Rename Launcher to Trebuchet

Launcher2 is now Trebuchet
application_name removed from localized strings and made un-translatable
com.android.launcher is now com.cyanogenmod.trebuchet

1 files changed, 1924 insertions, 0 deletions

diff --git a/src/com/cyanogenmod/trebuchet/PagedView.java b/src/com/cyanogenmod/trebuchet/PagedView.java
new file mode 100644
index 0000000..d9d3521
--- /dev/null
+++ b/src/com/cyanogenmod/trebuchet/PagedView.java
@@ -0,0 +1,1924 @@
+/*
+ * Copyright (C) 2010 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.cyanogenmod.trebuchet;
+
+import android.animation.Animator;
+import android.animation.AnimatorListenerAdapter;
+import android.animation.ValueAnimator;
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.graphics.Canvas;
+import android.graphics.Rect;
+import android.os.Bundle;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.InputDevice;
+import android.view.KeyEvent;
+import android.view.MotionEvent;
+import android.view.VelocityTracker;
+import android.view.View;
+import android.view.ViewConfiguration;
+import android.view.ViewGroup;
+import android.view.ViewParent;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityManager;
+import android.view.accessibility.AccessibilityNodeInfo;
+import android.view.animation.Interpolator;
+import android.widget.Scroller;
+
+import com.cyanogenmod.trebuchet.R;
+
+import java.util.ArrayList;
+
+/**
+ * An abstraction of the original Workspace which supports browsing through a
+ * sequential list of "pages"
+ */
+public abstract class PagedView extends ViewGroup implements ViewGroup.OnHierarchyChangeListener {
+    private static final String TAG = "PagedView";
+    private static final boolean DEBUG = false;
+    protected static final int INVALID_PAGE = -1;
+
+    // the min drag distance for a fling to register, to prevent random page shifts
+    private static final int MIN_LENGTH_FOR_FLING = 25;
+
+    protected static final int PAGE_SNAP_ANIMATION_DURATION = 550;
+    protected static final int MAX_PAGE_SNAP_DURATION = 750;
+    protected static final int SLOW_PAGE_SNAP_ANIMATION_DURATION = 950;
+    protected static final float NANOTIME_DIV = 1000000000.0f;
+
+    private static final float OVERSCROLL_ACCELERATE_FACTOR = 2;
+    private static final float OVERSCROLL_DAMP_FACTOR = 0.14f;
+
+    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.
+    private static final float SIGNIFICANT_MOVE_THRESHOLD = 0.4f;
+
+    // The following constants need to be scaled based on density. The scaled versions will be
+    // assigned to the corresponding member variables below.
+    private static final int FLING_THRESHOLD_VELOCITY = 500;
+    private static final int MIN_SNAP_VELOCITY = 1500;
+    private static final int MIN_FLING_VELOCITY = 250;
+
+    static final int AUTOMATIC_PAGE_SPACING = -1;
+
+    protected int mFlingThresholdVelocity;
+    protected int mMinFlingVelocity;
+    protected int mMinSnapVelocity;
+
+    protected float mDensity;
+    protected float mSmoothingTime;
+    protected float mTouchX;
+
+    protected boolean mFirstLayout = true;
+
+    protected int mCurrentPage;
+    protected int mNextPage = INVALID_PAGE;
+    protected int mMaxScrollX;
+    protected Scroller mScroller;
+    private VelocityTracker mVelocityTracker;
+
+    private float mDownMotionX;
+    protected float mLastMotionX;
+    protected float mLastMotionXRemainder;
+    protected float mLastMotionY;
+    protected float mTotalMotionX;
+    private int mLastScreenCenter = -1;
+    private int[] mChildOffsets;
+    private int[] mChildRelativeOffsets;
+    private int[] mChildOffsetsWithLayoutScale;
+
+    protected final static int TOUCH_STATE_REST = 0;
+    protected final static int TOUCH_STATE_SCROLLING = 1;
+    protected final static int TOUCH_STATE_PREV_PAGE = 2;
+    protected final static int TOUCH_STATE_NEXT_PAGE = 3;
+    protected final static float ALPHA_QUANTIZE_LEVEL = 0.0001f;
+
+    protected int mTouchState = TOUCH_STATE_REST;
+    protected boolean mForceScreenScrolled = false;
+
+    protected OnLongClickListener mLongClickListener;
+
+    protected boolean mAllowLongPress = true;
+
+    protected int mTouchSlop;
+    private int mPagingTouchSlop;
+    private int mMaximumVelocity;
+    private int mMinimumWidth;
+    protected int mPageSpacing;
+    protected int mPageLayoutPaddingTop;
+    protected int mPageLayoutPaddingBottom;
+    protected int mPageLayoutPaddingLeft;
+    protected int mPageLayoutPaddingRight;
+    protected int mPageLayoutWidthGap;
+    protected int mPageLayoutHeightGap;
+    protected int mCellCountX = 0;
+    protected int mCellCountY = 0;
+    protected boolean mCenterPagesVertically;
+    protected boolean mAllowOverScroll = true;
+    protected int mUnboundedScrollX;
+    protected int[] mTempVisiblePagesRange = new int[2];
+    protected boolean mForceDrawAllChildrenNextFrame;
+
+    // mOverScrollX is equal to getScrollX() when we're within the normal scroll range. Otherwise
+    // it is equal to the scaled overscroll position. We use a separate value so as to prevent
+    // the screens from continuing to translate beyond the normal bounds.
