Merge "Handle termination of disallow correctly." into snap-temp-L23500000669881336

9 files changed, 275 insertions, 150 deletions

diff --git a/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/EventRouterTest.java b/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/EventRouterTest.java
index 41aca917aa1..1d7c9116109 100644
--- a/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/EventRouterTest.java
+++ b/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/EventRouterTest.java
@@ -17,6 +17,8 @@
 package androidx.recyclerview.selection;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 import android.view.MotionEvent;
 
@@ -64,38 +66,37 @@ public class EventRouterTest {
     public void testDropsEventAfterDisallowCalled() {
         mRouter.onRequestDisallowInterceptTouchEvent(true);
 
-        mRouter.onInterceptTouchEvent(mRecyclerView, TestEvents.Touch.DOWN);
-        mRouter.onTouchEvent(mRecyclerView, TestEvents.Touch.DOWN);
+        mRouter.onInterceptTouchEvent(mRecyclerView, TestEvents.Touch.MOVE);
+        mRouter.onTouchEvent(mRecyclerView, TestEvents.Touch.MOVE);
 
         mListener.assertOnInterceptTouchEventCalled(0);
         mListener.assertOnTouchEventCalled(0);
     }
 
     @Test
-    public void testResetsDisallowOnUplEvents() {
+    public void testResetsDisallowOnDownEvents() {
         mRouter.onRequestDisallowInterceptTouchEvent(true);
-        mRouter.onInterceptTouchEvent(mRecyclerView, TestEvents.Touch.UP);
         mRouter.onInterceptTouchEvent(mRecyclerView, TestEvents.Touch.DOWN);
-        mRouter.onTouchEvent(mRecyclerView, TestEvents.Touch.DOWN);
+        mRouter.onInterceptTouchEvent(mRecyclerView, TestEvents.Touch.UP);
+        mRouter.onTouchEvent(mRecyclerView, TestEvents.Touch.UP);
 
-        // The FINGER/UP event that resets "disallow" is also dispatched to touch-event
+        // The FINGER/DOWN event that resets "disallow" is also dispatched to touch-event
         // listeners. So expect 2 calls.
         mListener.assertOnInterceptTouchEventCalled(2);
         mListener.assertOnTouchEventCalled(1);
     }
 
     @Test
-    public void testResetsDisallowOnCancelEvents() {
+    public void testResettable() {
+        // Only resettable when disallowIntercept has been requested.
         mRouter.onRequestDisallowInterceptTouchEvent(true);
-        mRouter.onInterceptTouchEvent(mRecyclerView,
-                TestEvents.builder().action(MotionEvent.ACTION_CANCEL).build());
-        mRouter.onInterceptTouchEvent(mRecyclerView, TestEvents.Touch.DOWN);
-        mRouter.onTouchEvent(mRecyclerView, TestEvents.Touch.DOWN);
+        assertTrue(mRouter.isResetRequired());
 
-        // The UNKNOWN/CANCEL event that resets "disallow" is not dispatched to any listeners
-        // (because there are no listeners registered for "UNKNOWN" tooltype. So expect 1 call.
-        mListener.assertOnInterceptTouchEventCalled(1);
-        mListener.assertOnTouchEventCalled(1);
+        ResetManager<?> mgr = new ResetManager<>();
+        mgr.addResetHandler(mRouter);
+        mgr.getSelectionObserver().onSelectionCleared();  // Results in reset.
+
+        assertFalse(mRouter.isResetRequired());
     }
 
