diff --git a/res/layout/folder_application.xml b/res/layout/folder_application.xml
index de861a0..9d4af0d 100644
--- a/res/layout/folder_application.xml
+++ b/res/layout/folder_application.xml
@@ -19,4 +19,9 @@
     xmlns:launcher="http://schemas.android.com/apk/res-auto"
     style="@style/BaseIcon"
     android:includeFontPadding="false"
-    launcher:iconDisplay="folder" />
+    android:paddingLeft="@dimen/folder_cell_x_padding"
+    android:paddingTop="@dimen/folder_cell_y_padding"
+    android:paddingRight="@dimen/folder_cell_x_padding"
+    android:paddingBottom="@dimen/folder_cell_y_padding"
+    launcher:centerVertically="true"
+    launcher:iconDisplay="folder"/>
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 356de78..0eb3982 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -138,10 +138,11 @@
     <dimen name="folder_preview_padding">10dp</dimen>
     <dimen name="page_indicator_dot_size">8dp</dimen>
 
-    <dimen name="folder_cell_x_padding">9dp</dimen>
-    <dimen name="folder_cell_y_padding">6dp</dimen>
+    <dimen name="folder_cell_x_padding">8dp</dimen>
+    <dimen name="folder_cell_y_padding">8dp</dimen>
     <dimen name="folder_child_text_size">13sp</dimen>
-    <dimen name="folder_label_padding_top">4dp</dimen>
+    <dimen name="folder_child_icon_drawable_padding">8dp</dimen>
+    <dimen name="folder_label_padding_top">12dp</dimen>
     <dimen name="folder_label_padding_bottom">12dp</dimen>
     <dimen name="folder_label_text_size">14sp</dimen>
 
diff --git a/src/com/android/launcher3/DeviceProfile.java b/src/com/android/launcher3/DeviceProfile.java
index 2d5f8d0..38011ea 100644
--- a/src/com/android/launcher3/DeviceProfile.java
+++ b/src/com/android/launcher3/DeviceProfile.java
@@ -108,6 +108,7 @@
     public int folderChildIconSizePx;
     public int folderChildTextSizePx;
     public int folderChildDrawablePaddingPx;
+    public final int folderChildDrawablePaddingOriginalPx;
 
     // Hotseat
     public int hotseatCellHeightPx;
@@ -220,6 +221,9 @@
         hotseatLandRightNavBarGutterPx = res.getDimensionPixelSize(
                 R.dimen.dynamic_grid_hotseat_land_right_nav_bar_gutter_width);
 
+        folderChildDrawablePaddingOriginalPx =
+                res.getDimensionPixelSize(R.dimen.folder_child_icon_drawable_padding);
+
         // Determine sizes.
         widthPx = width;
         heightPx = height;
@@ -390,15 +394,15 @@
         folderChildIconSizePx = (int) (Utilities.pxFromDp(inv.iconSize, dm) * scale);
         folderChildTextSizePx =
                 (int) (res.getDimensionPixelSize(R.dimen.folder_child_text_size) * scale);
+        folderChildDrawablePaddingPx = (int) (folderChildDrawablePaddingOriginalPx * scale);
 
         int textHeight = Utilities.calculateTextHeight(folderChildTextSizePx);
         int cellPaddingX = (int) (res.getDimensionPixelSize(R.dimen.folder_cell_x_padding) * scale);
         int cellPaddingY = (int) (res.getDimensionPixelSize(R.dimen.folder_cell_y_padding) * scale);
 
         folderCellWidthPx = folderChildIconSizePx + 2 * cellPaddingX;
-        folderCellHeightPx = folderChildIconSizePx + 2 * cellPaddingY + textHeight;
-        folderChildDrawablePaddingPx = Math.max(0,
-                (folderCellHeightPx - folderChildIconSizePx - textHeight) / 3);
+        folderCellHeightPx = folderChildIconSizePx + 2 * cellPaddingY + textHeight
+                + folderChildDrawablePaddingPx;
     }
 
     public void updateInsets(Rect insets) {
diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index 185c887..87f3dda 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -48,6 +48,7 @@
 
 import com.android.launcher3.anim.PropertyListBuilder;
 import com.android.launcher3.pageindicators.PageIndicator;
+import com.android.launcher3.touch.OverScroll;
 import com.android.launcher3.util.Themes;
 import com.android.launcher3.util.Thunk;
 
@@ -68,10 +69,8 @@
     public static final int PAGE_SNAP_ANIMATION_DURATION = 750;
     protected static final int SLOW_PAGE_SNAP_ANIMATION_DURATION = 950;
 
-    // Overscroll constants
+    // OverScroll constants
     private final static int OVERSCROLL_PAGE_SNAP_ANIMATION_DURATION = 270;
-    private static final float OVERSCROLL_ACCELERATE_FACTOR = 2;
-    private static final float OVERSCROLL_DAMP_FACTOR = 0.07f;
 
     private static final float RETURN_TO_ORIGINAL_PAGE_THRESHOLD = 0.33f;
     // The page is moved more than halfway, automatically move to the next page on touch up.
@@ -188,7 +187,6 @@
     // Convenience/caching
     private static final Matrix sTmpInvMatrix = new Matrix();
     private static final float[] sTmpPoint = new float[2];
-    private static final int[] sTmpIntPoint = new int[2];
     private static final Rect sTmpRect = new Rect();
 
     protected final Rect mInsets = new Rect();
@@ -233,8 +231,6 @@
         mMinSnapVelocity = (int) (MIN_SNAP_VELOCITY * density);
         setOnHierarchyChangeListener(this);
         setWillNotDraw(false);
-
-        int edgeEffectColor = Themes.getAttrColor(getContext(), android.R.attr.colorEdgeEffect);
     }
 
     protected void setDefaultInterpolator(Interpolator interpolator) {
@@ -1305,29 +1301,6 @@
         }
     }
 
-    // This curve determines how the effect of scrolling over the limits of the page dimishes
-    // as the user pulls further and further from the bounds
-    private float overScrollInfluenceCurve(float f) {
-        f -= 1.0f;
-        return f * f * f + 1.0f;
-    }
-
-    protected float acceleratedOverFactor(float amount) {
-        int screenSize = getViewportWidth();
-
-        // We want to reach the max over scroll effect when the user has
-        // over scrolled half the size of the screen
-        float f = OVERSCROLL_ACCELERATE_FACTOR * (amount / screenSize);
-
-        if (Float.compare(f, 0f) == 0) return 0;
-
-        // Clamp this factor, f, to -1 < f < 1
-        if (Math.abs(f) >= 1) {
-            f /= Math.abs(f);
-        }
-        return f;
-    }
-
     // While layout transitions are occurring, a child's position may stray from its baseline
     // position. This method returns the magnitude of this stray at any given time.
     public int getLayoutTransitionOffsetForPage(int index) {
@@ -1348,20 +1321,9 @@
     }
 
     protected void dampedOverScroll(float amount) {
-        int screenSize = getViewportWidth();
+        if (Float.compare(amount, 0f) == 0) return;
 
-        float f = (amount / screenSize);
-
-        if (Float.compare(f, 0f) == 0) return;
-
-        f = f / (Math.abs(f)) * (overScrollInfluenceCurve(Math.abs(f)));
-
-        // Clamp this factor, f, to -1 < f < 1
-        if (Math.abs(f) >= 1) {
-            f /= Math.abs(f);
-        }
-
-        int overScrollAmount = (int) Math.round(OVERSCROLL_DAMP_FACTOR * f * screenSize);
+        int overScrollAmount = OverScroll.dampedScroll(amount, getViewportWidth());
         if (amount < 0) {
             mOverScrollX = overScrollAmount;
             super.scrollTo(mOverScrollX, getScrollY());
@@ -1376,14 +1338,6 @@
         dampedOverScroll(amount);
     }
 
-    protected float maxOverScroll() {
-        // Using the formula in overScroll, assuming that f = 1.0 (which it should generally not
-        // exceed). Used to find out how much extra wallpaper we need for the over scroll effect
-        float f = 1.0f;
-        f = f / (Math.abs(f)) * (overScrollInfluenceCurve(Math.abs(f)));
-        return OVERSCROLL_DAMP_FACTOR * f;
-    }
-
     /**
      * return true if freescroll has been enabled, false otherwise
      */
diff --git a/src/com/android/launcher3/accessibility/ShortcutMenuAccessibilityDelegate.java b/src/com/android/launcher3/accessibility/ShortcutMenuAccessibilityDelegate.java
index 8161219..b7c500f 100644
--- a/src/com/android/launcher3/accessibility/ShortcutMenuAccessibilityDelegate.java
+++ b/src/com/android/launcher3/accessibility/ShortcutMenuAccessibilityDelegate.java
@@ -50,8 +50,7 @@
         if ((host.getParent() instanceof DeepShortcutView)) {
             info.addAction(mActions.get(ADD_TO_WORKSPACE));
         } else if (host instanceof NotificationMainView) {
-            NotificationMainView notificationView = (NotificationMainView) host;
-            if (notificationView.canChildBeDismissed(notificationView)) {
+            if (((NotificationMainView) host).canChildBeDismissed()) {
                 info.addAction(mActions.get(DISMISS_NOTIFICATION));
             }
         }
@@ -88,8 +87,7 @@
             if (!(host instanceof NotificationMainView)) {
                 return false;
             }
-            NotificationMainView notificationView = (NotificationMainView) host;
-            notificationView.onChildDismissed(notificationView);
+            ((NotificationMainView) host).onChildDismissed();
             announceConfirmation(R.string.notification_dismissed);
             return true;
         }
diff --git a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
index 2abb766..ab589d8 100644
--- a/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
+++ b/src/com/android/launcher3/allapps/AllAppsRecyclerView.java
@@ -36,6 +36,7 @@
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.graphics.DrawableFactory;
 import com.android.launcher3.logging.UserEventDispatcher.LogContainerProvider;
+import com.android.launcher3.touch.OverScroll;
 import com.android.launcher3.touch.SwipeDetector;
 import com.android.launcher3.userevent.nano.LauncherLogProto.ContainerType;
 import com.android.launcher3.userevent.nano.LauncherLogProto.Target;
@@ -98,8 +99,7 @@
                 R.dimen.all_apps_empty_search_bg_top_offset);
 
         mOverScrollHelper = new OverScrollHelper();
-        mPullDetector = new SwipeDetector(getContext());
-        mPullDetector.setListener(mOverScrollHelper);
+        mPullDetector = new SwipeDetector(getContext(), mOverScrollHelper, SwipeDetector.VERTICAL);
         mPullDetector.setDetectableScrollConditions(SwipeDetector.DIRECTION_BOTH, true);
     }
 
