange = -glowChange;
+        }
+        if (mPullDistance == 0) {
+            mGlowScaleY = 0;
+        }
+
+        // Do not allow glow to get larger than MAX_GLOW_HEIGHT.
+        mGlowScaleY = mGlowScaleYStart = Math.min(MAX_GLOW_HEIGHT, Math.max(
+                0, mGlowScaleY + glowChange * PULL_DISTANCE_GLOW_FACTOR));
+
+        mEdgeAlphaFinish = mEdgeAlpha;
+        mEdgeScaleYFinish = mEdgeScaleY;
+        mGlowAlphaFinish = mGlowAlpha;
+        mGlowScaleYFinish = mGlowScaleY;
+    }
+
+    /**
+     * Call when the object is released after being pulled.
+     */
+    public void onRelease() {
+        mPullDistance = 0;
+
+        if (mState != STATE_PULL && mState != STATE_PULL_DECAY) {
+            return;
+        }
+
+        mState = STATE_RECEDE;
+        mEdgeAlphaStart = mEdgeAlpha;
+        mEdgeScaleYStart = mEdgeScaleY;
+        mGlowAlphaStart = mGlowAlpha;
+        mGlowScaleYStart = mGlowScaleY;
+
+        mEdgeAlphaFinish = 0.f;
+        mEdgeScaleYFinish = 0.f;
+        mGlowAlphaFinish = 0.f;
+        mGlowScaleYFinish = 0.f;
+
+        mStartTime = AnimationUtils.currentAnimationTimeMillis();
+        mDuration = RECEDE_TIME;
+    }
+
+    /**
+     * Call when the effect absorbs an impact at the given velocity.
+     *
+     * @param velocity Velocity at impact in pixels per second.
+     */
+    public void onAbsorb(int velocity) {
+        mState = STATE_ABSORB;
+        velocity = Math.max(MIN_VELOCITY, Math.abs(velocity));
+
+        mStartTime = AnimationUtils.currentAnimationTimeMillis();
+        mDuration = 0.1f + (velocity * 0.03f);
+
+        // The edge should always be at least partially visible, regardless
+        // of velocity.
+        mEdgeAlphaStart = 0.f;
+        mEdgeScaleY = mEdgeScaleYStart = 0.f;
+        // The glow depends more on the velocity, and therefore starts out
+        // nearly invisible.
+        mGlowAlphaStart = 0.5f;
+        mGlowScaleYStart = 0.f;
+
+        // Factor the velocity by 8. Testing on device shows this works best to
+        // reflect the strength of the user's scrolling.
+        mEdgeAlphaFinish = Math.max(0, Math.min(velocity * VELOCITY_EDGE_FACTOR, 1));
+        // Edge should never get larger than the size of its asset.
+        mEdgeScaleYFinish = Math.max(
+                HELD_EDGE_SCALE_Y, Math.min(velocity * VELOCITY_EDGE_FACTOR, 1.f));
+
+        // Growth for the size of the glow should be quadratic to properly
+        // respond
+        // to a user's scrolling speed. The faster the scrolling speed, the more
+        // intense the effect should be for both the size and the saturation.
+        mGlowScaleYFinish = Math.min(0.025f + (velocity * (velocity / 100) * 0.00015f), 1.75f);
+        // Alpha should change for the glow as well as size.
+        mGlowAlphaFinish = Math.max(
+                mGlowAlphaStart, Math.min(velocity * VELOCITY_GLOW_FACTOR * .00001f, MAX_ALPHA));
+    }
+
+
+    /**
+     * Draw into the provided canvas. Assumes that the canvas has been rotated
+     * accordingly and the size has been set. The effect will be drawn the full
+     * width of X=0 to X=width, emitting from Y=0 and extending to some factor <
+     * 1.f of height.
+     *
+     * @param canvas Canvas to draw into
+     * @return true if drawing should continue beyond this frame to continue the
+     *         animation
+     */
+    public boolean draw(Canvas canvas) {
+        update();
+
+        final int edgeHeight = mEdge.getIntrinsicHeight();
+        final int glowHeight = mGlow.getIntrinsicHeight();
+
+        final float distScale = (float) mHeight / mWidth;
+
+        mGlow.setAlpha((int) (Math.max(0, Math.min(mGlowAlpha, 1)) * 255));
+        // Width of the image should be 3 * the width of the screen.
+        // Should start off screen to the left.
+        mGlow.setBounds(-mWidth, 0, mWidth * 2, (int) Math.min(
+                glowHeight * mGlowScaleY * distScale * 0.6f, mHeight * MAX_GLOW_HEIGHT));
+        mGlow.draw(canvas);
+
+        mEdge.setAlpha((int) (Math.max(0, Math.min(mEdgeAlpha, 1)) * 255));
+        mEdge.setBounds(0, 0, mWidth, (int) (edgeHeight * mEdgeScaleY));
+        mEdge.draw(canvas);
+
+        return mState != STATE_IDLE;
+    }
+
+    private void update() {
+        final long time = AnimationUtils.currentAnimationTimeMillis();
+        final float t = Math.min((time - mStartTime) / mDuration, 1.f);
+
+        final float interp = mInterpolator.getInterpolation(t);
+
+        mEdgeAlpha = mEdgeAlphaStart + (mEdgeAlphaFinish - mEdgeAlphaStart) * interp;
+        mEdgeScaleY = mEdgeScaleYStart + (mEdgeScaleYFinish - mEdgeScaleYStart) * interp;
+        mGlowAlpha = mGlowAlphaStart + (mGlowAlphaFinish - mGlowAlphaStart) * interp;
+        mGlowScaleY = mGlowScaleYStart + (mGlowScaleYFinish - mGlowScaleYStart) * interp;
+
+        if (t >= 1.f - EPSILON) {
+            switch (mState) {
+                case STATE_ABSORB:
+                    mState = STATE_RECEDE;
+                    mStartTime = AnimationUtils.currentAnimationTimeMillis();
+                    mDuration = RECEDE_TIME;
+
+                    mEdgeAlphaStart = mEdgeAlpha;
+                    mEdgeScaleYStart = mEdgeScaleY;
+                    mGlowAlphaStart = mGlowAlpha;
+                    mGlowScaleYStart = mGlowScaleY;
+
+                    // After absorb, the glow and edge should fade to nothing.
+                    mEdgeAlphaFinish = 0.f;
+                    mEdgeScaleYFinish = 0.f;
+                    mGlowAlphaFinish = 0.f;
+                    mGlowScaleYFinish = 0.f;
+                    break;
+                case STATE_PULL:
+                    mState = STATE_PULL_DECAY;
+                    mStartTime = AnimationUtils.currentAnimationTimeMillis();
+                    mDuration = PULL_DECAY_TIME;
+
+                    mEdgeAlphaStart = mEdgeAlpha;
+                    mEdgeScaleYStart = mEdgeScaleY;
+                    mGlowAlphaStart = mGlowAlpha;
+                    mGlowScaleYStart = mGlowScaleY;
+
+                    // After pull, the glow and edge should fade to nothing.
+                    mEdgeAlphaFinish = 0.f;
+                    mEdgeScaleYFinish = 0.f;
+                    mGlowAlphaFinish = 0.f;
+                    mGlowScaleYFinish = 0.f;
+                    break;
+                case STATE_PULL_DECAY:
+                    // When receding, we want edge to decrease more slowly
+                    // than the glow.
+                    float factor = mGlowScaleYFinish != 0 ? 1
+                            / (mGlowScaleYFinish * mGlowScaleYFinish)
+                            : Float.MAX_VALUE;
+                    mEdgeScaleY = mEdgeScaleYStart +
+                        (mEdgeScaleYFinish - mEdgeScaleYStart) *
+                            interp * factor;
+                    break;
+                case STATE_RECEDE:
+                    mState = STATE_IDLE;
+                    break;
+            }
+        }
+    }
+}
diff --git a/core/java/android/widget/GridView.java b/core/java/android/widget/GridView.java
index 114ae81..4146460 100644
--- a/core/java/android/widget/GridView.java
+++ b/core/java/android/widget/GridView.java
@@ -1954,7 +1954,12 @@
         // TODO: Account for vertical spacing too
         final int numColumns = mNumColumns;
         final int rowCount = (mItemCount + numColumns - 1) / numColumns;
-        return Math.max(rowCount * 100, 0);
+        int result = Math.max(rowCount * 100, 0);
+        if (mScrollY != 0) {
+            // Compensate for overscroll
+            result += Math.abs((int) ((float) mScrollY / getHeight() * rowCount * 100));
+        }
+        return result;
     }
 }
 
diff --git a/core/java/android/widget/HorizontalScrollView.java b/core/java/android/widget/HorizontalScrollView.java
index e30d4c8..9fc91da 100644
--- a/core/java/android/widget/HorizontalScrollView.java
+++ b/core/java/android/widget/HorizontalScrollView.java
@@ -16,19 +16,24 @@
 
 package android.widget;
 
-import android.content.Context;
-import android.content.res.TypedArray;
-import android.graphics.Rect;
+import com.android.internal.R;
+
 import android.util.AttributeSet;
-import android.view.FocusFinder;
-import android.view.KeyEvent;
-import android.view.MotionEvent;
-import android.view.VelocityTracker;
+import android.graphics.Canvas;
+import android.graphics.Rect;
+import android.graphics.drawable.Drawable;
 import android.view.View;
+import android.view.VelocityTracker;
 import android.view.ViewConfiguration;
 import android.view.ViewGroup;
+import android.view.KeyEvent;
+import android.view.FocusFinder;
+import android.view.MotionEvent;
 import android.view.ViewParent;
 import android.view.animation.AnimationUtils;
+import android.content.Context;
+import android.content.res.Resources;
+import android.content.res.TypedArray;
 
 import java.util.List;
 
@@ -65,7 +70,9 @@
     private long mLastScroll;
 
     private final Rect mTempRect = new Rect();
-    private Scroller mScroller;
+    private OverScroller mScroller;
+    private EdgeGlow mEdgeGlowLeft;
+    private EdgeGlow mEdgeGlowRight;
 