     private static final class TestOnItemTouchListener implements OnItemTouchListener {
diff --git a/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/GestureDetectorOnItemTouchListenerAdapterTest.java b/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/GestureDetectorOnItemTouchListenerAdapterTest.java
deleted file mode 100644
index 7c26ec6fb02..00000000000
--- a/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/GestureDetectorOnItemTouchListenerAdapterTest.java
+++ /dev/null
@@ -1,107 +0,0 @@
-/*
- * Copyright 2019 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 androidx.recyclerview.selection;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import android.content.Context;
-import android.os.Looper;
-import android.view.GestureDetector;
-import android.view.MotionEvent;
-
-import androidx.recyclerview.selection.testing.TestEvents;
-import androidx.test.core.app.ApplicationProvider;
-import androidx.test.ext.junit.runners.AndroidJUnit4;
-import androidx.test.filters.SmallTest;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.ArrayList;
-import java.util.List;
-
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public final class GestureDetectorOnItemTouchListenerAdapterTest {
-
-    private GestureDetectorOnItemTouchListenerAdapter mAdapter;
-    private TestGestureDetector mDetector;
-
-    @Before
-    public void setUp() {
-        if (Looper.myLooper() == null) {
-            Looper.prepare();
-        }
-        mDetector = new TestGestureDetector(
-                ApplicationProvider.getApplicationContext(),
-                new GestureDetector.SimpleOnGestureListener()  // do nothing listener
-        );
-        mAdapter = new GestureDetectorOnItemTouchListenerAdapter(mDetector);
-    }
-
-    @Test
-    public void testReflectsGestureDetectorReturnValue() {
-        mDetector.mReturnValue = true;
-        assertTrue(mAdapter.onInterceptTouchEvent(null, TestEvents.Mouse.SECONDARY_CLICK));
-
-        mDetector.mReturnValue = false;
-        assertFalse(mAdapter.onInterceptTouchEvent(null, TestEvents.Mouse.SECONDARY_CLICK));
-    }
-
-    @Test
-    public void testAdapterRespectsDisallowIntercept() {
-        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.DOWN);
-        mDetector.assertOnTouchCalled(1);
-
-        // After disallow intercept, no more calls to onTouch should be forwarded.
-        mAdapter.onRequestDisallowInterceptTouchEvent(true);
-        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.MOVE);
-        mDetector.assertOnTouchCalled(1);
-
-        // UP event should reset event handling, allowing forwarding of events again.
-        // Num touch events forwarded to GestureDetector should increase by 1 (for the DOWN)
-        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.UP);
-        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.DOWN);
-        mDetector.assertOnTouchCalled(2);
-    }
-
-    private static final class TestGestureDetector extends GestureDetector {
-
-        private final List<MotionEvent> mDetectorEvents = new ArrayList<>();
-        boolean mReturnValue;
-
-        TestGestureDetector(Context context, SimpleOnGestureListener listener) {
-            super(context, listener);
-        }
-
-        @Override
-        public boolean onTouchEvent(MotionEvent ev) {
-            mDetectorEvents.add(ev);
-            return mReturnValue;
-        }
-
-        void assertOnTouchCalled(int expectedTimes) {
-            assertEquals(expectedTimes, mDetectorEvents.size());
-        }
-    }
-
-    ;
-}
diff --git a/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/GestureDetectorWrapperTest.java b/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/GestureDetectorWrapperTest.java
new file mode 100644
index 00000000000..584bacb26ba
--- /dev/null
+++ b/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/GestureDetectorWrapperTest.java
@@ -0,0 +1,176 @@
+/*
+ * Copyright 2019 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 androidx.recyclerview.selection;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import android.content.Context;
+import android.os.Looper;
+import android.view.GestureDetector;
+import android.view.MotionEvent;
+
+import androidx.recyclerview.selection.testing.TestEvents;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.ArrayList;
+import java.util.List;
+
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public final class GestureDetectorWrapperTest {
+
+    private GestureDetectorWrapper mAdapter;
+    private TestGestureDetector mDetector;
+    private TestListener mListener;
+
+    @Before
+    public void setUp() {
+        if (Looper.myLooper() == null) {
+            Looper.prepare();
+        }
+        mListener = new TestListener();
+        mDetector = new TestGestureDetector(
+                ApplicationProvider.getApplicationContext(),
