am c0880491: Highlighting sectioned apps on fast-scroll.

* commit 'c088049113c261331b5685e64050d14a31cd72df':
  Highlighting sectioned apps on fast-scroll.

15 files changed, 682 insertions, 355 deletions

diff --git a/proguard.flags b/proguard.flags
index 22ffa3c8c..05963f7bc 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -19,11 +19,6 @@
   public float getAlpha();
 }
 
--keep class com.android.launcher3.BubbleTextView {
-  public void setFastScrollFocus(float);
-  public float getFastScrollFocus();
-}
-
 -keep class com.android.launcher3.ButtonDropTarget {
   public int getTextColor();
 }
@@ -56,8 +51,10 @@
 }
 
 -keep class com.android.launcher3.FastBitmapDrawable {
-  public int getBrightness();
-  public void setBrightness(int);
+  public void setDesaturation(float);
+  public float getDesaturation();
+  public void setBrightness(float);
+  public float getBrightness();
 }
 
 -keep class com.android.launcher3.MemoryDumpActivity {
diff --git a/src/com/android/launcher3/BaseRecyclerView.java b/src/com/android/launcher3/BaseRecyclerView.java
index 9d713e338..f8ef1e156 100644
--- a/src/com/android/launcher3/BaseRecyclerView.java
+++ b/src/com/android/launcher3/BaseRecyclerView.java
@@ -52,8 +52,8 @@ public abstract class BaseRecyclerView extends RecyclerView
         public int rowIndex;
         // The offset of the first visible row
         public int rowTopOffset;
-        // The height of a given row (they are currently all the same height)
-        public int rowHeight;
+        // The adapter position of the first visible item
+        public int itemPos;
     }
 
     protected BaseRecyclerViewFastScrollBar mScrollbar;
@@ -187,15 +187,21 @@ public abstract class BaseRecyclerView extends RecyclerView
     }
 
     /**
+     * Returns the visible height of the recycler view:
+     *   VisibleHeight = View height - top padding - bottom padding
+     */
+    protected int getVisibleHeight() {
+        int visibleHeight = getHeight() - mBackgroundPadding.top - mBackgroundPadding.bottom;
+        return visibleHeight;
+    }
+
+    /**
      * Returns the available scroll height:
      *   AvailableScrollHeight = Total height of the all items - last page height
-     *
-     * This assumes that all rows are the same height.
      */
-    protected int getAvailableScrollHeight(int rowCount, int rowHeight) {
-        int visibleHeight = getHeight() - mBackgroundPadding.top - mBackgroundPadding.bottom;
-        int scrollHeight = getPaddingTop() + rowCount * rowHeight + getPaddingBottom();
-        int availableScrollHeight = scrollHeight - visibleHeight;
+    protected int getAvailableScrollHeight(int rowCount) {
+        int totalHeight = getPaddingTop() + getTop(rowCount) + getPaddingBottom();
+        int availableScrollHeight = totalHeight - getVisibleHeight();
         return availableScrollHeight;
     }
 
@@ -204,8 +210,7 @@ public abstract class BaseRecyclerView extends RecyclerView
      *   AvailableScrollBarHeight = Total height of the visible view - thumb height
      */
     protected int getAvailableScrollBarHeight() {
-        int visibleHeight = getHeight() - mBackgroundPadding.top - mBackgroundPadding.bottom;
-        int availableScrollBarHeight = visibleHeight - mScrollbar.getThumbHeight();
+        int availableScrollBarHeight = getVisibleHeight() - mScrollbar.getThumbHeight();
         return availableScrollBarHeight;
     }
 
@@ -223,6 +228,13 @@ public abstract class BaseRecyclerView extends RecyclerView
         return defaultInactiveThumbColor;
     }
 
+    /**
+     * Returns the scrollbar for this recycler view.
+     */
+    public BaseRecyclerViewFastScrollBar getScrollBar() {
+        return mScrollbar;
+    }
+
     @Override
     protected void dispatchDraw(Canvas canvas) {
         super.dispatchDraw(canvas);
@@ -243,7 +255,7 @@ public abstract class BaseRecyclerView extends RecyclerView
             int rowCount) {
         // Only show the scrollbar if there is height to be scrolled
         int availableScrollBarHeight = getAvailableScrollBarHeight();
-        int availableScrollHeight = getAvailableScrollHeight(rowCount, scrollPosState.rowHeight);
+        int availableScrollHeight = getAvailableScrollHeight(rowCount);
         if (availableScrollHeight <= 0) {
             mScrollbar.setThumbOffset(-1, -1);
             return;
@@ -252,8 +264,7 @@ public abstract class BaseRecyclerView extends RecyclerView
         // Calculate the current scroll position, the scrollY of the recycler view accounts for the
         // view padding, while the scrollBarY is drawn right up to the background padding (ignoring
         // padding)
-        int scrollY = getPaddingTop() +
-                (scrollPosState.rowIndex * scrollPosState.rowHeight) - scrollPosState.rowTopOffset;
+        int scrollY = getScrollTop(scrollPosState);
         int scrollBarY = mBackgroundPadding.top +
                 (int) (((float) scrollY / availableScrollHeight) * availableScrollBarHeight);
 
@@ -268,7 +279,7 @@ public abstract class BaseRecyclerView extends RecyclerView
     }
 
     /**
-     * Returns whether fast scrolling is supported in the current state.
+     * @return whether fast scrolling is supported in the current state.
      */
     protected boolean supportsFastScrolling() {
         return true;
@@ -277,22 +288,38 @@ public abstract class BaseRecyclerView extends RecyclerView
     /**
      * Maps the touch (from 0..1) to the adapter position that should be visible.
      * <p>Override in each subclass of this base class.
+     *
+     * @return the scroll top of this recycler view.
      */
-    public abstract String scrollToPositionAtProgress(float touchFraction);
+    protected int getScrollTop(ScrollPositionState scrollPosState) {
+        return getPaddingTop() + getTop(scrollPosState.rowIndex) -
+                scrollPosState.rowTopOffset;
+    }
 
     /**
-     * Updates the bounds for the scrollbar.
+     * Returns information about the item that the recycler view is currently scrolled to.
+     */
+    protected abstract void getCurScrollState(ScrollPositionState stateOut, int viewTypeMask);
+
+    /**
+     * Returns the top (or y position) of the row at the specified index.
+     */
+    protected abstract int getTop(int rowIndex);
+
+    /**
+     * Maps the touch (from 0..1) to the adapter position that should be visible.
      * <p>Override in each subclass of this base class.
      */
-    public abstract void onUpdateScrollbar(int dy);
+    protected abstract String scrollToPositionAtProgress(float touchFraction);
 
     /**
+     * Updates the bounds for the scrollbar.
      * <p>Override in each subclass of this base class.
      */
-    public void onFastScrollCompleted() {}
+    protected abstract void onUpdateScrollbar(int dy);
 
     /**
-     * Returns information about the item that the recycler view is currently scrolled to.
+     * <p>Override in each subclass of this base class.
      */
-    protected abstract void getCurScrollState(ScrollPositionState stateOut);
+    protected void onFastScrollCompleted() {}
 }
\ No newline at end of file
diff --git a/src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java b/src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java
index 32ea57667..a6801696a 100644
--- a/src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java
+++ b/src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java
@@ -27,6 +27,7 @@ import android.graphics.Path;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.view.MotionEvent;
+import android.view.VelocityTracker;
 import android.view.ViewConfiguration;
 
 import com.android.launcher3.util.Thunk;
@@ -37,7 +38,7 @@ import com.android.launcher3.util.Thunk;
 public class BaseRecyclerViewFastScrollBar {
 
     public interface FastScrollFocusableView {
-        void setFastScrollFocused(boolean focused, boolean animated);
+        void setFastScrollFocusState(final FastBitmapDrawable.State focusState, boolean animated);
     }
 
     private final static int MAX_TRACK_ALPHA = 30;
@@ -199,7 +200,7 @@ public class BaseRecyclerViewFastScrollBar {
                     }
                     mTouchOffset += (lastY - downY);
                     mPopup.animateVisibility(true);
-                    animateScrollbar(true);
+                    showActiveScrollbar(true);
                 }
                 if (mIsDragging) {
                     // Update the fastscroller section name at this touch position
@@ -210,7 +211,7 @@ public class BaseRecyclerViewFastScrollBar {
                             (bottom - top));
                     mPopup.setSectionName(sectionName);
                     mPopup.animateVisibility(!sectionName.isEmpty());
-                    mRv.invalidate(mPopup.updateFastScrollerBounds(mRv, lastY));
+                    mRv.invalidate(mPopup.updateFastScrollerBounds(lastY));
                     mLastTouchY = boundedY;
                 }
                 break;
@@ -222,7 +223,7 @@ public class BaseRecyclerViewFastScrollBar {
                 if (mIsDragging) {
                     mIsDragging = false;
                     mPopup.animateVisibility(false);
-                    animateScrollbar(false);
+                    showActiveScrollbar(false);
                 }
                 break;
         }
@@ -246,7 +247,7 @@ public class BaseRecyclerViewFastScrollBar {
     /**
      * Animates the width and color of the scrollbar.
      */
-    private void animateScrollbar(boolean isScrolling) {
+    private void showActiveScrollbar(boolean isScrolling) {
         if (mScrollbarAnimator != null) {
             mScrollbarAnimator.cancel();
         }
diff --git a/src/com/android/launcher3/BaseRecyclerViewFastScrollPopup.java b/src/com/android/launcher3/BaseRecyclerViewFastScrollPopup.java
index aeeb5156d..ebaba1880 100644
--- a/src/com/android/launcher3/BaseRecyclerViewFastScrollPopup.java
+++ b/src/com/android/launcher3/BaseRecyclerViewFastScrollPopup.java
@@ -77,26 +77,26 @@ public class BaseRecyclerViewFastScrollPopup {
      * Updates the bounds for the fast scroller.
      * @return the invalidation rect for this update.
      */
-    public Rect updateFastScrollerBounds(BaseRecyclerView rv, int lastTouchY) {
+    public Rect updateFastScrollerBounds(int lastTouchY) {
         mInvalidateRect.set(mBgBounds);
 
