diff --git a/src/com/android/launcher3/FastScrollRecyclerView.java b/src/com/android/launcher3/FastScrollRecyclerView.java
index 747b755..2f927d3 100644
--- a/src/com/android/launcher3/FastScrollRecyclerView.java
+++ b/src/com/android/launcher3/FastScrollRecyclerView.java
@@ -24,7 +24,6 @@
 import android.view.accessibility.AccessibilityNodeInfo;
 
 import androidx.annotation.Nullable;
-import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.android.launcher3.compat.AccessibilityManagerCompat;
@@ -92,8 +91,7 @@
     protected int getAvailableScrollHeight() {
         // AvailableScrollHeight = Total height of the all items - first page height
         int firstPageHeight = getMeasuredHeight() - getPaddingTop() - getPaddingBottom();
-        int totalHeightOfAllItems = getItemsHeight(/* untilIndex= */ getAdapter().getItemCount());
-        int availableScrollHeight = totalHeightOfAllItems - firstPageHeight;
+        int availableScrollHeight = computeVerticalScrollRange() - firstPageHeight;
         return Math.max(0, availableScrollHeight);
     }
 
@@ -146,10 +144,7 @@
 
         // IF scroller is at the very top OR there is no scroll bar because there is probably not
         // enough items to scroll, THEN it's okay for the container to be pulled down.
-        if (getCurrentScrollY() == 0) {
-            return true;
-        }
-        return getAdapter() == null || getAdapter().getItemCount() == 0;
+        return computeVerticalScrollOffset() == 0;
     }
 
     /**
@@ -160,53 +155,6 @@
     }
 
     /**
-     * @return the scroll top of this recycler view.
-     */
-    public int getCurrentScrollY() {
-        Adapter adapter = getAdapter();
-        if (adapter == null) {
-            return -1;
-        }
-        if (adapter.getItemCount() == 0 || getChildCount() == 0) {
-            return -1;
-        }
-
-        int itemPosition = NO_POSITION;
-        View child = null;
-
-        LayoutManager layoutManager = getLayoutManager();
-        if (layoutManager instanceof LinearLayoutManager) {
-            // Use the LayoutManager as the source of truth for visible positions. During
-            // animations, the view group child may not correspond to the visible views that appear
-            // at the top.
-            itemPosition = ((LinearLayoutManager) layoutManager).findFirstVisibleItemPosition();
-            child = layoutManager.findViewByPosition(itemPosition);
-        }
-
-        if (child == null) {
-            // If the layout manager returns null for any reason, which can happen before layout
-            // has occurred for the position, then look at the child of this view as a ViewGroup.
-            child = getChildAt(0);
-            itemPosition = getChildAdapterPosition(child);
-        }
-        if (itemPosition == NO_POSITION) {
-            return -1;
-        }
-        return getPaddingTop() + getItemsHeight(itemPosition)
-                - layoutManager.getDecoratedTop(child);
-    }
-
-    /**
-     * Returns the sum of the height, in pixels, of this list adapter's items from index
-     * 0 (inclusive) until {@code untilIndex} (exclusive). If untilIndex is same as the itemCount,
-     * it returns the full height of all the items.
-     *
-     * <p>If the untilIndex is larger than the total number of items in this adapter, returns the
-     * sum of all items' height.
-     */
-    protected abstract int getItemsHeight(int untilIndex);
-
-    /**
      * Maps the touch (from 0..1) to the adapter position that should be visible.
      * <p>Override in each subclass of this base class.
      */
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index 6bdfa1c..c85924e 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -2779,7 +2779,7 @@
             View v = getFirstMatch(Collections.singletonList(activeRecyclerView),
                     preferredItem, packageAndUserAndApp);
 
-            if (v != null && activeRecyclerView.getCurrentScrollY() > 0) {
+            if (v != null && activeRecyclerView.computeVerticalScrollOffset() > 0) {
                 RectF locationBounds = new RectF();
                 FloatingIconView.getLocationBoundsForView(this, v, false, locationBounds,
                         new Rect());
diff --git a/src/com/android/launcher3/allapps/AllAppsGridAdapter.java b/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
index 33d2f2b..e0b4951 100644
--- a/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
+++ b/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
@@ -26,7 +26,9 @@
 import androidx.core.view.accessibility.AccessibilityRecordCompat;
 import androidx.recyclerview.widget.GridLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
+import androidx.recyclerview.widget.RecyclerView.Adapter;
 