+    protected int mOverScrollX;
+
+    // parameter that adjusts the layout to be optimized for pages with that scale factor
+    protected float mLayoutScale = 1.0f;
+
+    protected static final int INVALID_POINTER = -1;
+
+    protected int mActivePointerId = INVALID_POINTER;
+
+    private PageSwitchListener mPageSwitchListener;
+
+    protected ArrayList<Boolean> mDirtyPageContent;
+
+    // If true, syncPages and syncPageItems will be called to refresh pages
+    protected boolean mContentIsRefreshable = true;
+
+    // If true, modify alpha of neighboring pages as user scrolls left/right
+    protected boolean mFadeInAdjacentScreens = true;
+
+    // It true, use a different slop parameter (pagingTouchSlop = 2 * touchSlop) for deciding
+    // to switch to a new page
+    protected boolean mUsePagingTouchSlop = true;
+
+    // If true, the subclass should directly update scrollX itself in its computeScroll method
+    // (SmoothPagedView does this)
+    protected boolean mDeferScrollUpdate = false;
+
+    protected boolean mIsPageMoving = false;
+
+    // All syncs and layout passes are deferred until data is ready.
+    protected boolean mIsDataReady = false;
+
+    // Scrolling indicator
+    private ValueAnimator mScrollIndicatorAnimator;
+    private View mScrollIndicator;
+    private int mScrollIndicatorPaddingLeft;
+    private int mScrollIndicatorPaddingRight;
+    private boolean mHasScrollIndicator = true;
+    private boolean mShouldShowScrollIndicator = false;
+    private boolean mShouldShowScrollIndicatorImmediately = false;
+    protected static final int sScrollIndicatorFadeInDuration = 150;
+    protected static final int sScrollIndicatorFadeOutDuration = 650;
+    protected static final int sScrollIndicatorFlashDuration = 650;
+    private boolean mScrollingPaused = false;
+
+    // If set, will defer loading associated pages until the scrolling settles
+    private boolean mDeferLoadAssociatedPagesUntilScrollCompletes;
+
+    public interface PageSwitchListener {
+        void onPageSwitch(View newPage, int newPageIndex);
+    }
+
+    public PagedView(Context context) {
+        this(context, null);
+    }
+
+    public PagedView(Context context, AttributeSet attrs) {
+        this(context, attrs, 0);
+    }
+
+    public PagedView(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+
+        TypedArray a = context.obtainStyledAttributes(attrs,
+                R.styleable.PagedView, defStyle, 0);
+        setPageSpacing(a.getDimensionPixelSize(R.styleable.PagedView_pageSpacing, 0));
+        mPageLayoutPaddingTop = a.getDimensionPixelSize(
+                R.styleable.PagedView_pageLayoutPaddingTop, 0);
+        mPageLayoutPaddingBottom = a.getDimensionPixelSize(
+                R.styleable.PagedView_pageLayoutPaddingBottom, 0);
+        mPageLayoutPaddingLeft = a.getDimensionPixelSize(
+                R.styleable.PagedView_pageLayoutPaddingLeft, 0);
+        mPageLayoutPaddingRight = a.getDimensionPixelSize(
+                R.styleable.PagedView_pageLayoutPaddingRight, 0);
+        mPageLayoutWidthGap = a.getDimensionPixelSize(
+                R.styleable.PagedView_pageLayoutWidthGap, 0);
+        mPageLayoutHeightGap = a.getDimensionPixelSize(
+                R.styleable.PagedView_pageLayoutHeightGap, 0);
+        mScrollIndicatorPaddingLeft =
+            a.getDimensionPixelSize(R.styleable.PagedView_scrollIndicatorPaddingLeft, 0);
+        mScrollIndicatorPaddingRight =
+            a.getDimensionPixelSize(R.styleable.PagedView_scrollIndicatorPaddingRight, 0);
+        a.recycle();
+
+        setHapticFeedbackEnabled(false);
+        init();
+    }
+
+    /**
+     * Initializes various states for this workspace.
+     */
+    protected void init() {
+        mDirtyPageContent = new ArrayList<Boolean>();
+        mDirtyPageContent.ensureCapacity(32);
+        mScroller = new Scroller(getContext(), new ScrollInterpolator());
+        mCurrentPage = 0;
+        mCenterPagesVertically = true;
+
+        final ViewConfiguration configuration = ViewConfiguration.get(getContext());
+        mTouchSlop = configuration.getScaledTouchSlop();
+        mPagingTouchSlop = configuration.getScaledPagingTouchSlop();
+        mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
+        mDensity = getResources().getDisplayMetrics().density;
+
+        mFlingThresholdVelocity = (int) (FLING_THRESHOLD_VELOCITY * mDensity);
+        mMinFlingVelocity = (int) (MIN_FLING_VELOCITY * mDensity);
+        mMinSnapVelocity = (int) (MIN_SNAP_VELOCITY * mDensity);
+        setOnHierarchyChangeListener(this);
+    }
+
+    public void setPageSwitchListener(PageSwitchListener pageSwitchListener) {
+        mPageSwitchListener = pageSwitchListener;
+        if (mPageSwitchListener != null) {
+            mPageSwitchListener.onPageSwitch(getPageAt(mCurrentPage), mCurrentPage);
+        }
+    }
+
+    /**
+     * Called by subclasses to mark that data is ready, and that we can begin loading and laying
+     * out pages.
+     */
+    protected void setDataIsReady() {
+        mIsDataReady = true;
+    }
+    protected boolean isDataReady() {
+        return mIsDataReady;
+    }
+
+    /**
+     * Returns the index of the currently displayed page.
+     *
+     * @return The index of the currently displayed page.
+     */
+    int getCurrentPage() {
+        return mCurrentPage;
+    }
+    int getNextPage() {
+        return (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage;
+    }
+
+    int getPageCount() {
+        return getChildCount();
+    }
+
+    View getPageAt(int index) {
+        return getChildAt(index);
+    }
+
+    protected int indexToPage(int index) {
+        return index;
+    }
+
+    /**
+     * Updates the scroll of the current page immediately to its final scroll position.  We use this
+     * in CustomizePagedView to allow tabs to share the same PagedView while resetting the scroll of
+     * the previous tab page.
+     */
+    protected void updateCurrentPageScroll() {
+        int offset = getChildOffset(mCurrentPage);
+        int relOffset = getRelativeChildOffset(mCurrentPage);
+        int newX = offset - relOffset;
+        scrollTo(newX, 0);
+        mScroller.setFinalX(newX);
+        mScroller.forceFinished(true);
+    }
+
+    /**
+     * Called during AllApps/Home transitions to avoid unnecessary work. When that other animation
+     * ends, {@link #resumeScrolling()} should be called, along with
+     * {@link #updateCurrentPageScroll()} to correctly set the final state and re-enable scrolling.
