Merge "Updating fast scrollbar UI in Landscape" into ub-launcher3-dorval-polish

9 files changed, 253 insertions, 228 deletions

diff --git a/src/com/android/launcher3/BaseRecyclerView.java b/src/com/android/launcher3/BaseRecyclerView.java
index 84358ea37..3ee6e51b8 100644
--- a/src/com/android/launcher3/BaseRecyclerView.java
+++ b/src/com/android/launcher3/BaseRecyclerView.java
@@ -22,8 +22,9 @@ import android.support.v7.widget.RecyclerView;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.ViewGroup;
+import android.widget.TextView;
 
-import com.android.launcher3.util.Thunk;
+import com.android.launcher3.views.RecyclerViewFastScroller;
 
 
 /**
@@ -36,19 +37,7 @@ import com.android.launcher3.util.Thunk;
 public abstract class BaseRecyclerView extends RecyclerView
         implements RecyclerView.OnItemTouchListener {
 
-    private static final int SCROLL_DELTA_THRESHOLD_DP = 4;
-
-    /** Keeps the last known scrolling delta/velocity along y-axis. */
-    @Thunk int mDy = 0;
-    private float mDeltaThreshold;
-
-    protected final BaseRecyclerViewFastScrollBar mScrollbar;
-
-    private int mDownX;
-    private int mDownY;
-    private int mLastY;
-
-    private boolean mScrollBarVisible = true;
+    protected RecyclerViewFastScroller mScrollbar;
 
     public BaseRecyclerView(Context context) {
         this(context, null);
@@ -60,28 +49,6 @@ public abstract class BaseRecyclerView extends RecyclerView
 
     public BaseRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
-        mDeltaThreshold = getResources().getDisplayMetrics().density * SCROLL_DELTA_THRESHOLD_DP;
-        mScrollbar = new BaseRecyclerViewFastScrollBar(this, getResources());
-
-        ScrollListener listener = new ScrollListener();
-        setOnScrollListener(listener);
-    }
-
-    private class ScrollListener extends OnScrollListener {
-        public ScrollListener() {
-            // Do nothing
-        }
-
-        @Override
-        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
-            mDy = dy;
-
-            // TODO(winsonc): If we want to animate the section heads while scrolling, we can
-            //                initiate that here if the recycler view scroll state is not
-            //                RecyclerView.SCROLL_STATE_IDLE.
-
-            onUpdateScrollbar(dy);
-        }
     }
 
     @Override
@@ -93,7 +60,9 @@ public abstract class BaseRecyclerView extends RecyclerView
     @Override
     protected void onAttachedToWindow() {
         super.onAttachedToWindow();
-        mScrollbar.setPopupView(((ViewGroup) getParent()).findViewById(R.id.fast_scroller_popup));
+        ViewGroup parent = (ViewGroup) getParent();
+        mScrollbar = parent.findViewById(R.id.fast_scroller);
+        mScrollbar.setRecyclerView(this, (TextView) parent.findViewById(R.id.fast_scroller_popup));
     }
 
     /**
@@ -115,32 +84,15 @@ public abstract class BaseRecyclerView extends RecyclerView
      * it is already showing).
      */
     private boolean handleTouchEvent(MotionEvent ev) {
-        ev.offsetLocation(0, -getPaddingTop());
-        int action = ev.getAction();
-        int x = (int) ev.getX();
-        int y = (int) ev.getY();
-        switch (action) {
-            case MotionEvent.ACTION_DOWN:
-                // Keep track of the down positions
-                mDownX = x;
-                mDownY = mLastY = y;
-                if (shouldStopScroll(ev)) {
-                    stopScroll();
-                }
-                mScrollbar.handleTouchEvent(ev, mDownX, mDownY, mLastY);
-                break;
-            case MotionEvent.ACTION_MOVE:
-                mLastY = y;
-                mScrollbar.handleTouchEvent(ev, mDownX, mDownY, mLastY);
-                break;
-            case MotionEvent.ACTION_UP:
-            case MotionEvent.ACTION_CANCEL:
-                onFastScrollCompleted();
-                mScrollbar.handleTouchEvent(ev, mDownX, mDownY, mLastY);
-                break;
+        // Move to mScrollbar's coordinate system.
+        int left = getLeft() - mScrollbar.getLeft();
+        int top = getTop() - mScrollbar.getTop();
+        ev.offsetLocation(left, top);
+        try {
+            return mScrollbar.handleTouchEvent(ev);
+        } finally {
+            ev.offsetLocation(-left, -top);
         }
-        ev.offsetLocation(0, getPaddingTop());
-        return mScrollbar.isDraggingThumb();
     }
 
     public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
@@ -148,24 +100,9 @@ public abstract class BaseRecyclerView extends RecyclerView
     }
 