     /**
      * Flag to indicate that we are moving focus ourselves. This is so the
@@ -119,6 +126,9 @@
     private int mMinimumVelocity;
     private int mMaximumVelocity;
     
+    private int mOverscrollDistance;
+    private int mOverflingDistance;
+
     /**
      * ID of the active pointer. This is used to retain consistency during
      * drags/flings if multiple pointers are used.
@@ -191,7 +201,7 @@
 
 
     private void initScrollView() {
-        mScroller = new Scroller(getContext());
+        mScroller = new OverScroller(getContext());
         setFocusable(true);
         setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
         setWillNotDraw(false);
@@ -199,6 +209,8 @@
         mTouchSlop = configuration.getScaledTouchSlop();
         mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
         mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
+        mOverscrollDistance = configuration.getScaledOverscrollDistance();
+        mOverflingDistance = configuration.getScaledOverflingDistance();
     }
 
     @Override
@@ -463,6 +475,9 @@
                 /* Release the drag */
                 mIsBeingDragged = false;
                 mActivePointerId = INVALID_POINTER;
+                if (mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0)) {
+                    invalidate();
+                }
                 break;
             case MotionEvent.ACTION_POINTER_UP:
                 onSecondaryPointerUp(ev);
@@ -495,9 +510,7 @@
         switch (action & MotionEvent.ACTION_MASK) {
             case MotionEvent.ACTION_DOWN: {
                 final float x = ev.getX();
-                if (!(mIsBeingDragged = inChild((int) x, (int) ev.getY()))) {
-                    return false;
-                }
+                mIsBeingDragged = true;
 
                 /*
                  * If being flinged and user touches, stop the fling. isFinished
@@ -520,7 +533,36 @@
                     final int deltaX = (int) (mLastMotionX - x);
                     mLastMotionX = x;
 
-                    scrollBy(deltaX, 0);
+                    final int oldX = mScrollX;
+                    final int oldY = mScrollY;
+                    final int range = getScrollRange();
+                    if (overScrollBy(deltaX, 0, mScrollX, 0, range, 0,
+                            mOverscrollDistance, 0, true)) {
+                        // Break our velocity if we hit a scroll barrier.
+                        mVelocityTracker.clear();
+                    }
+                    onScrollChanged(mScrollX, mScrollY, oldX, oldY);
+
+                    final int overscrollMode = getOverScrollMode();
+                    if (overscrollMode == OVER_SCROLL_ALWAYS ||
+                            (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0)) {
+                        final int pulledToX = oldX + deltaX;
+                        if (pulledToX < 0) {
+                            mEdgeGlowLeft.onPull((float) deltaX / getWidth());
+                            if (!mEdgeGlowRight.isFinished()) {
+                                mEdgeGlowRight.onRelease();
+                            }
+                        } else if (pulledToX > range) {
+                            mEdgeGlowRight.onPull((float) deltaX / getWidth());
+                            if (!mEdgeGlowLeft.isFinished()) {
+                                mEdgeGlowLeft.onRelease();
+                            }
+                        }
+                        if (mEdgeGlowLeft != null
+                                && (!mEdgeGlowLeft.isFinished() || !mEdgeGlowRight.isFinished())) {
+                            invalidate();
+                        }
+                    }
                 }
                 break;
             case MotionEvent.ACTION_UP:
@@ -529,8 +571,15 @@
                     velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
                     int initialVelocity = (int) velocityTracker.getXVelocity(mActivePointerId);
 
-                    if (getChildCount() > 0 && Math.abs(initialVelocity) > mMinimumVelocity) {
-                        fling(-initialVelocity);
+                    if (getChildCount() > 0) {
+                        if ((Math.abs(initialVelocity) > mMinimumVelocity)) {
+                            fling(-initialVelocity);
+                        } else {
+                            final int right = getScrollRange();
+                            if (mScroller.springBack(mScrollX, mScrollY, 0, right, 0, 0)) {
+                                invalidate();
+                            }
+                        }
                     }
                     
                     mActivePointerId = INVALID_POINTER;
@@ -540,16 +589,27 @@
                         mVelocityTracker.recycle();
                         mVelocityTracker = null;
                     }
+                    if (mEdgeGlowLeft != null) {
+                        mEdgeGlowLeft.onRelease();
+                        mEdgeGlowRight.onRelease();
+                    }
                 }
                 break;
             case MotionEvent.ACTION_CANCEL:
                 if (mIsBeingDragged && getChildCount() > 0) {
+                    if (mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0)) {
+                        invalidate();
+                    }
                     mActivePointerId = INVALID_POINTER;
                     mIsBeingDragged = false;
                     if (mVelocityTracker != null) {
                         mVelocityTracker.recycle();
                         mVelocityTracker = null;
                     }
+                    if (mEdgeGlowLeft != null) {
+                        mEdgeGlowLeft.onRelease();
+                        mEdgeGlowRight.onRelease();
+                    }
                 }
                 break;
             case MotionEvent.ACTION_POINTER_UP:
@@ -576,12 +636,28 @@
         }
     }
     
+    @Override
+    protected void onOverScrolled(int scrollX, int scrollY,
+            boolean clampedX, boolean clampedY) {
+        // Treat animating scrolls differently; see #computeScroll() for why.
+        if (!mScroller.isFinished()) {
+            mScrollX = scrollX;
+            mScrollY = scrollY;
+            if (clampedX) {
+                mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0);
+            }
+        } else {
+            super.scrollTo(scrollX, scrollY);
+        }
+        awakenScrollBars();
+    }
+
     private int getScrollRange() {
         int scrollRange = 0;
         if (getChildCount() > 0) {
             View child = getChildAt(0);
             scrollRange = Math.max(0,
-                    child.getWidth() - getWidth() - mPaddingLeft - mPaddingRight);
+                    child.getWidth() - (getWidth() - mPaddingLeft - mPaddingRight));
         }
         return scrollRange;
     }
@@ -958,7 +1034,16 @@
             return contentWidth;
         }
         
-        return getChildAt(0).getRight();
+        int scrollRange = getChildAt(0).getRight();
+        final int scrollX = mScrollX;
+        final int overscrollRight = Math.max(0, scrollRange - contentWidth);
+        if (scrollX < 0) {
+            scrollRange -= scrollX;
+        } else if (scrollX > overscrollRight) {
+            scrollRange += scrollX - overscrollRight;
+        }
+
+        return scrollRange;
     }
     
     @Override
@@ -1019,14 +1104,20 @@
             int x = mScroller.getCurrX();
             int y = mScroller.getCurrY();
 
-            if (getChildCount() > 0) {
-                View child = getChildAt(0);
-                x = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth());
-                y = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight());
-                if (x != oldX || y != oldY) {
-                    mScrollX = x;
-                    mScrollY = y;
-                    onScrollChanged(x, y, oldX, oldY);
+            if (oldX != x || oldY != y) {
+                overScrollBy(x - oldX, y - oldY, oldX, oldY, getScrollRange(), 0,
+                        mOverflingDistance, 0, false);
+                onScrollChanged(mScrollX, mScrollY, oldX, oldY);
+
+                final int range = getScrollRange();
+                final int overscrollMode = getOverScrollMode();
+                if (overscrollMode == OVER_SCROLL_ALWAYS ||
+                        (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0)) {
+                    if (x < 0 && oldX >= 0) {
+                        mEdgeGlowLeft.onAbsorb((int) mScroller.getCurrVelocity());
+                    } else if (x > range && oldX <= range) {
+                        mEdgeGlowRight.onAbsorb((int) mScroller.getCurrVelocity());
+                    }
                 }
             }
             awakenScrollBars();
@@ -1263,7 +1354,7 @@
             int right = getChildAt(0).getWidth();
     
             mScroller.fling(mScrollX, mScrollY, velocityX, 0, 0, 
-                    Math.max(0, right - width), 0, 0);
+                    Math.max(0, right - width), 0, 0, width/2, 0);
     
             final boolean movingRight = velocityX > 0;
     
@@ -1301,6 +1392,56 @@
         }
     }
 
+    @Override
+    public void setOverScrollMode(int mode) {
+        if (mode != OVER_SCROLL_NEVER) {
+            if (mEdgeGlowLeft == null) {
+                final Resources res = getContext().getResources();
+                final Drawable edge = res.getDrawable(R.drawable.overscroll_edge);
+                final Drawable glow = res.getDrawable(R.drawable.overscroll_glow);
+                mEdgeGlowLeft = new EdgeGlow(edge, glow);
+                mEdgeGlowRight = new EdgeGlow(edge, glow);
+            }
+        } else {
+            mEdgeGlowLeft = null;
+            mEdgeGlowRight = null;
+        }
+        super.setOverScrollMode(mode);
+    }
+
+    @Override
+    public void draw(Canvas canvas) {
+        super.draw(canvas);
+        if (mEdgeGlowLeft != null) {
+            final int scrollX = mScrollX;
+            if (!mEdgeGlowLeft.isFinished()) {
+                final int restoreCount = canvas.save();
+                final int height = getHeight();
+
+                canvas.rotate(270);
+                canvas.translate(-height * 1.5f, Math.min(0, scrollX));
+                mEdgeGlowLeft.setSize(getHeight() * 2, getWidth());
+                if (mEdgeGlowLeft.draw(canvas)) {
+                    invalidate();
+                }
+                canvas.restoreToCount(restoreCount);
+            }
+            if (!mEdgeGlowRight.isFinished()) {
+                final int restoreCount = canvas.save();
+                final int width = getWidth();
+                final int height = getHeight();
+
+                canvas.rotate(90);
+                canvas.translate(-height / 2, -(Math.max(getScrollRange(), scrollX) + width));
+                mEdgeGlowRight.setSize(height * 2, width);
+                if (mEdgeGlowRight.draw(canvas)) {
+                    invalidate();
+                }
+                canvas.restoreToCount(restoreCount);
+            }
+        }
+    }
+
     private int clamp(int n, int my, int child) {
         if (my >= child || n < 0) {
             return 0;
diff --git a/core/java/android/widget/ListView.java b/core/java/android/widget/ListView.java
index 502cc38..fd4f950 100644
--- a/core/java/android/widget/ListView.java
+++ b/core/java/android/widget/ListView.java
@@ -104,6 +104,9 @@
     Drawable mDivider;
     int mDividerHeight;
     
