Refactoring RecentsActivity and TaskStackViewTouchHandler.

- Pulling out logic related to system bar scrims, and touch handlers to their own classes
- Pulling out shadow reflection code out of RecentsActivity
- Ensuring that we poke the doze trigger when scrolling

7 files changed, 621 insertions, 495 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/recents/DozeTrigger.java b/packages/SystemUI/src/com/android/systemui/recents/DozeTrigger.java
index 037af14a7c6d..f0b2cb6cb1a8 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/DozeTrigger.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/DozeTrigger.java
@@ -49,7 +49,7 @@ public class DozeTrigger {
 
     /** Starts dozing. This also resets the trigger flag. */
     public void startDozing() {
-        poke();
+        forcePoke();
         mHasTriggered = false;
     }
 
@@ -59,8 +59,15 @@ public class DozeTrigger {
         mIsDozing = false;
     }
 
-    /** Poke this dozer to wake it up for a little bit. */
+    /** Poke this dozer to wake it up for a little bit, if it is dozing. */
     public void poke() {
+        if (mIsDozing) {
+            forcePoke();
+        }
+    }
+
+    /** Poke this dozer to wake it up for a little bit. */
+    void forcePoke() {
         mHandler.removeCallbacks(mDozeRunnable);
         mHandler.postDelayed(mDozeRunnable, mDozeDurationSeconds * 1000);
         mIsDozing = true;
diff --git a/packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java b/packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java
index 4a02bac374a0..21704a42d7c7 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java
@@ -28,7 +28,6 @@ import android.content.IntentFilter;
 import android.os.Bundle;
 import android.os.UserHandle;
 import android.util.Pair;
-import android.view.Gravity;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -39,6 +38,7 @@ import com.android.systemui.recents.model.SpaceNode;
 import com.android.systemui.recents.model.TaskStack;
 import com.android.systemui.recents.views.FullScreenTransitionView;
 import com.android.systemui.recents.views.RecentsView;
+import com.android.systemui.recents.views.SystemBarScrimViews;
 import com.android.systemui.recents.views.ViewAnimation;
 
 import java.lang.reflect.InvocationTargetException;
@@ -50,6 +50,26 @@ public class RecentsActivity extends Activity implements RecentsView.RecentsView
         RecentsAppWidgetHost.RecentsAppWidgetHostCallbacks,
         FullScreenTransitionView.FullScreenTransitionViewCallbacks {
 
+    FrameLayout mContainerView;
+    RecentsView mRecentsView;
+    SystemBarScrimViews mScrimViews;
+    View mEmptyView;
+    FullScreenTransitionView mFullScreenshotView;
+
+    RecentsConfiguration mConfig;
+
+    RecentsAppWidgetHost mAppWidgetHost;
+    AppWidgetProviderInfo mSearchAppWidgetInfo;
+    AppWidgetHostView mSearchAppWidgetHostView;
+
+    boolean mVisible;
+    boolean mTaskLaunched;
+
+    // Runnables to finish the Recents activity
+    FinishRecentsRunnable mFinishRunnable = new FinishRecentsRunnable(true);
+    FinishRecentsRunnable mFinishWithoutAnimationRunnable = new FinishRecentsRunnable(false);
+    FinishRecentsRunnable mFinishLaunchHomeRunnable;
+
     /**
      * A Runnable to finish Recents either with/without a transition, and either by calling finish()
      * or just launching the specified intent.
@@ -90,40 +110,6 @@ public class RecentsActivity extends Activity implements RecentsView.RecentsView
         }
     }
 
-    FrameLayout mContainerView;
-    RecentsView mRecentsView;
-    View mEmptyView;
-    View mStatusBarScrimView;
-    View mNavBarScrimView;
-    FullScreenTransitionView mFullScreenshotView;
-
-    RecentsConfiguration mConfig;
-
-    RecentsAppWidgetHost mAppWidgetHost;
-    AppWidgetProviderInfo mSearchAppWidgetInfo;
-    AppWidgetHostView mSearchAppWidgetHostView;
-
-    boolean mVisible;
-    boolean mTaskLaunched;
-
-    // Runnables to finish the Recents activity
-    FinishRecentsRunnable mFinishRunnable = new FinishRecentsRunnable(true);
-    FinishRecentsRunnable mFinishWithoutAnimationRunnable = new FinishRecentsRunnable(false);
-    FinishRecentsRunnable mFinishLaunchHomeRunnable;
-
-    private static Method sPropertyMethod;
-    static {
-        try {
-            Class<?> c = Class.forName("android.view.GLES20Canvas");
-            sPropertyMethod = c.getDeclaredMethod("setProperty", String.class, String.class);
-            if (!sPropertyMethod.isAccessible()) sPropertyMethod.setAccessible(true);
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
-        } catch (NoSuchMethodException e) {
-            e.printStackTrace();
-        }
-    }
-
     // Broadcast receiver to handle messages from our RecentsService
     BroadcastReceiver mServiceBroadcastReceiver = new BroadcastReceiver() {
         @Override
@@ -192,10 +178,7 @@ public class RecentsActivity extends Activity implements RecentsView.RecentsView
         mConfig.launchedWithNoRecentTasks = !root.hasTasks();
 
         // Show the scrim if we animate into Recents without window transitions
-        mNavBarScrimView.setVisibility(mConfig.hasNavBarScrim() &&
-                !mConfig.shouldAnimateNavBarScrim() ? View.VISIBLE : View.INVISIBLE);
-        mStatusBarScrimView.setVisibility(mConfig.hasStatusBarScrim() &&
-                !mConfig.shouldAnimateStatusBarScrim() ? View.VISIBLE : View.INVISIBLE);
+        mScrimViews.prepareEnterRecentsAnimation();
 