@@ -564,37 +564,7 @@
         }
 
         private float getDampedOverScroll(float y) {
-            return dampedOverScroll(y, getHeight()) * MAX_OVERSCROLL_PERCENTAGE;
-        }
-
-        /**
-         * This curve determines how the effect of scrolling over the limits of the page diminishes
-         * as the user pulls further and further from the bounds
-         *
-         * @param f The percentage of how much the user has overscrolled.
-         * @return A transformed percentage based on the influence curve.
-         */
-        private float overScrollInfluenceCurve(float f) {
-            f -= 1.0f;
-            return f * f * f + 1.0f;
-        }
-
-        /**
-         * @param amount The original amount overscrolled.
-         * @param max The maximum amount that the View can overscroll.
-         * @return The dampened overscroll amount.
-         */
-        private float dampedOverScroll(float amount, float max) {
-            float f = amount / max;
-            if (Float.compare(f, 0) == 0) return 0;
-            f = f / (Math.abs(f)) * (overScrollInfluenceCurve(Math.abs(f)));
-
-            // Clamp this factor, f, to -1 < f < 1
-            if (Math.abs(f) >= 1) {
-                f /= Math.abs(f);
-            }
-
-            return Math.round(f * max);
+            return OverScroll.dampedScroll(y, getHeight());
         }
     }
 }
diff --git a/src/com/android/launcher3/allapps/AllAppsTransitionController.java b/src/com/android/launcher3/allapps/AllAppsTransitionController.java
index ecb9724..a6194cc 100644
--- a/src/com/android/launcher3/allapps/AllAppsTransitionController.java
+++ b/src/com/android/launcher3/allapps/AllAppsTransitionController.java
@@ -107,8 +107,7 @@
 
     public AllAppsTransitionController(Launcher l) {
         mLauncher = l;
-        mDetector = new SwipeDetector(l);
-        mDetector.setListener(this);
+        mDetector = new SwipeDetector(l, this, SwipeDetector.VERTICAL);
         mShiftRange = DEFAULT_SHIFT_RANGE;
         mProgress = 1f;
 
@@ -137,15 +136,15 @@
 
                 if (mDetector.isIdleState()) {
                     if (mLauncher.isAllAppsVisible()) {
-                        directionsToDetectScroll |= SwipeDetector.DIRECTION_DOWN;
+                        directionsToDetectScroll |= SwipeDetector.DIRECTION_NEGATIVE;
                     } else {
-                        directionsToDetectScroll |= SwipeDetector.DIRECTION_UP;
+                        directionsToDetectScroll |= SwipeDetector.DIRECTION_POSITIVE;
                     }
                 } else {
                     if (isInDisallowRecatchBottomZone()) {
-                        directionsToDetectScroll |= SwipeDetector.DIRECTION_UP;
+                        directionsToDetectScroll |= SwipeDetector.DIRECTION_POSITIVE;
                     } else if (isInDisallowRecatchTopZone()) {
-                        directionsToDetectScroll |= SwipeDetector.DIRECTION_DOWN;
+                        directionsToDetectScroll |= SwipeDetector.DIRECTION_NEGATIVE;
                     } else {
                         directionsToDetectScroll |= SwipeDetector.DIRECTION_BOTH;
                         ignoreSlopWhenSettling = true;
@@ -368,7 +367,7 @@
     }
 
     private void calculateDuration(float velocity, float disp) {
-        mAnimationDuration = mDetector.calculateDuration(velocity, disp / mShiftRange);
+        mAnimationDuration = SwipeDetector.calculateDuration(velocity, disp / mShiftRange);
     }
 
     public boolean animateToAllApps(AnimatorSet animationOut, long duration) {
diff --git a/src/com/android/launcher3/folder/FolderAnimationManager.java b/src/com/android/launcher3/folder/FolderAnimationManager.java
index 69705d5..d7f5c2b 100644
--- a/src/com/android/launcher3/folder/FolderAnimationManager.java
+++ b/src/com/android/launcher3/folder/FolderAnimationManager.java
@@ -120,6 +120,7 @@
         final DragLayer.LayoutParams lp = (DragLayer.LayoutParams) mFolder.getLayoutParams();
         FolderIcon.PreviewLayoutRule rule = mFolderIcon.getLayoutRule();
         final List<BubbleTextView> itemsInPreview = mFolderIcon.getPreviewItems();
+        BubbleTextView btv = itemsInPreview.get(0);
 
         // Match position of the FolderIcon
         final Rect folderIconPos = new Rect();
@@ -131,7 +132,7 @@
         // Match size/scale of icons in the preview
         float previewScale = rule.scaleForItem(0, itemsInPreview.size());
         float previewSize = rule.getIconSize() * previewScale;
-        float initialScale = previewSize / itemsInPreview.get(0).getIconSize()
+        float initialScale = previewSize / btv.getIconSize()
                 * scaleRelativeToDragLayer;
         final float finalScale = 1f;
         float scale = mIsOpening ? initialScale : finalScale;
@@ -148,10 +149,12 @@
             previewItemOffsetX = (int) (lp.width * initialScale - initialSize - previewItemOffsetX);
         }
 
+        // Note that we do not include btv.getPaddingLeft() in the calculation, since it is
+        // handled in addPreviewItemAnimators as part of iconOffsetX.
         final int paddingOffsetX = (int) ((mFolder.getPaddingLeft() + mContent.getPaddingLeft())
                 * initialScale);
-        final int paddingOffsetY = (int) ((mFolder.getPaddingTop() + mContent.getPaddingTop())
-                * initialScale);
+        final int paddingOffsetY = (int) ((mFolder.getPaddingTop() + mContent.getPaddingTop()
+                + btv.getPaddingTop()) * initialScale);
 