+    Drawable mOverScrollHeader;
+    Drawable mOverScrollFooter;
+
     private boolean mIsCacheColorOpaque;
     private boolean mDividerIsOpaque;
 
@@ -152,6 +155,18 @@
             setDivider(d);
         }
         
+        final Drawable osHeader = a.getDrawable(
+                com.android.internal.R.styleable.ListView_overScrollHeader);
+        if (osHeader != null) {
+            setOverscrollHeader(osHeader);
+        }
+
+        final Drawable osFooter = a.getDrawable(
+                com.android.internal.R.styleable.ListView_overScrollFooter);
+        if (osFooter != null) {
+            setOverscrollFooter(osFooter);
+        }
+
         // Use the height specified, zero being the default
         final int dividerHeight = a.getDimensionPixelSize(
                 com.android.internal.R.styleable.ListView_dividerHeight, 0);
@@ -2962,14 +2977,52 @@
         }
         super.setCacheColorHint(color);
     }
-    
+
+    void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) {
+        final int height = drawable.getMinimumHeight();
+
+        canvas.save();
+        canvas.clipRect(bounds);
+
+        final int span = bounds.bottom - bounds.top;
+        if (span < height) {
+            bounds.top = bounds.bottom - height;
+        }
+
+        drawable.setBounds(bounds);
+        drawable.draw(canvas);
+
+        canvas.restore();
+    }
+
+    void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) {
+        final int height = drawable.getMinimumHeight();
+
+        canvas.save();
+        canvas.clipRect(bounds);
+
+        final int span = bounds.bottom - bounds.top;
+        if (span < height) {
+            bounds.bottom = bounds.top + height;
+        }
+
+        drawable.setBounds(bounds);
+        drawable.draw(canvas);
+
+        canvas.restore();
+    }
+
     @Override
     protected void dispatchDraw(Canvas canvas) {
         // Draw the dividers
         final int dividerHeight = mDividerHeight;
+        final Drawable overscrollHeader = mOverScrollHeader;
+        final Drawable overscrollFooter = mOverScrollFooter;
+        final boolean drawOverscrollHeader = overscrollHeader != null;
+        final boolean drawOverscrollFooter = overscrollFooter != null;
         final boolean drawDividers = dividerHeight > 0 && mDivider != null;
 
-        if (drawDividers) {
+        if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) {
             // Only modify the top and bottom in the loop, we set the left and right here
             final Rect bounds = mTempRect;
             bounds.left = mPaddingLeft;
@@ -2998,34 +3051,67 @@
 
             final int listBottom = mBottom - mTop - mListPadding.bottom + mScrollY;
             if (!mStackFromBottom) {
-                int bottom;
+                int bottom = 0;
                 
+                // Draw top divider or header for overscroll
+                final int scrollY = mScrollY;
+                if (count > 0 && scrollY < 0) {
+                    if (drawOverscrollHeader) {
+                        bounds.bottom = 0;
+                        bounds.top = scrollY;
+                        drawOverscrollHeader(canvas, overscrollHeader, bounds);
+                    } else if (drawDividers) {
+                        bounds.bottom = 0;
+                        bounds.top = -dividerHeight;
+                        drawDivider(canvas, bounds, -1);
+                    }
+                }
+
                 for (int i = 0; i < count; i++) {
                     if ((headerDividers || first + i >= headerCount) &&
                             (footerDividers || first + i < footerLimit)) {
                         View child = getChildAt(i);
                         bottom = child.getBottom();
                         // Don't draw dividers next to items that are not enabled
-                        if ((areAllItemsSelectable ||
-                                (adapter.isEnabled(first + i) && (i == count - 1 ||
-                                        adapter.isEnabled(first + i + 1))))) {
-                            bounds.top = bottom;
-                            bounds.bottom = bottom + dividerHeight;
-                            drawDivider(canvas, bounds, i);
-                        } else if (fillForMissingDividers) {
-                            bounds.top = bottom;
-                            bounds.bottom = bottom + dividerHeight;
-                            canvas.drawRect(bounds, paint);
+
+                        if (drawDividers &&
+                                (bottom < listBottom && !(drawOverscrollFooter && i == count - 1))) {
+                            if ((areAllItemsSelectable ||
+                                    (adapter.isEnabled(first + i) && (i == count - 1 ||
+                                            adapter.isEnabled(first + i + 1))))) {
+                                bounds.top = bottom;
+                                bounds.bottom = bottom + dividerHeight;
+                                drawDivider(canvas, bounds, i);
+                            } else if (fillForMissingDividers) {
+                                bounds.top = bottom;
+                                bounds.bottom = bottom + dividerHeight;
+                                canvas.drawRect(bounds, paint);
+                            }
                         }
                     }
                 }
+
+                final int overFooterBottom = mBottom + mScrollY;
+                if (drawOverscrollFooter && first + count == itemCount &&
+                        overFooterBottom > bottom) {
+                    bounds.top = bottom;
+                    bounds.bottom = overFooterBottom;
+                    drawOverscrollFooter(canvas, overscrollFooter, bounds);
+                }
             } else {
                 int top;
                 int listTop = mListPadding.top;
 
                 final int scrollY = mScrollY;
 
-                for (int i = 0; i < count; i++) {
+                if (count > 0 && drawOverscrollHeader) {
+                    bounds.top = scrollY;
+                    bounds.bottom = getChildAt(0).getTop();
+                    drawOverscrollHeader(canvas, overscrollHeader, bounds);
+                }
+
+                final int start = drawOverscrollHeader ? 1 : 0;
+                for (int i = start; i < count; i++) {
                     if ((headerDividers || first + i >= headerCount) &&
                             (footerDividers || first + i < footerLimit)) {
                         View child = getChildAt(i);
@@ -3052,9 +3138,16 @@
                 }
                 
                 if (count > 0 && scrollY > 0) {
-                    bounds.top = listBottom;
-                    bounds.bottom = listBottom + dividerHeight;
-                    drawDivider(canvas, bounds, -1);
+                    if (drawOverscrollFooter) {
+                        final int absListBottom = mBottom;
+                        bounds.top = absListBottom;
+                        bounds.bottom = absListBottom + scrollY;
+                        drawOverscrollFooter(canvas, overscrollFooter, bounds);
+                    } else if (drawDividers) {
+                        bounds.top = listBottom;
+                        bounds.bottom = listBottom + dividerHeight;
+                        drawDivider(canvas, bounds, -1);
+                    }
                 }
             }
         }
@@ -3150,6 +3243,45 @@
         invalidate();
     }
     