+import com.android.launcher3.util.ScrollableLayoutManager;
 import com.android.launcher3.views.ActivityContext;
 
 import java.util.List;
@@ -62,10 +64,10 @@
     /**
      * A subclass of GridLayoutManager that overrides accessibility values during app search.
      */
-    public class AppsGridLayoutManager extends GridLayoutManager {
+    public class AppsGridLayoutManager extends ScrollableLayoutManager {
 
         public AppsGridLayoutManager(Context context) {
-            super(context, 1, GridLayoutManager.VERTICAL, false);
+            super(context);
         }
 
         @Override
@@ -125,6 +127,15 @@
             }
             return extraRows;
         }
+
+        @Override
+        protected int incrementTotalHeight(Adapter adapter, int position, int heightUntilLastPos) {
+            AllAppsGridAdapter.AdapterItem item = mApps.getAdapterItems().get(position);
+            // only account for the first icon in the row since they are the same size within a row
+            return (isIconViewType(item.viewType) && item.rowAppIndex != 0)
+                    ? heightUntilLastPos
+                    : (heightUntilLastPos + mCachedSizes.get(item.viewType));
+        }
     }
 
     @Override
diff --git a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
index 21a7dfb..3d06fb5 100644
--- a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
+++ b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
@@ -15,8 +15,6 @@
  */
 package com.android.launcher3.allapps;
 
-import static android.view.View.MeasureSpec.UNSPECIFIED;
-
 import static com.android.launcher3.logging.StatsLogManager.LauncherEvent.LAUNCHER_ALLAPPS_SCROLLED;
 import static com.android.launcher3.logging.StatsLogManager.LauncherEvent.LAUNCHER_ALLAPPS_VERTICAL_SWIPE_BEGIN;
 import static com.android.launcher3.logging.StatsLogManager.LauncherEvent.LAUNCHER_ALLAPPS_VERTICAL_SWIPE_END;
@@ -26,7 +24,6 @@
 import android.graphics.Canvas;
 import android.util.AttributeSet;
 import android.util.Log;
-import android.util.SparseIntArray;
 
 import androidx.recyclerview.widget.RecyclerView;
 
@@ -49,40 +46,10 @@
     private static final boolean DEBUG = false;
     private static final boolean DEBUG_LATENCY = Utilities.isPropertyEnabled(SEARCH_LOGGING);
 
-    protected AlphabeticalAppsList<?> mApps;
     protected final int mNumAppsPerRow;
-
-    // The specific view heights that we use to calculate scroll
-    private final SparseIntArray mViewHeights = new SparseIntArray();
-    private final SparseIntArray mCachedScrollPositions = new SparseIntArray();
     private final AllAppsFastScrollHelper mFastScrollHelper;
 
-
-    private final AdapterDataObserver mObserver = new RecyclerView.AdapterDataObserver() {
-        public void onChanged() {
-            mCachedScrollPositions.clear();
-        }
-
-        @Override
-        public void onItemRangeChanged(int positionStart, int itemCount) {
-            onChanged();
-        }
-
-        @Override
-        public void onItemRangeInserted(int positionStart, int itemCount) {
-            onChanged();
-        }
-
-        @Override
-        public void onItemRangeRemoved(int positionStart, int itemCount) {
-            onChanged();
-        }
-
-        @Override
-        public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
-            onChanged();
-        }
-    };
+    protected AlphabeticalAppsList<?> mApps;
 
     public AllAppsRecyclerView(Context context) {
         this(context, null);
@@ -122,12 +89,8 @@
         pool.setMaxRecycledViews(AllAppsGridAdapter.VIEW_TYPE_ALL_APPS_DIVIDER, 1);
         pool.setMaxRecycledViews(AllAppsGridAdapter.VIEW_TYPE_ICON, approxRows
                 * (mNumAppsPerRow + 1));
-
-        mViewHeights.clear();
-        mViewHeights.put(AllAppsGridAdapter.VIEW_TYPE_ICON, grid.allAppsCellHeightPx);
     }
 
-
     @Override
     public void onDraw(Canvas c) {
         if (DEBUG) {
@@ -200,17 +163,6 @@
     }
 