+                mListener);
+
+        mAdapter = new GestureDetectorWrapper(mDetector);
+    }
+
+    @Test
+    public void testReflectsGestureDetectorReturnValue() {
+        mListener.mNextReturnVal = true;
+        assertTrue(mAdapter.onInterceptTouchEvent(null, TestEvents.Touch.DOWN));
+
+        mListener.mNextReturnVal = false;
+        assertFalse(mAdapter.onInterceptTouchEvent(null, TestEvents.Touch.DOWN));
+    }
+
+    @Test
+    public void testRelaysActions() {
+        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.DOWN);
+        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.MOVE);
+        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.UP);
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_DOWN);
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_MOVE);
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_UP);
+
+        mDetector.assertOnTouchCalled(3);
+    }
+
+    @Test
+    public void testRequestDisallowSendsFakeCancelEvent() {
+        mAdapter.onRequestDisallowInterceptTouchEvent(true);
+
+        // The adapter sends a synthetic ACTION_CANCEL event to GD when disallow is called.
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_CANCEL);
+        mDetector.assertOnTouchCalled(1);
+    }
+
+    @Test
+    public void testResettable() {
+        ResetManager<?> mgr = new ResetManager<>();
+        mgr.addResetHandler(mAdapter);
+        mgr.getSelectionObserver().onSelectionCleared();  // Results in reset.
+
+        // The adapter sends a synthetic ACTION_CANCEL event to GD when disallow is called.
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_CANCEL);
+        mDetector.assertOnTouchCalled(1);
+    }
+
+    @Test
+    public void testRespectsDisallowIntercept() {
+        mAdapter.onRequestDisallowInterceptTouchEvent(true);
+
+        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.MOVE);
+        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.UP);
+        // Sending DOWN would reset state, so we only test with MOVE and UP.
+
+        mDetector.assertOnTouchCalled(0, MotionEvent.ACTION_MOVE);
+        mDetector.assertOnTouchCalled(0, MotionEvent.ACTION_UP);
+
+        // Only the initial CANCEL event sent. Everything else ignored.
+        mDetector.assertOnTouchCalled(1);
+    }
+
+    @Test
+    public void testResetsDisallowInterceptOnDown() {
+        mAdapter.onRequestDisallowInterceptTouchEvent(true);
+        // Synthetic CANCEL event used to coerce GestureDetector into resetting internal state.
+        // Issued whenever disallowIntercept = true
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_CANCEL);
+
+        // Should reset DOWN
+        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.DOWN);
+        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.MOVE);
+        mAdapter.onInterceptTouchEvent(/* RecyclerView */ null, TestEvents.Touch.UP);
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_DOWN);
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_MOVE);
+        mDetector.assertOnTouchCalled(1, MotionEvent.ACTION_UP);
+
+        mDetector.assertOnTouchCalled(4); // CANCEL + DOWN,MOVE,UP
+    }
+
+    private static final class TestGestureDetector extends GestureDetector {
+
+        private final List<MotionEvent> mDetectorEvents = new ArrayList<>();
+
+        TestGestureDetector(Context context, SimpleOnGestureListener listener) {
+            super(context, listener);
+        }
+
+        @Override
+        public boolean onTouchEvent(MotionEvent ev) {
+            mDetectorEvents.add(ev);
+            return super.onTouchEvent(ev);
+        }
+
+        void assertOnTouchCalled(int expectedTimes) {
+            assertEquals(expectedTimes, mDetectorEvents.size());
+        }
+
+        void assertOnTouchCalled(int expectedTimes, int action) {
+            int total = 0;
+            for (MotionEvent e : mDetectorEvents) {
+                if (e.getAction() == action) {
+                    total++;
+                }
+            }
+            assertEquals(expectedTimes, total);
+        }
+    }
+
+    private static class TestListener extends GestureDetector.SimpleOnGestureListener {
+        boolean mNextReturnVal = false;
+
+        public boolean onSingleTapUp(MotionEvent e) {
+            return mNextReturnVal;
+        }
+
+        public boolean onDown(MotionEvent e) {
+            return mNextReturnVal;
+        }
+    }
+}
diff --git a/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/ResetMangerTest.java b/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/ResetMangerTest.java
index 2080ea75ca2..abbc75e526d 100644
--- a/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/ResetMangerTest.java
+++ b/recyclerview/recyclerview-selection/src/androidTest/java/androidx/recyclerview/selection/ResetMangerTest.java
@@ -44,7 +44,7 @@ public final class ResetMangerTest {
 