+     */
+    void pauseScrolling() {
+        mScroller.forceFinished(true);
+        cancelScrollingIndicatorAnimations();
+        mScrollingPaused = true;
+    }
+
+    /**
+     * Enables scrolling again.
+     * @see #pauseScrolling()
+     */
+    void resumeScrolling() {
+        mScrollingPaused = false;
+    }
+    /**
+     * Sets the current page.
+     */
+    void setCurrentPage(int currentPage) {
+        if (!mScroller.isFinished()) {
+            mScroller.abortAnimation();
+        }
+        // don't introduce any checks like mCurrentPage == currentPage here-- if we change the
+        // the default
+        if (getChildCount() == 0) {
+            return;
+        }
+
+
+        mCurrentPage = Math.max(0, Math.min(currentPage, getPageCount() - 1));
+        updateCurrentPageScroll();
+        updateScrollingIndicator();
+        notifyPageSwitchListener();
+        invalidate();
+    }
+
+    protected void notifyPageSwitchListener() {
+        if (mPageSwitchListener != null) {
+            mPageSwitchListener.onPageSwitch(getPageAt(mCurrentPage), mCurrentPage);
+        }
+    }
+
+    protected void pageBeginMoving() {
+        if (!mIsPageMoving) {
+            mIsPageMoving = true;
+            onPageBeginMoving();
+        }
+    }
+
+    protected void pageEndMoving() {
+        if (mIsPageMoving) {
+            mIsPageMoving = false;
+            onPageEndMoving();
+        }
+    }
+
+    protected boolean isPageMoving() {
+        return mIsPageMoving;
+    }
+
+    // a method that subclasses can override to add behavior
+    protected void onPageBeginMoving() {
+    }
+
+    // a method that subclasses can override to add behavior
+    protected void onPageEndMoving() {
+    }
+
+    /**
+     * Registers the specified listener on each page contained in this workspace.
+     *
+     * @param l The listener used to respond to long clicks.
+     */
+    @Override
+    public void setOnLongClickListener(OnLongClickListener l) {
+        mLongClickListener = l;
+        final int count = getPageCount();
+        for (int i = 0; i < count; i++) {
+            getPageAt(i).setOnLongClickListener(l);
+        }
+    }
+
+    @Override
+    public void scrollBy(int x, int y) {
+        scrollTo(mUnboundedScrollX + x, getScrollY() + y);
+    }
+
+    @Override
+    public void scrollTo(int x, int y) {
+        mUnboundedScrollX = x;
+
+        if (x < 0) {
+            super.scrollTo(0, y);
+            if (mAllowOverScroll) {
+                overScroll(x);
+            }
+        } else if (x > mMaxScrollX) {
+            super.scrollTo(mMaxScrollX, y);
+            if (mAllowOverScroll) {
+                overScroll(x - mMaxScrollX);
+            }
+        } else {
+            mOverScrollX = x;
+            super.scrollTo(x, y);
+        }
+
+        mTouchX = x;
+        mSmoothingTime = System.nanoTime() / NANOTIME_DIV;
+    }
+
+    // we moved this functionality to a helper function so SmoothPagedView can reuse it
+    protected boolean computeScrollHelper() {
+        if (mScroller.computeScrollOffset()) {
+            // Don't bother scrolling if the page does not need to be moved
+            if (getScrollX() != mScroller.getCurrX()
+                || getScrollY() != mScroller.getCurrY()
+                || mOverScrollX != mScroller.getCurrX()) {
+                scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
+            }
+            invalidate();
+            return true;
+        } else if (mNextPage != INVALID_PAGE) {
+            mCurrentPage = Math.max(0, Math.min(mNextPage, getPageCount() - 1));
+            mNextPage = INVALID_PAGE;
+            notifyPageSwitchListener();
+
+            // Load the associated pages if necessary
+            if (mDeferLoadAssociatedPagesUntilScrollCompletes) {
+                loadAssociatedPages(mCurrentPage);
+                mDeferLoadAssociatedPagesUntilScrollCompletes = false;
+            }
+
+            // We don't want to trigger a page end moving unless the page has settled
+            // and the user has stopped scrolling
+            if (mTouchState == TOUCH_STATE_REST) {
+                pageEndMoving();
+            }
+
+            // Notify the user when the page changes
+            AccessibilityManager accessibilityManager = (AccessibilityManager)
+                    getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
+            if (accessibilityManager.isEnabled()) {
+                AccessibilityEvent ev =
+                    AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_SCROLLED);
+                ev.getText().add(getCurrentPageDescription());
+                sendAccessibilityEventUnchecked(ev);
+            }
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public void computeScroll() {
+        computeScrollHelper();
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        if (!mIsDataReady) {
+            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+            return;
+        }
+
+        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
+        final int widthSize = MeasureSpec.getSize(widthMeasureSpec);
+        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
+        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
+        if (widthMode != MeasureSpec.EXACTLY) {
+            throw new IllegalStateException("Workspace can only be used in EXACTLY mode.");
+        }
+
+        // Return early if we aren't given a proper dimension
+        if (widthSize <= 0 || heightSize <= 0) {
+            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+            return;
+        }
+
+        /* Allow the height to be set as WRAP_CONTENT. This allows the particular case
+         * of the All apps view on XLarge displays to not take up more space then it needs. Width
+         * is still not allowed to be set as WRAP_CONTENT since many parts of the code expect
+         * each page to have the same width.