         if (isVisible()) {
             // Calculate the dimensions and position of the fast scroller popup
-            int edgePadding = rv.getMaxScrollbarWidth();
+            int edgePadding = mRv.getMaxScrollbarWidth();
             int bgPadding = (mBgOriginalSize - mTextBounds.height()) / 2;
             int bgHeight = mBgOriginalSize;
             int bgWidth = Math.max(mBgOriginalSize, mTextBounds.width() + (2 * bgPadding));
             if (Utilities.isRtl(mRes)) {
-                mBgBounds.left = rv.getBackgroundPadding().left + (2 * rv.getMaxScrollbarWidth());
+                mBgBounds.left = mRv.getBackgroundPadding().left + (2 * mRv.getMaxScrollbarWidth());
                 mBgBounds.right = mBgBounds.left + bgWidth;
             } else {
-                mBgBounds.right = rv.getWidth() - rv.getBackgroundPadding().right -
-                        (2 * rv.getMaxScrollbarWidth());
+                mBgBounds.right = mRv.getWidth() - mRv.getBackgroundPadding().right -
+                        (2 * mRv.getMaxScrollbarWidth());
                 mBgBounds.left = mBgBounds.right - bgWidth;
             }
             mBgBounds.top = lastTouchY - (int) (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * bgHeight);
             mBgBounds.top = Math.max(edgePadding,
-                    Math.min(mBgBounds.top, rv.getHeight() - edgePadding - bgHeight));
+                    Math.min(mBgBounds.top, mRv.getHeight() - edgePadding - bgHeight));
             mBgBounds.bottom = mBgBounds.top + bgHeight;
         } else {
             mBgBounds.setEmpty();
diff --git a/src/com/android/launcher3/BubbleTextView.java b/src/com/android/launcher3/BubbleTextView.java
index c8af600ba..db1e4f5c4 100644
--- a/src/com/android/launcher3/BubbleTextView.java
+++ b/src/com/android/launcher3/BubbleTextView.java
@@ -16,7 +16,6 @@
 
 package com.android.launcher3;
 
-import android.animation.ObjectAnimator;
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.res.ColorStateList;
@@ -25,7 +24,6 @@ import android.content.res.Resources.Theme;
 import android.content.res.TypedArray;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
-import android.graphics.Paint;
 import android.graphics.Region;
 import android.graphics.drawable.Drawable;
 import android.os.Build;
@@ -37,8 +35,6 @@ import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewConfiguration;
 import android.view.ViewParent;
-import android.view.animation.AccelerateInterpolator;
-import android.view.animation.DecelerateInterpolator;
 import android.widget.TextView;
 
 import com.android.launcher3.IconCache.IconLoadRequest;
@@ -63,13 +59,6 @@ public class BubbleTextView extends TextView
     private static final int DISPLAY_WORKSPACE = 0;
     private static final int DISPLAY_ALL_APPS = 1;
 
-    private static final float FAST_SCROLL_FOCUS_MAX_SCALE = 1.15f;
-    private static final int FAST_SCROLL_FOCUS_MODE_NONE = 0;
-    private static final int FAST_SCROLL_FOCUS_MODE_SCALE_ICON = 1;
-    private static final int FAST_SCROLL_FOCUS_MODE_DRAW_CIRCLE_BG = 2;
-    private static final int FAST_SCROLL_FOCUS_FADE_IN_DURATION = 175;
-    private static final int FAST_SCROLL_FOCUS_FADE_OUT_DURATION = 125;
-
     private final Launcher mLauncher;
     private Drawable mIcon;
     private final Drawable mBackground;
@@ -93,12 +82,6 @@ public class BubbleTextView extends TextView
     private boolean mIgnorePressedStateChange;
     private boolean mDisableRelayout = false;
 
-    private ObjectAnimator mFastScrollFocusAnimator;
-    private Paint mFastScrollFocusBgPaint;
-    private float mFastScrollFocusFraction;
-    private boolean mFastScrollFocused;
-    private final int mFastScrollMode = FAST_SCROLL_FOCUS_MODE_SCALE_ICON;
-
     private IconLoadRequest mIconLoadRequest;
 
     public BubbleTextView(Context context) {
@@ -151,13 +134,6 @@ public class BubbleTextView extends TextView
             setShadowLayer(SHADOW_LARGE_RADIUS, 0.0f, SHADOW_Y_OFFSET, SHADOW_LARGE_COLOUR);
         }
 
-        if (mFastScrollMode == FAST_SCROLL_FOCUS_MODE_DRAW_CIRCLE_BG) {
-            mFastScrollFocusBgPaint = new Paint();
-            mFastScrollFocusBgPaint.setAntiAlias(true);
-            mFastScrollFocusBgPaint.setColor(
-                    getResources().getColor(R.color.container_fastscroll_thumb_active_color));
-        }
-
         setAccessibilityDelegate(LauncherAppState.getInstance().getAccessibilityDelegate());
     }
 
@@ -170,8 +146,9 @@ public class BubbleTextView extends TextView
         Bitmap b = info.getIcon(iconCache);
 
         FastBitmapDrawable iconDrawable = mLauncher.createIconDrawable(b);
-        iconDrawable.setGhostModeEnabled(info.isDisabled != 0);
-
+        if (info.isDisabled != 0) {
+            iconDrawable.setState(FastBitmapDrawable.State.DISABLED);
+        }
         setIcon(iconDrawable, mIconSize);
         if (info.contentDescription != null) {
             setContentDescription(info.contentDescription);
@@ -259,7 +236,12 @@ public class BubbleTextView extends TextView
 
     private void updateIconState() {
         if (mIcon instanceof FastBitmapDrawable) {
-            ((FastBitmapDrawable) mIcon).setPressed(isPressed() || mStayPressed);
+            FastBitmapDrawable d = (FastBitmapDrawable) mIcon;
+            if (isPressed() || mStayPressed) {
+                d.animateState(FastBitmapDrawable.State.PRESSED);
+            } else {
+                d.animateState(FastBitmapDrawable.State.NORMAL);
+            }
         }
     }
 
@@ -362,18 +344,7 @@ public class BubbleTextView extends TextView
     @Override
     public void draw(Canvas canvas) {
         if (!mCustomShadowsEnabled) {
-            // Draw the fast scroll focus bg if we have one
-            if (mFastScrollMode == FAST_SCROLL_FOCUS_MODE_DRAW_CIRCLE_BG &&
-                    mFastScrollFocusFraction > 0f) {
-                DeviceProfile grid = mLauncher.getDeviceProfile();
-                int iconCenterX = getScrollX() + (getWidth() / 2);
-                int iconCenterY = getScrollY() + getPaddingTop() + (grid.iconSizePx / 2);
-                canvas.drawCircle(iconCenterX, iconCenterY,
-                        mFastScrollFocusFraction * (getWidth() / 2), mFastScrollFocusBgPaint);
-            }
-
             super.draw(canvas);
-
             return;
         }
 
@@ -533,8 +504,13 @@ public class BubbleTextView extends TextView
      */
     public void reapplyItemInfo(final ItemInfo info) {
         if (getTag() == info) {
+            FastBitmapDrawable.State prevState = FastBitmapDrawable.State.NORMAL;
+            if (mIcon instanceof FastBitmapDrawable) {
+                prevState = ((FastBitmapDrawable) mIcon).getCurrentState();
+            }
             mIconLoadRequest = null;
             mDisableRelayout = true;
+
             if (info instanceof AppInfo) {
                 applyFromApplicationInfo((AppInfo) info);
             } else if (info instanceof ShortcutInfo) {
@@ -550,6 +526,13 @@ public class BubbleTextView extends TextView
             } else if (info instanceof PackageItemInfo) {
                 applyFromPackageItemInfo((PackageItemInfo) info);
             }
+
+            // If we are reapplying over an old icon, then we should update the new icon to the same
+            // state as the old icon
+            if (mIcon instanceof FastBitmapDrawable) {
+                ((FastBitmapDrawable) mIcon).setState(prevState);
+            }
+
             mDisableRelayout = false;
         }
     }
@@ -583,55 +566,53 @@ public class BubbleTextView extends TextView
         }
     }
 