+    /**
+     * Sets the drawable that will be drawn above all other list content.
+     * This area can become visible when the user overscrolls the list.
+     *
+     * @param header The drawable to use
+     */
+    public void setOverscrollHeader(Drawable header) {
+        mOverScrollHeader = header;
+        if (mScrollY < 0) {
+            invalidate();
+        }
+    }
+
+    /**
+     * @return The drawable that will be drawn above all other list content
+     */
+    public Drawable getOverscrollHeader() {
+        return mOverScrollHeader;
+    }
+
+    /**
+     * Sets the drawable that will be drawn below all other list content.
+     * This area can become visible when the user overscrolls the list,
+     * or when the list's content does not fully fill the container area.
+     *
+     * @param footer The drawable to use
+     */
+    public void setOverscrollFooter(Drawable footer) {
+        mOverScrollFooter = footer;
+        invalidate();
+    }
+
+    /**
+     * @return The drawable that will be drawn below all other list content
+     */
+    public Drawable getOverscrollFooter() {
+        return mOverScrollFooter;
+    }
+
     @Override
     protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) {
         super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);
diff --git a/core/java/android/widget/OverScroller.java b/core/java/android/widget/OverScroller.java
new file mode 100644
index 0000000..cd81e31
--- /dev/null
+++ b/core/java/android/widget/OverScroller.java
@@ -0,0 +1,888 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.widget;
+
+import android.content.Context;
+import android.graphics.Interpolator;
+import android.view.ViewConfiguration;
+import android.view.animation.AnimationUtils;
+
+/**
+ * This class encapsulates scrolling with the ability to overshoot the bounds
+ * of a scrolling operation. This class is a drop-in replacement for
+ * {@link android.widget.Scroller} in most cases.
+ */
+public class OverScroller {
+    int mMode;
+
+    private final MagneticOverScroller mScrollerX;
+    private final MagneticOverScroller mScrollerY;
+
+    private float mDeceleration;
+    private final float mPpi;
+    private final boolean mFlywheel;
+
+    private static float DECELERATION_RATE = (float) (Math.log(0.75) / Math.log(0.9));
+    private static float ALPHA = 800; // pixels / seconds
+    private static float START_TENSION = 0.4f; // Tension at start: (0.4 * total T, 1.0 * Distance)
+    private static float END_TENSION = 1.0f - START_TENSION;
+    private static final int NB_SAMPLES = 100;
+    private static final float[] SPLINE_POSITION = new float[NB_SAMPLES + 1];
+    private static final float[] SPLINE_TIME = new float[NB_SAMPLES + 1];
+
+    private static final int DEFAULT_DURATION = 250;
+    private static final int SCROLL_MODE = 0;
+    private static final int FLING_MODE = 1;
+
+    static {
+        float x_min = 0.0f;
+        float y_min = 0.0f;
+        for (int i = 0; i < NB_SAMPLES; i++) {
+            final float alpha = (float) i / NB_SAMPLES;
+            {
+                float x_max = 1.0f;
+                float x, tx, coef;
+                while (true) {
+                    x = x_min + (x_max - x_min) / 2.0f;
+                    coef = 3.0f * x * (1.0f - x);
+                    tx = coef * ((1.0f - x) * START_TENSION + x * END_TENSION) + x * x * x;
+                    if (Math.abs(tx - alpha) < 1E-5) break;
+                    if (tx > alpha) x_max = x;
+                    else x_min = x;
+                }
+                SPLINE_POSITION[i] = coef + x * x * x;
+            }
+
+            {
+                float y_max = 1.0f;
+                float y, dy, coef;
+                while (true) {
+                    y = y_min + (y_max - y_min) / 2.0f;
+                    coef = 3.0f * y * (1.0f - y);
+                    dy = coef + y * y * y;
+                    if (Math.abs(dy - alpha) < 1E-5) break;
+                    if (dy > alpha) y_max = y;
+                    else y_min = y;
+                }
+                SPLINE_TIME[i] = coef * ((1.0f - y) * START_TENSION + y * END_TENSION) + y * y * y;
+            }
+        }
+        SPLINE_POSITION[NB_SAMPLES] = SPLINE_TIME[NB_SAMPLES] = 1.0f;
+    }
+
+    public OverScroller(Context context) {
+        this(context, null, 0.f, 0.f, true);
+    }
+
+    /**
+     * Creates an OverScroller.
+     * @param context The context of this application.
+     * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will
+     * be used.
+     * @param bounceCoefficientX A value between 0 and 1 that will determine the proportion of the
+     * velocity which is preserved in the bounce when the horizontal edge is reached. A null value
+     * means no bounce.
+     * @param bounceCoefficientY Same as bounceCoefficientX but for the vertical direction.
+     */
+    public OverScroller(Context context, Interpolator interpolator,
+            float bounceCoefficientX, float bounceCoefficientY, boolean flywheel) {
+        mFlywheel = flywheel;
+        mPpi = context.getResources().getDisplayMetrics().density * 160.0f;
+        mDeceleration = computeDeceleration(ViewConfiguration.getScrollFriction());
+        mScrollerX = new MagneticOverScroller();
+        mScrollerY = new MagneticOverScroller();
+
+        mScrollerX.setBounceCoefficient(bounceCoefficientX);
+        mScrollerY.setBounceCoefficient(bounceCoefficientY);
+    }
+
+
+    /**
+     * The amount of friction applied to flings. The default value
+     * is {@link ViewConfiguration#getScrollFriction}.
+     *
+     * @param friction A scalar dimension-less value representing the coefficient of
+     *         friction.
+     */
+    public final void setFriction(float friction) {
+        mDeceleration = computeDeceleration(friction);
+    }
+
+    private float computeDeceleration(float friction) {
+        return 9.81f   // g (m/s^2)
+        * 39.37f               // inch/meter
+        * mPpi                 // pixels per inch
+        * friction;
+    }
+
+    /**
+     *
+     * Returns whether the scroller has finished scrolling.
+     *
+     * @return True if the scroller has finished scrolling, false otherwise.
+     */
+    public final boolean isFinished() {
+        return mScrollerX.mFinished && mScrollerY.mFinished;
+    }
+
+    /**
+     * Force the finished field to a particular value. Contrary to
+     * {@link #abortAnimation()}, forcing the animation to finished
+     * does NOT cause the scroller to move to the final x and y
+     * position.
+     *
+     * @param finished The new finished value.
+     */
+    public final void forceFinished(boolean finished) {
+        mScrollerX.mFinished = mScrollerY.mFinished = finished;
+    }
+
+    /**
+     * Returns the current X offset in the scroll.
+     *
+     * @return The new X offset as an absolute distance from the origin.
+     */
+    public final int getCurrX() {
+        return mScrollerX.mCurrentPosition;
+    }
+
+    /**
+     * Returns the current Y offset in the scroll.
+     *
+     * @return The new Y offset as an absolute distance from the origin.
+     */
+    public final int getCurrY() {
+        return mScrollerY.mCurrentPosition;
+    }
+
+    /**
+     * @hide
+     * Returns the current velocity.
+     *
+     * @return The original velocity less the deceleration, norm of the X and Y velocity vector.
+     */
+    public float getCurrVelocity() {
+        float squaredNorm = mScrollerX.mCurrVelocity * mScrollerX.mCurrVelocity;
+        squaredNorm += mScrollerY.mCurrVelocity * mScrollerY.mCurrVelocity;
+        return (float) Math.sqrt(squaredNorm);
+    }
+
+    /**
+     * Returns the start X offset in the scroll.
+     *
+     * @return The start X offset as an absolute distance from the origin.
+     */
+    public final int getStartX() {
+        return mScrollerX.mStart;
+    }
+
+    /**
+     * Returns the start Y offset in the scroll.
+     *
+     * @return The start Y offset as an absolute distance from the origin.
+     */
+    public final int getStartY() {
+        return mScrollerY.mStart;
+    }
+
+    /**
+     * Returns where the scroll will end. Valid only for "fling" scrolls.
+     *
+     * @return The final X offset as an absolute distance from the origin.
+     */
+    public final int getFinalX() {
+        return mScrollerX.mFinal;
+    }
+
+    /**
+     * Returns where the scroll will end. Valid only for "fling" scrolls.
+     *
+     * @return The final Y offset as an absolute distance from the origin.
+     */
+    public final int getFinalY() {
+        return mScrollerY.mFinal;
+    }
+
+    /**
+     * Returns how long the scroll event will take, in milliseconds.
+     *
+     * @return The duration of the scroll in milliseconds.
+     *
+     * @hide Pending removal once nothing depends on it
+     * @deprecated OverScrollers don't necessarily have a fixed duration.
+     *             This function will lie to the best of its ability.
+     */
+    @Deprecated
+    public final int getDuration() {
+        return Math.max(mScrollerX.mDuration, mScrollerY.mDuration);
+    }
+
+    /**
+     * Extend the scroll animation. This allows a running animation to scroll
+     * further and longer, when used with {@link #setFinalX(int)} or {@link #setFinalY(int)}.
+     *
+     * @param extend Additional time to scroll in milliseconds.
+     * @see #setFinalX(int)
+     * @see #setFinalY(int)
+     *
+     * @hide Pending removal once nothing depends on it
+     * @deprecated OverScrollers don't necessarily have a fixed duration.
+     *             Instead of setting a new final position and extending
+     *             the duration of an existing scroll, use startScroll
+     *             to begin a new animation.
+     */
+    @Deprecated
+    public void extendDuration(int extend) {
+        mScrollerX.extendDuration(extend);
+        mScrollerY.extendDuration(extend);
+    }
+
+    /**
+     * Sets the final position (X) for this scroller.
+     *
+     * @param newX The new X offset as an absolute distance from the origin.
+     * @see #extendDuration(int)
+     * @see #setFinalY(int)
+     *
+     * @hide Pending removal once nothing depends on it
+     * @deprecated OverScroller's final position may change during an animation.
+     *             Instead of setting a new final position and extending
+     *             the duration of an existing scroll, use startScroll
+     *             to begin a new animation.
+     */
+    @Deprecated
+    public void setFinalX(int newX) {
+        mScrollerX.setFinalPosition(newX);
+    }
+
+    /**
+     * Sets the final position (Y) for this scroller.
+     *
+     * @param newY The new Y offset as an absolute distance from the origin.
+     * @see #extendDuration(int)
+     * @see #setFinalX(int)
+     *
+     * @hide Pending removal once nothing depends on it
+     * @deprecated OverScroller's final position may change during an animation.
+     *             Instead of setting a new final position and extending
+     *             the duration of an existing scroll, use startScroll
+     *             to begin a new animation.
+     */
+    @Deprecated
+    public void setFinalY(int newY) {
+        mScrollerY.setFinalPosition(newY);
+    }
+
+    /**
+     * Call this when you want to know the new location. If it returns true, the
+     * animation is not yet finished.
+     */
+    public boolean computeScrollOffset() {
+        if (isFinished()) {
+            return false;
+        }
+
+        switch (mMode) {
+            case SCROLL_MODE:
+                long time = AnimationUtils.currentAnimationTimeMillis();
+                // Any scroller can be used for time, since they were started
+                // together in scroll mode. We use X here.
+                final long elapsedTime = time - mScrollerX.mStartTime;
+
+                final int duration = mScrollerX.mDuration;
+                if (elapsedTime < duration) {