     @Override
-    public void setAdapter(Adapter adapter) {
-        if (getAdapter() != null) {
-            getAdapter().unregisterAdapterDataObserver(mObserver);
-        }
-        super.setAdapter(adapter);
-        if (adapter != null) {
-            adapter.registerAdapterDataObserver(mObserver);
-        }
-    }
-
-    @Override
     protected boolean isPaddingOffsetRequired() {
         return true;
     }
@@ -231,13 +183,13 @@
         List<AllAppsGridAdapter.AdapterItem> items = mApps.getAdapterItems();
 
         // Skip early if there are no items or we haven't been measured
-        if (items.isEmpty() || mNumAppsPerRow == 0) {
+        if (items.isEmpty() || mNumAppsPerRow == 0 || getChildCount() == 0) {
             mScrollbar.setThumbOffsetY(-1);
             return;
         }
 
         // Skip early if, there no child laid out in the container.
-        int scrollY = getCurrentScrollY();
+        int scrollY = computeVerticalScrollOffset();
         if (scrollY < 0) {
             mScrollbar.setThumbOffsetY(-1);
             return;
@@ -292,51 +244,6 @@
         }
     }
 
-    @Override
-    protected int getItemsHeight(int position) {
-        List<AllAppsGridAdapter.AdapterItem> items = mApps.getAdapterItems();
-        AllAppsGridAdapter.AdapterItem posItem = position < items.size()
-                ? items.get(position) : null;
-        int y = mCachedScrollPositions.get(position, -1);
-        if (y < 0) {
-            y = 0;
-            for (int i = 0; i < position; i++) {
-                AllAppsGridAdapter.AdapterItem item = items.get(i);
-                if (AllAppsGridAdapter.isIconViewType(item.viewType)) {
-                    // Break once we reach the desired row
-                    if (posItem != null && posItem.viewType == item.viewType &&
-                            posItem.rowIndex == item.rowIndex) {
-                        break;
-                    }
-                    // Otherwise, only account for the first icon in the row since they are the same
-                    // size within a row
-                    if (item.rowAppIndex == 0) {
-                        y += mViewHeights.get(item.viewType, 0);
-                    }
-                } else {
-                    // Rest of the views span the full width
-                    int elHeight = mViewHeights.get(item.viewType);
-                    if (elHeight == 0) {
-                        ViewHolder holder = findViewHolderForAdapterPosition(i);
-                        if (holder == null) {
-                            holder = getAdapter().createViewHolder(this, item.viewType);
-                            getAdapter().onBindViewHolder(holder, i);
-                            holder.itemView.measure(UNSPECIFIED, UNSPECIFIED);
-                            elHeight = holder.itemView.getMeasuredHeight();
-
-                            getRecycledViewPool().putRecycledView(holder);
-                        } else {
-                            elHeight = holder.itemView.getMeasuredHeight();
-                        }
-                    }
-                    y += elHeight;
-                }
-            }
-            mCachedScrollPositions.put(position, y);
-        }
-        return y;
-    }
-
     public int getScrollBarTop() {
         return getResources().getDimensionPixelOffset(R.dimen.all_apps_header_top_padding);
     }
diff --git a/src/com/android/launcher3/allapps/BaseAllAppsContainerView.java b/src/com/android/launcher3/allapps/BaseAllAppsContainerView.java
index 879a159..7660e16 100644
--- a/src/com/android/launcher3/allapps/BaseAllAppsContainerView.java
+++ b/src/com/android/launcher3/allapps/BaseAllAppsContainerView.java
@@ -103,7 +103,8 @@
             new RecyclerView.OnScrollListener() {
                 @Override
                 public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
-                    updateHeaderScroll(((AllAppsRecyclerView) recyclerView).getCurrentScrollY());
+                    updateHeaderScroll(
+                            ((AllAppsRecyclerView) recyclerView).computeVerticalScrollOffset());
                 }
             };
 
diff --git a/src/com/android/launcher3/allapps/FloatingHeaderView.java b/src/com/android/launcher3/allapps/FloatingHeaderView.java
index 8ec2aeb..73efd3f 100644
--- a/src/com/android/launcher3/allapps/FloatingHeaderView.java
+++ b/src/com/android/launcher3/allapps/FloatingHeaderView.java
@@ -68,7 +68,7 @@
                         mAnimator.cancel();
                     }
 