-    // Setters & getters for the animation
-    public void setFastScrollFocus(float fraction) {
-        mFastScrollFocusFraction = fraction;
-        if (mFastScrollMode == FAST_SCROLL_FOCUS_MODE_SCALE_ICON) {
-            setScaleX(1f + fraction * (FAST_SCROLL_FOCUS_MAX_SCALE - 1f));
-            setScaleY(1f + fraction * (FAST_SCROLL_FOCUS_MAX_SCALE - 1f));
-        } else {
-            invalidate();
-        }
-    }
-
-    public float getFastScrollFocus() {
-        return mFastScrollFocusFraction;
-    }
-
     @Override
-    public void setFastScrollFocused(final boolean focused, boolean animated) {
-        if (mFastScrollMode == FAST_SCROLL_FOCUS_MODE_NONE) {
+    public void setFastScrollFocusState(final FastBitmapDrawable.State focusState, boolean animated) {
+        // We can only set the fast scroll focus state on a FastBitmapDrawable
+        if (!(mIcon instanceof FastBitmapDrawable)) {
             return;
         }
 
-        if (mFastScrollFocused != focused) {
-            mFastScrollFocused = focused;
+        FastBitmapDrawable d = (FastBitmapDrawable) mIcon;
+        if (animated) {
+            FastBitmapDrawable.State prevState = d.getCurrentState();
+            if (d.animateState(focusState)) {
+                // If the state was updated, then update the view accordingly
+                animate().scaleX(focusState.viewScale)
+                        .scaleY(focusState.viewScale)
+                        .setStartDelay(getStartDelayForStateChange(prevState, focusState))
+                        .setDuration(d.getDurationForStateChange(prevState, focusState))
+                        .start();
+            }
+        } else {
+            if (d.setState(focusState)) {
+                // If the state was updated, then update the view accordingly
+                animate().cancel();
+                setScaleX(focusState.viewScale);
+                setScaleY(focusState.viewScale);
+            }
+        }
+    }
 
-            if (animated) {
-                // Clean up the previous focus animator
-                if (mFastScrollFocusAnimator != null) {
-                    mFastScrollFocusAnimator.cancel();
-                }
-                mFastScrollFocusAnimator = ObjectAnimator.ofFloat(this, "fastScrollFocus",
-                        focused ? 1f : 0f);
-                if (focused) {
-                    mFastScrollFocusAnimator.setInterpolator(new DecelerateInterpolator());
-                } else {
-                    mFastScrollFocusAnimator.setInterpolator(new AccelerateInterpolator());
+    /**
+     * Returns the start delay when animating between certain {@link FastBitmapDrawable} states.
+     */
+    private static int getStartDelayForStateChange(final FastBitmapDrawable.State fromState,
+            final FastBitmapDrawable.State toState) {
+        switch (toState) {
+            case NORMAL:
+                switch (fromState) {
+                    case FAST_SCROLL_HIGHLIGHTED:
+                        return FastBitmapDrawable.FAST_SCROLL_INACTIVE_DURATION / 4;
                 }
-                mFastScrollFocusAnimator.setDuration(focused ?
-                        FAST_SCROLL_FOCUS_FADE_IN_DURATION : FAST_SCROLL_FOCUS_FADE_OUT_DURATION);
-                mFastScrollFocusAnimator.start();
-            } else {
-                mFastScrollFocusFraction = focused ? 1f : 0f;
-            }
         }
+        return 0;
     }
 
     /**
      * Interface to be implemented by the grand parent to allow click shadow effect.
      */
-    public static interface BubbleTextShadowHandler {
+    public interface BubbleTextShadowHandler {
         void setPressedIcon(BubbleTextView icon, Bitmap background);
     }
 }
diff --git a/src/com/android/launcher3/FastBitmapDrawable.java b/src/com/android/launcher3/FastBitmapDrawable.java
index 28e923e67..30bc7eaa9 100644
--- a/src/com/android/launcher3/FastBitmapDrawable.java
+++ b/src/com/android/launcher3/FastBitmapDrawable.java
@@ -16,6 +16,7 @@
 
 package com.android.launcher3;
 
+import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
 import android.animation.TimeInterpolator;
 import android.graphics.Bitmap;
@@ -28,13 +29,40 @@ import android.graphics.Paint;
 import android.graphics.PixelFormat;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffColorFilter;
-import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.util.SparseArray;
+import android.view.animation.DecelerateInterpolator;
 
 public class FastBitmapDrawable extends Drawable {
 
-    static final TimeInterpolator CLICK_FEEDBACK_INTERPOLATOR = new TimeInterpolator() {
+    /**
+     * The possible states that a FastBitmapDrawable can be in.
+     */
+    public enum State {
+
+        NORMAL                      (0f, 0f, 1f, new DecelerateInterpolator()),
+        PRESSED                     (0f, 100f / 255f, 1f, CLICK_FEEDBACK_INTERPOLATOR),
+        FAST_SCROLL_HIGHLIGHTED     (0f, 0f, 1.1f, new DecelerateInterpolator()),
+        FAST_SCROLL_UNHIGHLIGHTED   (0.8f, 0.35f, 1f, new DecelerateInterpolator()),
+        DISABLED                    (1f, 0.5f, 1f, new DecelerateInterpolator());
+
+        public final float desaturation;
+        public final float brightness;
+        /**
+         * Used specifically by the view drawing this FastBitmapDrawable.
+         */
+        public final float viewScale;
+        public final TimeInterpolator interpolator;
+
+        State(float desaturation, float brightness, float viewScale, TimeInterpolator interpolator) {
+            this.desaturation = desaturation;
+            this.brightness = brightness;
+            this.viewScale = viewScale;
+            this.interpolator = interpolator;
+        }
+    }
+
+    public static final TimeInterpolator CLICK_FEEDBACK_INTERPOLATOR = new TimeInterpolator() {
 
         @Override
         public float getInterpolation(float input) {
@@ -47,42 +75,46 @@ public class FastBitmapDrawable extends Drawable {
             }
         }
     };
-    static final long CLICK_FEEDBACK_DURATION = 2000;
+    public static final int CLICK_FEEDBACK_DURATION = 2000;
+    public static final int FAST_SCROLL_HIGHLIGHT_DURATION = 225;
+    public static final int FAST_SCROLL_UNHIGHLIGHT_DURATION = 150;
+    public static final int FAST_SCROLL_UNHIGHLIGHT_FROM_NORMAL_DURATION = 225;
+    public static final int FAST_SCROLL_INACTIVE_DURATION = 275;
 
-    private static final int PRESSED_BRIGHTNESS = 100;
-    private static ColorMatrix sGhostModeMatrix;
-    private static final ColorMatrix sTempMatrix = new ColorMatrix();
+    // Since we don't need 256^2 values for combinations of both the brightness and saturation, we
+    // reduce the value space to a smaller value V, which reduces the number of cached
+    // ColorMatrixColorFilters that we need to keep to V^2
+    private static final int REDUCED_FILTER_VALUE_SPACE = 48;
 
-    /**
-     * Store the brightness colors filters to optimize animations during icon press. This
-     * only works for non-ghost-mode icons.
-     */
-    private static final SparseArray<ColorFilter> sCachedBrightnessFilter =
-            new SparseArray<ColorFilter>();
+    // A cache of ColorFilters for optimizing brightness and saturation animations
+    private static final SparseArray<ColorFilter> sCachedFilter = new SparseArray<>();
 
-    private static final int GHOST_MODE_MIN_COLOR_RANGE = 130;
+    // Temporary matrices used for calculation
+    private static final ColorMatrix sTempBrightnessMatrix = new ColorMatrix();
+    private static final ColorMatrix sTempFilterMatrix = new ColorMatrix();
 
     private final Paint mPaint = new Paint(Paint.FILTER_BITMAP_FLAG);
     private final Bitmap mBitmap;
-    private int mAlpha;
+    private State mState = State.NORMAL;
 
+    // The saturation and brightness are values that are mapped to REDUCED_FILTER_VALUE_SPACE and
+    // as a result, can be used to compose the key for the cached ColorMatrixColorFilters
+    private int mDesaturation = 0;
     private int mBrightness = 0;
-    private boolean mGhostModeEnabled = false;
+    private int mAlpha = 255;
+    private int mPrevUpdateKey = Integer.MAX_VALUE;
 
-    private boolean mPressed = false;
-    private ObjectAnimator mPressedAnimator;
+    // Animators for the fast bitmap drawable's properties
+    private AnimatorSet mPropertyAnimator;
 
     public FastBitmapDrawable(Bitmap b) {
-        mAlpha = 255;
         mBitmap = b;
         setBounds(0, 0, b.getWidth(), b.getHeight());
     }
 
     @Override
     public void draw(Canvas canvas) {
-        final Rect r = getBounds();
-        // Draw the bitmap into the bounding rect
-        canvas.drawBitmap(mBitmap, null, r, mPaint);
+        canvas.drawBitmap(mBitmap, null, getBounds(), mPaint);
     }
 
     @Override
@@ -136,96 +168,191 @@ public class FastBitmapDrawable extends Drawable {
     }
 