         // Add the default no-recents layout
         if (mConfig.launchedWithNoRecentTasks) {
@@ -348,14 +331,8 @@ public class RecentsActivity extends Activity implements RecentsView.RecentsView
         // Create the empty view
         LayoutInflater inflater = LayoutInflater.from(this);
         mEmptyView = inflater.inflate(R.layout.recents_empty, mContainerView, false);
-        mStatusBarScrimView = inflater.inflate(R.layout.recents_status_bar_scrim, mContainerView, false);
-        mStatusBarScrimView.setLayoutParams(new FrameLayout.LayoutParams(
-                ViewGroup.LayoutParams.MATCH_PARENT,
-                ViewGroup.LayoutParams.WRAP_CONTENT, Gravity.TOP));
-        mNavBarScrimView = inflater.inflate(R.layout.recents_nav_bar_scrim, mContainerView, false);
-        mNavBarScrimView.setLayoutParams(new FrameLayout.LayoutParams(
-                ViewGroup.LayoutParams.MATCH_PARENT,
-                ViewGroup.LayoutParams.WRAP_CONTENT, Gravity.BOTTOM));
+        mScrimViews = new SystemBarScrimViews(mConfig);
+        mScrimViews.inflate(inflater, mContainerView);
         if (Constants.DebugFlags.App.EnableScreenshotAppTransition) {
             mFullScreenshotView = new FullScreenTransitionView(this, this);
             mFullScreenshotView.setLayoutParams(new FrameLayout.LayoutParams(
@@ -364,13 +341,13 @@ public class RecentsActivity extends Activity implements RecentsView.RecentsView
 
         // Add the views to the layout
         mContainerView = new FrameLayout(this);
-        mContainerView.addView(mStatusBarScrimView);
+        mContainerView.addView(mScrimViews.getStatusBarScrimView());
         mContainerView.addView(mRecentsView);
         mContainerView.addView(mEmptyView);
         if (Constants.DebugFlags.App.EnableScreenshotAppTransition) {
             mContainerView.addView(mFullScreenshotView);
         }
-        mContainerView.addView(mNavBarScrimView);
+        mContainerView.addView(mScrimViews.getNavBarScrimView());
         setContentView(mContainerView);
 
         // Update the recent tasks
@@ -391,10 +368,10 @@ public class RecentsActivity extends Activity implements RecentsView.RecentsView
             onConfigurationChange();
         }
 
-        // XXX: Update the shadows
+        // Private API calls to make the shadows look better
         try {
-            sPropertyMethod.invoke(null, "ambientShadowStrength", String.valueOf(35f));
-            sPropertyMethod.invoke(null, "ambientRatio", String.valueOf(0.5f));
+            Utilities.setShadowProperty("ambientShadowStrength", String.valueOf(35f));
+            Utilities.setShadowProperty("ambientRatio", String.valueOf(0.5f));
         } catch (IllegalAccessException e) {
             e.printStackTrace();
         } catch (InvocationTargetException e) {
@@ -589,37 +566,8 @@ public class RecentsActivity extends Activity implements RecentsView.RecentsView
     }
 
     public void onEnterAnimationTriggered() {
-        // Fade in the scrims
-        if (mConfig.hasStatusBarScrim() && mConfig.shouldAnimateStatusBarScrim()) {
-            mStatusBarScrimView.setTranslationY(-mStatusBarScrimView.getMeasuredHeight());
-            mStatusBarScrimView.animate()
-                    .translationY(0)
-                    .setStartDelay(mConfig.taskBarEnterAnimDelay)
-                    .setDuration(mConfig.navBarScrimEnterDuration)
-                    .setInterpolator(mConfig.quintOutInterpolator)
-                    .withStartAction(new Runnable() {
-                        @Override
-                        public void run() {
-                            mStatusBarScrimView.setVisibility(View.VISIBLE);
-                        }
-                    })
-                    .start();
-        }
-        if (mConfig.hasNavBarScrim() && mConfig.shouldAnimateNavBarScrim()) {
-            mNavBarScrimView.setTranslationY(mNavBarScrimView.getMeasuredHeight());
-            mNavBarScrimView.animate()
-                    .translationY(0)
-                    .setStartDelay(mConfig.taskBarEnterAnimDelay)
-                    .setDuration(mConfig.navBarScrimEnterDuration)
-                    .setInterpolator(mConfig.quintOutInterpolator)
-                    .withStartAction(new Runnable() {
-                        @Override
-                        public void run() {
-                            mNavBarScrimView.setVisibility(View.VISIBLE);
-                        }
-                    })
-                    .start();
-        }
+        // Animate the scrims in
+        mScrimViews.startEnterRecentsAnimation();
     }
 
     /**** FullScreenTransitionView.FullScreenTransitionViewCallbacks Implementation ****/
@@ -642,16 +590,9 @@ public class RecentsActivity extends Activity implements RecentsView.RecentsView
     /**** RecentsView.RecentsViewCallbacks Implementation ****/
 
     @Override
-    public void onExitAnimationTriggered() {
-        // Fade out the scrim
-        if (mConfig.hasNavBarScrim() && mConfig.shouldAnimateNavBarScrim()) {
-            mNavBarScrimView.animate()
-                    .translationY(mNavBarScrimView.getMeasuredHeight())
-                    .setStartDelay(0)
-                    .setDuration(mConfig.taskBarExitAnimDuration)
-                    .setInterpolator(mConfig.fastOutSlowInInterpolator)
-                    .start();
-        }
+    public void onExitToHomeAnimationTriggered() {
+        // Animate the scrims out
+        mScrimViews.startExitRecentsAnimation();
     }
 
     @Override
diff --git a/packages/SystemUI/src/com/android/systemui/recents/Utilities.java b/packages/SystemUI/src/com/android/systemui/recents/Utilities.java
index 46e6ee9c8ece..25875bc6fef4 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/Utilities.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/Utilities.java
@@ -20,8 +20,26 @@ import android.graphics.Color;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
 /* Common code */
 public class Utilities {
+
+    // Reflection methods for altering shadows
+    private static Method sPropertyMethod;
+    static {
+        try {
+            Class<?> c = Class.forName("android.view.GLES20Canvas");
+            sPropertyMethod = c.getDeclaredMethod("setProperty", String.class, String.class);
+            if (!sPropertyMethod.isAccessible()) sPropertyMethod.setAccessible(true);
+        } catch (ClassNotFoundException e) {
+            e.printStackTrace();
+        } catch (NoSuchMethodException e) {
+            e.printStackTrace();
+        }
+    }
+
     /**
      * Calculates a consistent animation duration (ms) for all animations depending on the movement
      * of the object being animated.
@@ -66,4 +84,10 @@ public class Utilities {
         int greyscale = colorToGreyscale(color);
         return (greyscale < 128) ? lightRes : darkRes;
     }
+
+    /** Sets some private shadow properties. */
+    public static void setShadowProperty(String property, String value)
+            throws IllegalAccessException, InvocationTargetException {
+        sPropertyMethod.invoke(null, property, value);
+    }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java b/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java
index 724875867faf..d06c9d2e297d 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java
@@ -55,7 +55,7 @@ public class RecentsView extends FrameLayout implements TaskStackView.TaskStackV
     /** The RecentsView callbacks */
     public interface RecentsViewCallbacks {
         public void onTaskLaunching();
-        public void onExitAnimationTriggered();
+        public void onExitToHomeAnimationTriggered();
     }
 