+         */
+        int maxChildHeight = 0;
+
+        final int verticalPadding = getPaddingTop() + getPaddingBottom();
+        final int horizontalPadding = getPaddingLeft() + getPaddingRight();
+
+
+        // The children are given the same width and height as the workspace
+        // unless they were set to WRAP_CONTENT
+        if (DEBUG) Log.d(TAG, "PagedView.onMeasure(): " + widthSize + ", " + heightSize);
+        final int childCount = getChildCount();
+        for (int i = 0; i < childCount; i++) {
+            // disallowing padding in paged view (just pass 0)
+            final View child = getPageAt(i);
+            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
+
+            int childWidthMode;
+            if (lp.width == LayoutParams.WRAP_CONTENT) {
+                childWidthMode = MeasureSpec.AT_MOST;
+            } else {
+                childWidthMode = MeasureSpec.EXACTLY;
+            }
+
+            int childHeightMode;
+            if (lp.height == LayoutParams.WRAP_CONTENT) {
+                childHeightMode = MeasureSpec.AT_MOST;
+            } else {
+                childHeightMode = MeasureSpec.EXACTLY;
+            }
+
+            final int childWidthMeasureSpec =
+                MeasureSpec.makeMeasureSpec(widthSize - horizontalPadding, childWidthMode);
+            final int childHeightMeasureSpec =
+                MeasureSpec.makeMeasureSpec(heightSize - verticalPadding, childHeightMode);
+
+            child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
+            maxChildHeight = Math.max(maxChildHeight, child.getMeasuredHeight());
+            if (DEBUG) Log.d(TAG, "\tmeasure-child" + i + ": " + child.getMeasuredWidth() + ", "
+                    + child.getMeasuredHeight());
+        }
+
+        if (heightMode == MeasureSpec.AT_MOST) {
+            heightSize = maxChildHeight + verticalPadding;
+        }
+
+        setMeasuredDimension(widthSize, heightSize);
+
+        // We can't call getChildOffset/getRelativeChildOffset until we set the measured dimensions.
+        // We also wait until we set the measured dimensions before flushing the cache as well, to
+        // ensure that the cache is filled with good values.
+        invalidateCachedOffsets();
+
+        if (childCount > 0) {
+            if (DEBUG) Log.d(TAG, "getRelativeChildOffset(): " + getMeasuredWidth() + ", "
+                    + getChildWidth(0));
+
+            // Calculate the variable page spacing if necessary
+            if (mPageSpacing == AUTOMATIC_PAGE_SPACING) {
+                // The gap between pages in the PagedView should be equal to the gap from the page
+                // to the edge of the screen (so it is not visible in the current screen).  To
+                // account for unequal padding on each side of the paged view, we take the maximum
+                // of the left/right gap and use that as the gap between each page.
+                int offset = getRelativeChildOffset(0);
+                int spacing = Math.max(offset, widthSize - offset -
+                        getChildAt(0).getMeasuredWidth());
+                setPageSpacing(spacing);
+            }
+        }
+
+        updateScrollingIndicatorPosition();
+
+        if (childCount > 0) {
+            mMaxScrollX = getChildOffset(childCount - 1) - getRelativeChildOffset(childCount - 1);
+        } else {
+            mMaxScrollX = 0;
+        }
+    }
+
+    protected void scrollToNewPageWithoutMovingPages(int newCurrentPage) {
+        int newX = getChildOffset(newCurrentPage) - getRelativeChildOffset(newCurrentPage);
+        int delta = newX - getScrollX();
+
+        final int pageCount = getChildCount();
+        for (int i = 0; i < pageCount; i++) {
+            View page = (View) getPageAt(i);
+            page.setX(page.getX() + delta);
+        }
+        setCurrentPage(newCurrentPage);
+    }
+
+    // A layout scale of 1.0f assumes that the pages, in their unshrunken state, have a
+    // scale of 1.0f. A layout scale of 0.8f assumes the pages have a scale of 0.8f, and
+    // tightens the layout accordingly
+    public void setLayoutScale(float childrenScale) {
+        mLayoutScale = childrenScale;
+        invalidateCachedOffsets();
+
+        // Now we need to do a re-layout, but preserving absolute X and Y coordinates
+        int childCount = getChildCount();
+        float childrenX[] = new float[childCount];
+        float childrenY[] = new float[childCount];
+        for (int i = 0; i < childCount; i++) {
+            final View child = getPageAt(i);
+            childrenX[i] = child.getX();
+            childrenY[i] = child.getY();
+        }
+        // Trigger a full re-layout (never just call onLayout directly!)
+        int widthSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY);
+        int heightSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.EXACTLY);
+        requestLayout();
+        measure(widthSpec, heightSpec);
+        layout(getLeft(), getTop(), getRight(), getBottom());
+        for (int i = 0; i < childCount; i++) {
+            final View child = getPageAt(i);
+            child.setX(childrenX[i]);
+            child.setY(childrenY[i]);
+        }
+
+        // Also, the page offset has changed  (since the pages are now smaller);
+        // update the page offset, but again preserving absolute X and Y coordinates
+        scrollToNewPageWithoutMovingPages(mCurrentPage);
+    }
+
+    public void setPageSpacing(int pageSpacing) {
+        mPageSpacing = pageSpacing;
+        invalidateCachedOffsets();
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
+        if (!mIsDataReady) {
+            return;
+        }
+
+        if (DEBUG) Log.d(TAG, "PagedView.onLayout()");
+        final int verticalPadding = getPaddingTop() + getPaddingBottom();
+        final int childCount = getChildCount();
+        int childLeft = getRelativeChildOffset(0);
+
+        for (int i = 0; i < childCount; i++) {
+            final View child = getPageAt(i);
+            if (child.getVisibility() != View.GONE) {
+                final int childWidth = getScaledMeasuredWidth(child);
+                final int childHeight = child.getMeasuredHeight();
+                int childTop = getPaddingTop();
+                if (mCenterPagesVertically) {
+                    childTop += ((getMeasuredHeight() - verticalPadding) - childHeight) / 2;
+                }
+
+                if (DEBUG) Log.d(TAG, "\tlayout-child" + i + ": " + childLeft + ", " + childTop);
+                child.layout(childLeft, childTop,
+                        childLeft + child.getMeasuredWidth(), childTop + childHeight);
+                childLeft += childWidth + mPageSpacing;
+            }
+        }
+
+        if (mFirstLayout && mCurrentPage >= 0 && mCurrentPage < getChildCount()) {
+            setHorizontalScrollBarEnabled(false);
+            updateCurrentPageScroll();
+            setHorizontalScrollBarEnabled(true);
+            mFirstLayout = false;
+        }
+    }
+
+    protected void screenScrolled(int screenCenter) {
+        if (isScrollingIndicatorEnabled()) {
+            updateScrollingIndicator();
+        }
+        boolean isInOverscroll = mOverScrollX < 0 || mOverScrollX > mMaxScrollX;
+
+        if (mFadeInAdjacentScreens && !isInOverscroll) {
+            for (int i = 0; i < getChildCount(); i++) {
+                View child = getChildAt(i);
+                if (child != null) {
+                    float scrollProgress = getScrollProgress(screenCenter, child, i);
+                    float alpha = 1 - Math.abs(scrollProgress);
+                    child.setAlpha(alpha);
+                }
+            }
+            invalidate();
+        }
+    }
+
+    @Override
+    public void onChildViewAdded(View parent, View child) {
+        // This ensures that when children are added, they get the correct transforms / alphas
+        // in accordance with any scroll effects.