     /**
-     * When enabled, the icon is grayed out and the contrast is increased to give it a 'ghost'
-     * appearance.
+     * Animates this drawable to a new state.
+     *
+     * @return whether the state has changed.
      */
-    public void setGhostModeEnabled(boolean enabled) {
-        if (mGhostModeEnabled != enabled) {
-            mGhostModeEnabled = enabled;
-            updateFilter();
+    public boolean animateState(State newState) {
+        State prevState = mState;
+        if (mState != newState) {
+            mState = newState;
+
+            mPropertyAnimator = cancelAnimator(mPropertyAnimator);
+            mPropertyAnimator = new AnimatorSet();
+            mPropertyAnimator.playTogether(
+                    ObjectAnimator
+                            .ofFloat(this, "desaturation", newState.desaturation),
+                    ObjectAnimator
+                            .ofFloat(this, "brightness", newState.brightness));
+            mPropertyAnimator.setInterpolator(newState.interpolator);
+            mPropertyAnimator.setDuration(getDurationForStateChange(prevState, newState));
+            mPropertyAnimator.setStartDelay(getStartDelayForStateChange(prevState, newState));
+            mPropertyAnimator.start();
+            return true;
         }
+        return false;
     }
 
-    public void setPressed(boolean pressed) {
-        if (mPressed != pressed) {
-            mPressed = pressed;
-            if (mPressed) {
-                mPressedAnimator = ObjectAnimator
-                        .ofInt(this, "brightness", PRESSED_BRIGHTNESS)
-                        .setDuration(CLICK_FEEDBACK_DURATION);
-                mPressedAnimator.setInterpolator(CLICK_FEEDBACK_INTERPOLATOR);
-                mPressedAnimator.start();
-            } else if (mPressedAnimator != null) {
-                mPressedAnimator.cancel();
-                setBrightness(0);
-            }
+    /**
+     * Immediately sets this drawable to a new state.
+     *
+     * @return whether the state has changed.
+     */
+    public boolean setState(State newState) {
+        if (mState != newState) {
+            mState = newState;
+
+            mPropertyAnimator = cancelAnimator(mPropertyAnimator);
+
+            setDesaturation(newState.desaturation);
+            setBrightness(newState.brightness);
+            return true;
         }
-        invalidateSelf();
+        return false;
+    }
+
+    /**
+     * Returns the current state.
+     */
+    public State getCurrentState() {
+        return mState;
     }
 
-    public boolean isGhostModeEnabled() {
-        return mGhostModeEnabled;
+    /**
+     * Returns the duration for the state change animation.
+     */
+    public static int getDurationForStateChange(State fromState, State toState) {
+        switch (toState) {
+            case NORMAL:
+                switch (fromState) {
+                    case PRESSED:
+                        return 0;
+                    case FAST_SCROLL_HIGHLIGHTED:
+                    case FAST_SCROLL_UNHIGHLIGHTED:
+                        return FAST_SCROLL_INACTIVE_DURATION;
+                }
+            case PRESSED:
+                return CLICK_FEEDBACK_DURATION;
+            case FAST_SCROLL_HIGHLIGHTED:
+                return FAST_SCROLL_HIGHLIGHT_DURATION;
+            case FAST_SCROLL_UNHIGHLIGHTED:
+                switch (fromState) {
+                    case NORMAL:
+                        // When animating from normal state, take a little longer
+                        return FAST_SCROLL_UNHIGHLIGHT_FROM_NORMAL_DURATION;
+                    default:
+                        return FAST_SCROLL_UNHIGHLIGHT_DURATION;
+                }
+        }
+        return 0;
     }
 
-    public int getBrightness() {
-        return mBrightness;
+    /**
+     * Returns the start delay when animating between certain fast scroll states.
+     */
+    public static int getStartDelayForStateChange(State fromState, State toState) {
+        switch (toState) {
+            case FAST_SCROLL_UNHIGHLIGHTED:
+                switch (fromState) {
+                    case NORMAL:
+                        return FAST_SCROLL_UNHIGHLIGHT_DURATION / 4;
+                }
+        }
+        return 0;
     }
 
-    public void setBrightness(int brightness) {
-        if (mBrightness != brightness) {
-            mBrightness = brightness;
+    /**
+     * Sets the saturation of this icon, 0 [full color] -> 1 [desaturated]
+     */
+    public void setDesaturation(float desaturation) {
+        int newDesaturation = (int) Math.floor(desaturation * REDUCED_FILTER_VALUE_SPACE);
+        if (mDesaturation != newDesaturation) {
+            mDesaturation = newDesaturation;
+            updateFilter();
+        }
+    }
+
+    public float getDesaturation() {
+        return (float) mDesaturation / REDUCED_FILTER_VALUE_SPACE;
+    }
+
+    /**
+     * Sets the brightness of this icon, 0 [no add. brightness] -> 1 [2bright2furious]
+     */
+    public void setBrightness(float brightness) {
+        int newBrightness = (int) Math.floor(brightness * REDUCED_FILTER_VALUE_SPACE);
+        if (mBrightness != newBrightness) {
+            mBrightness = newBrightness;
             updateFilter();
-            invalidateSelf();
         }
     }
 
+    public float getBrightness() {
+        return (float) mBrightness / REDUCED_FILTER_VALUE_SPACE;
+    }
+
+    /**
+     * Updates the paint to reflect the current brightness and saturation.
+     */
     private void updateFilter() {
-        if (mGhostModeEnabled) {
-            if (sGhostModeMatrix == null) {
-                sGhostModeMatrix = new ColorMatrix();
-                sGhostModeMatrix.setSaturation(0);
-
-                // For ghost mode, set the color range to [GHOST_MODE_MIN_COLOR_RANGE, 255]
-                float range = (255 - GHOST_MODE_MIN_COLOR_RANGE) / 255.0f;
-                sTempMatrix.set(new float[] {
-                        range, 0, 0, 0, GHOST_MODE_MIN_COLOR_RANGE,
-                        0, range, 0, 0, GHOST_MODE_MIN_COLOR_RANGE,
-                        0, 0, range, 0, GHOST_MODE_MIN_COLOR_RANGE,
-                        0, 0, 0, 1, 0 });
-                sGhostModeMatrix.preConcat(sTempMatrix);
-            }
+        boolean usePorterDuffFilter = false;
+        int key = -1;
+        if (mDesaturation > 0) {
+            key = (mDesaturation << 16) | mBrightness;
+        } else if (mBrightness > 0) {
+            // Compose a key with a fully saturated icon if we are just animating brightness
+            key = (1 << 16) | mBrightness;
+
+            // We found that in L, ColorFilters cause drawing artifacts with shadows baked into
+            // icons, so just use a PorterDuff filter when we aren't animating saturation
+            usePorterDuffFilter = true;
+        }
 
-            if (mBrightness == 0) {
-                mPaint.setColorFilter(new ColorMatrixColorFilter(sGhostModeMatrix));
-            } else {
-                setBrightnessMatrix(sTempMatrix, mBrightness);
-                sTempMatrix.postConcat(sGhostModeMatrix);
-                mPaint.setColorFilter(new ColorMatrixColorFilter(sTempMatrix));
-            }
-        } else if (mBrightness != 0) {
-            ColorFilter filter = sCachedBrightnessFilter.get(mBrightness);
+        // Debounce multiple updates on the same frame
+        if (key == mPrevUpdateKey) {
+            return;
+        }
+        mPrevUpdateKey = key;
+
+        if (key != -1) {
+            ColorFilter filter = sCachedFilter.get(key);
             if (filter == null) {
-                filter = new PorterDuffColorFilter(Color.argb(mBrightness, 255, 255, 255),
-                        PorterDuff.Mode.SRC_ATOP);
-                sCachedBrightnessFilter.put(mBrightness, filter);
+                float brightnessF = getBrightness();
+                int brightnessI = (int) (255 * brightnessF);
+                if (usePorterDuffFilter) {
+                    filter = new PorterDuffColorFilter(Color.argb(brightnessI, 255, 255, 255),
+                            PorterDuff.Mode.SRC_ATOP);
+                } else {
+                    float saturationF = 1f - getDesaturation();
+                    sTempFilterMatrix.setSaturation(saturationF);
+                    if (mBrightness > 0) {
+                        // Brightness: C-new = C-old*(1-amount) + amount
+                        float scale = 1f - brightnessF;
+                        float[] mat = sTempBrightnessMatrix.getArray();
+                        mat[0] = scale;
+                        mat[6] = scale;
+                        mat[12] = scale;
+                        mat[4] = brightnessI;
+                        mat[9] = brightnessI;
+                        mat[14] = brightnessI;
+                        sTempFilterMatrix.preConcat(sTempBrightnessMatrix);
+                    }
+                    filter = new ColorMatrixColorFilter(sTempFilterMatrix);
+                }
+                sCachedFilter.append(key, filter);
             }
             mPaint.setColorFilter(filter);
         } else {
             mPaint.setColorFilter(null);
         }
+        invalidateSelf();
     }
 
-    private static void setBrightnessMatrix(ColorMatrix matrix, int brightness) {
-        // Brightness: C-new = C-old*(1-amount) + amount
-        float scale = 1 - brightness / 255.0f;
-        matrix.setScale(scale, scale, scale, 1);
-        float[] array = matrix.getArray();
-
-        // Add the amount to RGB components of the matrix, as per the above formula.
-        // Fifth elements in the array correspond to the constant being added to
-        // red, blue, green, and alpha channel respectively.
-        array[4] = brightness;
-        array[9] = brightness;
-        array[14] = brightness;
+    private AnimatorSet cancelAnimator(AnimatorSet animator) {
+        if (animator != null) {
+            animator.removeAllListeners();
+            animator.cancel();
+        }
+        return null;
     }
 }
diff --git a/src/com/android/launcher3/FolderIcon.java b/src/com/android/launcher3/FolderIcon.java
index bd61a6de5..07bd0aafa 100644
--- a/src/com/android/launcher3/FolderIcon.java
+++ b/src/com/android/launcher3/FolderIcon.java
@@ -521,7 +521,7 @@ public class FolderIcon extends FrameLayout implements FolderListener {
     }
 
     class PreviewItemDrawingParams {
-        PreviewItemDrawingParams(float transX, float transY, float scale, int overlayAlpha) {
+        PreviewItemDrawingParams(float transX, float transY, float scale, float overlayAlpha) {
             this.transX = transX;
             this.transY = transY;
             this.scale = scale;
@@ -530,7 +530,7 @@ public class FolderIcon extends FrameLayout implements FolderListener {
         float transX;
         float transY;
         float scale;
-        int overlayAlpha;
+        float overlayAlpha;
         Drawable drawable;
     }
 