     RecentsConfiguration mConfig;
@@ -194,7 +194,7 @@ public class RecentsView extends FrameLayout implements TaskStackView.TaskStackV
         ctx.postAnimationTrigger.decrement();
 
         // Notify of the exit animation
-        mCb.onExitAnimationTriggered();
+        mCb.onExitToHomeAnimationTriggered();
     }
 
     /** Adds the search bar */
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/SystemBarScrimViews.java b/packages/SystemUI/src/com/android/systemui/recents/views/SystemBarScrimViews.java
new file mode 100644
index 000000000000..932c345f246a
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/SystemBarScrimViews.java
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2014 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.systemui.recents.views;
+
+import android.view.Gravity;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.FrameLayout;
+import com.android.systemui.R;
+import com.android.systemui.recents.RecentsConfiguration;
+
+/** Manages the scrims for the various system bars. */
+public class SystemBarScrimViews {
+
+    RecentsConfiguration mConfig;
+
+    View mStatusBarScrimView;
+    View mNavBarScrimView;
+
+    boolean mHasNavBarScrim;
+    boolean mShouldAnimateStatusBarScrim;
+    boolean mHasStatusBarScrim;
+    boolean mShouldAnimateNavBarScrim;
+
+    public SystemBarScrimViews(RecentsConfiguration config) {
+        mConfig = config;
+    }
+
+    /** Inflates the scrim views */
+    public void inflate(LayoutInflater inflater, ViewGroup parent) {
+        mStatusBarScrimView = inflater.inflate(R.layout.recents_status_bar_scrim, parent, false);
+        mStatusBarScrimView.setLayoutParams(new FrameLayout.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                ViewGroup.LayoutParams.WRAP_CONTENT, Gravity.TOP));
+        mNavBarScrimView = inflater.inflate(R.layout.recents_nav_bar_scrim, parent, false);
+        mNavBarScrimView.setLayoutParams(new FrameLayout.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                ViewGroup.LayoutParams.WRAP_CONTENT, Gravity.BOTTOM));
+    }
+
+    /**
+     * Prepares the scrim views for animating when entering Recents. This will be called before
+     * the first draw.
+     */
+    public void prepareEnterRecentsAnimation() {
+        mHasNavBarScrim = mConfig.hasNavBarScrim();
+        mShouldAnimateNavBarScrim = mConfig.shouldAnimateNavBarScrim();
+        mHasStatusBarScrim = mConfig.hasStatusBarScrim();
+        mShouldAnimateStatusBarScrim = mConfig.shouldAnimateStatusBarScrim();
+
+        mNavBarScrimView.setVisibility(mHasNavBarScrim && !mShouldAnimateNavBarScrim ?
+                View.VISIBLE : View.INVISIBLE);
+        mStatusBarScrimView.setVisibility(mHasStatusBarScrim && !mShouldAnimateStatusBarScrim ?
+                View.VISIBLE : View.INVISIBLE);
+    }
+
+    /**
+     * Starts animating the scrim views when entering Recents.
+     */
+    public void startEnterRecentsAnimation() {
+        if (mHasStatusBarScrim && mShouldAnimateStatusBarScrim) {
+            mStatusBarScrimView.setTranslationY(-mStatusBarScrimView.getMeasuredHeight());
+            mStatusBarScrimView.animate()
+                    .translationY(0)
+                    .setStartDelay(mConfig.taskBarEnterAnimDelay)
+                    .setDuration(mConfig.navBarScrimEnterDuration)
+                    .setInterpolator(mConfig.quintOutInterpolator)
+                    .withStartAction(new Runnable() {
+                        @Override
+                        public void run() {
+                            mStatusBarScrimView.setVisibility(View.VISIBLE);
+                        }
+                    })
+                    .start();
+        }
+        if (mHasNavBarScrim && mShouldAnimateNavBarScrim) {
+            mNavBarScrimView.setTranslationY(mNavBarScrimView.getMeasuredHeight());
+            mNavBarScrimView.animate()
+                    .translationY(0)
+                    .setStartDelay(mConfig.taskBarEnterAnimDelay)
+                    .setDuration(mConfig.navBarScrimEnterDuration)
+                    .setInterpolator(mConfig.quintOutInterpolator)
+                    .withStartAction(new Runnable() {
+                        @Override
+                        public void run() {
+                            mNavBarScrimView.setVisibility(View.VISIBLE);
+                        }
+                    })
+                    .start();
+        }
+    }
+
+    /**
+     * Starts animating the scrim views when leaving Recents (either via launching a task, or
+     * going home).
+     */
+    public void startExitRecentsAnimation() {
+        if (mHasNavBarScrim && mShouldAnimateNavBarScrim) {
+            mNavBarScrimView.animate()
+                    .translationY(mNavBarScrimView.getMeasuredHeight())
+                    .setStartDelay(0)
+                    .setDuration(mConfig.taskBarExitAnimDuration)
+                    .setInterpolator(mConfig.fastOutSlowInInterpolator)
+                    .start();
+        }
+    }
+
+    /** Returns the status bar scrim view. */
+    public View getStatusBarScrimView() {
+        return mStatusBarScrimView;
+    }
+
+    /** Returns the nav bar scrim view. */
+    public View getNavBarScrimView() {
+        return mNavBarScrimView;
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
index 5380116b702b..74bc526f5915 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
@@ -28,10 +28,7 @@ import android.graphics.Rect;
 import android.graphics.Region;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
-import android.view.VelocityTracker;
 import android.view.View;
-import android.view.ViewConfiguration;
-import android.view.ViewParent;
 import android.widget.FrameLayout;
 import android.widget.OverScroller;
 import com.android.systemui.R;
@@ -389,11 +386,13 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
     /** Sets the current stack scroll */
     public void setStackScroll(int value) {
         mStackScroll = value;
+        mUIDozeTrigger.poke();
         requestSynchronizeStackViewsWithModel();
     }
     /** Sets the current stack scroll without synchronizing the stack view with the model */
     public void setStackScrollRaw(int value) {
         mStackScroll = value;
+        mUIDozeTrigger.poke();
     }
     /** Sets the current stack scroll to the initial state when you first enter recents */
     public void setStackScrollToInitialState() {
@@ -930,11 +929,8 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
     /** Pokes the dozer on user interaction. */
     void onUserInteraction() {
-        // If the dozer is not running, then either we have not yet laid out, or it has already
-        // fallen asleep, so just let it rest.
-        if (mUIDozeTrigger.isDozing()) {
-            mUIDozeTrigger.poke();
-        }
+        // Poke the doze trigger if it is dozing
+        mUIDozeTrigger.poke();
     }
 