     @Before
     public void setUp() {
-        mManager = new ResetManager();
+        mManager = new ResetManager<>();
         mResettable1 = new TestResettable(true);
         mResettable2 = new TestResettable(true);
         mManager.addResetHandler(mResettable1);
diff --git a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/EventRouter.java b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/EventRouter.java
index 9cb8aa0beb0..c2a454cb907 100644
--- a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/EventRouter.java
+++ b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/EventRouter.java
@@ -33,7 +33,7 @@ import androidx.recyclerview.widget.RecyclerView.OnItemTouchListener;
  * {@link RecyclerView#addOnItemTouchListener(OnItemTouchListener)}. Despite "Touch"
  * being in the name, it receives MotionEvents for all types of tools.
  */
-final class EventRouter implements OnItemTouchListener {
+final class EventRouter implements OnItemTouchListener, Resettable {
 
     private final ToolHandlerRegistry<OnItemTouchListener> mDelegates;
     private boolean mDisallowIntercept;
@@ -55,10 +55,8 @@ final class EventRouter implements OnItemTouchListener {
 
     @Override
     public boolean onInterceptTouchEvent(@NonNull RecyclerView rv, @NonNull MotionEvent e) {
-        // Reset disallow intercept when the event is Up or Cancel as described
-        // in https://developer.android.com/reference/android/widget/HorizontalScrollView
-        // #requestDisallowInterceptTouchEvent(boolean)
-        if (MotionEvents.isActionUp(e) || MotionEvents.isActionCancel(e)) {
+        // Reset disallow when the event is down as advised in http://b/139141511#comment20.
+        if (mDisallowIntercept && MotionEvents.isActionDown(e)) {
             mDisallowIntercept = false;
         }
         return !mDisallowIntercept && mDelegates.get(e).onInterceptTouchEvent(rv, e);
@@ -73,10 +71,25 @@ final class EventRouter implements OnItemTouchListener {
 
     @Override
     public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
+        if (!disallowIntercept) {
+            return;  // Ignore as advised in http://b/139141511#comment20
+        }
+
         // Some types of views, such as HorizontalScrollView, may want
         // to take over the input stream. In this case they'll call this method
         // with disallowIntercept=true. mDisallowIntercept is reset on UP or CANCEL
         // events in onInterceptTouchEvent.
         mDisallowIntercept = disallowIntercept;
     }
+
+
+    @Override
+    public boolean isResetRequired() {
+        return mDisallowIntercept;
+    }
+
+    @Override
+    public void reset() {
+        mDisallowIntercept = false;
+    }
 }
diff --git a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/GestureDetectorOnItemTouchListenerAdapter.java b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/GestureDetectorWrapper.java
index 94ffd03d19d..2a51ec9483e 100644
--- a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/GestureDetectorOnItemTouchListenerAdapter.java
+++ b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/GestureDetectorWrapper.java
@@ -25,14 +25,15 @@ import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
 /**
- * Class allowing GestureDetector to listen directly to RecyclerView touch events.
+ * A wrapper class for GestureDetector allowing it interact with SelectionTracker
+ * and its dependencies (like RecyclerView) on terms more amenable to SelectionTracker.
  */
-final class GestureDetectorOnItemTouchListenerAdapter implements RecyclerView.OnItemTouchListener {
+final class GestureDetectorWrapper implements RecyclerView.OnItemTouchListener, Resettable {
 
     private final GestureDetector mDetector;
     private boolean mDisallowIntercept;
 
-    GestureDetectorOnItemTouchListenerAdapter(@NonNull GestureDetector detector) {
+    GestureDetectorWrapper(@NonNull GestureDetector detector) {
         checkArgument(detector != null);
 
         mDetector = detector;
@@ -40,12 +41,9 @@ final class GestureDetectorOnItemTouchListenerAdapter implements RecyclerView.On
 