@@ -562,7 +562,7 @@ public class FolderIcon extends FrameLayout implements FolderListener {
         float transY = mAvailableSpaceInPreview - (offset + scaledSize + scaleOffsetCorrection) + getPaddingTop();
         float transX = (mAvailableSpaceInPreview - scaledSize) / 2;
         float totalScale = mBaselineIconScale * scale;
-        final int overlayAlpha = (int) (80 * (1 - r));
+        final float overlayAlpha = (80 * (1 - r)) / 255f;
 
         if (params == null) {
             params = new PreviewItemDrawingParams(transX, transY, totalScale, overlayAlpha);
@@ -586,12 +586,12 @@ public class FolderIcon extends FrameLayout implements FolderListener {
             d.setBounds(0, 0, mIntrinsicIconSize, mIntrinsicIconSize);
             if (d instanceof FastBitmapDrawable) {
                 FastBitmapDrawable fd = (FastBitmapDrawable) d;
-                int oldBrightness = fd.getBrightness();
+                float oldBrightness = fd.getBrightness();
                 fd.setBrightness(params.overlayAlpha);
                 d.draw(canvas);
                 fd.setBrightness(oldBrightness);
             } else {
-                d.setColorFilter(Color.argb(params.overlayAlpha, 255, 255, 255),
+                d.setColorFilter(Color.argb((int) (params.overlayAlpha * 255), 255, 255, 255),
                         PorterDuff.Mode.SRC_ATOP);
                 d.draw(canvas);
                 d.clearColorFilter();
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index a4f684f02..143d19b9b 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -46,6 +46,7 @@ import android.content.pm.ActivityInfo;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
+import android.content.pm.ResolveInfo;
 import android.content.res.Configuration;
 import android.database.sqlite.SQLiteDatabase;
 import android.graphics.Bitmap;
@@ -4573,6 +4574,18 @@ public class Launcher extends Activity
                 UserHandleCompat.myUserHandle());
     }
 
+    /**
+     * Generates a dummy AppInfo for us to use to calculate BubbleTextView sizes.
+     */
+    public AppInfo createDummyAppInfo() {
+        Intent intent = new Intent();
+        intent.setComponent(new ComponentName(this, Launcher.class));
+        PackageManager pm = getPackageManager();
+        ResolveInfo info = pm.resolveActivity(intent, 0);
+        return new AppInfo(this, LauncherActivityInfoCompat.fromResolveInfo(info, this),
+                UserHandleCompat.myUserHandle(), mIconCache);
+    }
+
     // TODO: This method should be a part of LauncherSearchCallback
     public void startDrag(View dragView, ItemInfo dragInfo, DragSource source) {
         dragView.setTag(dragInfo);
diff --git a/src/com/android/launcher3/PendingAppWidgetHostView.java b/src/com/android/launcher3/PendingAppWidgetHostView.java
index 40eadabd5..1d7694598 100644
--- a/src/com/android/launcher3/PendingAppWidgetHostView.java
+++ b/src/com/android/launcher3/PendingAppWidgetHostView.java
@@ -133,7 +133,7 @@ public class PendingAppWidgetHostView extends LauncherAppWidgetHostView implemen
             //   3) Setup icon in the center and app icon in the top right corner.
             if (mDisabledForSafeMode) {
                 FastBitmapDrawable disabledIcon = mLauncher.createIconDrawable(mIcon);
-                disabledIcon.setGhostModeEnabled(true);
+                disabledIcon.setState(FastBitmapDrawable.State.DISABLED);
                 mCenterDrawable = disabledIcon;
                 mSettingIconDrawable = null;
             } else if (isReadyForClickSetup()) {
diff --git a/src/com/android/launcher3/PreloadIconDrawable.java b/src/com/android/launcher3/PreloadIconDrawable.java
index 45e4b2c4a..908c8b9e2 100644
--- a/src/com/android/launcher3/PreloadIconDrawable.java
+++ b/src/com/android/launcher3/PreloadIconDrawable.java
@@ -179,7 +179,8 @@ class PreloadIconDrawable extends Drawable {
             mPaint.setColor(getIndicatorColor());
         }
         if (mIcon instanceof FastBitmapDrawable) {
-            ((FastBitmapDrawable) mIcon).setGhostModeEnabled(level <= 0);
+            ((FastBitmapDrawable) mIcon).setState(level <= 0 ?
+                    FastBitmapDrawable.State.DISABLED : FastBitmapDrawable.State.NORMAL);
         }
 
         invalidateSelf();
diff --git a/src/com/android/launcher3/allapps/AllAppsContainerView.java b/src/com/android/launcher3/allapps/AllAppsContainerView.java
index 979a7332b..c26463e5b 100644
--- a/src/com/android/launcher3/allapps/AllAppsContainerView.java
+++ b/src/com/android/launcher3/allapps/AllAppsContainerView.java
@@ -28,6 +28,7 @@ import android.text.SpannableStringBuilder;
 import android.text.method.TextKeyListener;
 import android.util.AttributeSet;
 import android.view.KeyEvent;
+import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewConfiguration;
@@ -35,6 +36,7 @@ import android.view.ViewGroup;
 import android.widget.LinearLayout;
 import com.android.launcher3.AppInfo;
 import com.android.launcher3.BaseContainerView;
+import com.android.launcher3.BubbleTextView;
 import com.android.launcher3.CellLayout;
 import com.android.launcher3.DeleteDropTarget;
 import com.android.launcher3.DeviceProfile;
@@ -332,6 +334,18 @@ public class AllAppsContainerView extends BaseContainerView implements DragSourc
             mAppsRecyclerView.addItemDecoration(mItemDecoration);
         }
 
+        // Precalculate the prediction icon and normal icon sizes
+        LayoutInflater layoutInflater = LayoutInflater.from(getContext());
+        BubbleTextView icon = (BubbleTextView) layoutInflater.inflate(R.layout.all_apps_icon, this, false);
+        icon.applyFromApplicationInfo(mLauncher.createDummyAppInfo());
+        icon.measure(MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE, MeasureSpec.AT_MOST),
+                MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE, MeasureSpec.AT_MOST));
+        BubbleTextView predIcon = (BubbleTextView) layoutInflater.inflate(R.layout.all_apps_prediction_bar_icon, this, false);
+        predIcon.applyFromApplicationInfo(mLauncher.createDummyAppInfo());
+        predIcon.measure(MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE, MeasureSpec.AT_MOST),
+                MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE, MeasureSpec.AT_MOST));
+        mAppsRecyclerView.setPremeasuredIconHeights(predIcon.getMeasuredHeight(), icon.getMeasuredHeight());
+
         updateBackgroundAndPaddings();
     }
 