+        mForceScreenScrolled = true;
+        invalidate();
+        invalidateCachedOffsets();
+    }
+
+    @Override
+    public void onChildViewRemoved(View parent, View child) {
+    }
+
+    protected void invalidateCachedOffsets() {
+        int count = getChildCount();
+        if (count == 0) {
+            mChildOffsets = null;
+            mChildRelativeOffsets = null;
+            mChildOffsetsWithLayoutScale = null;
+            return;
+        }
+
+        mChildOffsets = new int[count];
+        mChildRelativeOffsets = new int[count];
+        mChildOffsetsWithLayoutScale = new int[count];
+        for (int i = 0; i < count; i++) {
+            mChildOffsets[i] = -1;
+            mChildRelativeOffsets[i] = -1;
+            mChildOffsetsWithLayoutScale[i] = -1;
+        }
+    }
+
+    protected int getChildOffset(int index) {
+        int[] childOffsets = Float.compare(mLayoutScale, 1f) == 0 ?
+                mChildOffsets : mChildOffsetsWithLayoutScale;
+
+        if (childOffsets != null && childOffsets[index] != -1) {
+            return childOffsets[index];
+        } else {
+            if (getChildCount() == 0)
+                return 0;
+
+            int offset = getRelativeChildOffset(0);
+            for (int i = 0; i < index; ++i) {
+                offset += getScaledMeasuredWidth(getPageAt(i)) + mPageSpacing;
+            }
+            if (childOffsets != null) {
+                childOffsets[index] = offset;
+            }
+            return offset;
+        }
+    }
+
+    protected int getRelativeChildOffset(int index) {
+        if (mChildRelativeOffsets != null && mChildRelativeOffsets[index] != -1) {
+            return mChildRelativeOffsets[index];
+        } else {
+            final int padding = getPaddingLeft() + getPaddingRight();
+            final int offset = getPaddingLeft() +
+                    (getMeasuredWidth() - padding - getChildWidth(index)) / 2;
+            if (mChildRelativeOffsets != null) {
+                mChildRelativeOffsets[index] = offset;
+            }
+            return offset;
+        }
+    }
+
+    protected int getScaledMeasuredWidth(View child) {
+        // This functions are called enough times that it actually makes a difference in the
+        // profiler -- so just inline the max() here
+        final int measuredWidth = child.getMeasuredWidth();
+        final int minWidth = mMinimumWidth;
+        final int maxWidth = (minWidth > measuredWidth) ? minWidth : measuredWidth;
+        return (int) (maxWidth * mLayoutScale + 0.5f);
+    }
+
+    protected void getVisiblePages(int[] range) {
+        final int pageCount = getChildCount();
+
+        if (pageCount > 0) {
+            final int screenWidth = getMeasuredWidth();
+            int leftScreen = 0;
+            int rightScreen = 0;
+            View currPage = getPageAt(leftScreen);
+            while (leftScreen < pageCount - 1 &&
+                    currPage.getX() + currPage.getWidth() -
+                    currPage.getPaddingRight() < getScrollX()) {
+                leftScreen++;
+                currPage = getPageAt(leftScreen);
+            }
+            rightScreen = leftScreen;
+            currPage = getPageAt(rightScreen + 1);
+            while (rightScreen < pageCount - 1 &&
+                    currPage.getX() - currPage.getPaddingLeft() < getScrollX() + screenWidth) {
+                rightScreen++;
+                currPage = getPageAt(rightScreen + 1);
+            }
+            range[0] = leftScreen;
+            range[1] = rightScreen;
+        } else {
+            range[0] = -1;
+            range[1] = -1;
+        }
+    }
+
+    protected boolean shouldDrawChild(View child) {
+        return child.getAlpha() > 0;
+    }
+
+    @Override
+    protected void dispatchDraw(Canvas canvas) {
+        int halfScreenSize = getMeasuredWidth() / 2;
+        // mOverScrollX is equal to getScrollX() when we're within the normal scroll range.
+        // Otherwise it is equal to the scaled overscroll position.