+                    float q = (float) (elapsedTime) / duration;
+
+                    q = Scroller.viscousFluid(q);
+
+                    mScrollerX.updateScroll(q);
+                    mScrollerY.updateScroll(q);
+                } else {
+                    abortAnimation();
+                }
+                break;
+
+            case FLING_MODE:
+                if (!mScrollerX.mFinished) {
+                    if (!mScrollerX.update()) {
+                        if (!mScrollerX.continueWhenFinished()) {
+                            mScrollerX.finish();
+                        }
+                    }
+                }
+
+                if (!mScrollerY.mFinished) {
+                    if (!mScrollerY.update()) {
+                        if (!mScrollerY.continueWhenFinished()) {
+                            mScrollerY.finish();
+                        }
+                    }
+                }
+
+                break;
+        }
+
+        return true;
+    }
+
+    /**
+     * Start scrolling by providing a starting point and the distance to travel.
+     * The scroll will use the default value of 250 milliseconds for the
+     * duration.
+     *
+     * @param startX Starting horizontal scroll offset in pixels. Positive
+     *        numbers will scroll the content to the left.
+     * @param startY Starting vertical scroll offset in pixels. Positive numbers
+     *        will scroll the content up.
+     * @param dx Horizontal distance to travel. Positive numbers will scroll the
+     *        content to the left.
+     * @param dy Vertical distance to travel. Positive numbers will scroll the
+     *        content up.
+     */
+    public void startScroll(int startX, int startY, int dx, int dy) {
+        startScroll(startX, startY, dx, dy, DEFAULT_DURATION);
+    }
+
+    /**
+     * Start scrolling by providing a starting point and the distance to travel.
+     *
+     * @param startX Starting horizontal scroll offset in pixels. Positive
+     *        numbers will scroll the content to the left.
+     * @param startY Starting vertical scroll offset in pixels. Positive numbers
+     *        will scroll the content up.
+     * @param dx Horizontal distance to travel. Positive numbers will scroll the
+     *        content to the left.
+     * @param dy Vertical distance to travel. Positive numbers will scroll the
+     *        content up.
+     * @param duration Duration of the scroll in milliseconds.
+     */
+    public void startScroll(int startX, int startY, int dx, int dy, int duration) {
+        mMode = SCROLL_MODE;
+        mScrollerX.startScroll(startX, dx, duration);
+        mScrollerY.startScroll(startY, dy, duration);
+    }
+
+    /**
+     * Call this when you want to 'spring back' into a valid coordinate range.
+     *
+     * @param startX Starting X coordinate
+     * @param startY Starting Y coordinate
+     * @param minX Minimum valid X value
+     * @param maxX Maximum valid X value
+     * @param minY Minimum valid Y value
+     * @param maxY Minimum valid Y value
+     * @return true if a springback was initiated, false if startX and startY were
+     *          already within the valid range.
+     */
+    public boolean springBack(int startX, int startY, int minX, int maxX, int minY, int maxY) {
+        mMode = FLING_MODE;
+
+        // Make sure both methods are called.
+        final boolean spingbackX = mScrollerX.springback(startX, minX, maxX);
+        final boolean spingbackY = mScrollerY.springback(startY, minY, maxY);
+        return spingbackX || spingbackY;
+    }
+
+    public void fling(int startX, int startY, int velocityX, int velocityY,
+            int minX, int maxX, int minY, int maxY) {
+        fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY, 0, 0);
+    }
+
+    /**
+     * Start scrolling based on a fling gesture. The distance traveled will
+     * depend on the initial velocity of the fling.
+     *
+     * @param startX Starting point of the scroll (X)
+     * @param startY Starting point of the scroll (Y)
+     * @param velocityX Initial velocity of the fling (X) measured in pixels per
+     *            second.
+     * @param velocityY Initial velocity of the fling (Y) measured in pixels per
+     *            second
+     * @param minX Minimum X value. The scroller will not scroll past this point
+     *            unless overX > 0. If overfling is allowed, it will use minX as
+     *            a springback boundary.
+     * @param maxX Maximum X value. The scroller will not scroll past this point
+     *            unless overX > 0. If overfling is allowed, it will use maxX as
+     *            a springback boundary.
+     * @param minY Minimum Y value. The scroller will not scroll past this point
+     *            unless overY > 0. If overfling is allowed, it will use minY as
+     *            a springback boundary.
+     * @param maxY Maximum Y value. The scroller will not scroll past this point
+     *            unless overY > 0. If overfling is allowed, it will use maxY as
+     *            a springback boundary.
+     * @param overX Overfling range. If > 0, horizontal overfling in either
+     *            direction will be possible.
+     * @param overY Overfling range. If > 0, vertical overfling in either
+     *            direction will be possible.
+     */
+    public void fling(int startX, int startY, int velocityX, int velocityY,
+            int minX, int maxX, int minY, int maxY, int overX, int overY) {
+        // Continue a scroll or fling in progress
+        if (mFlywheel && !isFinished()) {
+            float oldVelocityX = mScrollerX.mCurrVelocity;
+            float oldVelocityY = mScrollerY.mCurrVelocity;
+            if (Math.signum(velocityX) == Math.signum(oldVelocityX) &&
+                    Math.signum(velocityY) == Math.signum(oldVelocityY)) {
+                velocityX += oldVelocityX;
+                velocityY += oldVelocityY;
+            }
+        }
+
+        mMode = FLING_MODE;
+        mScrollerX.fling(startX, velocityX, minX, maxX, overX);
+        mScrollerY.fling(startY, velocityY, minY, maxY, overY);
+    }
+
+    /**
+     * Notify the scroller that we've reached a horizontal boundary.
+     * Normally the information to handle this will already be known
+     * when the animation is started, such as in a call to one of the
+     * fling functions. However there are cases where this cannot be known
+     * in advance. This function will transition the current motion and
+     * animate from startX to finalX as appropriate.
+     *
+     * @param startX Starting/current X position
+     * @param finalX Desired final X position
+     * @param overX Magnitude of overscroll allowed. This should be the maximum
+     *              desired distance from finalX. Absolute value - must be positive.
+     */
+    public void notifyHorizontalEdgeReached(int startX, int finalX, int overX) {
+        mScrollerX.notifyEdgeReached(startX, finalX, overX);
+    }
+
+    /**
+     * Notify the scroller that we've reached a vertical boundary.
+     * Normally the information to handle this will already be known
+     * when the animation is started, such as in a call to one of the
+     * fling functions. However there are cases where this cannot be known
+     * in advance. This function will animate a parabolic motion from
+     * startY to finalY.
+     *
+     * @param startY Starting/current Y position
+     * @param finalY Desired final Y position
+     * @param overY Magnitude of overscroll allowed. This should be the maximum
+     *              desired distance from finalY. Absolute value - must be positive.
+     */
+    public void notifyVerticalEdgeReached(int startY, int finalY, int overY) {
+        mScrollerY.notifyEdgeReached(startY, finalY, overY);
+    }
+
+    /**
+     * Returns whether the current Scroller is currently returning to a valid position.
+     * Valid bounds were provided by the
+     * {@link #fling(int, int, int, int, int, int, int, int, int, int)} method.
+     *
+     * One should check this value before calling
+     * {@link #startScroll(int, int, int, int)} as the interpolation currently in progress
+     * to restore a valid position will then be stopped. The caller has to take into account
+     * the fact that the started scroll will start from an overscrolled position.
+     *
+     * @return true when the current position is overscrolled and in the process of
+     *         interpolating back to a valid value.
+     */
+    public boolean isOverScrolled() {
+        return ((!mScrollerX.mFinished &&
+                mScrollerX.mState != MagneticOverScroller.TO_EDGE) ||
+                (!mScrollerY.mFinished &&
+                        mScrollerY.mState != MagneticOverScroller.TO_EDGE));
+    }
+
+    /**
+     * Stops the animation. Contrary to {@link #forceFinished(boolean)},
+     * aborting the animating causes the scroller to move to the final x and y
+     * positions.
+     *
+     * @see #forceFinished(boolean)
+     */
+    public void abortAnimation() {
+        mScrollerX.finish();
+        mScrollerY.finish();
+    }
+
+    /**
+     * Returns the time elapsed since the beginning of the scrolling.
+     *
+     * @return The elapsed time in milliseconds.
+     *
+     * @hide
+     */
+    public int timePassed() {
+        final long time = AnimationUtils.currentAnimationTimeMillis();
+        final long startTime = Math.min(mScrollerX.mStartTime, mScrollerY.mStartTime);
+        return (int) (time - startTime);
+    }
+
+    /**
+     * @hide
+     */
+    public boolean isScrollingInDirection(float xvel, float yvel) {
+        final int dx = mScrollerX.mFinal - mScrollerX.mStart;
+        final int dy = mScrollerY.mFinal - mScrollerY.mStart;
+        return !isFinished() && Math.signum(xvel) == Math.signum(dx) &&
+        Math.signum(yvel) == Math.signum(dy);
+    }
+
+    class MagneticOverScroller {
+        // Initial position
+        int mStart;
+
+        // Current position
+        int mCurrentPosition;
+
+        // Final position
+        int mFinal;
+
+        // Initial velocity
+        int mVelocity;
+
+        // Current velocity
+        float mCurrVelocity;
+
+        // Constant current deceleration
+        float mDeceleration;
+
+        // Animation starting time, in system milliseconds
+        long mStartTime;
+
+        // Animation duration, in milliseconds
+        int mDuration;
+
+        // Duration to complete spline component of animation
+        int mSplineDuration;
+
+        // Distance to travel along spline animation
+        int mSplineDistance;
+
+        // Whether the animation is currently in progress
+        boolean mFinished;
+
+        private static final int TO_EDGE = 0;
+        private static final int TO_BOUNDARY = 1;
+        private static final int TO_BOUNCE = 2;
+
+        private int mState = TO_EDGE;
+
+        // The allowed overshot distance before boundary is reached.
+        private int mOver;
+
+        // If the velocity is smaller than this value, no bounce is triggered
+        // when the edge limits are reached (would result in a zero pixels
+        // displacement anyway).
+        private static final float MINIMUM_VELOCITY_FOR_BOUNCE = 140.0f; //Float.MAX_VALUE;//140.0f;
+
+        // Proportion of the velocity that is preserved when the edge is reached.
+        private static final float DEFAULT_BOUNCE_COEFFICIENT = 0.36f;
+
+        private float mBounceCoefficient = DEFAULT_BOUNCE_COEFFICIENT;
+
+        MagneticOverScroller() {
+            mFinished = true;
+        }
+
+        void updateScroll(float q) {
+            mCurrentPosition = mStart + Math.round(q * (mFinal - mStart));
+        }
+
+        /*
+         * Get a signed deceleration that will reduce the velocity.
+         */
+        float getDeceleration(int velocity) {
+            return velocity > 0 ? -OverScroller.this.mDeceleration : OverScroller.this.mDeceleration;