-                    int current = -mCurrentRV.getCurrentScrollY();
+                    int current = -mCurrentRV.computeVerticalScrollOffset();
                     boolean headerCollapsed = mHeaderCollapsed;
                     moved(current);
                     applyVerticalMove();
diff --git a/src/com/android/launcher3/testing/TestInformationHandler.java b/src/com/android/launcher3/testing/TestInformationHandler.java
index d3c9bc9..269baf0 100644
--- a/src/com/android/launcher3/testing/TestInformationHandler.java
+++ b/src/com/android/launcher3/testing/TestInformationHandler.java
@@ -112,12 +112,12 @@
 
             case TestProtocol.REQUEST_APPS_LIST_SCROLL_Y: {
                 return getLauncherUIProperty(Bundle::putInt,
-                        l -> l.getAppsView().getActiveRecyclerView().getCurrentScrollY());
+                        l -> l.getAppsView().getActiveRecyclerView().computeVerticalScrollOffset());
             }
 
             case TestProtocol.REQUEST_WIDGETS_SCROLL_Y: {
                 return getLauncherUIProperty(Bundle::putInt,
-                        l -> WidgetsFullSheet.getWidgetsView(l).getCurrentScrollY());
+                        l -> WidgetsFullSheet.getWidgetsView(l).computeVerticalScrollOffset());
             }
 