     /**** TaskStackCallbacks Implementation ****/
@@ -1331,393 +1327,4 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
             }
         }
     }
-}
-
-/* Handles touch events */
-class TaskStackViewTouchHandler implements SwipeHelper.Callback {
-    static int INACTIVE_POINTER_ID = -1;
-
-    TaskStackView mSv;
-    VelocityTracker mVelocityTracker;
-
-    boolean mIsScrolling;
-
-    int mInitialMotionX, mInitialMotionY;
-    int mLastMotionX, mLastMotionY;
-    int mActivePointerId = INACTIVE_POINTER_ID;
-    TaskView mActiveTaskView = null;
-
-    int mTotalScrollMotion;
-    int mMinimumVelocity;
-    int mMaximumVelocity;
-    // The scroll touch slop is used to calculate when we start scrolling
-    int mScrollTouchSlop;
-    // The page touch slop is used to calculate when we start swiping
-    float mPagingTouchSlop;
-
-    SwipeHelper mSwipeHelper;
-    boolean mInterceptedBySwipeHelper;
-
-    public TaskStackViewTouchHandler(Context context, TaskStackView sv) {
-        ViewConfiguration configuration = ViewConfiguration.get(context);
-        mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
-        mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
-        mScrollTouchSlop = configuration.getScaledTouchSlop();
-        mPagingTouchSlop = configuration.getScaledPagingTouchSlop();
-        mSv = sv;
-
-
-        float densityScale = context.getResources().getDisplayMetrics().density;
-        mSwipeHelper = new SwipeHelper(SwipeHelper.X, this, densityScale, mPagingTouchSlop);
-        mSwipeHelper.setMinAlpha(1f);
-    }
-
-    /** Velocity tracker helpers */
-    void initOrResetVelocityTracker() {
-        if (mVelocityTracker == null) {
-            mVelocityTracker = VelocityTracker.obtain();
-        } else {
-            mVelocityTracker.clear();
-        }
-    }
-    void initVelocityTrackerIfNotExists() {
-        if (mVelocityTracker == null) {
-            mVelocityTracker = VelocityTracker.obtain();
-        }
-    }
-    void recycleVelocityTracker() {
-        if (mVelocityTracker != null) {
-            mVelocityTracker.recycle();
-            mVelocityTracker = null;
-        }
-    }
-
-    /** Returns the view at the specified coordinates */
-    TaskView findViewAtPoint(int x, int y) {
-        int childCount = mSv.getChildCount();
-        for (int i = childCount - 1; i >= 0; i--) {
-            TaskView tv = (TaskView) mSv.getChildAt(i);
-            if (tv.getVisibility() == View.VISIBLE) {
-                if (mSv.isTransformedTouchPointInView(x, y, tv)) {
-                    return tv;
-                }
-            }
-        }
-        return null;
-    }
-
-    /** Touch preprocessing for handling below */
-    public boolean onInterceptTouchEvent(MotionEvent ev) {
-        if (Console.Enabled) {
-            Console.log(Constants.Log.UI.TouchEvents,
-                    "[TaskStackViewTouchHandler|interceptTouchEvent]",
-                    Console.motionEventActionToString(ev.getAction()), Console.AnsiBlue);
-        }
-
-        // Return early if we have no children
-        boolean hasChildren = (mSv.getChildCount() > 0);
-        if (!hasChildren) {
-            return false;
-        }
-
-        // Pass through to swipe helper if we are swiping
-        mInterceptedBySwipeHelper = mSwipeHelper.onInterceptTouchEvent(ev);
-        if (mInterceptedBySwipeHelper) {
-            return true;
-        }
-
-        boolean wasScrolling = !mSv.mScroller.isFinished() ||
-                (mSv.mScrollAnimator != null && mSv.mScrollAnimator.isRunning());
-        int action = ev.getAction();
-        switch (action & MotionEvent.ACTION_MASK) {
-            case MotionEvent.ACTION_DOWN: {
-                // Save the touch down info
-                mInitialMotionX = mLastMotionX = (int) ev.getX();
-                mInitialMotionY = mLastMotionY = (int) ev.getY();
-                mActivePointerId = ev.getPointerId(0);
-                mActiveTaskView = findViewAtPoint(mLastMotionX, mLastMotionY);
-                // Stop the current scroll if it is still flinging
-                mSv.abortScroller();
-                mSv.abortBoundScrollAnimation();
-                // Initialize the velocity tracker
-                initOrResetVelocityTracker();
-                mVelocityTracker.addMovement(ev);
-                // Check if the scroller is finished yet
-                mIsScrolling = !mSv.mScroller.isFinished();
-                break;
-            }
-            case MotionEvent.ACTION_MOVE: {
-                if (mActivePointerId == INACTIVE_POINTER_ID) break;
-
-                int activePointerIndex = ev.findPointerIndex(mActivePointerId);
-                int y = (int) ev.getY(activePointerIndex);
-                int x = (int) ev.getX(activePointerIndex);
-                if (Math.abs(y - mInitialMotionY) > mScrollTouchSlop) {
-                    // Save the touch move info
-                    mIsScrolling = true;
-                    // Initialize the velocity tracker if necessary
-                    initVelocityTrackerIfNotExists();
-                    mVelocityTracker.addMovement(ev);
-                    // Disallow parents from intercepting touch events
-                    final ViewParent parent = mSv.getParent();
-                    if (parent != null) {
-                        parent.requestDisallowInterceptTouchEvent(true);
-                    }
-                    // Enable HW layers
-                    mSv.addHwLayersRefCount("stackScroll");
-                }
-
-                mLastMotionX = x;
-                mLastMotionY = y;
-                break;
-            }
-            case MotionEvent.ACTION_CANCEL:
-            case MotionEvent.ACTION_UP: {
-                // Animate the scroll back if we've cancelled
-                mSv.animateBoundScroll();
-                // Disable HW layers
-                if (mIsScrolling) {
-                    mSv.decHwLayersRefCount("stackScroll");
-                }
-                // Reset the drag state and the velocity tracker
-                mIsScrolling = false;
-                mActivePointerId = INACTIVE_POINTER_ID;
-                mActiveTaskView = null;
-                mTotalScrollMotion = 0;
-                recycleVelocityTracker();
-                break;
-            }
-        }
-
-        return wasScrolling || mIsScrolling;
-    }
-
-    /** Handles touch events once we have intercepted them */
-    public boolean onTouchEvent(MotionEvent ev) {
-        if (Console.Enabled) {
-            Console.log(Constants.Log.UI.TouchEvents,