+        int screenCenter = mOverScrollX + halfScreenSize;
+
+        if (screenCenter != mLastScreenCenter || mForceScreenScrolled) {
+            // set mForceScreenScrolled before calling screenScrolled so that screenScrolled can
+            // set it for the next frame
+            mForceScreenScrolled = false;
+            screenScrolled(screenCenter);
+            mLastScreenCenter = screenCenter;
+        }
+
+        // Find out which screens are visible; as an optimization we only call draw on them
+        final int pageCount = getChildCount();
+        if (pageCount > 0) {
+            getVisiblePages(mTempVisiblePagesRange);
+            final int leftScreen = mTempVisiblePagesRange[0];
+            final int rightScreen = mTempVisiblePagesRange[1];
+            if (leftScreen != -1 && rightScreen != -1) {
+                final long drawingTime = getDrawingTime();
+                // Clip to the bounds
+                canvas.save();
+                canvas.clipRect(getScrollX(), getScrollY(), getScrollX() + getRight() - getLeft(),
+                        getScrollY() + getBottom() - getTop());
+
+                for (int i = getChildCount() - 1; i >= 0; i--) {
+                    final View v = getPageAt(i);
+                    if (mForceDrawAllChildrenNextFrame ||
+                               (leftScreen <= i && i <= rightScreen && shouldDrawChild(v))) {
+                        drawChild(canvas, v, drawingTime);
+                    }
+                }
+                mForceDrawAllChildrenNextFrame = false;
+                canvas.restore();
+            }
+        }
+    }
+
+    @Override
+    public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) {
+        int page = indexToPage(indexOfChild(child));
+        if (page != mCurrentPage || !mScroller.isFinished()) {
+            snapToPage(page);
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) {
+        int focusablePage;
+        if (mNextPage != INVALID_PAGE) {
+            focusablePage = mNextPage;
+        } else {
+            focusablePage = mCurrentPage;
+        }
+        View v = getPageAt(focusablePage);
+        if (v != null) {
+            return v.requestFocus(direction, previouslyFocusedRect);
+        }
+        return false;
+    }
+
+    @Override
+    public boolean dispatchUnhandledMove(View focused, int direction) {
+        if (direction == View.FOCUS_LEFT) {
+            if (getCurrentPage() > 0) {
+                snapToPage(getCurrentPage() - 1);
+                return true;
+            }
+        } else if (direction == View.FOCUS_RIGHT) {
+            if (getCurrentPage() < getPageCount() - 1) {
+                snapToPage(getCurrentPage() + 1);
+                return true;
+            }
+        }
+        return super.dispatchUnhandledMove(focused, direction);
+    }
+
+    @Override
+    public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
+        if (mCurrentPage >= 0 && mCurrentPage < getPageCount()) {
+            getPageAt(mCurrentPage).addFocusables(views, direction, focusableMode);
+        }
+        if (direction == View.FOCUS_LEFT) {
+            if (mCurrentPage > 0) {
+                getPageAt(mCurrentPage - 1).addFocusables(views, direction, focusableMode);
+            }
+        } else if (direction == View.FOCUS_RIGHT){
+            if (mCurrentPage < getPageCount() - 1) {
+                getPageAt(mCurrentPage + 1).addFocusables(views, direction, focusableMode);
+            }
+        }
+    }
+
+    /**
+     * If one of our descendant views decides that it could be focused now, only
+     * pass that along if it's on the current page.
+     *
+     * This happens when live folders requery, and if they're off page, they
+     * end up calling requestFocus, which pulls it on page.
+     */
+    @Override
+    public void focusableViewAvailable(View focused) {
+        View current = getPageAt(mCurrentPage);
+        View v = focused;
+        while (true) {
+            if (v == current) {
+                super.focusableViewAvailable(focused);
+                return;
+            }
+            if (v == this) {
+                return;
+            }
+            ViewParent parent = v.getParent();
+            if (parent instanceof View) {
+                v = (View)v.getParent();
+            } else {
+                return;
+            }
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) {
+        if (disallowIntercept) {
+            // We need to make sure to cancel our long press if
+            // a scrollable widget takes over touch events
+            final View currentPage = getPageAt(mCurrentPage);
+            currentPage.cancelLongPress();
+        }
+        super.requestDisallowInterceptTouchEvent(disallowIntercept);
+    }
+
+    /**
+     * Return true if a tap at (x, y) should trigger a flip to the previous page.
+     */
+    protected boolean hitsPreviousPage(float x, float y) {
+        return (x < getRelativeChildOffset(mCurrentPage) - mPageSpacing);
+    }
+
+    /**
+     * Return true if a tap at (x, y) should trigger a flip to the next page.
+     */
+    protected boolean hitsNextPage(float x, float y) {
+        return  (x > (getMeasuredWidth() - getRelativeChildOffset(mCurrentPage) + mPageSpacing));
+    }
+
+    @Override
+    public boolean onInterceptTouchEvent(MotionEvent ev) {
+        /*
+         * This method JUST determines whether we want to intercept the motion.
+         * If we return true, onTouchEvent will be called and we do the actual
+         * scrolling there.
+         */
+        acquireVelocityTrackerAndAddMovement(ev);
+
+        // Skip touch handling if there are no pages to swipe
+        if (getChildCount() <= 0) return super.onInterceptTouchEvent(ev);
+
+        /*
+         * Shortcut the most recurring case: the user is in the dragging
+         * state and he is moving his finger.  We want to intercept this
+         * motion.
+         */
+        final int action = ev.getAction();
+        if ((action == MotionEvent.ACTION_MOVE) &&
+                (mTouchState == TOUCH_STATE_SCROLLING)) {
+            return true;
+        }
+
+        switch (action & MotionEvent.ACTION_MASK) {
+            case MotionEvent.ACTION_MOVE: {
+                /*
+                 * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check
+                 * whether the user has moved far enough from his original down touch.
+                 */
+                if (mActivePointerId != INVALID_POINTER) {
+                    determineScrollingStart(ev);
+                    break;
+                }
+                // if mActivePointerId is INVALID_POINTER, then we must have missed an ACTION_DOWN
+                // event. in that case, treat the first occurence of a move event as a ACTION_DOWN
+                // i.e. fall through to the next case (don't break)
+                // (We sometimes miss ACTION_DOWN events in Workspace because it ignores all events
+                // while it's small- this was causing a crash before we checked for INVALID_POINTER)
+            }
+
+            case MotionEvent.ACTION_DOWN: {
+                final float x = ev.getX();
+                final float y = ev.getY();
+                // Remember location of down touch
+                mDownMotionX = x;
+                mLastMotionX = x;
+                mLastMotionY = y;
+                mLastMotionXRemainder = 0;
+                mTotalMotionX = 0;
+                mActivePointerId = ev.getPointerId(0);
+                mAllowLongPress = true;
+
+                /*
+                 * If being flinged and user touches the screen, initiate drag;
+                 * otherwise don't.  mScroller.isFinished should be false when
+                 * being flinged.