         int initialX = folderIconPos.left + mPreviewBackground.getOffsetX() - paddingOffsetX
                 - previewItemOffsetX;
diff --git a/src/com/android/launcher3/notification/FlingAnimationUtils.java b/src/com/android/launcher3/notification/FlingAnimationUtils.java
deleted file mode 100644
index a1f7e49..0000000
--- a/src/com/android/launcher3/notification/FlingAnimationUtils.java
+++ /dev/null
@@ -1,356 +0,0 @@
-/*
- * 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.notification;
-
-import android.animation.Animator;
-import android.content.Context;
-import android.view.ViewPropertyAnimator;
-import android.view.animation.Interpolator;
-import android.view.animation.PathInterpolator;
-
-/**
- * Utility class to calculate general fling animation when the finger is released.
- *
- * This class was copied from com.android.systemui.statusbar.
- */
-public class FlingAnimationUtils {
-
-    private static final float LINEAR_OUT_SLOW_IN_X2 = 0.35f;
-    private static final float LINEAR_OUT_SLOW_IN_X2_MAX = 0.68f;
-    private static final float LINEAR_OUT_FASTER_IN_X2 = 0.5f;
-    private static final float LINEAR_OUT_FASTER_IN_Y2_MIN = 0.4f;
-    private static final float LINEAR_OUT_FASTER_IN_Y2_MAX = 0.5f;
-    private static final float MIN_VELOCITY_DP_PER_SECOND = 250;
-    private static final float HIGH_VELOCITY_DP_PER_SECOND = 3000;
-
-    private static final float LINEAR_OUT_SLOW_IN_START_GRADIENT = 0.75f;
-    private final float mSpeedUpFactor;
-    private final float mY2;
-
-    private float mMinVelocityPxPerSecond;
-    private float mMaxLengthSeconds;
-    private float mHighVelocityPxPerSecond;
-    private float mLinearOutSlowInX2;
-
-    private AnimatorProperties mAnimatorProperties = new AnimatorProperties();
-    private PathInterpolator mInterpolator;
-    private float mCachedStartGradient = -1;
-    private float mCachedVelocityFactor = -1;
-
-    public FlingAnimationUtils(Context ctx, float maxLengthSeconds) {
-        this(ctx, maxLengthSeconds, 0.0f);
-    }
-
-    /**
-     * @param maxLengthSeconds the longest duration an animation can become in seconds
-     * @param speedUpFactor a factor from 0 to 1 how much the slow down should be shifted towards
-     *                      the end of the animation. 0 means it's at the beginning and no
-     *                      acceleration will take place.
-     */
-    public FlingAnimationUtils(Context ctx, float maxLengthSeconds, float speedUpFactor) {
-        this(ctx, maxLengthSeconds, speedUpFactor, -1.0f, 1.0f);
-    }
-
-    /**
-     * @param maxLengthSeconds the longest duration an animation can become in seconds
-     * @param speedUpFactor a factor from 0 to 1 how much the slow down should be shifted towards
-     *                      the end of the animation. 0 means it's at the beginning and no
-     *                      acceleration will take place.
-     * @param x2 the x value to take for the second point of the bezier spline. If a value below 0
-     *           is provided, the value is automatically calculated.
-     * @param y2 the y value to take for the second point of the bezier spline
-     */
-    public FlingAnimationUtils(Context ctx, float maxLengthSeconds, float speedUpFactor, float x2,
-            float y2) {
-        mMaxLengthSeconds = maxLengthSeconds;
-        mSpeedUpFactor = speedUpFactor;
-        if (x2 < 0) {
-            mLinearOutSlowInX2 = interpolate(LINEAR_OUT_SLOW_IN_X2,
-                    LINEAR_OUT_SLOW_IN_X2_MAX,
-                    mSpeedUpFactor);
-        } else {
-            mLinearOutSlowInX2 = x2;
-        }
-        mY2 = y2;
-
-        mMinVelocityPxPerSecond
-                = MIN_VELOCITY_DP_PER_SECOND * ctx.getResources().getDisplayMetrics().density;
-        mHighVelocityPxPerSecond
-                = HIGH_VELOCITY_DP_PER_SECOND * ctx.getResources().getDisplayMetrics().density;
-    }
-
-    private static float interpolate(float start, float end, float amount) {
-        return start * (1.0f - amount) + end * amount;
-    }
-
-    /**
-     * Applies the interpolator and length to the animator, such that the fling animation is
-     * consistent with the finger motion.
-     *
-     * @param animator the animator to apply
-     * @param currValue the current value
-     * @param endValue the end value of the animator
-     * @param velocity the current velocity of the motion
-     */
-    public void apply(Animator animator, float currValue, float endValue, float velocity) {
-        apply(animator, currValue, endValue, velocity, Math.abs(endValue - currValue));
-    }
-
-    /**
-     * Applies the interpolator and length to the animator, such that the fling animation is
-     * consistent with the finger motion.
-     *
-     * @param animator the animator to apply
-     * @param currValue the current value
-     * @param endValue the end value of the animator
-     * @param velocity the current velocity of the motion
-     */
-    public void apply(ViewPropertyAnimator animator, float currValue, float endValue,
-            float velocity) {
-        apply(animator, currValue, endValue, velocity, Math.abs(endValue - currValue));
-    }
-
-    /**
-     * Applies the interpolator and length to the animator, such that the fling animation is
-     * consistent with the finger motion.
-     *
-     * @param animator the animator to apply
-     * @param currValue the current value
-     * @param endValue the end value of the animator
-     * @param velocity the current velocity of the motion
-     * @param maxDistance the maximum distance for this interaction; the maximum animation length
-     *                    gets multiplied by the ratio between the actual distance and this value
-     */
-    public void apply(Animator animator, float currValue, float endValue, float velocity,
-            float maxDistance) {
-        AnimatorProperties properties = getProperties(currValue, endValue, velocity,
-                maxDistance);
-        animator.setDuration(properties.duration);
-        animator.setInterpolator(properties.interpolator);
-    }
-
-    /**
-     * Applies the interpolator and length to the animator, such that the fling animation is
-     * consistent with the finger motion.
-     *
-     * @param animator the animator to apply
-     * @param currValue the current value
-     * @param endValue the end value of the animator
-     * @param velocity the current velocity of the motion
-     * @param maxDistance the maximum distance for this interaction; the maximum animation length
-     *                    gets multiplied by the ratio between the actual distance and this value
-     */
-    public void apply(ViewPropertyAnimator animator, float currValue, float endValue,
-            float velocity, float maxDistance) {
-        AnimatorProperties properties = getProperties(currValue, endValue, velocity,
-                maxDistance);
-        animator.setDuration(properties.duration);
-        animator.setInterpolator(properties.interpolator);
-    }
-
-    private AnimatorProperties getProperties(float currValue,
-            float endValue, float velocity, float maxDistance) {
-        float maxLengthSeconds = (float) (mMaxLengthSeconds
-                * Math.sqrt(Math.abs(endValue - currValue) / maxDistance));
-        float diff = Math.abs(endValue - currValue);
-        float velAbs = Math.abs(velocity);
-        float velocityFactor = mSpeedUpFactor == 0.0f
-                ? 1.0f : Math.min(velAbs / HIGH_VELOCITY_DP_PER_SECOND, 1.0f);
-        float startGradient = interpolate(LINEAR_OUT_SLOW_IN_START_GRADIENT,
-                mY2 / mLinearOutSlowInX2, velocityFactor);
-        float durationSeconds = startGradient * diff / velAbs;
-        Interpolator slowInInterpolator = getInterpolator(startGradient, velocityFactor);
-        if (durationSeconds <= maxLengthSeconds) {
-            mAnimatorProperties.interpolator = slowInInterpolator;
-        } else if (velAbs >= mMinVelocityPxPerSecond) {
-
-            // Cross fade between fast-out-slow-in and linear interpolator with current velocity.
-            durationSeconds = maxLengthSeconds;
-            VelocityInterpolator velocityInterpolator
-                    = new VelocityInterpolator(durationSeconds, velAbs, diff);
-            InterpolatorInterpolator superInterpolator = new InterpolatorInterpolator(
-                    velocityInterpolator, slowInInterpolator, Interpolators.LINEAR_OUT_SLOW_IN);
-            mAnimatorProperties.interpolator = superInterpolator;
-        } else {
-
-            // Just use a normal interpolator which doesn't take the velocity into account.
-            durationSeconds = maxLengthSeconds;
-            mAnimatorProperties.interpolator = Interpolators.FAST_OUT_SLOW_IN;
-        }
-        mAnimatorProperties.duration = (long) (durationSeconds * 1000);
-        return mAnimatorProperties;
-    }
-
-    private Interpolator getInterpolator(float startGradient, float velocityFactor) {
-        if (startGradient != mCachedStartGradient
-                || velocityFactor != mCachedVelocityFactor) {
-            float speedup = mSpeedUpFactor * (1.0f - velocityFactor);
-            mInterpolator = new PathInterpolator(speedup,
-                    speedup * startGradient,
-                    mLinearOutSlowInX2, mY2);
-            mCachedStartGradient = startGradient;
-            mCachedVelocityFactor = velocityFactor;
-        }
-        return mInterpolator;
-    }
-
-    /**
-     * Applies the interpolator and length to the animator, such that the fling animation is
-     * consistent with the finger motion for the case when the animation is making something
-     * disappear.
-     *
-     * @param animator the animator to apply
-     * @param currValue the current value
-     * @param endValue the end value of the animator
-     * @param velocity the current velocity of the motion
-     * @param maxDistance the maximum distance for this interaction; the maximum animation length
-     *                    gets multiplied by the ratio between the actual distance and this value
-     */
-    public void applyDismissing(Animator animator, float currValue, float endValue,
-            float velocity, float maxDistance) {
-        AnimatorProperties properties = getDismissingProperties(currValue, endValue, velocity,
-                maxDistance);
-        animator.setDuration(properties.duration);
-        animator.setInterpolator(properties.interpolator);
-    }
-
-    /**
-     * Applies the interpolator and length to the animator, such that the fling animation is
-     * consistent with the finger motion for the case when the animation is making something
-     * disappear.
-     *
-     * @param animator the animator to apply
-     * @param currValue the current value
-     * @param endValue the end value of the animator
-     * @param velocity the current velocity of the motion
-     * @param maxDistance the maximum distance for this interaction; the maximum animation length
-     *                    gets multiplied by the ratio between the actual distance and this value
-     */
-    public void applyDismissing(ViewPropertyAnimator animator, float currValue, float endValue,
-            float velocity, float maxDistance) {
-        AnimatorProperties properties = getDismissingProperties(currValue, endValue, velocity,
-                maxDistance);
-        animator.setDuration(properties.duration);
-        animator.setInterpolator(properties.interpolator);
-    }
-
-    private AnimatorProperties getDismissingProperties(float currValue, float endValue,
-            float velocity, float maxDistance) {
-        float maxLengthSeconds = (float) (mMaxLengthSeconds
-                * Math.pow(Math.abs(endValue - currValue) / maxDistance, 0.5f));
-        float diff = Math.abs(endValue - currValue);
-        float velAbs = Math.abs(velocity);
-        float y2 = calculateLinearOutFasterInY2(velAbs);
-
-        float startGradient = y2 / LINEAR_OUT_FASTER_IN_X2;
-        Interpolator mLinearOutFasterIn = new PathInterpolator(0, 0, LINEAR_OUT_FASTER_IN_X2, y2);
-        float durationSeconds = startGradient * diff / velAbs;
-        if (durationSeconds <= maxLengthSeconds) {
-            mAnimatorProperties.interpolator = mLinearOutFasterIn;
-        } else if (velAbs >= mMinVelocityPxPerSecond) {
-
-            // Cross fade between linear-out-faster-in and linear interpolator with current
-            // velocity.
-            durationSeconds = maxLengthSeconds;
-            VelocityInterpolator velocityInterpolator
-                    = new VelocityInterpolator(durationSeconds, velAbs, diff);
-            InterpolatorInterpolator superInterpolator = new InterpolatorInterpolator(
-                    velocityInterpolator, mLinearOutFasterIn, Interpolators.LINEAR_OUT_SLOW_IN);
-            mAnimatorProperties.interpolator = superInterpolator;
-        } else {
-
-            // Just use a normal interpolator which doesn't take the velocity into account.
-            durationSeconds = maxLengthSeconds;
-            mAnimatorProperties.interpolator = Interpolators.FAST_OUT_LINEAR_IN;
-        }
-        mAnimatorProperties.duration = (long) (durationSeconds * 1000);
-        return mAnimatorProperties;
-    }
-
-    /**
-     * Calculates the y2 control point for a linear-out-faster-in path interpolator depending on the
-     * velocity. The faster the velocity, the more "linear" the interpolator gets.
-     *
-     * @param velocity the velocity of the gesture.
-     * @return the y2 control point for a cubic bezier path interpolator
-     */
-    private float calculateLinearOutFasterInY2(float velocity) {
-        float t = (velocity - mMinVelocityPxPerSecond)
-                / (mHighVelocityPxPerSecond - mMinVelocityPxPerSecond);
-        t = Math.max(0, Math.min(1, t));
-        return (1 - t) * LINEAR_OUT_FASTER_IN_Y2_MIN + t * LINEAR_OUT_FASTER_IN_Y2_MAX;
-    }
-
-    /**
-     * @return the minimum velocity a gesture needs to have to be considered a fling
-     */
-    public float getMinVelocityPxPerSecond() {
-        return mMinVelocityPxPerSecond;
-    }
-
-    /**
-     * An interpolator which interpolates two interpolators with an interpolator.
-     */
-    private static final class InterpolatorInterpolator implements Interpolator {
-
-        private Interpolator mInterpolator1;
-        private Interpolator mInterpolator2;
-        private Interpolator mCrossfader;
-
-        InterpolatorInterpolator(Interpolator interpolator1, Interpolator interpolator2,
-                Interpolator crossfader) {
-            mInterpolator1 = interpolator1;
-            mInterpolator2 = interpolator2;
-            mCrossfader = crossfader;
-        }
-
-        @Override
-        public float getInterpolation(float input) {
-            float t = mCrossfader.getInterpolation(input);
-            return (1 - t) * mInterpolator1.getInterpolation(input)
-                    + t * mInterpolator2.getInterpolation(input);
-        }
-    }
-
-    /**
-     * An interpolator which interpolates with a fixed velocity.
-     */
-    private static final class VelocityInterpolator implements Interpolator {
-
-        private float mDurationSeconds;
-        private float mVelocity;
-        private float mDiff;
-
-        private VelocityInterpolator(float durationSeconds, float velocity, float diff) {
-            mDurationSeconds = durationSeconds;
-            mVelocity = velocity;
-            mDiff = diff;
-        }
-
-        @Override
-        public float getInterpolation(float input) {
-            float time = input * mDurationSeconds;
-            return time * mVelocity / mDiff;
-        }
-    }
-
-    private static class AnimatorProperties {
-        Interpolator interpolator;
-        long duration;
-    }
-
-}
diff --git a/src/com/android/launcher3/notification/NotificationItemView.java b/src/com/android/launcher3/notification/NotificationItemView.java
index 11f6aa0..78c64d7 100644
--- a/src/com/android/launcher3/notification/NotificationItemView.java
+++ b/src/com/android/launcher3/notification/NotificationItemView.java
@@ -37,6 +37,7 @@
 import com.android.launcher3.graphics.IconPalette;
 import com.android.launcher3.logging.UserEventDispatcher.LogContainerProvider;
 import com.android.launcher3.popup.PopupItemView;
+import com.android.launcher3.touch.SwipeDetector;
 import com.android.launcher3.userevent.nano.LauncherLogProto;
 import com.android.launcher3.util.Themes;
 