+        }
+
+        /*
+         * Modifies mDuration to the duration it takes to get from start to newFinal using the
+         * spline interpolation. The previous duration was needed to get to oldFinal.
+         */
+        void adjustDuration(int start, int oldFinal, int newFinal) {
+            final int oldDistance = oldFinal - start;
+            final int newDistance = newFinal - start;
+            final float x = (float) Math.abs((float) newDistance / oldDistance);
+            final int index = (int) (NB_SAMPLES * x);
+            if (index < NB_SAMPLES) {
+                final float x_inf = (float) index / NB_SAMPLES;
+                final float x_sup = (float) (index + 1) / NB_SAMPLES;
+                final float t_inf = SPLINE_TIME[index];
+                final float t_sup = SPLINE_TIME[index + 1];
+                final float timeCoef = t_inf + (x - x_inf) / (x_sup - x_inf) * (t_sup - t_inf);
+
+                mDuration *= timeCoef;
+            }
+        }
+
+        void startScroll(int start, int distance, int duration) {
+            mFinished = false;
+
+            mStart = start;
+            mFinal = start + distance;
+
+            mStartTime = AnimationUtils.currentAnimationTimeMillis();
+            mDuration = duration;
+
+            // Unused
+            mDeceleration = 0.0f;
+            mVelocity = 0;
+        }
+
+        void finish() {
+            mCurrentPosition = mFinal;
+            // Not reset since WebView relies on this value for fast fling.
+            // TODO: restore when WebView uses the fast fling implemented in this class.
+            // mCurrVelocity = 0.0f;
+            mFinished = true;
+        }
+
+        void setFinalPosition(int position) {
+            mFinal = position;
+            mFinished = false;
+        }
+
+        void extendDuration(int extend) {
+            final long time = AnimationUtils.currentAnimationTimeMillis();
+            final int elapsedTime = (int) (time - mStartTime);
+            mDuration = elapsedTime + extend;
+            mFinished = false;
+        }
+
+        void setBounceCoefficient(float coefficient) {
+            mBounceCoefficient = coefficient;
+        }
+
+        boolean springback(int start, int min, int max) {
+            mFinished = true;
+
+            mStart = mFinal = start;
+            mVelocity = 0;
+
+            mStartTime = AnimationUtils.currentAnimationTimeMillis();
+            mDuration = 0;
+
+            if (start < min) {
+                startSpringback(start, min, 0);
+            } else if (start > max) {
+                startSpringback(start, max, 0);
+            }
+
+            return !mFinished;
+        }
+
+        private void startSpringback(int start, int end, int velocity) {
+            mFinished = false;
+            mState = TO_BOUNCE;
+            mStart = mFinal = end;
+            final float velocitySign = Math.signum(start - end);
+            mDeceleration = getDeceleration((int) velocitySign);
+            fitOnBounceCurve(start, end, velocity);
+            mDuration = - (int) (2000.0f * mVelocity / mDeceleration);
+        }
+
+        void fling(int start, int velocity, int min, int max, int over) {
+            mOver = over;
+            mFinished = false;
+            mCurrVelocity = mVelocity = velocity;
+            mDuration = mSplineDuration = 0;
+            mStartTime = AnimationUtils.currentAnimationTimeMillis();
+            mStart = start;
+
+            if (start > max || start < min) {
+                startAfterEdge(start, min, max, velocity);
+                return;
+            }
+
+            mState = TO_EDGE;
+            double totalDistance = 0.0;
+
+            if (velocity != 0) {
+                final double l = Math.log(START_TENSION * Math.abs(velocity) / ALPHA);
+                // Duration are expressed in milliseconds
+                mDuration = mSplineDuration = (int) (1000.0 * Math.exp(l / (DECELERATION_RATE - 1.0)));
+                totalDistance = (ALPHA * Math.exp(DECELERATION_RATE / (DECELERATION_RATE - 1.0) * l));
+            }
+
+            mSplineDistance = (int) (totalDistance * Math.signum(velocity));
+            mFinal = start + mSplineDistance;
+
+            // Clamp to a valid final position
+            if (mFinal < min) {
+                adjustDuration(mStart, mFinal, min);
+                mFinal = min;
+            }
+
+            if (mFinal > max) {
+                adjustDuration(mStart, mFinal, max);
+                mFinal = max;
+            }
+        }
+
+        private void fitOnBounceCurve(int start, int end, int velocity) {
+            // Simulate a bounce that started from edge
+            final float durationToApex = - velocity / mDeceleration;
+            final float distanceToApex = velocity * velocity / 2.0f / Math.abs(mDeceleration);
+            final float distanceToEdge = Math.abs(end - start);
+            final float totalDuration = (float) Math.sqrt(
+                    2.0 * (distanceToApex + distanceToEdge) / Math.abs(mDeceleration));
+            mStartTime -= (int) (1000.0f * (totalDuration - durationToApex));
+            mStart = end;
+            mVelocity = (int) (- mDeceleration * totalDuration);
+        }
+
+        private void startBounceAfterEdge(int start, int end, int velocity) {
+            mDeceleration = getDeceleration(velocity == 0 ? start - end : velocity);
+            fitOnBounceCurve(start, end, velocity);
+            onEdgeReached();
+        }
+
+        private void startAfterEdge(int start, int min, int max, int velocity) {
+            if (start > min && start < max) {
+                mFinished = true;
+                return;
+            }
+            final boolean positive = start > max;
+            final int edge = positive ? max : min;
+            final int overDistance = start - edge;
+            boolean keepIncreasing = overDistance * velocity >= 0;
+            if (keepIncreasing) {
+                // Will result in a bounce or a to_boundary depending on velocity.
+                startBounceAfterEdge(start, edge, velocity);
+            } else {
+                final double l = Math.log(START_TENSION * Math.abs(velocity) / ALPHA);
+                final double totalDistance =
+                    (ALPHA * Math.exp(DECELERATION_RATE / (DECELERATION_RATE - 1.0) * l));
+                if (totalDistance > Math.abs(overDistance)) {
+                    fling(start, velocity, positive ? min : start, positive ? start : max, mOver);
+                } else {
+                    startSpringback(start, edge, velocity);
+                }
+            }
+        }
+
+        void notifyEdgeReached(int start, int end, int over) {
+            mOver = over;
+            mStartTime = AnimationUtils.currentAnimationTimeMillis();
+            // We were in fling/scroll mode before: current velocity is such that distance to edge
+            // is increasing. Ensures that startAfterEdge will not start a new fling.
+            startAfterEdge(start, end, end, (int) mCurrVelocity);
+        }
+
+        private void onEdgeReached() {
+            // mStart, mVelocity and mStartTime were adjusted to their values when edge was reached.
+            final float distance = - mVelocity * mVelocity / (2.0f * mDeceleration);
+
+            if (Math.abs(distance) < mOver) {
+                // Spring force will bring us back to final position
+                mState = TO_BOUNCE;
+                mFinal = mStart;
+                mDuration = - (int) (2000.0f * mVelocity / mDeceleration);
+            } else {
+                // Velocity is too high, we will hit the boundary limit
+                mState = TO_BOUNDARY;
+                int over = mVelocity > 0 ? mOver : -mOver;
+                mFinal = mStart + over;
+                mDuration = (int) (1000.0 * Math.PI * over / 2.0 / mVelocity);
+            }
+        }
+
+        boolean continueWhenFinished() {
+            switch (mState) {
+                case TO_EDGE:
+                    // Duration from start to null velocity
+                    if (mDuration < mSplineDuration) {
+                        // If the animation was clamped, we reached the edge
+                        mStart = mFinal;
+                        // Speed when edge was reached
+                        mVelocity = (int) mCurrVelocity;
+                        mDeceleration = getDeceleration(mVelocity);
+                        mStartTime += mDuration;
+                        onEdgeReached();
+                    } else {
+                        // Normal stop, no need to continue
+                        return false;
+                    }
+                    break;
+                case TO_BOUNDARY:
+                    mStartTime += mDuration;
+                    startSpringback(mFinal, mFinal - (mVelocity > 0 ? mOver:-mOver), 0);
+                    break;
+                case TO_BOUNCE:
+                    mVelocity = (int) (mVelocity * mBounceCoefficient);
+                    if (Math.abs(mVelocity) < MINIMUM_VELOCITY_FOR_BOUNCE) {
+                        return false;
+                    }
+                    mStartTime += mDuration;
+                    mDuration = - (int) (mVelocity / mDeceleration);
+                    break;
+            }
+
+            update();
+            return true;
+        }
+
+        /*
+         * Update the current position and velocity for current time. Returns
+         * true if update has been done and false if animation duration has been
+         * reached.
+         */
+        boolean update() {
+            final long time = AnimationUtils.currentAnimationTimeMillis();
+            final long currentTime = time - mStartTime;
+
+            if (currentTime > mDuration) {
+                return false;
+            }
+
+            double distance = 0.0;
+            switch (mState) {
+                case TO_EDGE: {
+                    final float t = (float) currentTime / mSplineDuration;
+                    final int index = (int) (NB_SAMPLES * t);
+                    float distanceCoef = 1.f;
+                    float velocityCoef = 0.f;
+                    if (index < NB_SAMPLES) {
+                        final float t_inf = (float) index / NB_SAMPLES;
+                        final float t_sup = (float) (index + 1) / NB_SAMPLES;
+                        final float d_inf = SPLINE_POSITION[index];
+                        final float d_sup = SPLINE_POSITION[index + 1];
+                        velocityCoef = (d_sup - d_inf) / (t_sup - t_inf);
+                        distanceCoef = d_inf + (t - t_inf) * velocityCoef;
+                    }
+
+                    distance = distanceCoef * mSplineDistance;
+                    mCurrVelocity = velocityCoef * mSplineDistance / mSplineDuration * 1000;
+                    break;
+                }
+
+                case TO_BOUNCE: {
+                    final float t = currentTime / 1000.0f;
+                    mCurrVelocity = mVelocity + mDeceleration * t;
+                    distance = mVelocity * t + mDeceleration * t * t / 2.0f;
+                    break;
+                }
+
+                case TO_BOUNDARY: {
+                    final float t = currentTime / 1000.0f;
+                    final float d = t * Math.abs(mVelocity) / mOver;
+                    mCurrVelocity = mVelocity * (float) Math.cos(d);
+                    distance = (mVelocity > 0 ? mOver : -mOver) * Math.sin(d);
+                    break;
+                }
+            }
+
+            mCurrentPosition = mStart + (int) Math.round(distance);
+            return true;
+        }
+    }
+}
diff --git a/core/java/android/widget/ScrollView.java b/core/java/android/widget/ScrollView.java
index eb527eb..3faec55 100644
--- a/core/java/android/widget/ScrollView.java
+++ b/core/java/android/widget/ScrollView.java
@@ -19,8 +19,11 @@
 import com.android.internal.R;
 