diff --git a/src/com/android/launcher3/allapps/AllAppsFastScrollHelper.java b/src/com/android/launcher3/allapps/AllAppsFastScrollHelper.java
new file mode 100644
index 000000000..10453420a
--- /dev/null
+++ b/src/com/android/launcher3/allapps/AllAppsFastScrollHelper.java
@@ -0,0 +1,228 @@
+/*
+ * Copyright (C) 2015 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 com.android.launcher3.allapps;
+
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+
+import com.android.launcher3.BaseRecyclerView;
+import com.android.launcher3.BaseRecyclerViewFastScrollBar;
+import com.android.launcher3.FastBitmapDrawable;
+import com.android.launcher3.util.Thunk;
+
+import java.util.HashSet;
+
+public class AllAppsFastScrollHelper implements AllAppsGridAdapter.BindViewCallback {
+
+    private static final int INITIAL_TOUCH_SETTLING_DURATION = 300;
+    private static final int REPEAT_TOUCH_SETTLING_DURATION = 200;
+    private static final float FAST_SCROLL_TOUCH_VELOCITY_BARRIER = 1900f;
+
+    private AllAppsRecyclerView mRv;
+    private AlphabeticalAppsList mApps;
+
+    // Keeps track of the current and targetted fast scroll section (the section to scroll to after
+    // the initial delay)
+    int mTargetFastScrollPosition = -1;
+    @Thunk String mCurrentFastScrollSection;
+    @Thunk String mTargetFastScrollSection;
+
+    // The settled states affect the delay before the fast scroll animation is applied
+    private boolean mHasFastScrollTouchSettled;
+    private boolean mHasFastScrollTouchSettledAtLeastOnce;
+
+    // Set of all views animated during fast scroll.  We keep track of these ourselves since there
+    // is no way to reset a view once it gets scrapped or recycled without other hacks
+    private HashSet<BaseRecyclerViewFastScrollBar.FastScrollFocusableView> mTrackedFastScrollViews =
+            new HashSet<>();
+
+    // Smooth fast-scroll animation frames
+    @Thunk int mFastScrollFrameIndex;
+    @Thunk final int[] mFastScrollFrames = new int[10];
+
+    /**
+     * This runnable runs a single frame of the smooth scroll animation and posts the next frame
+     * if necessary.
+     */
+    @Thunk Runnable mSmoothSnapNextFrameRunnable = new Runnable() {
+        @Override
+        public void run() {
+            if (mFastScrollFrameIndex < mFastScrollFrames.length) {
+                mRv.scrollBy(0, mFastScrollFrames[mFastScrollFrameIndex]);
+                mFastScrollFrameIndex++;
+                mRv.postOnAnimation(mSmoothSnapNextFrameRunnable);
+            }
+        }
+    };
+
+    /**
+     * This runnable updates the current fast scroll section to the target fastscroll section.
+     */
+    Runnable mFastScrollToTargetSectionRunnable = new Runnable() {
+        @Override
+        public void run() {
+            // Update to the target section
+            mCurrentFastScrollSection = mTargetFastScrollSection;
+            mHasFastScrollTouchSettled = true;
+            mHasFastScrollTouchSettledAtLeastOnce = true;
+            updateTrackedViewsFastScrollFocusState();
+        }
+    };
+
+    public AllAppsFastScrollHelper(AllAppsRecyclerView rv, AlphabeticalAppsList apps) {
+        mRv = rv;
+        mApps = apps;
+    }
+
+    public void onSetAdapter(AllAppsGridAdapter adapter) {
+        adapter.setBindViewCallback(this);
+    }
+
+    /**
+     * Smooth scrolls the recycler view to the given section.
+     *
+     * @return whether the fastscroller can scroll to the new section.
+     */
+    public boolean smoothScrollToSection(int scrollY, int availableScrollHeight,
+            AlphabeticalAppsList.FastScrollSectionInfo info) {
+        if (mTargetFastScrollPosition != info.fastScrollToItem.position) {
+            mTargetFastScrollPosition = info.fastScrollToItem.position;
+            smoothSnapToPosition(scrollY, availableScrollHeight, info);
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Smoothly snaps to a given position.  We do this manually by calculating the keyframes
+     * ourselves and animating the scroll on the recycler view.
+     */
+    private void smoothSnapToPosition(int scrollY, int availableScrollHeight,
+            AlphabeticalAppsList.FastScrollSectionInfo info) {
+        mRv.removeCallbacks(mSmoothSnapNextFrameRunnable);
+        mRv.removeCallbacks(mFastScrollToTargetSectionRunnable);
+
+        trackAllChildViews();
+        if (mHasFastScrollTouchSettled) {
+            // In this case, the user has already settled once (and the fast scroll state has
+            // animated) and they are just fine-tuning their section from the last section, so
+            // we should make it feel fast and update immediately.
+            mCurrentFastScrollSection = info.sectionName;
+            mTargetFastScrollSection = null;
+            updateTrackedViewsFastScrollFocusState();
+        } else {
+            // Otherwise, the user has scrubbed really far, and we don't want to distract the user
+            // with the flashing fast scroll state change animation in addition to the fast scroll
+            // section popup, so reset the views to normal, and wait for the touch to settle again
+            // before animating the fast scroll state.
+            mCurrentFastScrollSection = null;
+            mTargetFastScrollSection = info.sectionName;
+            mHasFastScrollTouchSettled = false;
+            updateTrackedViewsFastScrollFocusState();
+
+            // Delay scrolling to a new section until after some duration.  If the user has been
+            // scrubbing a while and makes multiple big jumps, then reduce the time needed for the
+            // fast scroll to settle so it doesn't feel so long.
+            mRv.postDelayed(mFastScrollToTargetSectionRunnable,
+                    mHasFastScrollTouchSettledAtLeastOnce ?
+                            REPEAT_TOUCH_SETTLING_DURATION :
+                            INITIAL_TOUCH_SETTLING_DURATION);
+        }
+
+        // Calculate the full animation from the current scroll position to the final scroll
+        // position, and then run the animation for the duration.
+        int newScrollY = Math.min(availableScrollHeight,
+                mRv.getPaddingTop() + mRv.getTop(info.fastScrollToItem.rowIndex));
+        int numFrames = mFastScrollFrames.length;
+        for (int i = 0; i < numFrames; i++) {
+            // TODO(winsonc): We can interpolate this as well.
+            mFastScrollFrames[i] = (newScrollY - scrollY) / numFrames;
+        }
+        mFastScrollFrameIndex = 0;
+        mRv.postOnAnimation(mSmoothSnapNextFrameRunnable);
+    }
+
+    public void onFastScrollCompleted() {
+        // TODO(winsonc): Handle the case when the user scrolls and releases before the animation
+        //                runs
+
+        // Stop animating the fast scroll position and state
+        mRv.removeCallbacks(mSmoothSnapNextFrameRunnable);
+        mRv.removeCallbacks(mFastScrollToTargetSectionRunnable);
+
+        // Reset the tracking variables
+        mHasFastScrollTouchSettled = false;
+        mHasFastScrollTouchSettledAtLeastOnce = false;
+        mCurrentFastScrollSection = null;
+        mTargetFastScrollSection = null;
+        mTargetFastScrollPosition = -1;
+
+        updateTrackedViewsFastScrollFocusState();
+        mTrackedFastScrollViews.clear();
+    }
+
+    @Override
+    public void onBindView(AllAppsGridAdapter.ViewHolder holder) {
+        // Update newly bound views to the current fast scroll state if we are fast scrolling
+        if (mCurrentFastScrollSection != null || mTargetFastScrollSection != null) {
+            if (holder.mContent instanceof BaseRecyclerViewFastScrollBar.FastScrollFocusableView) {
+                BaseRecyclerViewFastScrollBar.FastScrollFocusableView v =
+                        (BaseRecyclerViewFastScrollBar.FastScrollFocusableView) holder.mContent;
+                updateViewFastScrollFocusState(v, holder.getPosition(), false /* animated */);
+                mTrackedFastScrollViews.add(v);
+            }
+        }
+    }
+
+    /**
+     * Starts tracking all the recycler view's children which are FastScrollFocusableViews.
+     */
+    private void trackAllChildViews() {
+        int childCount = mRv.getChildCount();
+        for (int i = 0; i < childCount; i++) {
+            View v = mRv.getChildAt(i);
+            if (v instanceof BaseRecyclerViewFastScrollBar.FastScrollFocusableView) {
+                mTrackedFastScrollViews.add((BaseRecyclerViewFastScrollBar.FastScrollFocusableView) v);
+            }
+        }
+    }
+
+    /**
+     * Updates the fast scroll focus on all the children.
+     */
+    private void updateTrackedViewsFastScrollFocusState() {
+        for (BaseRecyclerViewFastScrollBar.FastScrollFocusableView v : mTrackedFastScrollViews) {
+            RecyclerView.ViewHolder viewHolder = mRv.getChildViewHolder((View) v);
+            int pos = (viewHolder != null) ? viewHolder.getPosition() : -1;
+            updateViewFastScrollFocusState(v, pos, true);
+        }
+    }
+
+    /**
+     * Updates the fast scroll focus on all a given view.
+     */
+    private void updateViewFastScrollFocusState(BaseRecyclerViewFastScrollBar.FastScrollFocusableView v,
+                                                int pos, boolean animated) {
+        FastBitmapDrawable.State newState = FastBitmapDrawable.State.NORMAL;
+        if (mCurrentFastScrollSection != null && pos > -1) {
+            AlphabeticalAppsList.AdapterItem item = mApps.getAdapterItems().get(pos);
+            newState = item.sectionName.equals(mCurrentFastScrollSection) ?
+                    FastBitmapDrawable.State.FAST_SCROLL_HIGHLIGHTED :
+                    FastBitmapDrawable.State.FAST_SCROLL_UNHIGHLIGHTED;
+        }
+        v.setFastScrollFocusState(newState, animated);
+    }
+}
diff --git a/src/com/android/launcher3/allapps/AllAppsGridAdapter.java b/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
index f885567ac..b7fa43d44 100644
--- a/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
+++ b/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
@@ -69,6 +69,10 @@ public class AllAppsGridAdapter extends RecyclerView.Adapter<AllAppsGridAdapter.
     // The message to continue to a market search when there are no filtered results
     public static final int SEARCH_MARKET_VIEW_TYPE = 5;
 
+    public interface BindViewCallback {
+        public void onBindView(ViewHolder holder);
+    }
+
     /**
      * ViewHolder for each icon.
      */
@@ -328,6 +332,7 @@ public class AllAppsGridAdapter extends RecyclerView.Adapter<AllAppsGridAdapter.
     private View.OnTouchListener mTouchListener;
     private View.OnClickListener mIconClickListener;
     private View.OnLongClickListener mIconLongClickListener;
+    private BindViewCallback mBindViewCallback;
     @Thunk final Rect mBackgroundPadding = new Rect();
     @Thunk int mPredictionBarDividerOffset;
     @Thunk int mAppsPerRow;
@@ -424,6 +429,13 @@ public class AllAppsGridAdapter extends RecyclerView.Adapter<AllAppsGridAdapter.
     }
 