-                    "[TaskStackViewTouchHandler|touchEvent]",
-                    Console.motionEventActionToString(ev.getAction()), Console.AnsiBlue);
-        }
-
-        // Short circuit if we have no children
-        boolean hasChildren = (mSv.getChildCount() > 0);
-        if (!hasChildren) {
-            return false;
-        }
-
-        // Pass through to swipe helper if we are swiping
-        if (mInterceptedBySwipeHelper && mSwipeHelper.onTouchEvent(ev)) {
-            return true;
-        }
-
-        // Update the velocity tracker
-        initVelocityTrackerIfNotExists();
-        mVelocityTracker.addMovement(ev);
-
-        int action = ev.getAction();
-        switch (action & MotionEvent.ACTION_MASK) {
-            case MotionEvent.ACTION_DOWN: {
-                // Save the touch down info
-                mInitialMotionX = mLastMotionX = (int) ev.getX();
-                mInitialMotionY = mLastMotionY = (int) ev.getY();
-                mActivePointerId = ev.getPointerId(0);
-                mActiveTaskView = findViewAtPoint(mLastMotionX, mLastMotionY);
-                // Stop the current scroll if it is still flinging
-                mSv.abortScroller();
-                mSv.abortBoundScrollAnimation();
-                // Initialize the velocity tracker
-                initOrResetVelocityTracker();
-                mVelocityTracker.addMovement(ev);
-                // Disallow parents from intercepting touch events
-                final ViewParent parent = mSv.getParent();
-                if (parent != null) {
-                    parent.requestDisallowInterceptTouchEvent(true);
-                }
-                break;
-            }
-            case MotionEvent.ACTION_POINTER_DOWN: {
-                final int index = ev.getActionIndex();
-                mActivePointerId = ev.getPointerId(index);
-                mLastMotionX = (int) ev.getX(index);
-                mLastMotionY = (int) ev.getY(index);
-                break;
-            }
-            case MotionEvent.ACTION_MOVE: {
-                if (mActivePointerId == INACTIVE_POINTER_ID) break;
-
-                int activePointerIndex = ev.findPointerIndex(mActivePointerId);
-                int x = (int) ev.getX(activePointerIndex);
-                int y = (int) ev.getY(activePointerIndex);
-                int yTotal = Math.abs(y - mInitialMotionY);
-                int deltaY = mLastMotionY - y;
-                if (!mIsScrolling) {
-                    if (yTotal > mScrollTouchSlop) {
-                        mIsScrolling = true;
-                        // Initialize the velocity tracker
-                        initOrResetVelocityTracker();
-                        mVelocityTracker.addMovement(ev);
-                        // Disallow parents from intercepting touch events
-                        final ViewParent parent = mSv.getParent();
-                        if (parent != null) {
-                            parent.requestDisallowInterceptTouchEvent(true);
-                        }
-                        // Enable HW layers
-                        mSv.addHwLayersRefCount("stackScroll");
-                    }
-                }
-                if (mIsScrolling) {
-                    int curStackScroll = mSv.getStackScroll();
-                    int overScrollAmount = mSv.getScrollAmountOutOfBounds(curStackScroll + deltaY);
-                    if (overScrollAmount != 0) {
-                        // Bound the overscroll to a fixed amount, and inversely scale the y-movement
-                        // relative to how close we are to the max overscroll
-                        float maxOverScroll = mSv.mTaskRect.height() / 3f;
-                        deltaY = Math.round(deltaY * (1f - (Math.min(maxOverScroll, overScrollAmount)
-                                / maxOverScroll)));
-                    }
-                    mSv.setStackScroll(curStackScroll + deltaY);
-                    if (mSv.isScrollOutOfBounds()) {
-                        mVelocityTracker.clear();
-                    }
-                }
-                mLastMotionX = x;
-                mLastMotionY = y;
-                mTotalScrollMotion += Math.abs(deltaY);
-                break;
-            }
-            case MotionEvent.ACTION_UP: {
-                final VelocityTracker velocityTracker = mVelocityTracker;
-                velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
-                int velocity = (int) velocityTracker.getYVelocity(mActivePointerId);
-
-                if (mIsScrolling && (Math.abs(velocity) > mMinimumVelocity)) {
-                    // Enable HW layers on the stack
-                    mSv.addHwLayersRefCount("flingScroll");
-                    // XXX: Make this animation a function of the velocity AND distance
-                    int overscrollRange = (int) (Math.min(1f,
-                            Math.abs((float) velocity / mMaximumVelocity)) *
-                            Constants.Values.TaskStackView.TaskStackOverscrollRange);
-
-                    if (Console.Enabled) {
-                        Console.log(Constants.Log.UI.TouchEvents,
-                                "[TaskStackViewTouchHandler|fling]",
-                                "scroll: " + mSv.getStackScroll() + " velocity: " + velocity +
-                                        " maxVelocity: " + mMaximumVelocity +
-                                        " overscrollRange: " + overscrollRange,
-                                Console.AnsiGreen);
-                    }
-
-                    // Fling scroll
-                    mSv.mScroller.fling(0, mSv.getStackScroll(),
-                            0, -velocity,
-                            0, 0,
-                            mSv.mMinScroll, mSv.mMaxScroll,
-                            0, overscrollRange);
-                    // Invalidate to kick off computeScroll
-                    mSv.invalidate(mSv.mStackRect);
-                } else if (mSv.isScrollOutOfBounds()) {
-                    // Animate the scroll back into bounds
-                    // XXX: Make this animation a function of the velocity OR distance
-                    mSv.animateBoundScroll();
-                }
-
-                if (mIsScrolling) {
-                    // Disable HW layers
-                    mSv.decHwLayersRefCount("stackScroll");
-                }
-                mActivePointerId = INACTIVE_POINTER_ID;
-                mIsScrolling = false;
-                mTotalScrollMotion = 0;
-                recycleVelocityTracker();
-                break;