     /**
-     * Returns whether this {@link MotionEvent} should trigger the scroll to be stopped.
-     */
-    protected boolean shouldStopScroll(MotionEvent ev) {
-        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
-            if ((Math.abs(mDy) < mDeltaThreshold &&
-                    getScrollState() != RecyclerView.SCROLL_STATE_IDLE)) {
-                // now the touch events are being passed to the {@link WidgetCell} until the
-                // touch sequence goes over the touch slop.
-                return true;
-            }
-        }
-        return false;
-    }
-
-    /**
      * Returns the height of the fast scroll bar
      */
-    protected int getScrollbarTrackHeight() {
+    public int getScrollbarTrackHeight() {
         return getHeight() - getPaddingTop() - getPaddingBottom();
     }
 
@@ -187,25 +124,14 @@ public abstract class BaseRecyclerView extends RecyclerView
     /**
      * Returns the scrollbar for this recycler view.
      */
-    public BaseRecyclerViewFastScrollBar getScrollBar() {
+    public RecyclerViewFastScroller getScrollBar() {
         return mScrollbar;
     }
 
     @Override
     protected void dispatchDraw(Canvas canvas) {
+        onUpdateScrollbar(0);
         super.dispatchDraw(canvas);
-        if (mScrollBarVisible) {
-            onUpdateScrollbar(0);
-            mScrollbar.draw(canvas);
-        }
-    }
-
-    /**
-     * Sets the scrollbar visibility. The call does not refresh the UI, its the responsibility
-     * of the caller to call {@link #invalidate()}.
-     */
-    public void setScrollBarVisible(boolean visible) {
-        mScrollBarVisible = visible;
     }
 
     /**
@@ -236,7 +162,7 @@ public abstract class BaseRecyclerView extends RecyclerView
     /**
      * @return whether fast scrolling is supported in the current state.
      */
-    protected boolean supportsFastScrolling() {
+    public boolean supportsFastScrolling() {
         return true;
     }
 
@@ -252,16 +178,16 @@ 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.
      */
-    protected abstract String scrollToPositionAtProgress(float touchFraction);
+    public abstract String scrollToPositionAtProgress(float touchFraction);
 
     /**
      * Updates the bounds for the scrollbar.
      * <p>Override in each subclass of this base class.
      */
-    protected abstract void onUpdateScrollbar(int dy);
+    public abstract void onUpdateScrollbar(int dy);
 
     /**
      * <p>Override in each subclass of this base class.
      */
-    protected void onFastScrollCompleted() {}
+    public void onFastScrollCompleted() {}
 }
\ No newline at end of file
diff --git a/src/com/android/launcher3/allapps/AllAppsContainerView.java b/src/com/android/launcher3/allapps/AllAppsContainerView.java
index 4954e0c44..47b68a2ee 100644
--- a/src/com/android/launcher3/allapps/AllAppsContainerView.java
+++ b/src/com/android/launcher3/allapps/AllAppsContainerView.java
@@ -171,19 +171,19 @@ public class AllAppsContainerView extends BaseContainerView implements DragSourc
      * Returns whether the view itself will handle the touch event or not.
      */
     public boolean shouldContainerScroll(MotionEvent ev) {
-        int[] point = new int[2];
-        point[0] = (int) ev.getX();
-        point[1] = (int) ev.getY();
-        Utilities.mapCoordInSelfToDescendant(mAppsRecyclerView, this, point);
-
         // IF the MotionEvent is inside the search box, and the container keeps on receiving
         // touch input, container should move down.
         if (mLauncher.getDragLayer().isEventOverView(mSearchContainer, ev)) {
             return true;
         }
 
+        int[] point = new int[2];
+        point[0] = (int) ev.getX();
+        point[1] = (int) ev.getY();
+        Utilities.mapCoordInSelfToDescendant(
+                mAppsRecyclerView.getScrollBar(), mLauncher.getDragLayer(), point);
         // IF the MotionEvent is inside the thumb, container should not be pulled down.
-        if (mAppsRecyclerView.getScrollBar().isNearThumb(point[0], point[1])) {
+        if (mAppsRecyclerView.getScrollBar().shouldBlockIntercept(point[0], point[1])) {
             return false;
         }
 
diff --git a/src/com/android/launcher3/allapps/AllAppsGridAdapter.java b/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
index d6514a83f..1054a5633 100644
--- a/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
+++ b/src/com/android/launcher3/allapps/AllAppsGridAdapter.java
@@ -69,16 +69,13 @@ public class AllAppsGridAdapter extends RecyclerView.Adapter<AllAppsGridAdapter.
 