@@ -56,7 +57,7 @@
     private TextView mHeaderCount;
     private NotificationMainView mMainView;
     private NotificationFooterLayout mFooter;
-    private SwipeHelper mSwipeHelper;
+    private SwipeDetector mSwipeDetector;
     private boolean mAnimatingNextIcon;
     private int mNotificationHeaderTextColor = Notification.COLOR_DEFAULT;
 
@@ -75,12 +76,14 @@
     @Override
     protected void onFinishInflate() {
         super.onFinishInflate();
-        mHeaderText = (TextView) findViewById(R.id.notification_text);
-        mHeaderCount = (TextView) findViewById(R.id.notification_count);
-        mMainView = (NotificationMainView) findViewById(R.id.main_view);
-        mFooter = (NotificationFooterLayout) findViewById(R.id.footer);
-        mSwipeHelper = new SwipeHelper(SwipeHelper.X, mMainView, getContext());
-        mSwipeHelper.setDisableHardwareLayers(true);
+        mHeaderText = findViewById(R.id.notification_text);
+        mHeaderCount = findViewById(R.id.notification_count);
+        mMainView = findViewById(R.id.main_view);
+        mFooter = findViewById(R.id.footer);
+
+        mSwipeDetector = new SwipeDetector(getContext(), mMainView, SwipeDetector.HORIZONTAL);
+        mSwipeDetector.setDetectableScrollConditions(SwipeDetector.DIRECTION_BOTH, false);
+        mMainView.setSwipeDetector(mSwipeDetector);
     }
 
     public NotificationMainView getMainView() {
@@ -136,7 +139,8 @@
             return false;
         }
         getParent().requestDisallowInterceptTouchEvent(true);
-        return mSwipeHelper.onInterceptTouchEvent(ev);
+        mSwipeDetector.onTouchEvent(ev);
+        return mSwipeDetector.isDraggingOrSettling();
     }
 
     @Override
@@ -145,7 +149,7 @@
             // The notification hasn't been populated yet.
             return false;
         }
-        return mSwipeHelper.onTouchEvent(ev) || super.onTouchEvent(ev);
+        return mSwipeDetector.onTouchEvent(ev) || super.onTouchEvent(ev);
     }
 
     public void applyNotificationInfos(final List<NotificationInfo> notificationInfos) {
diff --git a/src/com/android/launcher3/notification/NotificationMainView.java b/src/com/android/launcher3/notification/NotificationMainView.java
index 9b8dd64..5aff28d 100644
--- a/src/com/android/launcher3/notification/NotificationMainView.java
+++ b/src/com/android/launcher3/notification/NotificationMainView.java
@@ -23,15 +23,17 @@
 import android.graphics.drawable.RippleDrawable;
 import android.text.TextUtils;
 import android.util.AttributeSet;
-import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.ViewPropertyAnimator;
 import android.widget.FrameLayout;
 import android.widget.TextView;
 
 import com.android.launcher3.ItemInfo;
 import com.android.launcher3.Launcher;
 import com.android.launcher3.R;
+import com.android.launcher3.touch.OverScroll;
+import com.android.launcher3.touch.SwipeDetector;
 import com.android.launcher3.userevent.nano.LauncherLogProto;
 import com.android.launcher3.util.Themes;
 
@@ -39,7 +41,7 @@
  * A {@link android.widget.FrameLayout} that contains a single notification,
  * e.g. icon + title + text.
  */
-public class NotificationMainView extends FrameLayout implements SwipeHelper.Callback {
+public class NotificationMainView extends FrameLayout implements SwipeDetector.Listener {
 
     private NotificationInfo mNotificationInfo;
     private ViewGroup mTextAndBackground;
@@ -47,6 +49,8 @@
     private TextView mTitleView;
     private TextView mTextView;
 
+    private SwipeDetector mSwipeDetector;
+
     public NotificationMainView(Context context) {
         this(context, null, 0);
     }
@@ -78,6 +82,10 @@
         applyNotificationInfo(mainNotification, iconView, false);
     }
 
+    public void setSwipeDetector(SwipeDetector swipeDetector) {
+        mSwipeDetector = swipeDetector;
+    }
+
     /**
      * Sets the content of this view, animating it after a new icon shifts up if necessary.
      */
@@ -113,29 +121,11 @@
     }
 
 
-    // SwipeHelper.Callback's
-
-    @Override
-    public View getChildAtPosition(MotionEvent ev) {
-        return this;
-    }
-
-    @Override
-    public boolean canChildBeDismissed(View v) {
+    public boolean canChildBeDismissed() {
         return mNotificationInfo != null && mNotificationInfo.dismissable;
     }
 
-    @Override
-    public boolean isAntiFalsingNeeded() {
-        return false;
-    }
-
-    @Override
-    public void onBeginDrag(View v) {
-    }
-
-    @Override
-    public void onChildDismissed(View v) {
+    public void onChildDismissed() {
         Launcher launcher = Launcher.getLauncher(getContext());
         launcher.getPopupDataProvider().cancelNotification(
                 mNotificationInfo.notificationKey);
@@ -145,22 +135,55 @@
                 LauncherLogProto.ItemType.NOTIFICATION);
     }
 
+    // SwipeDetector.Listener's
     @Override
-    public void onDragCancelled(View v) {
-    }
+    public void onDragStart(boolean start) { }
+
 
     @Override
-    public void onChildSnappedBack(View animView, float targetLeft) {
-    }
-
-    @Override
-    public boolean updateSwipeProgress(View animView, boolean dismissable, float swipeProgress) {
-        // Don't fade out.
+    public boolean onDrag(float displacement, float velocity) {
+        setTranslationX(canChildBeDismissed()
+                ? displacement : OverScroll.dampedScroll(displacement, getWidth()));
+        animate().cancel();
         return true;
     }
 