+                 */
+                final int xDist = Math.abs(mScroller.getFinalX() - mScroller.getCurrX());
+                final boolean finishedScrolling = (mScroller.isFinished() || xDist < mTouchSlop);
+                if (finishedScrolling) {
+                    mTouchState = TOUCH_STATE_REST;
+                    mScroller.abortAnimation();
+                } else {
+                    mTouchState = TOUCH_STATE_SCROLLING;
+                }
+
+                // check if this can be the beginning of a tap on the side of the pages
+                // to scroll the current page
+                if (mTouchState != TOUCH_STATE_PREV_PAGE && mTouchState != TOUCH_STATE_NEXT_PAGE) {
+                    if (getChildCount() > 0) {
+                        if (hitsPreviousPage(x, y)) {
+                            mTouchState = TOUCH_STATE_PREV_PAGE;
+                        } else if (hitsNextPage(x, y)) {
+                            mTouchState = TOUCH_STATE_NEXT_PAGE;
+                        }
+                    }
+                }
+                break;
+            }
+
+            case MotionEvent.ACTION_UP:
+            case MotionEvent.ACTION_CANCEL:
+                mTouchState = TOUCH_STATE_REST;
+                mAllowLongPress = false;
+                mActivePointerId = INVALID_POINTER;
+                releaseVelocityTracker();
+                break;
+
+            case MotionEvent.ACTION_POINTER_UP:
+                onSecondaryPointerUp(ev);
+                releaseVelocityTracker();
+                break;
+        }
+
+        /*
+         * The only time we want to intercept motion events is if we are in the
+         * drag mode.
+         */
+        return mTouchState != TOUCH_STATE_REST;
+    }
+
+    protected void determineScrollingStart(MotionEvent ev) {
+        determineScrollingStart(ev, 1.0f);
+    }
+
+    /*
+     * Determines if we should change the touch state to start scrolling after the
+     * user moves their touch point too far.
+     */
+    protected void determineScrollingStart(MotionEvent ev, float touchSlopScale) {
+        /*
+         * Locally do absolute value. mLastMotionX is set to the y value
+         * of the down event.
+         */
+        final int pointerIndex = ev.findPointerIndex(mActivePointerId);
+        if (pointerIndex == -1) {
+            return;
+        }
+        final float x = ev.getX(pointerIndex);
+        final float y = ev.getY(pointerIndex);
+        final int xDiff = (int) Math.abs(x - mLastMotionX);
+        final int yDiff = (int) Math.abs(y - mLastMotionY);
+
+        final int touchSlop = Math.round(touchSlopScale * mTouchSlop);
+        boolean xPaged = xDiff > mPagingTouchSlop;
+        boolean xMoved = xDiff > touchSlop;
+        boolean yMoved = yDiff > touchSlop;
+
+        if (xMoved || xPaged || yMoved) {
+            if (mUsePagingTouchSlop ? xPaged : xMoved) {
+                // Scroll if the user moved far enough along the X axis
+                mTouchState = TOUCH_STATE_SCROLLING;
+                mTotalMotionX += Math.abs(mLastMotionX - x);
+                mLastMotionX = x;
+                mLastMotionXRemainder = 0;
+                mTouchX = getScrollX();
+                mSmoothingTime = System.nanoTime() / NANOTIME_DIV;
+                pageBeginMoving();
+            }
+            // Either way, cancel any pending longpress
+            cancelCurrentPageLongPress();
+        }
+    }
+
+    protected void cancelCurrentPageLongPress() {
+        if (mAllowLongPress) {
+            mAllowLongPress = false;
+            // Try canceling the long press. It could also have been scheduled
+            // by a distant descendant, so use the mAllowLongPress flag to block
+            // everything
+            final View currentPage = getPageAt(mCurrentPage);
+            if (currentPage != null) {
+                currentPage.cancelLongPress();
+            }
+        }
+    }
+
+    protected float getScrollProgress(int screenCenter, View v, int page) {
+        final int halfScreenSize = getMeasuredWidth() / 2;
+
+        int totalDistance = getScaledMeasuredWidth(v) + mPageSpacing;
+        int delta = screenCenter - (getChildOffset(page) -
+                getRelativeChildOffset(page) + halfScreenSize);
+
+        float scrollProgress = delta / (totalDistance * 1.0f);
+        scrollProgress = Math.min(scrollProgress, 1.0f);
+        scrollProgress = Math.max(scrollProgress, -1.0f);
+        return scrollProgress;
+    }
+
+    // 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 void acceleratedOverScroll(float amount) {
+        int screenSize = getMeasuredWidth();
+
+        // 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 (f == 0) return;
+
+        // Clamp this factor, f, to -1 < f < 1
+        if (Math.abs(f) >= 1) {
+            f /= Math.abs(f);
+        }
+
+        int overScrollAmount = (int) Math.round(f * screenSize);
+        if (amount < 0) {
+            mOverScrollX = overScrollAmount;
+            super.scrollTo(0, getScrollY());
+        } else {
+            mOverScrollX = mMaxScrollX + overScrollAmount;
+            super.scrollTo(mMaxScrollX, getScrollY());
+        }
+        invalidate();
+    }
+
+    protected void dampedOverScroll(float amount) {
+        int screenSize = getMeasuredWidth();
+
+        float f = (amount / screenSize);
+
+        if (f == 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);
+        if (amount < 0) {
+            mOverScrollX = overScrollAmount;
+            super.scrollTo(0, getScrollY());
+        } else {
+            mOverScrollX = mMaxScrollX + overScrollAmount;
+            super.scrollTo(mMaxScrollX, getScrollY());
+        }
+        invalidate();
+    }
+
+    protected void overScroll(float amount) {
+        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;
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent ev) {
+        // Skip touch handling if there are no pages to swipe
+        if (getChildCount() <= 0) return super.onTouchEvent(ev);
+
+        acquireVelocityTrackerAndAddMovement(ev);
+
+        final int action = ev.getAction();
+
+        switch (action & MotionEvent.ACTION_MASK) {
+        case MotionEvent.ACTION_DOWN:
+            /*
+             * If being flinged and user touches, stop the fling. isFinished
+             * will be false if being flinged.