     // A divider that separates the apps list and the search market button
     public static final int VIEW_TYPE_SEARCH_MARKET_DIVIDER = 1 << 5;
-    // The divider under the search field
-    public static final int VIEW_TYPE_SEARCH_DIVIDER = 1 << 6;
     // The divider that separates prediction icons from the app list
-    public static final int VIEW_TYPE_PREDICTION_DIVIDER = 1 << 7;
-    public static final int VIEW_TYPE_APPS_LOADING_DIVIDER = 1 << 8;
-    public static final int VIEW_TYPE_DISCOVERY_ITEM = 1 << 9;
+    public static final int VIEW_TYPE_PREDICTION_DIVIDER = 1 << 6;
+    public static final int VIEW_TYPE_APPS_LOADING_DIVIDER = 1 << 7;
+    public static final int VIEW_TYPE_DISCOVERY_ITEM = 1 << 8;
 
     // Common view type masks
-    public static final int VIEW_TYPE_MASK_DIVIDER = VIEW_TYPE_SEARCH_DIVIDER
-            | VIEW_TYPE_SEARCH_MARKET_DIVIDER
+    public static final int VIEW_TYPE_MASK_DIVIDER = VIEW_TYPE_SEARCH_MARKET_DIVIDER
             | VIEW_TYPE_PREDICTION_DIVIDER;
     public static final int VIEW_TYPE_MASK_ICON = VIEW_TYPE_ICON
             | VIEW_TYPE_PREDICTION_ICON;
@@ -319,9 +316,6 @@ public class AllAppsGridAdapter extends RecyclerView.Adapter<AllAppsGridAdapter.
                     }
                 });
                 return new ViewHolder(searchMarketView);
-            case VIEW_TYPE_SEARCH_DIVIDER:
-                return new ViewHolder(mLayoutInflater.inflate(
-                        R.layout.all_apps_search_divider, parent, false));
             case VIEW_TYPE_APPS_LOADING_DIVIDER:
                 View loadingDividerView = mLayoutInflater.inflate(
                         R.layout.all_apps_discovery_loading_divider, parent, false);
diff --git a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
index 0607a1e5d..2b2fddcdd 100644
--- a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
+++ b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
@@ -72,7 +72,6 @@ public class AllAppsRecyclerView extends BaseRecyclerView {
         super(context, attrs, defStyleAttr);
         Resources res = getResources();
         addOnItemTouchListener(this);
-        mScrollbar.setDetachThumbOnFastScroll();
         mEmptySearchBackgroundTopOffset = res.getDimensionPixelSize(
                 R.dimen.all_apps_empty_search_bg_top_offset);
     }
@@ -110,7 +109,6 @@ public class AllAppsRecyclerView extends BaseRecyclerView {
         RecyclerView.RecycledViewPool pool = getRecycledViewPool();
         int approxRows = (int) Math.ceil(grid.availableHeightPx / grid.allAppsIconSizePx);
         pool.setMaxRecycledViews(AllAppsGridAdapter.VIEW_TYPE_EMPTY_SEARCH, 1);
-        pool.setMaxRecycledViews(AllAppsGridAdapter.VIEW_TYPE_SEARCH_DIVIDER, 1);
         pool.setMaxRecycledViews(AllAppsGridAdapter.VIEW_TYPE_SEARCH_MARKET_DIVIDER, 1);
         pool.setMaxRecycledViews(AllAppsGridAdapter.VIEW_TYPE_SEARCH_MARKET, 1);
         pool.setMaxRecycledViews(AllAppsGridAdapter.VIEW_TYPE_ICON, approxRows * mNumAppsPerRow);
@@ -137,8 +135,6 @@ public class AllAppsRecyclerView extends BaseRecyclerView {
                 AllAppsGridAdapter.VIEW_TYPE_PREDICTION_DIVIDER,
                 AllAppsGridAdapter.VIEW_TYPE_SEARCH_MARKET_DIVIDER);
         putSameHeightFor(adapter, widthMeasureSpec, heightMeasureSpec,
-                AllAppsGridAdapter.VIEW_TYPE_SEARCH_DIVIDER);
-        putSameHeightFor(adapter, widthMeasureSpec, heightMeasureSpec,
                 AllAppsGridAdapter.VIEW_TYPE_SEARCH_MARKET);
         putSameHeightFor(adapter, widthMeasureSpec, heightMeasureSpec,
                 AllAppsGridAdapter.VIEW_TYPE_EMPTY_SEARCH);
@@ -164,7 +160,9 @@ public class AllAppsRecyclerView extends BaseRecyclerView {
      */
     public void scrollToTop() {
         // Ensure we reattach the scrollbar if it was previously detached while fast-scrolling
-        mScrollbar.reattachThumbToScroll();
+        if (mScrollbar != null) {
+            mScrollbar.reattachThumbToScroll();
+        }
         scrollToPosition(0);
     }
 
@@ -356,7 +354,7 @@ public class AllAppsRecyclerView extends BaseRecyclerView {
     }
 
     @Override
-    protected boolean supportsFastScrolling() {
+    public boolean supportsFastScrolling() {
         // Only allow fast scrolling when the user is not searching, since the results are not
         // grouped in a meaningful order
         return !mApps.hasFilter();
diff --git a/src/com/android/launcher3/allapps/AlphabeticalAppsList.java b/src/com/android/launcher3/allapps/AlphabeticalAppsList.java
index 7bf66510a..608e898ae 100644
--- a/src/com/android/launcher3/allapps/AlphabeticalAppsList.java
+++ b/src/com/android/launcher3/allapps/AlphabeticalAppsList.java
@@ -138,13 +138,6 @@ public class AlphabeticalAppsList {
             return item;
         }
 