     @Override
-    public float getFalsingThresholdFactor() {
-        return 1;
+    public void onDragEnd(float velocity, boolean fling) {
+        final boolean willExit;
+        final float endTranslation;
+
+        if (!canChildBeDismissed()) {
+            willExit = false;
+            endTranslation = 0;
+        } else if (fling) {
+            willExit = true;
+            endTranslation = velocity < 0 ? - getWidth() : getWidth();
+        } else if (Math.abs(getTranslationX()) > getWidth() / 2) {
+            willExit = true;
+            endTranslation = (getTranslationX() < 0 ? -getWidth() : getWidth());
+        } else {
+            willExit = false;
+            endTranslation = 0;
+        }
+
+        SwipeDetector.ScrollInterpolator interpolator = new SwipeDetector.ScrollInterpolator();
+        interpolator.setVelocityAtZero(velocity);
+
+        long duration = SwipeDetector.calculateDuration(velocity,
+                (endTranslation - getTranslationX()) / getWidth());
+        animate()
+                .setDuration(duration)
+                .setInterpolator(interpolator)
+                .translationX(endTranslation)
+                .withEndAction(new Runnable() {
+                    @Override
+                    public void run() {
+                        mSwipeDetector.finishedScrolling();
+                        if (willExit) {
+                            onChildDismissed();
+                        }
+                    }
+                }).start();
     }
 }
diff --git a/src/com/android/launcher3/notification/SwipeHelper.java b/src/com/android/launcher3/notification/SwipeHelper.java
deleted file mode 100644
index ebbe5fc..0000000
--- a/src/com/android/launcher3/notification/SwipeHelper.java
+++ /dev/null
@@ -1,687 +0,0 @@
-/*
- * 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.notification;
-
-import android.animation.Animator;
-import android.animation.AnimatorListenerAdapter;
-import android.animation.ObjectAnimator;
-import android.animation.ValueAnimator;
-import android.animation.ValueAnimator.AnimatorUpdateListener;
-import android.content.Context;
-import android.graphics.RectF;
-import android.os.Handler;
-import android.util.ArrayMap;
-import android.util.Log;
-import android.view.MotionEvent;
-import android.view.VelocityTracker;
-import android.view.View;
-import android.view.ViewConfiguration;
-import android.view.accessibility.AccessibilityEvent;
-import com.android.launcher3.R;
-
-/**
- * This class was copied from com.android.systemui.
- */
-public class SwipeHelper {
-    private static final String TAG = "SwipeHelper";
-    private static final boolean DEBUG_INVALIDATE = false;
-    private static final boolean SLOW_ANIMATIONS = false; // DEBUG;
-    private static final boolean CONSTRAIN_SWIPE = true;
-    private static final boolean FADE_OUT_DURING_SWIPE = true;
-    private static final boolean DISMISS_IF_SWIPED_FAR_ENOUGH = true;
-
-    public static final int X = 0;
-    public static final int Y = 1;
-
-    private static final float SWIPE_ESCAPE_VELOCITY = 100f; // dp/sec
-    private static final int DEFAULT_ESCAPE_ANIMATION_DURATION = 200; // ms
-    private static final int MAX_ESCAPE_ANIMATION_DURATION = 400; // ms
-    private static final int MAX_DISMISS_VELOCITY = 4000; // dp/sec
-    private static final int SNAP_ANIM_LEN = SLOW_ANIMATIONS ? 1000 : 150; // ms
-
-    static final float SWIPE_PROGRESS_FADE_END = 0.5f; // fraction of thumbnail width
-                                                // beyond which swipe progress->0
-    private float mMinSwipeProgress = 0f;
-    private float mMaxSwipeProgress = 1f;
-
-    private final FlingAnimationUtils mFlingAnimationUtils;
-    private float mPagingTouchSlop;
-    private final Callback mCallback;
-    private final Handler mHandler;
-    private final int mSwipeDirection;
-    private final VelocityTracker mVelocityTracker;
-
-    private float mInitialTouchPos;
-    private float mPerpendicularInitialTouchPos;
-    private boolean mDragging;
-    private boolean mSnappingChild;
-    private View mCurrView;
-    private boolean mCanCurrViewBeDimissed;
-    private float mDensityScale;
-    private float mTranslation = 0;
-
-    private boolean mLongPressSent;
-    private LongPressListener mLongPressListener;
-    private Runnable mWatchLongPress;
-    private final long mLongPressTimeout;
-
-    final private int[] mTmpPos = new int[2];
-    private final int mFalsingThreshold;
-    private boolean mTouchAboveFalsingThreshold;
-    private boolean mDisableHwLayers;
-
-    private final ArrayMap<View, Animator> mDismissPendingMap = new ArrayMap<>();
-
-    public SwipeHelper(int swipeDirection, Callback callback, Context context) {
-        mCallback = callback;
-        mHandler = new Handler();
-        mSwipeDirection = swipeDirection;
-        mVelocityTracker = VelocityTracker.obtain();
-        mDensityScale =  context.getResources().getDisplayMetrics().density;
-        mPagingTouchSlop = ViewConfiguration.get(context).getScaledPagingTouchSlop();
-
-        mLongPressTimeout = (long) (ViewConfiguration.getLongPressTimeout() * 1.5f); // extra long-press!
-        mFalsingThreshold = context.getResources().getDimensionPixelSize(
-                R.dimen.swipe_helper_falsing_threshold);
-        mFlingAnimationUtils = new FlingAnimationUtils(context, getMaxEscapeAnimDuration() / 1000f);
-    }
-
-    public void setLongPressListener(LongPressListener listener) {
-        mLongPressListener = listener;
-    }
-
-    public void setDensityScale(float densityScale) {
-        mDensityScale = densityScale;
-    }
-
-    public void setPagingTouchSlop(float pagingTouchSlop) {
-        mPagingTouchSlop = pagingTouchSlop;
-    }
-
-    public void setDisableHardwareLayers(boolean disableHwLayers) {
-        mDisableHwLayers = disableHwLayers;
-    }
-
-    private float getPos(MotionEvent ev) {
-        return mSwipeDirection == X ? ev.getX() : ev.getY();
-    }
-
-    private float getPerpendicularPos(MotionEvent ev) {
-        return mSwipeDirection == X ? ev.getY() : ev.getX();
-    }
-
-    protected float getTranslation(View v) {
-        return mSwipeDirection == X ? v.getTranslationX() : v.getTranslationY();
-    }
-
-    private float getVelocity(VelocityTracker vt) {
-        return mSwipeDirection == X ? vt.getXVelocity() :
-                vt.getYVelocity();
-    }
-
-    protected ObjectAnimator createTranslationAnimation(View v, float newPos) {
-        ObjectAnimator anim = ObjectAnimator.ofFloat(v,
-                mSwipeDirection == X ? View.TRANSLATION_X : View.TRANSLATION_Y, newPos);
-        return anim;
-    }
-
-    private float getPerpendicularVelocity(VelocityTracker vt) {
-        return mSwipeDirection == X ? vt.getYVelocity() :
-                vt.getXVelocity();
-    }
-
-    protected Animator getViewTranslationAnimator(View v, float target,
-            AnimatorUpdateListener listener) {
-        ObjectAnimator anim = createTranslationAnimation(v, target);
-        if (listener != null) {
-            anim.addUpdateListener(listener);
-        }
-        return anim;
-    }
-
-    protected void setTranslation(View v, float translate) {
-        if (v == null) {
-            return;
-        }
-        if (mSwipeDirection == X) {
-            v.setTranslationX(translate);
-        } else {
-            v.setTranslationY(translate);
-        }
-    }
-
-    protected float getSize(View v) {
-        return mSwipeDirection == X ? v.getMeasuredWidth() :
-                v.getMeasuredHeight();
-    }
-
-    public void setMinSwipeProgress(float minSwipeProgress) {
-        mMinSwipeProgress = minSwipeProgress;
-    }
-
-    public void setMaxSwipeProgress(float maxSwipeProgress) {
-        mMaxSwipeProgress = maxSwipeProgress;
-    }
-
-    private float getSwipeProgressForOffset(View view, float translation) {
-        float viewSize = getSize(view);
-        float result = Math.abs(translation / viewSize);
-        return Math.min(Math.max(mMinSwipeProgress, result), mMaxSwipeProgress);
-    }
-
-    private float getSwipeAlpha(float progress) {
-        return Math.min(0, Math.max(1, progress / SWIPE_PROGRESS_FADE_END));
-    }
-
-    private void updateSwipeProgressFromOffset(View animView, boolean dismissable) {
-        updateSwipeProgressFromOffset(animView, dismissable, getTranslation(animView));
-    }
-
-    private void updateSwipeProgressFromOffset(View animView, boolean dismissable,
-            float translation) {
-        float swipeProgress = getSwipeProgressForOffset(animView, translation);
-        if (!mCallback.updateSwipeProgress(animView, dismissable, swipeProgress)) {
-            if (FADE_OUT_DURING_SWIPE && dismissable) {
-                float alpha = swipeProgress;
-                if (!mDisableHwLayers) {
-                    if (alpha != 0f && alpha != 1f) {
-                        animView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
-                    } else {
-                        animView.setLayerType(View.LAYER_TYPE_NONE, null);
-                    }
-                }
-                animView.setAlpha(getSwipeAlpha(swipeProgress));
-            }
-        }
-        invalidateGlobalRegion(animView);
-    }
-
-    // invalidate the view's own bounds all the way up the view hierarchy
-    public static void invalidateGlobalRegion(View view) {
-        invalidateGlobalRegion(
-                view,
-                new RectF(view.getLeft(), view.getTop(), view.getRight(), view.getBottom()));
-    }
-
-    // invalidate a rectangle relative to the view's coordinate system all the way up the view
-    // hierarchy
-    public static void invalidateGlobalRegion(View view, RectF childBounds) {
-        //childBounds.offset(view.getTranslationX(), view.getTranslationY());
-        if (DEBUG_INVALIDATE)
-            Log.v(TAG, "-------------");
-        while (view.getParent() != null && view.getParent() instanceof View) {
-            view = (View) view.getParent();
-            view.getMatrix().mapRect(childBounds);
-            view.invalidate((int) Math.floor(childBounds.left),
-                    (int) Math.floor(childBounds.top),
-                    (int) Math.ceil(childBounds.right),
-                    (int) Math.ceil(childBounds.bottom));
-            if (DEBUG_INVALIDATE) {
-                Log.v(TAG, "INVALIDATE(" + (int) Math.floor(childBounds.left)
-                        + "," + (int) Math.floor(childBounds.top)
-                        + "," + (int) Math.ceil(childBounds.right)
-                        + "," + (int) Math.ceil(childBounds.bottom));
-            }
-        }
-    }
-
-    public void removeLongPressCallback() {
-        if (mWatchLongPress != null) {
-            mHandler.removeCallbacks(mWatchLongPress);
-            mWatchLongPress = null;
-        }
-    }
-
-    public boolean onInterceptTouchEvent(final MotionEvent ev) {
-        final int action = ev.getAction();
-
-        switch (action) {
-            case MotionEvent.ACTION_DOWN:
-                mTouchAboveFalsingThreshold = false;
-                mDragging = false;
-                mSnappingChild = false;
-                mLongPressSent = false;
-                mVelocityTracker.clear();
-                mCurrView = mCallback.getChildAtPosition(ev);
-
-                if (mCurrView != null) {
-                    onDownUpdate(mCurrView);
-                    mCanCurrViewBeDimissed = mCallback.canChildBeDismissed(mCurrView);
-                    mVelocityTracker.addMovement(ev);
-                    mInitialTouchPos = getPos(ev);
-                    mPerpendicularInitialTouchPos = getPerpendicularPos(ev);
-                    mTranslation = getTranslation(mCurrView);
-                    if (mLongPressListener != null) {
-                        if (mWatchLongPress == null) {
-                            mWatchLongPress = new Runnable() {
-                                @Override
-                                public void run() {
-                                    if (mCurrView != null && !mLongPressSent) {
-                                        mLongPressSent = true;
-                                        mCurrView.sendAccessibilityEvent(
-                                                AccessibilityEvent.TYPE_VIEW_LONG_CLICKED);
-                                        mCurrView.getLocationOnScreen(mTmpPos);
-                                        final int x = (int) ev.getRawX() - mTmpPos[0];
-                                        final int y = (int) ev.getRawY() - mTmpPos[1];
-                                        mLongPressListener.onLongPress(mCurrView, x, y);
-                                    }
-                                }
-                            };
-                        }
-                        mHandler.postDelayed(mWatchLongPress, mLongPressTimeout);
-                    }
-                }
-                break;
-
-            case MotionEvent.ACTION_MOVE:
-                if (mCurrView != null && !mLongPressSent) {
-                    mVelocityTracker.addMovement(ev);
-                    float pos = getPos(ev);
-                    float perpendicularPos = getPerpendicularPos(ev);
-                    float delta = pos - mInitialTouchPos;
-                    float deltaPerpendicular = perpendicularPos - mPerpendicularInitialTouchPos;
-                    if (Math.abs(delta) > mPagingTouchSlop
-                            && Math.abs(delta) > Math.abs(deltaPerpendicular)) {
-                        mCallback.onBeginDrag(mCurrView);
-                        mDragging = true;
-                        mInitialTouchPos = getPos(ev);
-                        mTranslation = getTranslation(mCurrView);
-                        removeLongPressCallback();
-                    }
-                }
-                break;
-
-            case MotionEvent.ACTION_UP:
-            case MotionEvent.ACTION_CANCEL:
-                final boolean captured = (mDragging || mLongPressSent);
-                mDragging = false;
-                mCurrView = null;
-                mLongPressSent = false;
-                removeLongPressCallback();
-                if (captured) return true;
-                break;
-        }
-        return mDragging || mLongPressSent;
-    }
-
-    /**
-     * @param view The view to be dismissed
-     * @param velocity The desired pixels/second speed at which the view should move
-     * @param useAccelerateInterpolator Should an accelerating Interpolator be used
-     */
-    public void dismissChild(final View view, float velocity, boolean useAccelerateInterpolator) {
-        dismissChild(view, velocity, null /* endAction */, 0 /* delay */,
-                useAccelerateInterpolator, 0 /* fixedDuration */, false /* isDismissAll */);
-    }
-
-    /**
-     * @param animView The view to be dismissed
-     * @param velocity The desired pixels/second speed at which the view should move
-     * @param endAction The action to perform at the end
-     * @param delay The delay after which we should start
-     * @param useAccelerateInterpolator Should an accelerating Interpolator be used