 import android.content.Context;
+import android.content.res.Resources;
 import android.content.res.TypedArray;
+import android.graphics.Canvas;
 import android.graphics.Rect;
+import android.graphics.drawable.Drawable;
 import android.util.AttributeSet;
 import android.view.FocusFinder;
 import android.view.KeyEvent;
@@ -61,7 +64,9 @@
     private long mLastScroll;
 
     private final Rect mTempRect = new Rect();
-    private Scroller mScroller;
+    private OverScroller mScroller;
+    private EdgeGlow mEdgeGlowTop;
+    private EdgeGlow mEdgeGlowBottom;
 
     /**
      * Flag to indicate that we are moving focus ourselves. This is so the
@@ -115,6 +120,9 @@
     private int mMinimumVelocity;
     private int mMaximumVelocity;
     
+    private int mOverscrollDistance;
+    private int mOverflingDistance;
+
     /**
      * ID of the active pointer. This is used to retain consistency during
      * drags/flings if multiple pointers are used.
@@ -187,7 +195,7 @@
 
 
     private void initScrollView() {
-        mScroller = new Scroller(getContext());
+        mScroller = new OverScroller(getContext());
         setFocusable(true);
         setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
         setWillNotDraw(false);
@@ -195,6 +203,8 @@
         mTouchSlop = configuration.getScaledTouchSlop();
         mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
         mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
+        mOverscrollDistance = configuration.getScaledOverscrollDistance();
+        mOverflingDistance = configuration.getScaledOverflingDistance();
     }
 
     @Override
@@ -459,6 +469,9 @@
                 /* Release the drag */
                 mIsBeingDragged = false;
                 mActivePointerId = INVALID_POINTER;
+                if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange())) {
+                    invalidate();
+                }
                 break;
             case MotionEvent.ACTION_POINTER_UP:
                 onSecondaryPointerUp(ev);
@@ -491,9 +504,7 @@
         switch (action & MotionEvent.ACTION_MASK) {
             case MotionEvent.ACTION_DOWN: {
                 final float y = ev.getY();
-                if (!(mIsBeingDragged = inChild((int) ev.getX(), (int) y))) {
-                    return false;
-                }
+                mIsBeingDragged = true;
                 
                 /*
                  * If being flinged and user touches, stop the fling. isFinished
@@ -516,7 +527,36 @@
                     final int deltaY = (int) (mLastMotionY - y);
                     mLastMotionY = y;
 
-                    scrollBy(0, deltaY);
+                    final int oldX = mScrollX;
+                    final int oldY = mScrollY;
+                    final int range = getScrollRange();
+                    if (overScrollBy(0, deltaY, 0, mScrollY, 0, range,
+                            0, mOverscrollDistance, true)) {
+                        // Break our velocity if we hit a scroll barrier.
+                        mVelocityTracker.clear();
+                    }
+                    onScrollChanged(mScrollX, mScrollY, oldX, oldY);
+
+                    final int overscrollMode = getOverScrollMode();
+                    if (overscrollMode == OVER_SCROLL_ALWAYS ||
+                            (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0)) {
+                        final int pulledToY = oldY + deltaY;
+                        if (pulledToY < 0) {
+                            mEdgeGlowTop.onPull((float) deltaY / getHeight());
+                            if (!mEdgeGlowBottom.isFinished()) {
+                                mEdgeGlowBottom.onRelease();
+                            }
+                        } else if (pulledToY > range) {
+                            mEdgeGlowBottom.onPull((float) deltaY / getHeight());
+                            if (!mEdgeGlowTop.isFinished()) {
+                                mEdgeGlowTop.onRelease();
+                            }
+                        }
+                        if (mEdgeGlowTop != null
+                                && (!mEdgeGlowTop.isFinished() || !mEdgeGlowBottom.isFinished())) {
+                            invalidate();
+                        }
+                    }
                 }
                 break;
             case MotionEvent.ACTION_UP: 
@@ -525,8 +565,15 @@
                     velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
                     int initialVelocity = (int) velocityTracker.getYVelocity(mActivePointerId);
 
-                    if (getChildCount() > 0 && Math.abs(initialVelocity) > mMinimumVelocity) {
-                        fling(-initialVelocity);
+                    if (getChildCount() > 0) {
+                        if ((Math.abs(initialVelocity) > mMinimumVelocity)) {
+                            fling(-initialVelocity);
+                        } else {
+                            final int bottom = getScrollRange();
+                            if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, bottom)) {
+                                invalidate();
+                            }
+                        }
                     }
 
                     mActivePointerId = INVALID_POINTER;
@@ -536,16 +583,27 @@
                         mVelocityTracker.recycle();
                         mVelocityTracker = null;
                     }
+                    if (mEdgeGlowTop != null) {
+                        mEdgeGlowTop.onRelease();
+                        mEdgeGlowBottom.onRelease();
+                    }
                 }
                 break;
             case MotionEvent.ACTION_CANCEL:
                 if (mIsBeingDragged && getChildCount() > 0) {
+                    if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange())) {
+                        invalidate();
+                    }
                     mActivePointerId = INVALID_POINTER;
                     mIsBeingDragged = false;
                     if (mVelocityTracker != null) {
                         mVelocityTracker.recycle();
                         mVelocityTracker = null;
                     }
+                    if (mEdgeGlowTop != null) {
+                        mEdgeGlowTop.onRelease();
+                        mEdgeGlowBottom.onRelease();
+                    }
                 }
                 break;
             case MotionEvent.ACTION_POINTER_UP:
@@ -572,6 +630,32 @@
         }
     }
     
+    @Override
+    protected void onOverScrolled(int scrollX, int scrollY,
+            boolean clampedX, boolean clampedY) {
+        // Treat animating scrolls differently; see #computeScroll() for why.
+        if (!mScroller.isFinished()) {
+            mScrollX = scrollX;
+            mScrollY = scrollY;
+            if (clampedY) {
+                mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange());
+            }
+        } else {
+            super.scrollTo(scrollX, scrollY);
+        }
+        awakenScrollBars();
+    }
+
+    private int getScrollRange() {
+        int scrollRange = 0;
+        if (getChildCount() > 0) {
+            View child = getChildAt(0);
+            scrollRange = Math.max(0,
+                    child.getHeight() - (getHeight() - mPaddingBottom - mPaddingTop));
+        }
+        return scrollRange;
+    }
+
     /**
      * <p>
      * Finds the next focusable component that fits in this View's bounds
@@ -948,7 +1032,16 @@
             return contentHeight;
         }
         
-        return getChildAt(0).getBottom();
+        int scrollRange = getChildAt(0).getBottom();
+        final int scrollY = mScrollY;
+        final int overscrollBottom = Math.max(0, scrollRange - contentHeight);
+        if (scrollY < 0) {
+            scrollRange -= scrollY;
+        } else if (scrollY > overscrollBottom) {
+            scrollRange += scrollY - overscrollBottom;
+        }
+
+        return scrollRange;
     }
 
     @Override
@@ -1009,14 +1102,20 @@
             int x = mScroller.getCurrX();
             int y = mScroller.getCurrY();
 
-            if (getChildCount() > 0) {
-                View child = getChildAt(0);
-                x = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth());
-                y = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight());
-                if (x != oldX || y != oldY) {
-                    mScrollX = x;
-                    mScrollY = y;
-                    onScrollChanged(x, y, oldX, oldY);
+            if (oldX != x || oldY != y) {
+                overScrollBy(x - oldX, y - oldY, oldX, oldY, 0, getScrollRange(),
+                        0, mOverflingDistance, false);
+                onScrollChanged(mScrollX, mScrollY, oldX, oldY);
+
+                final int range = getScrollRange();
+                final int overscrollMode = getOverScrollMode();
+                if (overscrollMode == OVER_SCROLL_ALWAYS ||
+                        (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0)) {
+                    if (y < 0 && oldY >= 0) {
+                        mEdgeGlowTop.onAbsorb((int) mScroller.getCurrVelocity());
+                    } else if (y > range && oldY <= range) {
+                        mEdgeGlowBottom.onAbsorb((int) mScroller.getCurrVelocity());
+                    }
                 }
             }
             awakenScrollBars();
@@ -1254,7 +1353,7 @@
             int bottom = getChildAt(0).getHeight();
     
             mScroller.fling(mScrollX, mScrollY, 0, velocityY, 0, 0, 0, 
-                    Math.max(0, bottom - height));
+                    Math.max(0, bottom - height), 0, height/2);
     
             final boolean movingDown = velocityY > 0;
     