             case TestProtocol.REQUEST_TARGET_INSETS: {
diff --git a/src/com/android/launcher3/util/ScrollableLayoutManager.java b/src/com/android/launcher3/util/ScrollableLayoutManager.java
new file mode 100644
index 0000000..17eaefd
--- /dev/null
+++ b/src/com/android/launcher3/util/ScrollableLayoutManager.java
@@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2022 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.util;
+
+import android.content.Context;
+import android.util.SparseIntArray;
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.GridLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.recyclerview.widget.RecyclerView.Adapter;
+import androidx.recyclerview.widget.RecyclerView.State;
+import androidx.recyclerview.widget.RecyclerView.ViewHolder;
+
+/**
+ * Extension of {@link GridLayoutManager} with support for smooth scrolling
+ */
+public class ScrollableLayoutManager extends GridLayoutManager {
+
+    // keyed on item type
+    protected final SparseIntArray mCachedSizes = new SparseIntArray();
+
+    private RecyclerView mRv;
+
+    /**
+     * Precalculated total height keyed on the item position. This is always incremental.
+     * Subclass can override {@link #incrementTotalHeight} to incorporate the layout logic.
+     * For example all-apps should have same values for items in same row,
+     *     sample values: 0, 10, 10, 10, 10, 20, 20, 20, 20
+     * whereas widgets will have strictly increasing values
+     *     sample values: 0, 10, 50, 60, 110
+     */
+
+    //
+    private int[] mTotalHeightCache = new int[1];
+    private int mLastValidHeightIndex = 0;
+
+    public ScrollableLayoutManager(Context context) {
+        super(context, 1, GridLayoutManager.VERTICAL, false);
+    }
+
+    @Override
+    public void onAttachedToWindow(RecyclerView view) {
+        super.onAttachedToWindow(view);
+        mRv = view;
+    }
+
+    @Override
+    public void layoutDecorated(@NonNull View child, int left, int top, int right, int bottom) {
+        super.layoutDecorated(child, left, top, right, bottom);
+        mCachedSizes.put(
+                mRv.getChildViewHolder(child).getItemViewType(), child.getMeasuredHeight());
+    }
+
+    @Override
+    public void layoutDecoratedWithMargins(@NonNull View child, int left, int top, int right,
+            int bottom) {
+        super.layoutDecoratedWithMargins(child, left, top, right, bottom);
+        mCachedSizes.put(
+                mRv.getChildViewHolder(child).getItemViewType(), child.getMeasuredHeight());
+    }
+
+    @Override
+    public int computeVerticalScrollExtent(State state) {
+        return mRv == null ? 0 : mRv.getHeight();
+    }
+
+    @Override
+    public int computeVerticalScrollOffset(State state) {
+        Adapter adapter = mRv == null ? null : mRv.getAdapter();
+        if (adapter == null) {
+            return 0;
+        }
+        if (adapter.getItemCount() == 0 || getChildCount() == 0) {
+            return 0;
+        }
+        View child = getChildAt(0);
+        ViewHolder holder = mRv.findContainingViewHolder(child);
+        if (holder == null) {
+            return 0;
+        }
+        int itemPosition = holder.getLayoutPosition();
+        if (itemPosition < 0) {
+            return 0;
+        }
+        return getPaddingTop() + getItemsHeight(adapter, itemPosition) - getDecoratedTop(child);
+    }
+
+    @Override
+    public int computeVerticalScrollRange(State state) {
+        Adapter adapter = mRv == null ? null : mRv.getAdapter();
+        return adapter == null ? 0 : getItemsHeight(adapter, adapter.getItemCount());
+    }
+
+    /**
+     * Returns the sum of the height, in pixels, of this list adapter's items from index
+     * 0 (inclusive) until {@code untilIndex} (exclusive). If untilIndex is same as the itemCount,
+     * it returns the full height of all the items.
+     *
+     * <p>If the untilIndex is larger than the total number of items in this adapter, returns the
+     * sum of all items' height.
+     */
+    private int getItemsHeight(Adapter adapter, int untilIndex) {
+        final int totalItems = adapter.getItemCount();
+        if (mTotalHeightCache.length < (totalItems + 1)) {
+            mTotalHeightCache = new int[totalItems + 1];
+            mLastValidHeightIndex = 0;
+        }
+        if (untilIndex > totalItems) {
+            untilIndex = totalItems;
+        } else if (untilIndex < 0) {
+            untilIndex = 0;
+        }
+        if (untilIndex <= mLastValidHeightIndex) {
+            return mTotalHeightCache[untilIndex];
+        }
+
+        int totalItemsHeight = mTotalHeightCache[mLastValidHeightIndex];
+        for (int i = mLastValidHeightIndex; i < untilIndex; i++) {
+            totalItemsHeight = incrementTotalHeight(adapter, i, totalItemsHeight);
+            mTotalHeightCache[i + 1] = totalItemsHeight;
+        }
+        mLastValidHeightIndex = untilIndex;
+        return totalItemsHeight;
+    }
+
+    /**
+     * The current implementation assumes a linear list with every item taking up the whole row.
+     * Subclasses should override this method to account for any spanning logic
+     */
+    protected int incrementTotalHeight(Adapter adapter, int position, int heightUntilLastPos) {
+        return heightUntilLastPos + mCachedSizes.get(adapter.getItemViewType(position));
+    }
+
+    private void invalidateScrollCache() {
+        mLastValidHeightIndex = 0;
+    }
+
+    @Override
+    public void onItemsAdded(RecyclerView recyclerView, int positionStart, int itemCount) {
+        super.onItemsAdded(recyclerView, positionStart, itemCount);
+        invalidateScrollCache();
+    }
+
+    @Override
+    public void onItemsChanged(RecyclerView recyclerView) {
+        super.onItemsChanged(recyclerView);
+        invalidateScrollCache();
+    }
+
+    @Override
+    public void onItemsRemoved(RecyclerView recyclerView, int positionStart, int itemCount) {
+        super.onItemsRemoved(recyclerView, positionStart, itemCount);
+        invalidateScrollCache();
+    }
+
+    @Override
+    public void onItemsMoved(RecyclerView recyclerView, int from, int to, int itemCount) {
+        super.onItemsMoved(recyclerView, from, to, itemCount);
+        invalidateScrollCache();
+    }
+
+    @Override
+    public void onItemsUpdated(RecyclerView recyclerView, int positionStart, int itemCount,
+            Object payload) {
+        super.onItemsUpdated(recyclerView, positionStart, itemCount, payload);
+        invalidateScrollCache();
+    }
+}
diff --git a/src/com/android/launcher3/views/RecyclerViewFastScroller.java b/src/com/android/launcher3/views/RecyclerViewFastScroller.java
index 40e4ce1..3af2e3c 100644
--- a/src/com/android/launcher3/views/RecyclerViewFastScroller.java
+++ b/src/com/android/launcher3/views/RecyclerViewFastScroller.java
@@ -119,7 +119,6 @@
     // prevent jumping, this offset is applied as the user scrolls.
     protected int mTouchOffsetY;
     protected int mThumbOffsetY;
-    protected int mRvOffsetY;
 