-            }
-            case MotionEvent.ACTION_POINTER_UP: {
-                int pointerIndex = ev.getActionIndex();
-                int pointerId = ev.getPointerId(pointerIndex);
-                if (pointerId == mActivePointerId) {
-                    // Select a new active pointer id and reset the motion state
-                    final int newPointerIndex = (pointerIndex == 0) ? 1 : 0;
-                    mActivePointerId = ev.getPointerId(newPointerIndex);
-                    mLastMotionX = (int) ev.getX(newPointerIndex);
-                    mLastMotionY = (int) ev.getY(newPointerIndex);
-                    mVelocityTracker.clear();
-                }
-                break;
-            }
-            case MotionEvent.ACTION_CANCEL: {
-                if (mIsScrolling) {
-                    // Disable HW layers
-                    mSv.decHwLayersRefCount("stackScroll");
-                }
-                if (mSv.isScrollOutOfBounds()) {
-                    // Animate the scroll back into bounds
-                    // XXX: Make this animation a function of the velocity OR distance
-                    mSv.animateBoundScroll();
-                }
-                mActivePointerId = INACTIVE_POINTER_ID;
-                mIsScrolling = false;
-                mTotalScrollMotion = 0;
-                recycleVelocityTracker();
-                break;
-            }
-        }
-        return true;
-    }
-
-    /**** SwipeHelper Implementation ****/
-
-    @Override
-    public View getChildAtPosition(MotionEvent ev) {
-        return findViewAtPoint((int) ev.getX(), (int) ev.getY());
-    }
-
-    @Override
-    public boolean canChildBeDismissed(View v) {
-        return true;
-    }
-
-    @Override
-    public void onBeginDrag(View v) {
-        // Enable HW layers
-        mSv.addHwLayersRefCount("swipeBegin");
-        // Disable clipping with the stack while we are swiping
-        TaskView tv = (TaskView) v;
-        tv.setClipViewInStack(false);
-        // Disallow parents from intercepting touch events
-        final ViewParent parent = mSv.getParent();
-        if (parent != null) {
-            parent.requestDisallowInterceptTouchEvent(true);
-        }
-    }
-
-    @Override
-    public void onSwipeChanged(View v, float delta) {
-        // Do nothing
-    }
-
-    @Override
-    public void onChildDismissed(View v) {
-        TaskView tv = (TaskView) v;
-        mSv.onTaskDismissed(tv);
-
-        // Re-enable clipping with the stack (we will reuse this view)
-        tv.setClipViewInStack(true);
-
-        // Disable HW layers
-        mSv.decHwLayersRefCount("swipeComplete");
-    }
-
-    @Override
-    public void onSnapBackCompleted(View v) {
-        // Re-enable clipping with the stack
-        TaskView tv = (TaskView) v;
-        tv.setClipViewInStack(true);
-    }
-
-    @Override
-    public void onDragCancelled(View v) {
-        // Disable HW layers
-        mSv.decHwLayersRefCount("swipeCancelled");
-    }
-}
+}
\ No newline at end of file
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackViewTouchHandler.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackViewTouchHandler.java
new file mode 100644
index 000000000000..d2f18aecbcae
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackViewTouchHandler.java
@@ -0,0 +1,415 @@
+/*
+ * Copyright (C) 2014 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.systemui.recents.views;
+
+import android.content.Context;
+import android.view.MotionEvent;
+import android.view.VelocityTracker;
+import android.view.View;
+import android.view.ViewConfiguration;
+import android.view.ViewParent;
+import com.android.systemui.recents.Console;
+import com.android.systemui.recents.Constants;
+
+/* Handles touch events for a TaskStackView. */
+class TaskStackViewTouchHandler implements SwipeHelper.Callback {
+    static int INACTIVE_POINTER_ID = -1;
+
+    TaskStackView mSv;
+    VelocityTracker mVelocityTracker;
+
+    boolean mIsScrolling;
+
+    int mInitialMotionX, mInitialMotionY;
+    int mLastMotionX, mLastMotionY;
+    int mActivePointerId = INACTIVE_POINTER_ID;
+    TaskView mActiveTaskView = null;
+
+    int mTotalScrollMotion;
+    int mMinimumVelocity;
+    int mMaximumVelocity;
+    // The scroll touch slop is used to calculate when we start scrolling
+    int mScrollTouchSlop;
+    // The page touch slop is used to calculate when we start swiping
+    float mPagingTouchSlop;
+
+    SwipeHelper mSwipeHelper;
+    boolean mInterceptedBySwipeHelper;
+
+    public TaskStackViewTouchHandler(Context context, TaskStackView sv) {
+        ViewConfiguration configuration = ViewConfiguration.get(context);
+        mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
+        mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
+        mScrollTouchSlop = configuration.getScaledTouchSlop();
+        mPagingTouchSlop = configuration.getScaledPagingTouchSlop();
+        mSv = sv;
+
+
+        float densityScale = context.getResources().getDisplayMetrics().density;
+        mSwipeHelper = new SwipeHelper(SwipeHelper.X, this, densityScale, mPagingTouchSlop);
+        mSwipeHelper.setMinAlpha(1f);
+    }
+
+    /** Velocity tracker helpers */
+    void initOrResetVelocityTracker() {
+        if (mVelocityTracker == null) {
+            mVelocityTracker = VelocityTracker.obtain();
+        } else {
+            mVelocityTracker.clear();
+        }
+    }
+    void initVelocityTrackerIfNotExists() {
+        if (mVelocityTracker == null) {
+            mVelocityTracker = VelocityTracker.obtain();
+        }
+    }
+    void recycleVelocityTracker() {
+        if (mVelocityTracker != null) {
+            mVelocityTracker.recycle();
+            mVelocityTracker = null;
+        }
+    }
+
+    /** Returns the view at the specified coordinates */
+    TaskView findViewAtPoint(int x, int y) {
+        int childCount = mSv.getChildCount();
+        for (int i = childCount - 1; i >= 0; i--) {
+            TaskView tv = (TaskView) mSv.getChildAt(i);
+            if (tv.getVisibility() == View.VISIBLE) {
+                if (mSv.isTransformedTouchPointInView(x, y, tv)) {
+                    return tv;
+                }
+            }
+        }
+        return null;
+    }
+
+    /** Touch preprocessing for handling below */
+    public boolean onInterceptTouchEvent(MotionEvent ev) {
+        if (Console.Enabled) {
+            Console.log(Constants.Log.UI.TouchEvents,
+                    "[TaskStackViewTouchHandler|interceptTouchEvent]",
+                    Console.motionEventActionToString(ev.getAction()), Console.AnsiBlue);