     @Override
     public boolean onInterceptTouchEvent(@NonNull RecyclerView rv, @NonNull MotionEvent e) {
-        // Reset disallow intercept when the event is Up or Cancel as described
-        // in https://developer.android.com/reference/android/widget/HorizontalScrollView
-        // #requestDisallowInterceptTouchEvent(boolean)
-        if (MotionEvents.isActionUp(e) || MotionEvents.isActionCancel(e)) {
+        // Reset disallow when the event is down as advised in http://b/139141511#comment20.
+        if (mDisallowIntercept && MotionEvents.isActionDown(e)) {
             mDisallowIntercept = false;
-            return false;
         }
 
         // While the idea of "intercepting" an event stream isn't consistent
@@ -62,10 +60,39 @@ final class GestureDetectorOnItemTouchListenerAdapter implements RecyclerView.On
 
     @Override
     public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
+        if (!disallowIntercept) {
+            return;  // Ignore as advised in http://b/139141511#comment20
+        }
+
         // Some types of views, such as HorizontalScrollView, may want
         // to take over the input stream. In this case they'll call this method
         // with disallowIntercept=true. mDisallowIntercept is reset on UP or CANCEL
         // events in onInterceptTouchEvent.
         mDisallowIntercept = disallowIntercept;
+
+
+        // GestureDetector may have internal state (such as timers) that can
+        // result in subsequent event handlers being called, even after
+        // we receive a request to disallow intercept (e.g. LONG_PRESS).
+        // For that reason we proactively reset GestureDetector.
+        sendCancelEvent();
+    }
+
+    @Override
+    public boolean isResetRequired() {
+        // Always resettable as we don't know the specifics of GD's internal state.
+        return true;
+    }
+
+    @Override
+    public void reset() {
+        mDisallowIntercept = false;
+        sendCancelEvent();
+    }
+
+    private void sendCancelEvent() {
+        // GestureDetector does not provide a public affordance for resetting
+        // it's internal state, so we send it a synthetic ACTION_CANCEL event.
+        mDetector.onTouchEvent(MotionEvents.createCancelEvent());
     }
 }
diff --git a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/MotionEvents.java b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/MotionEvents.java
index aac3c0674d5..d2278a39b1d 100644
--- a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/MotionEvents.java
+++ b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/MotionEvents.java
@@ -27,7 +27,8 @@ import androidx.annotation.NonNull;
  */
 final class MotionEvents {
 
-    private MotionEvents() {}
+    private MotionEvents() {
+    }
 
     static boolean isMouseEvent(@NonNull MotionEvent e) {
         return e.getToolType(0) == MotionEvent.TOOL_TYPE_MOUSE;
@@ -107,7 +108,6 @@ final class MotionEvents {
     /**
      * Returns true if the event is a drag event (which is presumbaly, but not
      * explicitly required to be a mouse event).
-     * @param e
      */
     static boolean isPointerDragEvent(MotionEvent e) {
         return isPrimaryMouseButtonPressed(e)
@@ -117,4 +117,15 @@ final class MotionEvents {
     private static boolean hasBit(int metaState, int bit) {
         return (metaState & bit) != 0;
     }
+
+    static MotionEvent createCancelEvent() {
+        return MotionEvent.obtain(
+                0,     // down time
+                1,     // event time
+                MotionEvent.ACTION_CANCEL,
+                0,  // x
+                0,  // y
+                0  // metaState
+        );
+    }
 }
diff --git a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/OperationMonitor.java b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/OperationMonitor.java
index 53d4b82ed38..8d0ac571146 100644
--- a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/OperationMonitor.java
+++ b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/OperationMonitor.java
@@ -52,7 +52,7 @@ public final class OperationMonitor {
     // Ideally OperationMonitor would implement Resettable
     // directly, but Metalava couldn't understand that
     // `OperationMonitor` was public API while `Resettable` was
-    // not. This is our klunkuy workaround.
+    // not. This is our clever workaround :)
     private final Resettable mResettable = new Resettable() {
 