-     * @param fixedDuration If not 0, this exact duration will be taken
-     */
-    public void dismissChild(final View animView, float velocity, final Runnable endAction,
-            long delay, boolean useAccelerateInterpolator, long fixedDuration,
-            boolean isDismissAll) {
-        final boolean canBeDismissed = mCallback.canChildBeDismissed(animView);
-        float newPos;
-        boolean isLayoutRtl = animView.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
-
-        // if we use the Menu to dismiss an item in landscape, animate up
-        boolean animateUpForMenu = velocity == 0 && (getTranslation(animView) == 0 || isDismissAll)
-                && mSwipeDirection == Y;
-        // if the language is rtl we prefer swiping to the left
-        boolean animateLeftForRtl = velocity == 0 && (getTranslation(animView) == 0 || isDismissAll)
-                && isLayoutRtl;
-        boolean animateLeft = velocity < 0
-                || (velocity == 0 && getTranslation(animView) < 0 && !isDismissAll);
-
-        if (animateLeft || animateLeftForRtl || animateUpForMenu) {
-            newPos = -getSize(animView);
-        } else {
-            newPos = getSize(animView);
-        }
-        long duration;
-        if (fixedDuration == 0) {
-            duration = MAX_ESCAPE_ANIMATION_DURATION;
-            if (velocity != 0) {
-                duration = Math.min(duration,
-                        (int) (Math.abs(newPos - getTranslation(animView)) * 1000f / Math
-                                .abs(velocity))
-                );
-            } else {
-                duration = DEFAULT_ESCAPE_ANIMATION_DURATION;
-            }
-        } else {
-            duration = fixedDuration;
-        }
-
-        if (!mDisableHwLayers) {
-            animView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
-        }
-        AnimatorUpdateListener updateListener = new AnimatorUpdateListener() {
-            public void onAnimationUpdate(ValueAnimator animation) {
-                onTranslationUpdate(animView, (float) animation.getAnimatedValue(), canBeDismissed);
-            }
-        };
-
-        Animator anim = getViewTranslationAnimator(animView, newPos, updateListener);
-        if (anim == null) {
-            return;
-        }
-        if (useAccelerateInterpolator) {
-            anim.setInterpolator(Interpolators.FAST_OUT_LINEAR_IN);
-            anim.setDuration(duration);
-        } else {
-            mFlingAnimationUtils.applyDismissing(anim, getTranslation(animView),
-                    newPos, velocity, getSize(animView));
-        }
-        if (delay > 0) {
-            anim.setStartDelay(delay);
-        }
-        anim.addListener(new AnimatorListenerAdapter() {
-            private boolean mCancelled;
-
-            public void onAnimationCancel(Animator animation) {
-                mCancelled = true;
-            }
-
-            public void onAnimationEnd(Animator animation) {
-                updateSwipeProgressFromOffset(animView, canBeDismissed);
-                mDismissPendingMap.remove(animView);
-                if (!mCancelled) {
-                    mCallback.onChildDismissed(animView);
-                }
-                if (endAction != null) {
-                    endAction.run();
-                }
-                if (!mDisableHwLayers) {
-                    animView.setLayerType(View.LAYER_TYPE_NONE, null);
-                }
-            }
-        });
-
-        prepareDismissAnimation(animView, anim);
-        mDismissPendingMap.put(animView, anim);
-        anim.start();
-    }
-
-    /**
-     * Called to update the dismiss animation.
-     */
-    protected void prepareDismissAnimation(View view, Animator anim) {
-        // Do nothing
-    }
-
-    public void snapChild(final View animView, final float targetLeft, float velocity) {
-        final boolean canBeDismissed = mCallback.canChildBeDismissed(animView);
-        AnimatorUpdateListener updateListener = new AnimatorUpdateListener() {
-            public void onAnimationUpdate(ValueAnimator animation) {
-                onTranslationUpdate(animView, (float) animation.getAnimatedValue(), canBeDismissed);
-            }
-        };
-
-        Animator anim = getViewTranslationAnimator(animView, targetLeft, updateListener);
-        if (anim == null) {
-            return;
-        }
-        int duration = SNAP_ANIM_LEN;
-        anim.setDuration(duration);
-        anim.addListener(new AnimatorListenerAdapter() {
-            public void onAnimationEnd(Animator animator) {
-                mSnappingChild = false;
-                updateSwipeProgressFromOffset(animView, canBeDismissed);
-                mCallback.onChildSnappedBack(animView, targetLeft);
-            }
-        });
-        prepareSnapBackAnimation(animView, anim);
-        mSnappingChild = true;
-        anim.start();
-    }
-
-    /**
-     * Called to update the snap back animation.
-     */
-    protected void prepareSnapBackAnimation(View view, Animator anim) {
-        // Do nothing
-    }
-
-    /**
-     * Called when there's a down event.
-     */
-    public void onDownUpdate(View currView) {
-        // Do nothing
-    }
-
-    /**
-     * Called on a move event.
-     */
-    protected void onMoveUpdate(View view, float totalTranslation, float delta) {
-        // Do nothing
-    }
-
-    /**
-     * Called in {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)} when the current
-     * view is being animated to dismiss or snap.
-     */
-    public void onTranslationUpdate(View animView, float value, boolean canBeDismissed) {
-        updateSwipeProgressFromOffset(animView, canBeDismissed, value);
-    }
-
-    private void snapChildInstantly(final View view) {
-        final boolean canAnimViewBeDismissed = mCallback.canChildBeDismissed(view);
-        setTranslation(view, 0);
-        updateSwipeProgressFromOffset(view, canAnimViewBeDismissed);
-    }
-
-    /**
-     * Called when a view is updated to be non-dismissable, if the view was being dismissed before
-     * the update this will handle snapping it back into place.
-     *
-     * @param view the view to snap if necessary.
-     * @param animate whether to animate the snap or not.
-     * @param targetLeft the target to snap to.
-     */
-    public void snapChildIfNeeded(final View view, boolean animate, float targetLeft) {
-        if ((mDragging && mCurrView == view) || mSnappingChild) {
-            return;
-        }
-        boolean needToSnap = false;
-        Animator dismissPendingAnim = mDismissPendingMap.get(view);
-        if (dismissPendingAnim != null) {
-            needToSnap = true;
-            dismissPendingAnim.cancel();
-        } else if (getTranslation(view) != 0) {
-            needToSnap = true;
-        }
-        if (needToSnap) {
-            if (animate) {
-                snapChild(view, targetLeft, 0.0f /* velocity */);
-            } else {
-                snapChildInstantly(view);
-            }
-        }
-    }
-
-    public boolean onTouchEvent(MotionEvent ev) {
-        if (mLongPressSent) {
-            return true;
-        }
-
-        if (!mDragging) {
-            if (mCallback.getChildAtPosition(ev) != null) {
-
-                // We are dragging directly over a card, make sure that we also catch the gesture
-                // even if nobody else wants the touch event.
-                onInterceptTouchEvent(ev);
-                 return true;
-            } else {
-
-                // We are not doing anything, make sure the long press callback
-                // is not still ticking like a bomb waiting to go off.
-                removeLongPressCallback();
-                return false;
-            }
-        }
-
-        mVelocityTracker.addMovement(ev);
-        final int action = ev.getAction();
-        switch (action) {
-            case MotionEvent.ACTION_OUTSIDE:
-            case MotionEvent.ACTION_MOVE:
-                if (mCurrView != null) {
-                    float delta = getPos(ev) - mInitialTouchPos;
-                    float absDelta = Math.abs(delta);
-                    if (absDelta >= getFalsingThreshold()) {
-                        mTouchAboveFalsingThreshold = true;
-                    }
-                    // don't let items that can't be dismissed be dragged more than
-                    // maxScrollDistance
-                    if (CONSTRAIN_SWIPE && !mCallback.canChildBeDismissed(mCurrView)) {
-                        float size = getSize(mCurrView);
-                        float maxScrollDistance = 0.25f * size;
-                        if (absDelta >= size) {
-                            delta = delta > 0 ? maxScrollDistance : -maxScrollDistance;
-                        } else {
-                            delta = maxScrollDistance * (float) Math.sin((delta/size)*(Math.PI/2));
-                        }
-                    }
-
-                    setTranslation(mCurrView, mTranslation + delta);
-                    updateSwipeProgressFromOffset(mCurrView, mCanCurrViewBeDimissed);
-                    onMoveUpdate(mCurrView, mTranslation + delta, delta);
-                }
-                break;
-            case MotionEvent.ACTION_UP:
-            case MotionEvent.ACTION_CANCEL:
-                if (mCurrView == null) {
-                    break;
-                }
-                mVelocityTracker.computeCurrentVelocity(1000 /* px/sec */, getMaxVelocity());
-                float velocity = getVelocity(mVelocityTracker);
-
-                if (!handleUpEvent(ev, mCurrView, velocity, getTranslation(mCurrView))) {
-                    if (isDismissGesture(ev)) {
-                        // flingadingy
-                        dismissChild(mCurrView, velocity,
-                                !swipedFastEnough() /* useAccelerateInterpolator */);
-                    } else {
-                        // snappity
-                        mCallback.onDragCancelled(mCurrView);
-                        snapChild(mCurrView, 0 /* leftTarget */, velocity);
-                    }
-                    mCurrView = null;
-                }
-                mDragging = false;
-                break;
-        }
-        return true;
-    }
-
-    private int getFalsingThreshold() {
-        float factor = mCallback.getFalsingThresholdFactor();
-        return (int) (mFalsingThreshold * factor);
-    }
-
-    private float getMaxVelocity() {
-        return MAX_DISMISS_VELOCITY * mDensityScale;
-    }
-
-    protected float getEscapeVelocity() {
-        return getUnscaledEscapeVelocity() * mDensityScale;
-    }
-
-    protected float getUnscaledEscapeVelocity() {
-        return SWIPE_ESCAPE_VELOCITY;
-    }
-
-    protected long getMaxEscapeAnimDuration() {
-        return MAX_ESCAPE_ANIMATION_DURATION;
-    }
-
-    protected boolean swipedFarEnough() {
-        float translation = getTranslation(mCurrView);
-        return DISMISS_IF_SWIPED_FAR_ENOUGH && Math.abs(translation) > 0.4 * getSize(mCurrView);
-    }
-
-    protected boolean isDismissGesture(MotionEvent ev) {
-        boolean falsingDetected = mCallback.isAntiFalsingNeeded() && !mTouchAboveFalsingThreshold;
-        return !falsingDetected && (swipedFastEnough() || swipedFarEnough())
-                && ev.getActionMasked() == MotionEvent.ACTION_UP
-                && mCallback.canChildBeDismissed(mCurrView);
-    }
-
-    protected boolean swipedFastEnough() {
-        float velocity = getVelocity(mVelocityTracker);
-        float translation = getTranslation(mCurrView);
-        boolean ret = (Math.abs(velocity) > getEscapeVelocity())
-                && (velocity > 0) == (translation > 0);
-        return ret;
-    }
-
-    protected boolean handleUpEvent(MotionEvent ev, View animView, float velocity,
-            float translation) {
-        return false;
-    }
-
-    public interface Callback {
-        View getChildAtPosition(MotionEvent ev);
-
-        boolean canChildBeDismissed(View v);
-
-        boolean isAntiFalsingNeeded();
-
-        void onBeginDrag(View v);
-
-        void onChildDismissed(View v);
-
-        void onDragCancelled(View v);
-
-        /**
-         * Called when the child is snapped to a position.
-         *
-         * @param animView the view that was snapped.
-         * @param targetLeft the left position the view was snapped to.
-         */
-        void onChildSnappedBack(View animView, float targetLeft);
-
-        /**
-         * Updates the swipe progress on a child.
-         *
-         * @return if true, prevents the default alpha fading.
-         */
-        boolean updateSwipeProgress(View animView, boolean dismissable, float swipeProgress);
-
-        /**
-         * @return The factor the falsing threshold should be multiplied with
-         */
-        float getFalsingThresholdFactor();
-    }
-
-    /**
-     * Equivalent to View.OnLongClickListener with coordinates
-     */
-    public interface LongPressListener {
-        /**
-         * Equivalent to {@link View.OnLongClickListener#onLongClick(View)} with coordinates
-         * @return whether the longpress was handled
-         */
-        boolean onLongPress(View v, int x, int y);
-    }
-}
\ No newline at end of file
diff --git a/src/com/android/launcher3/touch/OverScroll.java b/src/com/android/launcher3/touch/OverScroll.java
new file mode 100644
index 0000000..dc801ec
--- /dev/null
+++ b/src/com/android/launcher3/touch/OverScroll.java
@@ -0,0 +1,55 @@
+/*
+ * 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.touch;
+
+/**
+ * Utility methods for overscroll damping and related effect.
+ */
+public class OverScroll {
+
+    private static final float OVERSCROLL_DAMP_FACTOR = 0.07f;
+
+    /**
+     * This curve determines how the effect of scrolling over the limits of the page diminishes
+     * as the user pulls further and further from the bounds
+     *
+     * @param f The percentage of how much the user has overscrolled.
+     * @return A transformed percentage based on the influence curve.
+     */
+    private static float overScrollInfluenceCurve(float f) {
+        f -= 1.0f;
+        return f * f * f + 1.0f;
+    }
+
+    /**
+     * @param amount The original amount overscrolled.
+     * @param max The maximum amount that the View can overscroll.
+     * @return The dampened overscroll amount.
+     */
+    public static int dampedScroll(float amount, int max) {
+        if (Float.compare(amount, 0) == 0) return 0;
+
+        float f = amount / max;
+        f = f / (Math.abs(f)) * (overScrollInfluenceCurve(Math.abs(f)));
+
+        // Clamp this factor, f, to -1 < f < 1
+        if (Math.abs(f) >= 1) {
+            f /= Math.abs(f);
+        }
+
+        return Math.round(OVERSCROLL_DAMP_FACTOR * f * max);
+    }
+}
diff --git a/src/com/android/launcher3/touch/SwipeDetector.java b/src/com/android/launcher3/touch/SwipeDetector.java
index ec5493b..be4648e 100644
--- a/src/com/android/launcher3/touch/SwipeDetector.java
+++ b/src/com/android/launcher3/touch/SwipeDetector.java
@@ -1,7 +1,25 @@
+/*
+ * 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.touch;
 