+        }
+
+        // Return early if we have no children
+        boolean hasChildren = (mSv.getChildCount() > 0);
+        if (!hasChildren) {
+            return false;
+        }
+
+        // Pass through to swipe helper if we are swiping
+        mInterceptedBySwipeHelper = mSwipeHelper.onInterceptTouchEvent(ev);
+        if (mInterceptedBySwipeHelper) {
+            return true;
+        }
+
+        boolean wasScrolling = !mSv.mScroller.isFinished() ||
+                (mSv.mScrollAnimator != null && mSv.mScrollAnimator.isRunning());
+        int action = ev.getAction();
+        switch (action & MotionEvent.ACTION_MASK) {
+            case MotionEvent.ACTION_DOWN: {
+                // Save the touch down info
+                mInitialMotionX = mLastMotionX = (int) ev.getX();
+                mInitialMotionY = mLastMotionY = (int) ev.getY();
+                mActivePointerId = ev.getPointerId(0);
+                mActiveTaskView = findViewAtPoint(mLastMotionX, mLastMotionY);
+                // Stop the current scroll if it is still flinging
+                mSv.abortScroller();
+                mSv.abortBoundScrollAnimation();
+                // Initialize the velocity tracker
+                initOrResetVelocityTracker();
+                mVelocityTracker.addMovement(ev);
+                // Check if the scroller is finished yet
+                mIsScrolling = !mSv.mScroller.isFinished();
+                break;
+            }
+            case MotionEvent.ACTION_MOVE: {
+                if (mActivePointerId == INACTIVE_POINTER_ID) break;
+
+                int activePointerIndex = ev.findPointerIndex(mActivePointerId);
+                int y = (int) ev.getY(activePointerIndex);
+                int x = (int) ev.getX(activePointerIndex);
+                if (Math.abs(y - mInitialMotionY) > mScrollTouchSlop) {
+                    // Save the touch move info
+                    mIsScrolling = true;
+                    // Initialize the velocity tracker if necessary
+                    initVelocityTrackerIfNotExists();
+                    mVelocityTracker.addMovement(ev);
+                    // Disallow parents from intercepting touch events
+                    final ViewParent parent = mSv.getParent();
+                    if (parent != null) {
+                        parent.requestDisallowInterceptTouchEvent(true);
+                    }
+                    // Enable HW layers
+                    mSv.addHwLayersRefCount("stackScroll");
+                }
+
+                mLastMotionX = x;
+                mLastMotionY = y;
+                break;
+            }
+            case MotionEvent.ACTION_CANCEL:
+            case MotionEvent.ACTION_UP: {
+                // Animate the scroll back if we've cancelled
+                mSv.animateBoundScroll();
+                // Disable HW layers
+                if (mIsScrolling) {
+                    mSv.decHwLayersRefCount("stackScroll");
+                }
+                // Reset the drag state and the velocity tracker
+                mIsScrolling = false;
+                mActivePointerId = INACTIVE_POINTER_ID;
+                mActiveTaskView = null;
+                mTotalScrollMotion = 0;
+                recycleVelocityTracker();
+                break;
+            }
+        }
+
+        return wasScrolling || mIsScrolling;
+    }
+
+    /** Handles touch events once we have intercepted them */
+    public boolean onTouchEvent(MotionEvent ev) {
+        if (Console.Enabled) {
+            Console.log(Constants.Log.UI.TouchEvents,
+                    "[TaskStackViewTouchHandler|touchEvent]",
+                    Console.motionEventActionToString(ev.getAction()), Console.AnsiBlue);
+        }
+
+        // Short circuit if we have no children
+        boolean hasChildren = (mSv.getChildCount() > 0);
+        if (!hasChildren) {
+            return false;
+        }
+
+        // Pass through to swipe helper if we are swiping
+        if (mInterceptedBySwipeHelper && mSwipeHelper.onTouchEvent(ev)) {
+            return true;
+        }
+
+        // Update the velocity tracker
+        initVelocityTrackerIfNotExists();
+        mVelocityTracker.addMovement(ev);
+
+        int action = ev.getAction();
+        switch (action & MotionEvent.ACTION_MASK) {
+            case MotionEvent.ACTION_DOWN: {
+                // Save the touch down info
+                mInitialMotionX = mLastMotionX = (int) ev.getX();
+                mInitialMotionY = mLastMotionY = (int) ev.getY();
+                mActivePointerId = ev.getPointerId(0);
+                mActiveTaskView = findViewAtPoint(mLastMotionX, mLastMotionY);
+                // Stop the current scroll if it is still flinging
+                mSv.abortScroller();
+                mSv.abortBoundScrollAnimation();
+                // Initialize the velocity tracker
+                initOrResetVelocityTracker();
+                mVelocityTracker.addMovement(ev);
+                // Disallow parents from intercepting touch events
+                final ViewParent parent = mSv.getParent();
+                if (parent != null) {
+                    parent.requestDisallowInterceptTouchEvent(true);
+                }
+                break;
+            }
+            case MotionEvent.ACTION_POINTER_DOWN: {
+                final int index = ev.getActionIndex();
+                mActivePointerId = ev.getPointerId(index);
+                mLastMotionX = (int) ev.getX(index);
+                mLastMotionY = (int) ev.getY(index);
+                break;
+            }
+            case MotionEvent.ACTION_MOVE: {
+                if (mActivePointerId == INACTIVE_POINTER_ID) break;
+
+                int activePointerIndex = ev.findPointerIndex(mActivePointerId);
+                int x = (int) ev.getX(activePointerIndex);
+                int y = (int) ev.getY(activePointerIndex);
+                int yTotal = Math.abs(y - mInitialMotionY);
+                int deltaY = mLastMotionY - y;
+                if (!mIsScrolling) {
+                    if (yTotal > mScrollTouchSlop) {
+                        mIsScrolling = true;
+                        // Initialize the velocity tracker
+                        initOrResetVelocityTracker();
+                        mVelocityTracker.addMovement(ev);
+                        // Disallow parents from intercepting touch events
+                        final ViewParent parent = mSv.getParent();
+                        if (parent != null) {
+                            parent.requestDisallowInterceptTouchEvent(true);