     /**
+     * Sets the callback for when views are bound.
+     */
+    public void setBindViewCallback(BindViewCallback cb) {
+        mBindViewCallback = cb;
+    }
+
+    /**
      * Notifies the adapter of the background padding so that it can draw things correctly in the
      * item decorator.
      */
@@ -528,6 +540,15 @@ public class AllAppsGridAdapter extends RecyclerView.Adapter<AllAppsGridAdapter.
                 }
                 break;
         }
+        if (mBindViewCallback != null) {
+            mBindViewCallback.onBindView(holder);
+        }
+    }
+
+    @Override
+    public boolean onFailedToRecycleView(ViewHolder holder) {
+        // Always recycle and we will reset the view when it is bound
+        return true;
     }
 
     @Override
diff --git a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
index 10d10f11b..48b9494b7 100644
--- a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
+++ b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
@@ -15,24 +15,20 @@
  */
 package com.android.launcher3.allapps;
 
-import android.animation.ObjectAnimator;
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
-import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.util.AttributeSet;
 import android.view.View;
 
 import com.android.launcher3.BaseRecyclerView;
-import com.android.launcher3.BaseRecyclerViewFastScrollBar;
 import com.android.launcher3.DeviceProfile;
 import com.android.launcher3.R;
 import com.android.launcher3.Stats;
 import com.android.launcher3.Utilities;
-import com.android.launcher3.util.Thunk;
 
 import java.util.List;
 
@@ -42,25 +38,17 @@ import java.util.List;
 public class AllAppsRecyclerView extends BaseRecyclerView
         implements Stats.LaunchSourceProvider {
 
-    private static final int FAST_SCROLL_MODE_JUMP_TO_FIRST_ICON = 0;
-    private static final int FAST_SCROLL_MODE_FREE_SCROLL = 1;
-
-    private static final int FAST_SCROLL_BAR_MODE_DISTRIBUTE_BY_ROW = 0;
-    private static final int FAST_SCROLL_BAR_MODE_DISTRIBUTE_BY_SECTIONS = 1;
-
     private AlphabeticalAppsList mApps;
+    private AllAppsFastScrollHelper mFastScrollHelper;
+    private BaseRecyclerView.ScrollPositionState mScrollPosState =
+            new BaseRecyclerView.ScrollPositionState();
     private int mNumAppsPerRow;
 
-    @Thunk BaseRecyclerViewFastScrollBar.FastScrollFocusableView mLastFastScrollFocusedView;
-    @Thunk int mPrevFastScrollFocusedPosition;
-    @Thunk int mFastScrollFrameIndex;
-    @Thunk final int[] mFastScrollFrames = new int[10];
-
-    private final int mFastScrollMode = FAST_SCROLL_MODE_JUMP_TO_FIRST_ICON;
-    private final int mScrollBarMode = FAST_SCROLL_BAR_MODE_DISTRIBUTE_BY_ROW;
-
-    private ScrollPositionState mScrollPosState = new ScrollPositionState();
+    // The specific icon heights that we use to calculate scroll
+    private int mPredictionIconHeight;
+    private int mIconHeight;
 
+    // The empty-search result background
     private AllAppsBackgroundDrawable mEmptySearchBackground;
     private int mEmptySearchBackgroundTopOffset;
 
@@ -79,8 +67,8 @@ public class AllAppsRecyclerView extends BaseRecyclerView
     public AllAppsRecyclerView(Context context, AttributeSet attrs, int defStyleAttr,
             int defStyleRes) {
         super(context, attrs, defStyleAttr);
-
         Resources res = getResources();
+        addOnItemTouchListener(this);
         mScrollbar.setDetachThumbOnFastScroll();
         mEmptySearchBackgroundTopOffset = res.getDimensionPixelSize(
                 R.dimen.all_apps_empty_search_bg_top_offset);
@@ -91,6 +79,7 @@ public class AllAppsRecyclerView extends BaseRecyclerView
      */
     public void setApps(AlphabeticalAppsList apps) {
         mApps = apps;
+        mFastScrollHelper = new AllAppsFastScrollHelper(this, apps);
     }
 
     /**
@@ -110,6 +99,14 @@ public class AllAppsRecyclerView extends BaseRecyclerView
     }
 
     /**
+     * Sets the heights of the icons in this view (for scroll calculations).
+     */
+    public void setPremeasuredIconHeights(int predictionIconHeight, int iconHeight) {
+        mPredictionIconHeight = predictionIconHeight;
+        mIconHeight = iconHeight;
+    }
+
+    /**
      * Scrolls this recycler view to the top.
      */
     public void scrollToTop() {
@@ -126,6 +123,7 @@ public class AllAppsRecyclerView extends BaseRecyclerView
      */
     @Override
     protected void dispatchDraw(Canvas canvas) {
+        // Clip to ensure that we don't draw the overscroll effect beyond the background bounds
         canvas.clipRect(mBackgroundPadding.left, mBackgroundPadding.top,
                 getWidth() - mBackgroundPadding.right,
                 getHeight() - mBackgroundPadding.bottom);
@@ -157,14 +155,6 @@ public class AllAppsRecyclerView extends BaseRecyclerView
     }
 
     @Override
-    protected void onFinishInflate() {
-        super.onFinishInflate();
-
-        // Bind event handlers
-        addOnItemTouchListener(this);
-    }
-
-    @Override
     public void fillInLaunchSourceData(Bundle sourceData) {
         sourceData.putString(Stats.SOURCE_EXTRA_CONTAINER, Stats.CONTAINER_ALL_APPS);
         if (mApps.hasFilter()) {
@@ -212,63 +202,31 @@ public class AllAppsRecyclerView extends BaseRecyclerView
         List<AlphabeticalAppsList.FastScrollSectionInfo> fastScrollSections =
                 mApps.getFastScrollerSections();
         AlphabeticalAppsList.FastScrollSectionInfo lastInfo = fastScrollSections.get(0);
-        if (mScrollBarMode == FAST_SCROLL_BAR_MODE_DISTRIBUTE_BY_ROW) {
-            for (int i = 1; i < fastScrollSections.size(); i++) {
-                AlphabeticalAppsList.FastScrollSectionInfo info = fastScrollSections.get(i);
-                if (info.touchFraction > touchFraction) {
-                    break;
-                }
-                lastInfo = info;
+        for (int i = 1; i < fastScrollSections.size(); i++) {
+            AlphabeticalAppsList.FastScrollSectionInfo info = fastScrollSections.get(i);
+            if (info.touchFraction > touchFraction) {
+                break;
             }
-        } else if (mScrollBarMode == FAST_SCROLL_BAR_MODE_DISTRIBUTE_BY_SECTIONS){
-            lastInfo = fastScrollSections.get((int) (touchFraction * (fastScrollSections.size() - 1)));
-        } else {
-            throw new RuntimeException("Unexpected scroll bar mode");
+            lastInfo = info;
         }
 
-        // Map the touch position back to the scroll of the recycler view
-        getCurScrollState(mScrollPosState);
-        int availableScrollHeight = getAvailableScrollHeight(rowCount, mScrollPosState.rowHeight);
-        LinearLayoutManager layoutManager = (LinearLayoutManager) getLayoutManager();
-        if (mFastScrollMode == FAST_SCROLL_MODE_FREE_SCROLL) {
-            layoutManager.scrollToPositionWithOffset(0, (int) -(availableScrollHeight * touchFraction));
-        }
-
-        if (mPrevFastScrollFocusedPosition != lastInfo.fastScrollToItem.position) {
-            mPrevFastScrollFocusedPosition = lastInfo.fastScrollToItem.position;
-
-            // Reset the last focused view
-            if (mLastFastScrollFocusedView != null) {
-                mLastFastScrollFocusedView.setFastScrollFocused(false, true);
-                mLastFastScrollFocusedView = null;
-            }
-
-            if (mFastScrollMode == FAST_SCROLL_MODE_JUMP_TO_FIRST_ICON) {
-                smoothSnapToPosition(mPrevFastScrollFocusedPosition, mScrollPosState);
-            } else if (mFastScrollMode == FAST_SCROLL_MODE_FREE_SCROLL) {
-                final ViewHolder vh = findViewHolderForPosition(mPrevFastScrollFocusedPosition);
-                if (vh != null &&
-                        vh.itemView instanceof BaseRecyclerViewFastScrollBar.FastScrollFocusableView) {
-                    mLastFastScrollFocusedView =
-                            (BaseRecyclerViewFastScrollBar.FastScrollFocusableView) vh.itemView;
-                    mLastFastScrollFocusedView.setFastScrollFocused(true, true);
-                }
-            } else {
-                throw new RuntimeException("Unexpected fast scroll mode");
-            }
-        }
+        // Update the fast scroll
+        int scrollY = getScrollTop(mScrollPosState);
+        int availableScrollHeight = getAvailableScrollHeight(mApps.getNumAppRows());
+        mFastScrollHelper.smoothScrollToSection(scrollY, availableScrollHeight, lastInfo);
         return lastInfo.sectionName;
     }
 
     @Override
     public void onFastScrollCompleted() {
         super.onFastScrollCompleted();
-        // Reset and clean up the last focused view
-        if (mLastFastScrollFocusedView != null) {
-            mLastFastScrollFocusedView.setFastScrollFocused(false, true);
-            mLastFastScrollFocusedView = null;
-        }
-        mPrevFastScrollFocusedPosition = -1;
+        mFastScrollHelper.onFastScrollCompleted();
+    }
+
+    @Override
+    public void setAdapter(Adapter adapter) {
+        super.setAdapter(adapter);
+        mFastScrollHelper.onSetAdapter((AllAppsGridAdapter) adapter);
     }
 