-        public static AdapterItem asSearchDivider(int pos) {
-            AdapterItem item = new AdapterItem();
-            item.viewType = AllAppsGridAdapter.VIEW_TYPE_SEARCH_DIVIDER;
-            item.position = pos;
-            return item;
-        }
-
         public static AdapterItem asMarketDivider(int pos) {
             AdapterItem item = new AdapterItem();
             item.viewType = AllAppsGridAdapter.VIEW_TYPE_SEARCH_MARKET_DIVIDER;
@@ -195,8 +188,6 @@ public class AlphabeticalAppsList {
     private int mNumPredictedAppsPerRow;
     private int mNumAppRowsInAdapter;
 
-    private boolean mHasSearchDivider = true;
-
     public AlphabeticalAppsList(Context context) {
         mLauncher = Launcher.getLauncher(context);
         mIndexer = new AlphabeticIndexCompat(context);
@@ -352,10 +343,6 @@ public class AlphabeticalAppsList {
         onAppsUpdated();
     }
 
-    public void disableSearchDivider() {
-        mHasSearchDivider = false;
-    }
-
     /**
      * Updates internals when the set of apps are updated.
      */
@@ -442,11 +429,6 @@ public class AlphabeticalAppsList {
             }
         }
 
-        if (mHasSearchDivider) {
-            // Add the search divider
-            mAdapterItems.add(AdapterItem.asSearchDivider(position++));
-        }
-
         // Process the predicted app components
         mPredictedApps.clear();
         if (mPredictedAppComponents != null && !mPredictedAppComponents.isEmpty() && !hasFilter()) {
diff --git a/src/com/android/launcher3/allapps/LandscapeFastScroller.java b/src/com/android/launcher3/allapps/LandscapeFastScroller.java
new file mode 100644
index 000000000..cdde65760
--- /dev/null
+++ b/src/com/android/launcher3/allapps/LandscapeFastScroller.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2017 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.content.Context;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+
+import com.android.launcher3.views.RecyclerViewFastScroller;
+
+/**
+ * Extension of {@link RecyclerViewFastScroller} to be used in landscape layout.
+ */
+public class LandscapeFastScroller extends RecyclerViewFastScroller {
+
+    public LandscapeFastScroller(Context context) {
+        super(context);
+    }
+
+    public LandscapeFastScroller(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public LandscapeFastScroller(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    @Override
+    public boolean handleTouchEvent(MotionEvent ev) {
+        // We handle our own touch event, no need to handle recycler view touch delegates.
+        return false;
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        event.offsetLocation(0, -mRv.getPaddingTop());
+        if (super.handleTouchEvent(event)) {
+            getParent().requestDisallowInterceptTouchEvent(true);
+        }
+        event.offsetLocation(0, mRv.getPaddingTop());
+        return true;
+    }
+
+    @Override
+    public boolean shouldBlockIntercept(int x, int y) {
+        // If the user touched the scroll bar area, block swipe
+        return x >= 0 && x < getWidth() && y >= 0 && y < getHeight();
+    }
+}
diff --git a/src/com/android/launcher3/allapps/search/AppsSearchContainerLayout.java b/src/com/android/launcher3/allapps/search/AppsSearchContainerLayout.java
index 3f06ec9dd..5cb12d592 100644
--- a/src/com/android/launcher3/allapps/search/AppsSearchContainerLayout.java
+++ b/src/com/android/launcher3/allapps/search/AppsSearchContainerLayout.java
@@ -54,12 +54,13 @@ public class AppsSearchContainerLayout extends FrameLayout
     private final int mSearchBoxHeight;
     private final AllAppsSearchBarController mSearchBarController;
     private final SpannableStringBuilder mSearchQueryBuilder;
-    private final HeaderElevationController mElevationController;
 
     private ExtendedEditText mSearchInput;
     private AlphabeticalAppsList mApps;
     private AllAppsRecyclerView mAppsRecyclerView;
     private AllAppsGridAdapter mAdapter;
+    private View mDivider;
+    private HeaderElevationController mElevationController;
 
     public AppsSearchContainerLayout(Context context) {
         this(context, null);
@@ -77,7 +78,6 @@ public class AppsSearchContainerLayout extends FrameLayout
         mSearchBoxHeight = getResources()
                 .getDimensionPixelSize(R.dimen.all_apps_search_bar_field_height);
         mSearchBarController = new AllAppsSearchBarController();
-        mElevationController = new HeaderElevationController(this);
 
         mSearchQueryBuilder = new SpannableStringBuilder();
         Selection.setSelection(mSearchQueryBuilder, 0);
@@ -87,6 +87,8 @@ public class AppsSearchContainerLayout extends FrameLayout
     protected void onFinishInflate() {
         super.onFinishInflate();
         mSearchInput = findViewById(R.id.search_box_input);
+        mDivider = findViewById(R.id.search_divider);
+        mElevationController = new HeaderElevationController(mDivider);
 