+                        }
+                        // Enable HW layers
+                        mSv.addHwLayersRefCount("stackScroll");
+                    }
+                }
+                if (mIsScrolling) {
+                    int curStackScroll = mSv.getStackScroll();
+                    int overScrollAmount = mSv.getScrollAmountOutOfBounds(curStackScroll + deltaY);
+                    if (overScrollAmount != 0) {
+                        // Bound the overscroll to a fixed amount, and inversely scale the y-movement
+                        // relative to how close we are to the max overscroll
+                        float maxOverScroll = mSv.mTaskRect.height() / 3f;
+                        deltaY = Math.round(deltaY * (1f - (Math.min(maxOverScroll, overScrollAmount)
+                                / maxOverScroll)));
+                    }
+                    mSv.setStackScroll(curStackScroll + deltaY);
+                    if (mSv.isScrollOutOfBounds()) {
+                        mVelocityTracker.clear();
+                    }
+                }
+                mLastMotionX = x;
+                mLastMotionY = y;
+                mTotalScrollMotion += Math.abs(deltaY);
+                break;
+            }
+            case MotionEvent.ACTION_UP: {
+                final VelocityTracker velocityTracker = mVelocityTracker;
+                velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
+                int velocity = (int) velocityTracker.getYVelocity(mActivePointerId);
+
+                if (mIsScrolling && (Math.abs(velocity) > mMinimumVelocity)) {
+                    // Enable HW layers on the stack
+                    mSv.addHwLayersRefCount("flingScroll");
+                    // XXX: Make this animation a function of the velocity AND distance
+                    int overscrollRange = (int) (Math.min(1f,
+                            Math.abs((float) velocity / mMaximumVelocity)) *
+                            Constants.Values.TaskStackView.TaskStackOverscrollRange);
+
+                    if (Console.Enabled) {
+                        Console.log(Constants.Log.UI.TouchEvents,
+                                "[TaskStackViewTouchHandler|fling]",
+                                "scroll: " + mSv.getStackScroll() + " velocity: " + velocity +
+                                        " maxVelocity: " + mMaximumVelocity +
+                                        " overscrollRange: " + overscrollRange,
+                                Console.AnsiGreen);
+                    }
+
+                    // Fling scroll
+                    mSv.mScroller.fling(0, mSv.getStackScroll(),
+                            0, -velocity,
+                            0, 0,
+                            mSv.mMinScroll, mSv.mMaxScroll,
+                            0, overscrollRange);
+                    // Invalidate to kick off computeScroll
+                    mSv.invalidate(mSv.mStackRect);
+                } else if (mSv.isScrollOutOfBounds()) {
+                    // Animate the scroll back into bounds
+                    // XXX: Make this animation a function of the velocity OR distance
+                    mSv.animateBoundScroll();
+                }
+
+                if (mIsScrolling) {
+                    // Disable HW layers
+                    mSv.decHwLayersRefCount("stackScroll");
+                }
+                mActivePointerId = INACTIVE_POINTER_ID;
+                mIsScrolling = false;
+                mTotalScrollMotion = 0;
+                recycleVelocityTracker();
+                break;
+            }
+            case MotionEvent.ACTION_POINTER_UP: {
+                int pointerIndex = ev.getActionIndex();
+                int pointerId = ev.getPointerId(pointerIndex);
+                if (pointerId == mActivePointerId) {
+                    // Select a new active pointer id and reset the motion state
+                    final int newPointerIndex = (pointerIndex == 0) ? 1 : 0;
+                    mActivePointerId = ev.getPointerId(newPointerIndex);
+                    mLastMotionX = (int) ev.getX(newPointerIndex);
+                    mLastMotionY = (int) ev.getY(newPointerIndex);
+                    mVelocityTracker.clear();
+                }
+                break;
+            }
+            case MotionEvent.ACTION_CANCEL: {
+                if (mIsScrolling) {
+                    // Disable HW layers
+                    mSv.decHwLayersRefCount("stackScroll");
+                }
+                if (mSv.isScrollOutOfBounds()) {
+                    // Animate the scroll back into bounds
+                    // XXX: Make this animation a function of the velocity OR distance
+                    mSv.animateBoundScroll();
+                }
+                mActivePointerId = INACTIVE_POINTER_ID;
+                mIsScrolling = false;
+                mTotalScrollMotion = 0;
+                recycleVelocityTracker();
+                break;
+            }
+        }
+        return true;
+    }
+
+    /**** SwipeHelper Implementation ****/
+
+    @Override
+    public View getChildAtPosition(MotionEvent ev) {
+        return findViewAtPoint((int) ev.getX(), (int) ev.getY());
+    }
+
+    @Override
+    public boolean canChildBeDismissed(View v) {
+        return true;
+    }
+
+    @Override
+    public void onBeginDrag(View v) {
+        // Enable HW layers
+        mSv.addHwLayersRefCount("swipeBegin");
+        // Disable clipping with the stack while we are swiping
+        TaskView tv = (TaskView) v;
+        tv.setClipViewInStack(false);
+        // Disallow parents from intercepting touch events
+        final ViewParent parent = mSv.getParent();
+        if (parent != null) {
+            parent.requestDisallowInterceptTouchEvent(true);
+        }
+    }
+
+    @Override
+    public void onSwipeChanged(View v, float delta) {
+        // Do nothing
+    }
+
+    @Override
+    public void onChildDismissed(View v) {
+        TaskView tv = (TaskView) v;
+        mSv.onTaskDismissed(tv);
+
+        // Re-enable clipping with the stack (we will reuse this view)
+        tv.setClipViewInStack(true);
+
+        // Disable HW layers
+        mSv.decHwLayersRefCount("swipeComplete");
+    }
+
+    @Override
+    public void onSnapBackCompleted(View v) {
+        // Re-enable clipping with the stack
+        TaskView tv = (TaskView) v;
+        tv.setClipViewInStack(true);
+    }
+
+    @Override
+    public void onDragCancelled(View v) {
+        // Disable HW layers
+        mSv.decHwLayersRefCount("swipeCancelled");
+    }
+}