     // Fast scroller popup
     private TextView mPopupView;
@@ -207,16 +206,11 @@
 
     public void setThumbOffsetY(int y) {
         if (mThumbOffsetY == y) {
-            int rvCurrentOffsetY = mRv.getCurrentScrollY();
-            if (mRvOffsetY != rvCurrentOffsetY) {
-                mRvOffsetY = mRv.getCurrentScrollY();
-            }
             return;
         }
         updatePopupY(y);
         mThumbOffsetY = y;
         invalidate();
-        mRvOffsetY = mRv.getCurrentScrollY();
     }
 
     public int getThumbOffsetY() {
diff --git a/src/com/android/launcher3/widget/picker/WidgetsRecyclerView.java b/src/com/android/launcher3/widget/picker/WidgetsRecyclerView.java
index 35fa7a4..5969e3e 100644
--- a/src/com/android/launcher3/widget/picker/WidgetsRecyclerView.java
+++ b/src/com/android/launcher3/widget/picker/WidgetsRecyclerView.java
@@ -19,7 +19,6 @@
 import android.content.Context;
 import android.graphics.Point;
 import android.util.AttributeSet;
-import android.util.SparseIntArray;
 import android.view.MotionEvent;
 
 import androidx.recyclerview.widget.LinearLayoutManager;
@@ -28,6 +27,7 @@
 
 import com.android.launcher3.FastScrollRecyclerView;
 import com.android.launcher3.R;
+import com.android.launcher3.util.ScrollableLayoutManager;
 
 /**
  * The widgets recycler view.
@@ -42,14 +42,6 @@
     private boolean mTouchDownOnScroller;
     private HeaderViewDimensionsProvider mHeaderViewDimensionsProvider;
 
-    /**
-     * There is always 1 or 0 item of VIEW_TYPE_WIDGETS_LIST. Other types have fixes sizes, so the
-     * the size can be used for all other items of same type. Caching the last know size for
-     * VIEW_TYPE_WIDGETS_LIST allows us to use it to estimate full size even when
-     * VIEW_TYPE_WIDGETS_LIST is not visible on the screen.
-     */
-    private final SparseIntArray mCachedSizes = new SparseIntArray();
-
     public WidgetsRecyclerView(Context context) {
         this(context, null);
     }
@@ -68,9 +60,7 @@
     @Override
     protected void onFinishInflate() {
         super.onFinishInflate();
-        // create a layout manager with Launcher's context so that scroll position
-        // can be preserved during screen rotation.
-        setLayoutManager(new LinearLayoutManager(getContext()));
+        setLayoutManager(new ScrollableLayoutManager(getContext()));
     }
 
     @Override
@@ -114,7 +104,7 @@
         }
 
         // Skip early if, there no child laid out in the container.
-        int scrollY = getCurrentScrollY();
+        int scrollY = computeVerticalScrollOffset();
         if (scrollY < 0) {
             mScrollbar.setThumbOffsetY(-1);
             return;
@@ -164,39 +154,6 @@
     }
 
     /**
-     * Returns the sum of the height, in pixels, of this list adapter's items from index 0 until
-     * {@code untilIndex}.
-     *
-     * <p>If the untilIndex is larger than the total number of items in this adapter, returns the
-     * sum of all items' height.
-     */
-    @Override
-    protected int getItemsHeight(int untilIndex) {
-        // Initialize cache
-        int childCount = getChildCount();
-        int startPosition;
-        if (childCount > 0
-                && ((startPosition = getChildAdapterPosition(getChildAt(0))) != NO_POSITION)) {
-            int loopCount = Math.min(getChildCount(), getAdapter().getItemCount() - startPosition);
-            for (int i = 0; i < loopCount; i++) {
-                mCachedSizes.put(
-                        mAdapter.getItemViewType(startPosition + i),
-                        getChildAt(i).getMeasuredHeight());
-            }
-        }
-
-        if (untilIndex > mAdapter.getItems().size()) {
-            untilIndex = mAdapter.getItems().size();
-        }
-        int totalItemsHeight = 0;
-        for (int i = 0; i < untilIndex; i++) {
-            int type = mAdapter.getItemViewType(i);
-            totalItemsHeight += mCachedSizes.get(type);
-        }
-        return totalItemsHeight;
-    }
-
-    /**
      * Provides dimensions of the header view that is shown at the top of a
      * {@link WidgetsRecyclerView}.
      */