         // Update the hint to contain the icon.
         // Prefix the original hint with two spaces. The first space gets replaced by the icon
@@ -96,6 +98,12 @@ public class AppsSearchContainerLayout extends FrameLayout
         spanned.setSpan(new TintedDrawableSpan(getContext(), R.drawable.ic_allapps_search),
                 0, 1, Spannable.SPAN_EXCLUSIVE_INCLUSIVE);
         mSearchInput.setHint(spanned);
+
+        DeviceProfile dp = mLauncher.getDeviceProfile();
+        if (!dp.isVerticalBarLayout()) {
+            LayoutParams lp = (LayoutParams) mDivider.getLayoutParams();
+            lp.leftMargin = lp.rightMargin = dp.edgeMarginPx;
+        }
     }
 
     @Override
diff --git a/src/com/android/launcher3/allapps/search/HeaderElevationController.java b/src/com/android/launcher3/allapps/search/HeaderElevationController.java
index ab4e88fc8..7cd32b26e 100644
--- a/src/com/android/launcher3/allapps/search/HeaderElevationController.java
+++ b/src/com/android/launcher3/allapps/search/HeaderElevationController.java
@@ -4,11 +4,11 @@ import android.content.res.Resources;
 import android.graphics.Outline;
 import android.support.v7.widget.RecyclerView;
 import android.view.View;
+import android.view.ViewGroup;
 import android.view.ViewOutlineProvider;
 
 import com.android.launcher3.BaseRecyclerView;
 import com.android.launcher3.R;
-import com.android.launcher3.Utilities;
 
 /**
  * Helper class for controlling the header elevation in response to RecyclerView scroll.
@@ -16,6 +16,7 @@ import com.android.launcher3.Utilities;
 public class HeaderElevationController extends RecyclerView.OnScrollListener {
 
     private final View mHeader;
+    private final View mHeaderChild;
     private final float mMaxElevation;
     private final float mScrollToElevation;
 
@@ -28,23 +29,27 @@ public class HeaderElevationController extends RecyclerView.OnScrollListener {
         mScrollToElevation = res.getDimension(R.dimen.all_apps_header_scroll_to_elevation);
 
         // We need to provide a custom outline so the shadow only appears on the bottom edge.
-        // The top, left and right edges are all extended out, and the shadow is clipped
-        // by the parent.
+        // The top, left and right edges are all extended out to match parent's edge, so that
+        // the shadow is clipped by the parent.
         final ViewOutlineProvider vop = new ViewOutlineProvider() {
             @Override
             public void getOutline(View view, Outline outline) {
-                final View parent = (View) mHeader.getParent();
+                // Set the left and top to be at the parents edge. Since the coordinates are
+                // relative to this view,
+                //    (x = -view.getLeft()) for this view => (x = 0) for parent
+                final int left = -view.getLeft();
+                final int top = -view.getTop();
 
-                final int left = parent.getLeft(); // Use the parent to account for offsets
-                final int top = view.getTop();
-                final int right = left + view.getWidth();
-                final int bottom = view.getBottom();
-
-                final int offset = Utilities.pxFromDp(mMaxElevation, res.getDisplayMetrics());
+                // Since the view is centered align, the spacing on left and right are same.
+                // Add same spacing on the right to reach parent's edge.
+                final int right = view.getWidth() - left;
+                final int bottom = view.getHeight();
+                final int offset = (int) mMaxElevation;
                 outline.setRect(left - offset, top - offset, right + offset, bottom);
             }
         };
         mHeader.setOutlineProvider(vop);
+        mHeaderChild = ((ViewGroup) mHeader).getChildAt(0);
     }
 
     public void reset() {
@@ -63,6 +68,13 @@ public class HeaderElevationController extends RecyclerView.OnScrollListener {
         float newElevation = mMaxElevation * elevationPct;
         if (Float.compare(mHeader.getElevation(), newElevation) != 0) {
             mHeader.setElevation(newElevation);
+
+            // To simulate a scrolling effect for the header, we translate the header down, and
+            // its content up by the same amount, so that it gets clipped by the parent, making it
+            // look like the content was scrolled out of the view.
+            int shift = Math.min(mHeader.getHeight(), scrollY);
+            mHeader.setTranslationY(-shift);
+            mHeaderChild.setTranslationY(shift);
         }
     }
 
diff --git a/src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java b/src/com/android/launcher3/views/RecyclerViewFastScroller.java
index 9e8d300ae..7b5bcdbd4 100644
--- a/src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java
+++ b/src/com/android/launcher3/views/RecyclerViewFastScroller.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2015 The Android Open Source Project
+ * Copyright (C) 2017 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.
@@ -13,21 +13,26 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.android.launcher3;
+
+package com.android.launcher3.views;
 
 import android.animation.ObjectAnimator;
+import android.content.Context;
 import android.content.res.Resources;
+import android.content.res.TypedArray;
 import android.graphics.Canvas;
-import android.graphics.Color;
 import android.graphics.Paint;
-import android.graphics.Path;
-import android.graphics.Rect;
+import android.support.v7.widget.RecyclerView;
+import android.util.AttributeSet;
 import android.util.Property;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewConfiguration;
 import android.widget.TextView;
 