 import static android.view.MotionEvent.INVALID_POINTER_ID;
 import android.content.Context;
+import android.graphics.PointF;
+import android.support.annotation.NonNull;
+import android.support.annotation.VisibleForTesting;
 import android.util.Log;
 import android.view.MotionEvent;
 import android.view.ViewConfiguration;
@@ -9,18 +27,20 @@
 
 /**
  * One dimensional scroll/drag/swipe gesture detector.
+ *
+ * Definition of swipe is different from android system in that this detector handles
+ * 'swipe to dismiss', 'swiping up/down a container' but also keeps scrolling state before
+ * swipe action happens
  */
 public class SwipeDetector {
 
     private static final boolean DBG = false;
     private static final String TAG = "SwipeDetector";
 
-    private final float mTouchSlop;
-
     private int mScrollConditions;
-    public static final int DIRECTION_UP = 1 << 0;
-    public static final int DIRECTION_DOWN = 1 << 1;
-    public static final int DIRECTION_BOTH = DIRECTION_DOWN | DIRECTION_UP;
+    public static final int DIRECTION_POSITIVE = 1 << 0;
+    public static final int DIRECTION_NEGATIVE = 1 << 1;
+    public static final int DIRECTION_BOTH = DIRECTION_NEGATIVE | DIRECTION_POSITIVE;
 
     private static final float ANIMATION_DURATION = 1200;
     private static final float FAST_FLING_PX_MS = 10;
@@ -47,6 +67,42 @@
         SETTLING       // onDragEnd
     }
 
+    public static abstract class Direction {
+
+        abstract float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint);
+
+        /**
+         * Distance in pixels a touch can wander before we think the user is scrolling.
+         */
+        abstract float getActiveTouchSlop(MotionEvent ev, int pointerIndex, PointF downPos);
+    }
+
+    public static final Direction VERTICAL = new Direction() {
+
+        @Override
+        float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint) {
+            return ev.getY(pointerIndex) - refPoint.y;
+        }
+
+        @Override
+        float getActiveTouchSlop(MotionEvent ev, int pointerIndex, PointF downPos) {
+            return Math.abs(ev.getX(pointerIndex) - downPos.x);
+        }
+    };
+
+    public static final Direction HORIZONTAL = new Direction() {
+
+        @Override
+        float getDisplacement(MotionEvent ev, int pointerIndex, PointF refPoint) {
+            return ev.getX(pointerIndex) - refPoint.x;
+        }
+
+        @Override
+        float getActiveTouchSlop(MotionEvent ev, int pointerIndex, PointF downPos) {
+            return Math.abs(ev.getY(pointerIndex) - downPos.y);
+        }
+    };
+
     //------------------- ScrollState transition diagram -----------------------------------
     //
     // IDLE ->      (mDisplacement > mTouchSlop) -> DRAGGING
@@ -93,28 +149,24 @@
         return mState == ScrollState.DRAGGING;
     }
 
-    private float mDownX;
-    private float mDownY;
+    private final PointF mDownPos = new PointF();
+    private final PointF mLastPos = new PointF();
+    private final Direction mDir;
 
-    private float mLastY;
+    private final float mTouchSlop;
+
+    /* Client of this gesture detector can register a callback. */
+    private final Listener mListener;
+
     private long mCurrentMillis;
 
     private float mVelocity;
-    private float mLastDisplacementX;
-    private float mLastDisplacementY;
-    private float mDisplacementY;
-    private float mDisplacementX;
+    private float mLastDisplacement;
+    private float mDisplacement;
 
     private float mSubtractDisplacement;
     private boolean mIgnoreSlopWhenSettling;
 
-    /* Client of this gesture detector can register a callback. */
-    private Listener mListener;
-
-    public void setListener(Listener l) {
-        mListener = l;
-    }
-
     public interface Listener {
         void onDragStart(boolean start);
 
@@ -123,8 +175,15 @@
         void onDragEnd(float velocity, boolean fling);
     }
 
-    public SwipeDetector(Context context) {
-        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
+    public SwipeDetector(@NonNull Context context, @NonNull Listener l, @NonNull Direction dir) {
+        this(ViewConfiguration.get(context).getScaledTouchSlop(), l, dir);
+    }
+
+    @VisibleForTesting
+    protected SwipeDetector(float touchSlope, @NonNull Listener l, @NonNull Direction dir) {
+        mTouchSlop = touchSlope;
+        mListener = l;
+        mDir = dir;
     }
 
     public void setDetectableScrollConditions(int scrollDirectionFlags, boolean ignoreSlop) {
@@ -132,21 +191,16 @@
         mIgnoreSlopWhenSettling = ignoreSlop;
     }
 
-    private boolean shouldScrollStart() {
-        // reject cases where the slop condition is not met.
-        if (Math.abs(mDisplacementY) < mTouchSlop) {
+    private boolean shouldScrollStart(MotionEvent ev, int pointerIndex) {
+        // reject cases where the angle or slop condition is not met.
+        if (Math.max(mDir.getActiveTouchSlop(ev, pointerIndex, mDownPos), mTouchSlop)
+                > Math.abs(mDisplacement)) {
             return false;
         }
 
-        // reject cases where the angle condition is not met.
-        float deltaY = Math.abs(mDisplacementY);
-        float deltaX = Math.max(Math.abs(mDisplacementX), 1);
-        if (deltaX > deltaY) {
-            return false;
-        }
         // Check if the client is interested in scroll in current direction.
-        if (((mScrollConditions & DIRECTION_DOWN) > 0 && mDisplacementY > 0) ||
-                ((mScrollConditions & DIRECTION_UP) > 0 && mDisplacementY < 0)) {
+        if (((mScrollConditions & DIRECTION_NEGATIVE) > 0 && mDisplacement > 0) ||
+                ((mScrollConditions & DIRECTION_POSITIVE) > 0 && mDisplacement < 0)) {
             return true;
         }
         return false;
@@ -155,12 +209,11 @@
     public boolean onTouchEvent(MotionEvent ev) {
         switch (ev.getActionMasked()) {
             case MotionEvent.ACTION_DOWN:
-                mDownX = ev.getX();
-                mDownY = ev.getY();
                 mActivePointerId = ev.getPointerId(0);
-                mLastDisplacementX = 0;
-                mLastDisplacementY = 0;
-                mDisplacementY = 0;
+                mDownPos.set(ev.getX(), ev.getY());
+                mLastPos.set(mDownPos);
+                mLastDisplacement = 0;
+                mDisplacement = 0;
                 mVelocity = 0;
 