@@ -1292,6 +1391,55 @@
         }
     }
 
+    @Override
+    public void setOverScrollMode(int mode) {
+        if (mode != OVER_SCROLL_NEVER) {
+            if (mEdgeGlowTop == null) {
+                final Resources res = getContext().getResources();
+                final Drawable edge = res.getDrawable(R.drawable.overscroll_edge);
+                final Drawable glow = res.getDrawable(R.drawable.overscroll_glow);
+                mEdgeGlowTop = new EdgeGlow(edge, glow);
+                mEdgeGlowBottom = new EdgeGlow(edge, glow);
+            }
+        } else {
+            mEdgeGlowTop = null;
+            mEdgeGlowBottom = null;
+        }
+        super.setOverScrollMode(mode);
+    }
+
+    @Override
+    public void draw(Canvas canvas) {
+        super.draw(canvas);
+        if (mEdgeGlowTop != null) {
+            final int scrollY = mScrollY;
+            if (!mEdgeGlowTop.isFinished()) {
+                final int restoreCount = canvas.save();
+                final int width = getWidth();
+
+                canvas.translate(-width / 2, Math.min(0, scrollY));
+                mEdgeGlowTop.setSize(width * 2, getHeight());
+                if (mEdgeGlowTop.draw(canvas)) {
+                    invalidate();
+                }
+                canvas.restoreToCount(restoreCount);
+            }
+            if (!mEdgeGlowBottom.isFinished()) {
+                final int restoreCount = canvas.save();
+                final int width = getWidth();
+                final int height = getHeight();
+
+                canvas.translate(-width / 2, Math.max(getScrollRange(), scrollY) + height);
+                canvas.rotate(180, width, 0);
+                mEdgeGlowBottom.setSize(width * 2, height);
+                if (mEdgeGlowBottom.draw(canvas)) {
+                    invalidate();
+                }
+                canvas.restoreToCount(restoreCount);
+            }
+        }
+    }
+
     private int clamp(int n, int my, int child) {
         if (my >= child || n < 0) {
             /* my >= child is this case:
diff --git a/core/java/android/widget/Scroller.java b/core/java/android/widget/Scroller.java
index b1f50ba..f00640e 100644
--- a/core/java/android/widget/Scroller.java
+++ b/core/java/android/widget/Scroller.java
@@ -52,14 +52,10 @@
     private float mDurationReciprocal;
     private float mDeltaX;
     private float mDeltaY;
-    private float mViscousFluidScale;
-    private float mViscousFluidNormalize;
     private boolean mFinished;
     private Interpolator mInterpolator;
     private boolean mFlywheel;
 
-    private float mCoeffX = 0.0f;
-    private float mCoeffY = 1.0f;
     private float mVelocity;
 
     private static final int DEFAULT_DURATION = 250;
@@ -94,8 +90,17 @@
             SPLINE[i] = d;
         }
         SPLINE[NB_SAMPLES] = 1.0f;
+
+        // This controls the viscous fluid effect (how much of it)
+        sViscousFluidScale = 8.0f;
+        // must be set to 1.0 (used in viscousFluid())
+        sViscousFluidNormalize = 1.0f;
+        sViscousFluidNormalize = 1.0f / viscousFluid(1.0f);
     }
 
+    private static float sViscousFluidScale;
+    private static float sViscousFluidNormalize;
+
     /**
      * Create a Scroller with the default duration and interpolator.
      */
@@ -103,6 +108,11 @@
         this(context, null);
     }
 
+    /**
+     * Create a Scroller with the specified interpolator. If the interpolator is
+     * null, the default (viscous) interpolator will be used. "Flywheel" behavior will
+     * be in effect for apps targeting Honeycomb or newer.
+     */
     public Scroller(Context context, Interpolator interpolator) {
         this(context, interpolator,
                 context.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.HONEYCOMB);
@@ -110,7 +120,8 @@
 
     /**
      * Create a Scroller with the specified interpolator. If the interpolator is
-     * null, the default (viscous) interpolator will be used.
+     * null, the default (viscous) interpolator will be used. Specify whether or
+     * not to support progressive "flywheel" behavior in flinging.
      */
     public Scroller(Context context, Interpolator interpolator, boolean flywheel) {
         mFinished = true;
@@ -332,12 +343,7 @@
         mFinalY = startY + dy;
         mDeltaX = dx;
         mDeltaY = dy;
-        mDurationReciprocal = 1.0f / mDuration;
-        // This controls the viscous fluid effect (how much of it)
-        mViscousFluidScale = 8.0f;
-        // must be set to 1.0 (used in viscousFluid())
-        mViscousFluidNormalize = 1.0f;
-        mViscousFluidNormalize = 1.0f / viscousFluid(1.0f);
+        mDurationReciprocal = 1.0f / (float) mDuration;
     }
 
     /**
@@ -393,8 +399,8 @@
         mStartX = startX;
         mStartY = startY;
 
-        mCoeffX = velocity == 0 ? 1.0f : velocityX / velocity; 
-        mCoeffY = velocity == 0 ? 1.0f : velocityY / velocity;
+        float coeffX = velocity == 0 ? 1.0f : velocityX / velocity;
+        float coeffY = velocity == 0 ? 1.0f : velocityY / velocity;
 
         int totalDistance =
                 (int) (ALPHA * Math.exp(DECELERATION_RATE / (DECELERATION_RATE - 1.0) * l));
@@ -404,22 +410,20 @@
         mMinY = minY;
         mMaxY = maxY;
 
-        mFinalX = startX + Math.round(totalDistance * mCoeffX);
+        mFinalX = startX + Math.round(totalDistance * coeffX);
         // Pin to mMinX <= mFinalX <= mMaxX
         mFinalX = Math.min(mFinalX, mMaxX);
         mFinalX = Math.max(mFinalX, mMinX);
         
-        mFinalY = startY + Math.round(totalDistance * mCoeffY);
+        mFinalY = startY + Math.round(totalDistance * coeffY);
         // Pin to mMinY <= mFinalY <= mMaxY
         mFinalY = Math.min(mFinalY, mMaxY);
         mFinalY = Math.max(mFinalY, mMinY);
     }
     
-    
-    
-    private float viscousFluid(float x)
+    static float viscousFluid(float x)
     {
-        x *= mViscousFluidScale;
+        x *= sViscousFluidScale;
         if (x < 1.0f) {
             x -= (1.0f - (float)Math.exp(-x));
         } else {
@@ -427,7 +431,7 @@
             x = 1.0f - (float)Math.exp(1.0f - x);
             x = start + x * (1.0f - start);
         }
-        x *= mViscousFluidNormalize;
+        x *= sViscousFluidNormalize;
         return x;
     }
     
diff --git a/core/res/res/layout/alert_dialog.xml b/core/res/res/layout/alert_dialog.xml
index 3982ed9..e3ba634 100644
--- a/core/res/res/layout/alert_dialog.xml
+++ b/core/res/res/layout/alert_dialog.xml
@@ -81,7 +81,8 @@
             android:paddingTop="2dip"
             android:paddingBottom="12dip"
             android:paddingLeft="14dip"
-            android:paddingRight="10dip">
+            android:paddingRight="10dip"
+            android:overScrollMode="ifContentScrolls">
             <TextView android:id="@+id/message"
                 style="?android:attr/textAppearanceMedium"
                 android:layout_width="match_parent"
diff --git a/core/res/res/layout/preference_dialog_edittext.xml b/core/res/res/layout/preference_dialog_edittext.xml
index 691ee8c..40b9e69 100644
--- a/core/res/res/layout/preference_dialog_edittext.xml
+++ b/core/res/res/layout/preference_dialog_edittext.xml
@@ -19,7 +19,8 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:layout_marginTop="48dp"
-    android:layout_marginBottom="48dp">
+    android:layout_marginBottom="48dp"
+    android:overScrollMode="ifContentScrolls">
 
     <LinearLayout
         android:id="@+android:id/edittext_container"
diff --git a/core/res/res/layout/select_dialog.xml b/core/res/res/layout/select_dialog.xml
index 94dcb6a..80d22f6 100644
--- a/core/res/res/layout/select_dialog.xml
+++ b/core/res/res/layout/select_dialog.xml
@@ -31,4 +31,5 @@
     android:layout_marginTop="5px"
     android:cacheColorHint="@null"
     android:divider="?android:attr/listDividerAlertDialog"
-    android:scrollbars="vertical" />
+    android:scrollbars="vertical"
+    android:overScrollMode="ifContentScrolls" />
diff --git a/core/res/res/values/attrs.xml b/core/res/res/values/attrs.xml
index 651bfea..770adf5 100755
--- a/core/res/res/values/attrs.xml
+++ b/core/res/res/values/attrs.xml
@@ -1632,6 +1632,20 @@
              <code>public void sayHello(View v)</code> method of your context
              (typically, your Activity). -->
         <attr name="onClick" format="string" />
+
+        <!-- Defines over-scrolling behavior. This property is used only if the
+             View is scrollable. Over-scrolling is the ability for the user to
+             receive feedback when attempting to scroll beyond meaningful content. -->
+        <attr name="overScrollMode">
+            <!-- Always show over-scroll effects, even if the content fits entirely
+                 within the available space. -->
+            <enum name="always" value="0" />
+            <!-- Only show over-scroll effects if the content is large
+                 enough to meaningfully scroll. -->
+            <enum name="ifContentScrolls" value="1" />
+            <!-- Never show over-scroll effects. -->
+            <enum name="never" value="2" />
+        </attr>
     </declare-styleable>
 
     <!-- Attributes that can be used with a {@link android.view.ViewGroup} or any
@@ -2116,6 +2130,10 @@
         <!-- When set to false, the ListView will not draw the divider before each footer view.
              The default value is true. -->
         <attr name="footerDividersEnabled" format="boolean" />
+        <!-- Drawable to draw above list content. -->
+        <attr name="overScrollHeader" format="reference|color" />
+        <!-- Drawable to draw below list content. -->
+        <attr name="overScrollFooter" format="reference|color" />
     </declare-styleable>
     <declare-styleable name="MenuView">
         <!-- Default appearance of menu item text. -->
diff --git a/core/res/res/values/public.xml b/core/res/res/values/public.xml
index f4d1df8..f2ab5cd 100644
--- a/core/res/res/values/public.xml
+++ b/core/res/res/values/public.xml
@@ -1253,6 +1253,9 @@
   <public type="attr" name="logo" id="0x010102be" />
   <public type="attr" name="xlargeScreens" id="0x010102bf" />
   <public type="attr" name="immersive" id="0x010102c0" />
+  <public type="attr" name="overScrollMode" id="0x010102c1" />
+  <public type="attr" name="overScrollHeader" id="0x010102c2" />
+  <public type="attr" name="overScrollFooter" id="0x010102c3" />
   <public type="attr" name="filterTouchesWhenObscured" id="0x010102c4" />
   <public type="attr" name="textSelectHandleLeft" id="0x010102c5" />
   <public type="attr" name="textSelectHandleRight" id="0x010102c6" />