+import com.android.launcher3.BaseRecyclerView;
+import com.android.launcher3.R;
+import com.android.launcher3.Utilities;
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.graphics.FastScrollThumbDrawable;
 import com.android.launcher3.util.Themes;
@@ -35,18 +40,20 @@ import com.android.launcher3.util.Themes;
 /**
  * The track and scrollbar that shows when you scroll the list.
  */
-public class BaseRecyclerViewFastScrollBar {
+public class RecyclerViewFastScroller extends View {
+
+    private static final int SCROLL_DELTA_THRESHOLD_DP = 4;
 
-    private static final Property<BaseRecyclerViewFastScrollBar, Integer> TRACK_WIDTH =
-            new Property<BaseRecyclerViewFastScrollBar, Integer>(Integer.class, "width") {
+    private static final Property<RecyclerViewFastScroller, Integer> TRACK_WIDTH =
+            new Property<RecyclerViewFastScroller, Integer>(Integer.class, "width") {
 
                 @Override
-                public Integer get(BaseRecyclerViewFastScrollBar scrollBar) {
+                public Integer get(RecyclerViewFastScroller scrollBar) {
                     return scrollBar.mWidth;
                 }
 
                 @Override
-                public void set(BaseRecyclerViewFastScrollBar scrollBar, Integer value) {
+                public void set(RecyclerViewFastScroller scrollBar, Integer value) {
                     scrollBar.setTrackWidth(value);
                 }
             };
@@ -55,93 +62,113 @@ public class BaseRecyclerViewFastScrollBar {
     private final static int SCROLL_BAR_VIS_DURATION = 150;
     private static final float FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR = 0.75f;
 
-    private final Rect mTmpRect = new Rect();
-    private final BaseRecyclerView mRv;
-
-    private final boolean mIsRtl;
-
-    // The inset is the buffer around which a point will still register as a click on the scrollbar
-    private final int mTouchInset;
-
     private final int mMinWidth;
     private final int mMaxWidth;
     private final int mThumbPadding;
 
+    /** Keeps the last known scrolling delta/velocity along y-axis. */
+    private int mDy = 0;
+    private final float mDeltaThreshold;
+
+    private final ViewConfiguration mConfig;
+
     // Current width of the track
     private int mWidth;
     private ObjectAnimator mWidthAnimator;
 
     private final Paint mThumbPaint;
-    private final int mThumbHeight;
+    protected final int mThumbHeight;
 
     private final Paint mTrackPaint;
 
     private float mLastTouchY;
     private boolean mIsDragging;
     private boolean mIsThumbDetached;
-    private boolean mCanThumbDetach;
+    private final boolean mCanThumbDetach;
     private boolean mIgnoreDragGesture;
 
     // This is the offset from the top of the scrollbar when the user first starts touching.  To
     // prevent jumping, this offset is applied as the user scrolls.
-    private int mTouchOffsetY;
-    private int mThumbOffsetY;
+    protected int mTouchOffsetY;
+    protected int mThumbOffsetY;
 
     // Fast scroller popup
     private TextView mPopupView;
     private boolean mPopupVisible;
     private String mPopupSectionName;
 
-    public BaseRecyclerViewFastScrollBar(BaseRecyclerView rv, Resources res) {
-        mRv = rv;
+    protected BaseRecyclerView mRv;
+
+    private int mDownX;
+    private int mDownY;
+    private int mLastY;
+
+    public RecyclerViewFastScroller(Context context) {
+        this(context, null);
+    }
+
+    public RecyclerViewFastScroller(Context context, AttributeSet attrs) {
+        this(context, attrs, 0);
+    }
+
+    public RecyclerViewFastScroller(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+
         mTrackPaint = new Paint();
-        mTrackPaint.setColor(Themes.getAttrColor(rv.getContext(), android.R.attr.textColorPrimary));
+        mTrackPaint.setColor(Themes.getAttrColor(context, android.R.attr.textColorPrimary));
         mTrackPaint.setAlpha(MAX_TRACK_ALPHA);
 
         mThumbPaint = new Paint();
         mThumbPaint.setAntiAlias(true);
-        mThumbPaint.setColor(Themes.getColorAccent(rv.getContext()));
+        mThumbPaint.setColor(Themes.getColorAccent(context));
         mThumbPaint.setStyle(Paint.Style.FILL);
 
+        Resources res = getResources();
         mWidth = mMinWidth = res.getDimensionPixelSize(R.dimen.fastscroll_track_min_width);
         mMaxWidth = res.getDimensionPixelSize(R.dimen.fastscroll_track_max_width);
 
         mThumbPadding = res.getDimensionPixelSize(R.dimen.fastscroll_thumb_padding);
         mThumbHeight = res.getDimensionPixelSize(R.dimen.fastscroll_thumb_height);
 