     /**
@@ -286,7 +244,7 @@ public class AllAppsRecyclerView extends BaseRecyclerView
 
         // Find the index and height of the first visible row (all rows have the same height)
         int rowCount = mApps.getNumAppRows();
-        getCurScrollState(mScrollPosState);
+        getCurScrollState(mScrollPosState, -1);
         if (mScrollPosState.rowIndex < 0) {
             mScrollbar.setThumbOffset(-1, -1);
             return;
@@ -294,7 +252,7 @@ public class AllAppsRecyclerView extends BaseRecyclerView
 
         // Only show the scrollbar if there is height to be scrolled
         int availableScrollBarHeight = getAvailableScrollBarHeight();
-        int availableScrollHeight = getAvailableScrollHeight(mApps.getNumAppRows(), mScrollPosState.rowHeight);
+        int availableScrollHeight = getAvailableScrollHeight(mApps.getNumAppRows());
         if (availableScrollHeight <= 0) {
             mScrollbar.setThumbOffset(-1, -1);
             return;
@@ -303,8 +261,7 @@ public class AllAppsRecyclerView extends BaseRecyclerView
         // Calculate the current scroll position, the scrollY of the recycler view accounts for the
         // view padding, while the scrollBarY is drawn right up to the background padding (ignoring
         // padding)
-        int scrollY = getPaddingTop() +
-                (mScrollPosState.rowIndex * mScrollPosState.rowHeight) - mScrollPosState.rowTopOffset;
+        int scrollY = getScrollTop(mScrollPosState);
         int scrollBarY = mBackgroundPadding.top +
                 (int) (((float) scrollY / availableScrollHeight) * availableScrollBarHeight);
 
@@ -355,58 +312,12 @@ public class AllAppsRecyclerView extends BaseRecyclerView
     }
 
     /**
-     * This runnable runs a single frame of the smooth scroll animation and posts the next frame
-     * if necessary.
-     */
-    @Thunk Runnable mSmoothSnapNextFrameRunnable = new Runnable() {
-        @Override
-        public void run() {
-            if (mFastScrollFrameIndex < mFastScrollFrames.length) {
-                scrollBy(0, mFastScrollFrames[mFastScrollFrameIndex]);
-                mFastScrollFrameIndex++;
-                postOnAnimation(mSmoothSnapNextFrameRunnable);
-            } else {
-                // Animation completed, set the fast scroll state on the target view
-                final ViewHolder vh = findViewHolderForPosition(mPrevFastScrollFocusedPosition);
-                if (vh != null &&
-                        vh.itemView instanceof BaseRecyclerViewFastScrollBar.FastScrollFocusableView &&
-                        mLastFastScrollFocusedView != vh.itemView) {
-                    mLastFastScrollFocusedView =
-                            (BaseRecyclerViewFastScrollBar.FastScrollFocusableView) vh.itemView;
-                    mLastFastScrollFocusedView.setFastScrollFocused(true, true);
-                }
-            }
-        }
-    };
-
-    /**
-     * Smoothly snaps to a given position.  We do this manually by calculating the keyframes
-     * ourselves and animating the scroll on the recycler view.
-     */
-    private void smoothSnapToPosition(final int position, ScrollPositionState scrollPosState) {
-        removeCallbacks(mSmoothSnapNextFrameRunnable);
-
-        // Calculate the full animation from the current scroll position to the final scroll
-        // position, and then run the animation for the duration.
-        int curScrollY = getPaddingTop() +
-                (scrollPosState.rowIndex * scrollPosState.rowHeight) - scrollPosState.rowTopOffset;
-        int newScrollY = getScrollAtPosition(position, scrollPosState.rowHeight);
-        int numFrames = mFastScrollFrames.length;
-        for (int i = 0; i < numFrames; i++) {
-            // TODO(winsonc): We can interpolate this as well.
-            mFastScrollFrames[i] = (newScrollY - curScrollY) / numFrames;
-        }
-        mFastScrollFrameIndex = 0;
-        postOnAnimation(mSmoothSnapNextFrameRunnable);
-    }
-
-    /**
      * Returns the current scroll state of the apps rows.
      */
-    protected void getCurScrollState(ScrollPositionState stateOut) {
+    protected void getCurScrollState(ScrollPositionState stateOut, int viewTypeMask) {
         stateOut.rowIndex = -1;
         stateOut.rowTopOffset = -1;
-        stateOut.rowHeight = -1;
+        stateOut.itemPos = -1;
 
         // Return early if there are no items or we haven't been measured
         List<AlphabeticalAppsList.AdapterItem> items = mApps.getAdapterItems();
@@ -420,15 +331,15 @@ public class AllAppsRecyclerView extends BaseRecyclerView
             int position = getChildPosition(child);
             if (position != NO_POSITION) {
                 AlphabeticalAppsList.AdapterItem item = items.get(position);
-                if (item.viewType == AllAppsGridAdapter.ICON_VIEW_TYPE ||
-                        item.viewType == AllAppsGridAdapter.PREDICTION_ICON_VIEW_TYPE) {
+                if ((item.viewType & viewTypeMask) != 0) {
                     stateOut.rowIndex = item.rowIndex;
                     stateOut.rowTopOffset = getLayoutManager().getDecoratedTop(child);
-                    stateOut.rowHeight = child.getHeight();
-                    break;
+                    stateOut.itemPos = position;
+                    return;
                 }
             }
         }
+        return;
     }
 
     @Override
@@ -438,18 +349,13 @@ public class AllAppsRecyclerView extends BaseRecyclerView
         return !mApps.hasFilter();
     }
 
-    /**
-     * Returns the scrollY for the given position in the adapter.
-     */
-    private int getScrollAtPosition(int position, int rowHeight) {
-        AlphabeticalAppsList.AdapterItem item = mApps.getAdapterItems().get(position);
-        if (item.viewType == AllAppsGridAdapter.ICON_VIEW_TYPE ||
-                item.viewType == AllAppsGridAdapter.PREDICTION_ICON_VIEW_TYPE) {
-            int offset = item.rowIndex > 0 ? getPaddingTop() : 0;
-            return offset + item.rowIndex * rowHeight;
-        } else {
+    protected int getTop(int rowIndex) {
+        if (getChildCount() == 0 || rowIndex <= 0) {
             return 0;
         }
+
+        // The prediction bar icons have more padding, so account for that in the row offset
+        return mPredictionIconHeight + (rowIndex - 1) * mIconHeight;
     }
 
     /**
diff --git a/src/com/android/launcher3/widget/WidgetsRecyclerView.java b/src/com/android/launcher3/widget/WidgetsRecyclerView.java
index 884bdc418..fe9c51c44 100644
--- a/src/com/android/launcher3/widget/WidgetsRecyclerView.java
+++ b/src/com/android/launcher3/widget/WidgetsRecyclerView.java
@@ -102,9 +102,9 @@ public class WidgetsRecyclerView extends BaseRecyclerView {
         // Stop the scroller if it is scrolling
         stopScroll();
 
-        getCurScrollState(mScrollPosState);
+        getCurScrollState(mScrollPosState, -1);
         float pos = rowCount * touchFraction;
-        int availableScrollHeight = getAvailableScrollHeight(rowCount, mScrollPosState.rowHeight);
+        int availableScrollHeight = getAvailableScrollHeight(rowCount);
         LinearLayoutManager layoutManager = ((LinearLayoutManager) getLayoutManager());
         layoutManager.scrollToPositionWithOffset(0, (int) -(availableScrollHeight * touchFraction));
 
@@ -131,7 +131,7 @@ public class WidgetsRecyclerView extends BaseRecyclerView {
         }
 
         // Skip early if, there no child laid out in the container.
-        getCurScrollState(mScrollPosState);
+        getCurScrollState(mScrollPosState, -1);
         if (mScrollPosState.rowIndex < 0) {
             mScrollbar.setThumbOffset(-1, -1);
             return;
@@ -143,10 +143,10 @@ public class WidgetsRecyclerView extends BaseRecyclerView {
     /**
      * Returns the current scroll state.
      */
-    protected void getCurScrollState(ScrollPositionState stateOut) {
+    protected void getCurScrollState(ScrollPositionState stateOut, int viewTypeMask) {
         stateOut.rowIndex = -1;
         stateOut.rowTopOffset = -1;
-        stateOut.rowHeight = -1;
+        stateOut.itemPos = -1;
 
         // Skip early if widgets are not bound.
         if (mWidgets == null) {
@@ -163,6 +163,17 @@ public class WidgetsRecyclerView extends BaseRecyclerView {
 
         stateOut.rowIndex = position;
         stateOut.rowTopOffset = getLayoutManager().getDecoratedTop(child);
-        stateOut.rowHeight = child.getHeight();
+        stateOut.itemPos = position;
+    }
+
+    @Override
+    protected int getTop(int rowIndex) {
+        if (getChildCount() == 0) {
+            return 0;
+        }
+
+        // All the rows are the same height, return any child height
+        View child = getChildAt(0);
+        return child.getMeasuredHeight() * rowIndex;
     }
 }
\ No newline at end of file