         @Override
diff --git a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/SelectionTracker.java b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/SelectionTracker.java
index dd045c66838..b8dc24aa15a 100644
--- a/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/SelectionTracker.java
+++ b/recyclerview/recyclerview-selection/src/main/java/androidx/recyclerview/selection/SelectionTracker.java
@@ -734,19 +734,20 @@ public abstract class SelectionTracker<K> {
             GestureDetector gestureDetector = new GestureDetector(mContext, gestureRouter);
 
             // GestureSelectionHelper provides logic that interprets a combination
-            // of motions and gestures in order to provide gesture driven selection support
-            // when used in conjunction with RecyclerView.
-            final GestureSelectionHelper gestureHelper = GestureSelectionHelper.create(
+            // of motions and gestures in order to provide fluid "long-press and drag"
+            // finger driven selection support.
+            final GestureSelectionHelper gestureSelectionHelper = GestureSelectionHelper.create(
                     tracker, mSelectionPredicate, mRecyclerView, scroller, mMonitor);
 
             // EventRouter receives events for RecyclerView, dispatching to handlers
             // registered by tool-type.
             EventRouter eventRouter = new EventRouter();
+            GestureDetectorWrapper gestureDetectorWrapper =
+                    new GestureDetectorWrapper(gestureDetector);
 
             // Finally hook the framework up to listening to RecycleView events.
             mRecyclerView.addOnItemTouchListener(eventRouter);
-            mRecyclerView.addOnItemTouchListener(
-                    new GestureDetectorOnItemTouchListenerAdapter(gestureDetector));
+            mRecyclerView.addOnItemTouchListener(gestureDetectorWrapper);
 
             // Reset manager listens for cancel events from RecyclerView. In response to that it
             // advises other classes it is time to reset state.
@@ -756,20 +757,23 @@ public abstract class SelectionTracker<K> {
             //
             // 1. Monitor selection reset which can be invoked by clients in response
             //    to back key press and some application lifecycle events.
-            //
-            // 2. Monitor ACTION_CANCEL events (which arrive exclusively
-            // via TOOL_TYPE_UNKNOWN).
             tracker.addObserver(resetMgr.getSelectionObserver());
 
+            // ...and  2. Monitor ACTION_CANCEL events (which arrive exclusively
+            // via TOOL_TYPE_UNKNOWN).
+            //
             // CAUTION! Registering resetMgr directly with RecyclerView#addOnItemTouchListener
             // will not work as expected. Once EventRouter returns true, RecyclerView will
             // no longer dispatch any events to other listeners for the duration of the
             // stream, not even ACTION_CANCEL events.
             eventRouter.set(MotionEvent.TOOL_TYPE_UNKNOWN, resetMgr.getInputListener());
 
+            // Finally register all of the Resettables.
             resetMgr.addResetHandler(tracker);
             resetMgr.addResetHandler(mMonitor.asResettable());
-            resetMgr.addResetHandler(gestureHelper);
+            resetMgr.addResetHandler(gestureSelectionHelper);
+            resetMgr.addResetHandler(gestureDetectorWrapper);
+            resetMgr.addResetHandler(eventRouter);
 
             // But before you move on, there's more work to do. Event plumbing has been
             // installed, but we haven't registered any of our helpers or callbacks.
@@ -821,7 +825,7 @@ public abstract class SelectionTracker<K> {
                         @Override
                         public void run() {
                             if (mSelectionPredicate.canSelectMultiple()) {
-                                gestureHelper.start();
+                                gestureSelectionHelper.start();
                             }
                         }
                     },
@@ -837,7 +841,7 @@ public abstract class SelectionTracker<K> {
 
             for (int toolType : mGestureToolTypes) {
                 gestureRouter.register(toolType, touchHandler);
-                eventRouter.set(toolType, gestureHelper);
+                eventRouter.set(toolType, gestureSelectionHelper);
             }
 
             // Provides high level glue for binding mouse events and gestures