-        mTouchInset = res.getDimensionPixelSize(R.dimen.fastscroll_thumb_touch_inset);
-        mIsRtl = Utilities.isRtl(res);
-    }
+        mConfig = ViewConfiguration.get(context);
+        mDeltaThreshold = res.getDisplayMetrics().density * SCROLL_DELTA_THRESHOLD_DP;
 
-    public void setPopupView(View popup) {
-        mPopupView = (TextView) popup;
-        mPopupView.setBackground(new FastScrollThumbDrawable(mThumbPaint, mIsRtl));
+        TypedArray ta =
+                context.obtainStyledAttributes(attrs, R.styleable.RecyclerViewFastScroller, defStyleAttr, 0);
+        mCanThumbDetach = ta.getBoolean(R.styleable.RecyclerViewFastScroller_canThumbDetach, false);
+        ta.recycle();
     }
 
-    public void setDetachThumbOnFastScroll() {
-        mCanThumbDetach = true;
+    public void setRecyclerView(BaseRecyclerView rv, TextView popupView) {
+        mRv = rv;
+        mRv.addOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
+                mDy = dy;
+
+                // TODO(winsonc): If we want to animate the section heads while scrolling, we can
+                //                initiate that here if the recycler view scroll state is not
+                //                RecyclerView.SCROLL_STATE_IDLE.
+
+                mRv.onUpdateScrollbar(dy);
+            }
+        });
+
+        mPopupView = popupView;
+        mPopupView.setBackground(
+                new FastScrollThumbDrawable(mThumbPaint, Utilities.isRtl(getResources())));
     }
 
     public void reattachThumbToScroll() {
         mIsThumbDetached = false;
     }
 
-    private int getDrawLeft() {
-        return mIsRtl ? 0 : (mRv.getWidth() - mMaxWidth);
-    }
-
     public void setThumbOffsetY(int y) {
         if (mThumbOffsetY == y) {
             return;
         }
-
-        // Invalidate the previous and new thumb area
-        int drawLeft = getDrawLeft();
-        mTmpRect.set(drawLeft, mThumbOffsetY, drawLeft + mMaxWidth, mThumbOffsetY + mThumbHeight);
         mThumbOffsetY = y;
-        mTmpRect.union(drawLeft, mThumbOffsetY, drawLeft + mMaxWidth, mThumbOffsetY + mThumbHeight);
-        mTmpRect.offset(0, mRv.getPaddingTop());
-        mRv.invalidate(mTmpRect);
+        invalidate();
     }
 
     public int getThumbOffsetY() {
@@ -152,12 +179,8 @@ public class BaseRecyclerViewFastScrollBar {
         if (mWidth == width) {
             return;
         }
-        int left = getDrawLeft();
-        int top = mRv.getPaddingTop();
-        // Invalidate the whole scroll bar area.
-        mRv.invalidate(left, top, left + mMaxWidth, top + mRv.getScrollbarTrackHeight());
-
         mWidth = width;
+        invalidate();
     }
 
     public int getThumbHeight() {
@@ -176,37 +199,48 @@ public class BaseRecyclerViewFastScrollBar {
      * Handles the touch event and determines whether to show the fast scroller (or updates it if
      * it is already showing).
      */
-    public void handleTouchEvent(MotionEvent ev, int downX, int downY, int lastY) {
-        ViewConfiguration config = ViewConfiguration.get(mRv.getContext());
-
-        int action = ev.getAction();
+    public boolean handleTouchEvent(MotionEvent ev) {
+        int x = (int) ev.getX();
         int y = (int) ev.getY();
-        switch (action) {
+        switch (ev.getAction()) {
             case MotionEvent.ACTION_DOWN:
-                if (isNearThumb(downX, downY)) {
-                    mTouchOffsetY = downY - mThumbOffsetY;
+                // Keep track of the down positions
+                mDownX = x;
+                mDownY = mLastY = y;
+
+                if ((Math.abs(mDy) < mDeltaThreshold &&
+                        mRv.getScrollState() != RecyclerView.SCROLL_STATE_IDLE)) {
+                    // now the touch events are being passed to the {@link WidgetCell} until the
+                    // touch sequence goes over the touch slop.
+                    mRv.stopScroll();
+                }
+                if (isNearThumb(x, y)) {
+                    mTouchOffsetY = mDownY - mThumbOffsetY;
                 } else if (FeatureFlags.LAUNCHER3_DIRECT_SCROLL
                         && mRv.supportsFastScrolling()
-                        && isNearScrollBar(downX)) {
-                    calcTouchOffsetAndPrepToFastScroll(downY, lastY);
-                    updateFastScrollSectionNameAndThumbOffset(lastY, y);
+                        && isNearScrollBar(mDownX)) {
+                    calcTouchOffsetAndPrepToFastScroll(mDownY, mLastY);
+                    updateFastScrollSectionNameAndThumbOffset(mLastY, y);
                 }
                 break;
             case MotionEvent.ACTION_MOVE:
+                mLastY = y;
+
                 // Check if we should start scrolling, but ignore this fastscroll gesture if we have
                 // exceeded some fixed movement
-                mIgnoreDragGesture |= Math.abs(y - downY) > config.getScaledPagingTouchSlop();
+                mIgnoreDragGesture |= Math.abs(y - mDownY) > mConfig.getScaledPagingTouchSlop();
                 if (!mIsDragging && !mIgnoreDragGesture && mRv.supportsFastScrolling() &&
-                        isNearThumb(downX, lastY) &&
-                        Math.abs(y - downY) > config.getScaledTouchSlop()) {
-                    calcTouchOffsetAndPrepToFastScroll(downY, lastY);
+                        isNearThumb(mDownX, mLastY) &&
+                        Math.abs(y - mDownY) > mConfig.getScaledTouchSlop()) {
+                    calcTouchOffsetAndPrepToFastScroll(mDownY, mLastY);
                 }
                 if (mIsDragging) {
-                    updateFastScrollSectionNameAndThumbOffset(lastY, y);
+                    updateFastScrollSectionNameAndThumbOffset(mLastY, y);
                 }
                 break;
             case MotionEvent.ACTION_UP:
             case MotionEvent.ACTION_CANCEL:
+                mRv.onFastScrollCompleted();
                 mTouchOffsetY = 0;
                 mLastTouchY = 0;
                 mIgnoreDragGesture = false;
@@ -217,6 +251,7 @@ public class BaseRecyclerViewFastScrollBar {
                 }
                 break;
         }
+        return mIsDragging;
     }
 
