Re-enable the fast scroll in widget picker

Fix: 258299457
Test: Manual
Change-Id: Ic069f5304827de40be88b80590f5c6c7d88b13b2

2 files changed, 56 insertions, 2 deletions

diff --git a/src/com/android/launcher3/widget/picker/WidgetsFullSheet.java b/src/com/android/launcher3/widget/picker/WidgetsFullSheet.java
index 220d1c1d55..38cdb4b500 100644
--- a/src/com/android/launcher3/widget/picker/WidgetsFullSheet.java
+++ b/src/com/android/launcher3/widget/picker/WidgetsFullSheet.java
@@ -169,6 +169,7 @@ public class WidgetsFullSheet extends BaseWidgetSheet
     private View mSearchBarContainer;
     private WidgetsSearchBar mSearchBar;
     private TextView mHeaderTitle;
+    private @Nullable WidgetsRecyclerView mCurrentTouchEventRecyclerView;
 
     public WidgetsFullSheet(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
@@ -642,6 +643,51 @@ public class WidgetsFullSheet extends BaseWidgetSheet
         return sheet;
     }
 
+    @Override
+    public boolean onInterceptTouchEvent(MotionEvent ev) {
+        return isTouchOnScrollbar(ev) || super.onInterceptTouchEvent(ev);
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent ev) {
+        return maybeHandleTouchEvent(ev) || super.onTouchEvent(ev);
+    }
+
+    private boolean maybeHandleTouchEvent(MotionEvent ev) {
+        boolean isEventHandled = false;
+
+        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
+            mCurrentTouchEventRecyclerView = isTouchOnScrollbar(ev) ? getRecyclerView() : null;
+        }
+
+        if (mCurrentTouchEventRecyclerView != null) {
+            final float offsetX = mContent.getX();
+            final float offsetY = mContent.getY();
+            ev.offsetLocation(-offsetX, -offsetY);
+            isEventHandled = mCurrentTouchEventRecyclerView.dispatchTouchEvent(ev);
+            ev.offsetLocation(offsetX, offsetY);
+        }
+
+        if (ev.getAction() == MotionEvent.ACTION_UP
+                || ev.getAction() == MotionEvent.ACTION_CANCEL) {
+            mCurrentTouchEventRecyclerView = null;
+        }
+
+        return isEventHandled;
+    }
+
+    private boolean isTouchOnScrollbar(MotionEvent ev) {
+        final float offsetX = mContent.getX();
+        final float offsetY = mContent.getY();
+        WidgetsRecyclerView rv = getRecyclerView();
+
+        ev.offsetLocation(-offsetX, -offsetY);
+        boolean isOnScrollBar = rv != null && rv.getScrollbar() != null && rv.isHitOnScrollBar(ev);
+        ev.offsetLocation(offsetX, offsetY);
+
+        return isOnScrollBar;
+    }
+
     /** Gets the {@link WidgetsRecyclerView} which shows all widgets in {@link WidgetsFullSheet}. */
     @VisibleForTesting
     public static WidgetsRecyclerView getWidgetsView(Launcher launcher) {
diff --git a/src/com/android/launcher3/widget/picker/WidgetsRecyclerView.java b/src/com/android/launcher3/widget/picker/WidgetsRecyclerView.java
index 5969e3e154..698e76498a 100644
--- a/src/com/android/launcher3/widget/picker/WidgetsRecyclerView.java
+++ b/src/com/android/launcher3/widget/picker/WidgetsRecyclerView.java
@@ -127,8 +127,7 @@ public class WidgetsRecyclerView extends FastScrollRecyclerView implements OnIte
     @Override
     public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
         if (e.getAction() == MotionEvent.ACTION_DOWN) {
-            mTouchDownOnScroller =
-                    mScrollbar.isHitInParent(e.getX(), e.getY(), mFastScrollerOffset);
+            mTouchDownOnScroller = isHitOnScrollBar(e);
         }
         if (mTouchDownOnScroller) {
             final boolean result = mScrollbar.handleTouchEvent(e, mFastScrollerOffset);
@@ -144,6 +143,15 @@ public class WidgetsRecyclerView extends FastScrollRecyclerView implements OnIte
         }
     }
 
+    /**
+     * Detects whether a {@code MotionEvent} is on the scroll bar
+     * @param e The {@code MotionEvent} on the screen
+     * @return {@code true} if the motion is on the scroll bar
+     */
+    boolean isHitOnScrollBar(MotionEvent e) {
+        return mScrollbar.isHitInParent(e.getX(), e.getY(), mFastScrollerOffset);
+    }
+
     @Override
     public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
     }