                 if (mState == ScrollState.SETTLING && mIgnoreSlopWhenSettling) {
@@ -169,13 +222,14 @@
                 break;
             //case MotionEvent.ACTION_POINTER_DOWN:
             case MotionEvent.ACTION_POINTER_UP:
-                int ptrIdx = (ev.getActionIndex() & MotionEvent.ACTION_POINTER_INDEX_MASK) >>
-                        MotionEvent.ACTION_POINTER_INDEX_SHIFT;
+                int ptrIdx = ev.getActionIndex();
                 int ptrId = ev.getPointerId(ptrIdx);
                 if (ptrId == mActivePointerId) {
                     final int newPointerIdx = ptrIdx == 0 ? 1 : 0;
-                    mDownX = ev.getX(newPointerIdx) - mLastDisplacementX;
-                    mDownY = ev.getY(newPointerIdx) - mLastDisplacementY;
+                    mDownPos.set(
+                            ev.getX(newPointerIdx) - (mLastPos.x - mDownPos.x),
+                            ev.getY(newPointerIdx) - (mLastPos.y - mDownPos.y));
+                    mLastPos.set(ev.getX(newPointerIdx), ev.getY(newPointerIdx));
                     mActivePointerId = ev.getPointerId(newPointerIdx);
                 }
                 break;
@@ -184,18 +238,18 @@
                 if (pointerIndex == INVALID_POINTER_ID) {
                     break;
                 }
-                mDisplacementX = ev.getX(pointerIndex) - mDownX;
-                mDisplacementY = ev.getY(pointerIndex) - mDownY;
-
-                computeVelocity(ev);
+                mDisplacement = mDir.getDisplacement(ev, pointerIndex, mDownPos);
+                computeVelocity(mDir.getDisplacement(ev, pointerIndex, mLastPos),
+                        ev.getEventTime());
 
                 // handle state and listener calls.
-                if (mState != ScrollState.DRAGGING && shouldScrollStart()) {
+                if (mState != ScrollState.DRAGGING && shouldScrollStart(ev, pointerIndex)) {
                     setState(ScrollState.DRAGGING);
                 }
                 if (mState == ScrollState.DRAGGING) {
                     reportDragging();
                 }
+                mLastPos.set(ev.getX(pointerIndex), ev.getY(pointerIndex));
                 break;
             case MotionEvent.ACTION_CANCEL:
             case MotionEvent.ACTION_UP:
@@ -205,16 +259,8 @@
                 }
                 break;
             default:
-                //TODO: add multi finger tracking by tracking active pointer.
                 break;
         }
-        // Do house keeping.
-        mLastDisplacementX = mDisplacementX;
-        mLastDisplacementY = mDisplacementY;
-        int pointerIndex = ev.findPointerIndex(mActivePointerId);
-        if (pointerIndex != INVALID_POINTER_ID) {
-            mLastY = ev.getY(pointerIndex);
-        }
         return true;
     }
 
@@ -234,7 +280,7 @@
         if (mState == ScrollState.SETTLING && mIgnoreSlopWhenSettling) {
             mSubtractDisplacement = 0;
         }
-        if (mDisplacementY > 0) {
+        if (mDisplacement > 0) {
             mSubtractDisplacement = mTouchSlop;
         } else {
             mSubtractDisplacement = -mTouchSlop;
@@ -242,14 +288,14 @@
     }
 
     private boolean reportDragging() {
-        float delta = mDisplacementY - mLastDisplacementY;
-        if (delta != 0) {
+        if (mDisplacement != mLastDisplacement) {
             if (DBG) {
                 Log.d(TAG, String.format("onDrag disp=%.1f, velocity=%.1f",
-                        mDisplacementY, mVelocity));
+                        mDisplacement, mVelocity));
             }
 
-            return mListener.onDrag(mDisplacementY - mSubtractDisplacement, mVelocity);
+            mLastDisplacement = mDisplacement;
+            return mListener.onDrag(mDisplacement - mSubtractDisplacement, mVelocity);
         }
         return true;
     }
@@ -257,19 +303,15 @@
     private void reportDragEnd() {
         if (DBG) {
             Log.d(TAG, String.format("onScrollEnd disp=%.1f, velocity=%.1f",
-                    mDisplacementY, mVelocity));
+                    mDisplacement, mVelocity));
         }
         mListener.onDragEnd(mVelocity, Math.abs(mVelocity) > RELEASE_VELOCITY_PX_MS);
 
     }
 
     /**
-     * Computes the damped velocity using the two motion events and the previous velocity.
+     * Computes the damped velocity.
      */
-    private float computeVelocity(MotionEvent to) {
-        return computeVelocity(to.getY() - mLastY, to.getEventTime());
-    }
-
     public float computeVelocity(float delta, long currentMillis) {
         long previousMillis = mCurrentMillis;
         mCurrentMillis = currentMillis;
@@ -299,7 +341,7 @@
         return (1.0f - alpha) * from + alpha * to;
     }
 
-    public long calculateDuration(float velocity, float progressNeeded) {
+    public static long calculateDuration(float velocity, float progressNeeded) {
         // TODO: make these values constants after tuning.
         float velocityDivisor = Math.max(2f, Math.abs(0.5f * velocity));
         float travelDistance = Math.max(0.2f, progressNeeded);
diff --git a/src/com/android/launcher3/widget/WidgetsBottomSheet.java b/src/com/android/launcher3/widget/WidgetsBottomSheet.java
index 99e6056..2f9f348 100644
--- a/src/com/android/launcher3/widget/WidgetsBottomSheet.java
+++ b/src/com/android/launcher3/widget/WidgetsBottomSheet.java
@@ -87,8 +87,7 @@
                 AnimationUtils.loadInterpolator(context, android.R.interpolator.fast_out_slow_in);
         mScrollInterpolator = new SwipeDetector.ScrollInterpolator();
         mInsets = new Rect();
-        mSwipeDetector = new SwipeDetector(context);
-        mSwipeDetector.setListener(this);
+        mSwipeDetector = new SwipeDetector(context, this, SwipeDetector.VERTICAL);
         mGradientBackground = (GradientView) mLauncher.findViewById(R.id.gradient_bg);
     }
 
@@ -283,12 +282,12 @@
     public void onDragEnd(float velocity, boolean fling) {
         if ((fling && velocity > 0) || getTranslationY() > (mTranslationYRange) / 2) {
             mScrollInterpolator.setVelocityAtZero(velocity);
-            mOpenCloseAnimator.setDuration(mSwipeDetector.calculateDuration(velocity,
+            mOpenCloseAnimator.setDuration(SwipeDetector.calculateDuration(velocity,
                     (mTranslationYClosed - getTranslationY()) / mTranslationYRange));
             close(true);
         } else {
             mIsOpen = false;
-            mOpenCloseAnimator.setDuration(mSwipeDetector.calculateDuration(velocity,
+            mOpenCloseAnimator.setDuration(SwipeDetector.calculateDuration(velocity,
                     (getTranslationY() - mTranslationYOpen) / mTranslationYRange));
             open(true);
         }
@@ -302,7 +301,7 @@
     @Override
     public boolean onControllerInterceptTouchEvent(MotionEvent ev) {
         int directionsToDetectScroll = mSwipeDetector.isIdleState() ?
-                SwipeDetector.DIRECTION_DOWN : 0;
+                SwipeDetector.DIRECTION_NEGATIVE : 0;
         mSwipeDetector.setDetectableScrollConditions(
                 directionsToDetectScroll, false);
         mSwipeDetector.onTouchEvent(ev);
diff --git a/tests/src/com/android/launcher3/touch/SwipeDetectorTest.java b/tests/src/com/android/launcher3/touch/SwipeDetectorTest.java
index 8724704..ff83131 100644
--- a/tests/src/com/android/launcher3/touch/SwipeDetectorTest.java
+++ b/tests/src/com/android/launcher3/touch/SwipeDetectorTest.java
@@ -15,7 +15,6 @@
  */
 package com.android.launcher3.touch;
 
-import android.content.Context;
 import android.support.test.InstrumentationRegistry;
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
@@ -33,11 +32,12 @@
 
 import static org.mockito.Matchers.anyBoolean;
 import static org.mockito.Matchers.anyFloat;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 
 @SmallTest
 @RunWith(AndroidJUnit4.class)
-public class SwipeDetectorTest{
+public class SwipeDetectorTest {
 
     private static final String TAG = SwipeDetectorTest.class.getSimpleName();
     public static void L(String s, Object... parts) {
@@ -54,22 +54,22 @@
     @Before
     public void setup() {
         MockitoAnnotations.initMocks(this);
-        Context context = InstrumentationRegistry.getTargetContext();
-        mDetector = new SwipeDetector(context);
         mGenerator = new TouchEventGenerator(new TouchEventGenerator.Listener() {
             @Override
             public void onTouchEvent(MotionEvent event) {
                 mDetector.onTouchEvent(event);
             }
         });
-        mDetector.setListener(mMockListener);
+
+        mDetector = new SwipeDetector(mTouchSlop, mMockListener, SwipeDetector.VERTICAL);
         mDetector.setDetectableScrollConditions(SwipeDetector.DIRECTION_BOTH, false);
-        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
+        mTouchSlop = ViewConfiguration.get(InstrumentationRegistry.getTargetContext())
+                .getScaledTouchSlop();
         L("mTouchSlop=", mTouchSlop);
     }
 
     @Test
-    public void testDragStart() throws Exception {
+    public void testDragStart_vertical() throws Exception {
         mGenerator.put(0, 100, 100);
         mGenerator.move(0, 100, 100 + mTouchSlop);
         // TODO: actually calculate the following parameters and do exact value checks.
@@ -77,6 +77,25 @@
     }
 
     @Test
+    public void testDragStart_failed() throws Exception {
+        mGenerator.put(0, 100, 100);
+        mGenerator.move(0, 100 + mTouchSlop, 100);
+        // TODO: actually calculate the following parameters and do exact value checks.
+        verify(mMockListener, never()).onDragStart(anyBoolean());
+    }
+
+    @Test
+    public void testDragStart_horizontal() throws Exception {
+        mDetector = new SwipeDetector(mTouchSlop, mMockListener, SwipeDetector.HORIZONTAL);
+        mDetector.setDetectableScrollConditions(SwipeDetector.DIRECTION_BOTH, false);
+
+        mGenerator.put(0, 100, 100);
+        mGenerator.move(0, 100 + mTouchSlop, 100);
+        // TODO: actually calculate the following parameters and do exact value checks.
+        verify(mMockListener).onDragStart(anyBoolean());
+    }
+
+    @Test
     public void testDrag() throws Exception {
         mGenerator.put(0, 100, 100);
         mGenerator.move(0, 100, 100 + mTouchSlop);