     private void calcTouchOffsetAndPrepToFastScroll(int downY, int lastY) {
@@ -245,25 +280,25 @@ public class BaseRecyclerViewFastScrollBar {
         setThumbOffsetY((int) mLastTouchY);
     }
 
-    public void draw(Canvas canvas) {
+    public void onDraw(Canvas canvas) {
         if (mThumbOffsetY < 0) {
             return;
         }
         int saveCount = canvas.save(Canvas.MATRIX_SAVE_FLAG);
-        if (!mIsRtl) {
-            canvas.translate(mRv.getWidth() - mWidth, 0);
-        }
-        canvas.translate(0, mRv.getPaddingTop());
+        canvas.translate(getWidth() / 2, mRv.getPaddingTop());
         // Draw the track
-        canvas.drawRoundRect(0, 0, mWidth, mRv.getScrollbarTrackHeight(),
+        float halfW = mWidth / 2;
+        canvas.drawRoundRect(-halfW, 0, halfW, mRv.getScrollbarTrackHeight(),
                 mWidth, mWidth, mTrackPaint);
 
-        canvas.translate(-mThumbPadding, mThumbOffsetY);
+        canvas.translate(0, mThumbOffsetY);
+        halfW += mThumbPadding;
         float r = mWidth + mThumbPadding + mThumbPadding;
-        canvas.drawRoundRect(0, 0, r, mThumbHeight, r, r, mThumbPaint);
+        canvas.drawRoundRect(-halfW, 0, halfW, mThumbHeight, r, r, mThumbPaint);
         canvas.restoreToCount(saveCount);
     }
 
+
     /**
      * Animates the width of the scrollbar.
      */
@@ -281,19 +316,25 @@ public class BaseRecyclerViewFastScrollBar {
     /**
      * Returns whether the specified point is inside the thumb bounds.
      */
-    public boolean isNearThumb(int x, int y) {
-        int left = getDrawLeft();
-        mTmpRect.set(left, mThumbOffsetY, left + mMaxWidth, mThumbOffsetY + mThumbHeight);
-        mTmpRect.inset(mTouchInset, mTouchInset);
-        return mTmpRect.contains(x, y);
+    private boolean isNearThumb(int x, int y) {
+        int offset = y - mRv.getPaddingTop() - mThumbOffsetY;
+
+        return x >= 0 && x < getWidth() && offset >= 0 && offset <= mThumbHeight;
+    }
+
+    /**
+     * Returns true if AllAppsTransitionController can handle vertical motion
+     * beginning at this point.
+     */
+    public boolean shouldBlockIntercept(int x, int y) {
+        return isNearThumb(x, y);
     }
 
     /**
      * Returns whether the specified x position is near the scroll bar.
      */
     public boolean isNearScrollBar(int x) {
-        int left = getDrawLeft();
-        return x >= left && x <= left + mMaxWidth;
+        return x >= (getWidth() - mMaxWidth) / 2 && x <= (getWidth() + mMaxWidth) / 2;
     }
 
     private void animatePopupVisibility(boolean visible) {
@@ -306,7 +347,8 @@ public class BaseRecyclerViewFastScrollBar {
 
     private void updatePopupY(int lastTouchY) {
         int height = mPopupView.getHeight();
-        float top = lastTouchY - (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * height);
+        float top = lastTouchY - (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * height)
+                + mRv.getPaddingTop();
         top = Utilities.boundToRange(top,
                 mMaxWidth, mRv.getScrollbarTrackHeight() - mMaxWidth - height);
         mPopupView.setTranslationY(top);