+             */
+            if (!mScroller.isFinished()) {
+                mScroller.abortAnimation();
+            }
+
+            // Remember where the motion event started
+            mDownMotionX = mLastMotionX = ev.getX();
+            mLastMotionXRemainder = 0;
+            mTotalMotionX = 0;
+            mActivePointerId = ev.getPointerId(0);
+            if (mTouchState == TOUCH_STATE_SCROLLING) {
+                pageBeginMoving();
+            }
+            break;
+
+        case MotionEvent.ACTION_MOVE:
+            if (mTouchState == TOUCH_STATE_SCROLLING) {
+                // Scroll to follow the motion event
+                final int pointerIndex = ev.findPointerIndex(mActivePointerId);
+                final float x = ev.getX(pointerIndex);
+                final float deltaX = mLastMotionX + mLastMotionXRemainder - x;
+
+                mTotalMotionX += Math.abs(deltaX);
+
+                // Only scroll and update mLastMotionX if we have moved some discrete amount.  We
+                // keep the remainder because we are actually testing if we've moved from the last
+                // scrolled position (which is discrete).
+                if (Math.abs(deltaX) >= 1.0f) {
+                    mTouchX += deltaX;
+                    mSmoothingTime = System.nanoTime() / NANOTIME_DIV;
+                    if (!mDeferScrollUpdate) {
+                        scrollBy((int) deltaX, 0);
+                        if (DEBUG) Log.d(TAG, "onTouchEvent().Scrolling: " + deltaX);
+                    } else {
+                        invalidate();
+                    }
+                    mLastMotionX = x;
+                    mLastMotionXRemainder = deltaX - (int) deltaX;
+                } else {
+                    awakenScrollBars();
+                }
+            } else {
+                determineScrollingStart(ev);
+            }
+            break;
+
+        case MotionEvent.ACTION_UP:
+            if (mTouchState == TOUCH_STATE_SCROLLING) {
+                final int activePointerId = mActivePointerId;
+                final int pointerIndex = ev.findPointerIndex(activePointerId);
+                final float x = ev.getX(pointerIndex);
+                final VelocityTracker velocityTracker = mVelocityTracker;
+                velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
+                int velocityX = (int) velocityTracker.getXVelocity(activePointerId);
+                final int deltaX = (int) (x - mDownMotionX);
+                final int pageWidth = getScaledMeasuredWidth(getPageAt(mCurrentPage));
+                boolean isSignificantMove = Math.abs(deltaX) > pageWidth *
+                        SIGNIFICANT_MOVE_THRESHOLD;
+
+                mTotalMotionX += Math.abs(mLastMotionX + mLastMotionXRemainder - x);
+
+                boolean isFling = mTotalMotionX > MIN_LENGTH_FOR_FLING &&
+                        Math.abs(velocityX) > mFlingThresholdVelocity;
+
+                // In the case that the page is moved far to one direction and then is flung
+                // in the opposite direction, we use a threshold to determine whether we should
+                // just return to the starting page, or if we should skip one further.
+                boolean returnToOriginalPage = false;
+                if (Math.abs(deltaX) > pageWidth * RETURN_TO_ORIGINAL_PAGE_THRESHOLD &&
+                        Math.signum(velocityX) != Math.signum(deltaX) && isFling) {
+                    returnToOriginalPage = true;
+                }
+
+                int finalPage;
+                // We give flings precedence over large moves, which is why we short-circuit our
+                // test for a large move if a fling has been registered. That is, a large
+                // move to the left and fling to the right will register as a fling to the right.
+                if (((isSignificantMove && deltaX > 0 && !isFling) ||
+                        (isFling && velocityX > 0)) && mCurrentPage > 0) {
+                    finalPage = returnToOriginalPage ? mCurrentPage : mCurrentPage - 1;
+                    snapToPageWithVelocity(finalPage, velocityX);
+                } else if (((isSignificantMove && deltaX < 0 && !isFling) ||
+                        (isFling && velocityX < 0)) &&
+                        mCurrentPage < getChildCount() - 1) {
+                    finalPage = returnToOriginalPage ? mCurrentPage : mCurrentPage + 1;
+                    snapToPageWithVelocity(finalPage, velocityX);
+                } else {
+                    snapToDestination();
+                }
+            } else if (mTouchState == TOUCH_STATE_PREV_PAGE) {
+                // at this point we have not moved beyond the touch slop
+                // (otherwise mTouchState would be TOUCH_STATE_SCROLLING), so
+                // we can just page
+                int nextPage = Math.max(0, mCurrentPage - 1);
+                if (nextPage != mCurrentPage) {
+                    snapToPage(nextPage);
+                } else {
+                    snapToDestination();
+                }
+            } else if (mTouchState == TOUCH_STATE_NEXT_PAGE) {
+                // at this point we have not moved beyond the touch slop
+                // (otherwise mTouchState would be TOUCH_STATE_SCROLLING), so
+                // we can just page
+                int nextPage = Math.min(getChildCount() - 1, mCurrentPage + 1);
+                if (nextPage != mCurrentPage) {
+                    snapToPage(nextPage);
+                } else {
+                    snapToDestination();
+                }
+            } else {
+                onUnhandledTap(ev);
+            }
+            mTouchState = TOUCH_STATE_REST;
+            mActivePointerId = INVALID_POINTER;
+            releaseVelocityTracker();
+            break;
+
+        case MotionEvent.ACTION_CANCEL:
+            if (mTouchState == TOUCH_STATE_SCROLLING) {
+                snapToDestination();
+            }
+            mTouchState = TOUCH_STATE_REST;
+            mActivePointerId = INVALID_POINTER;
+            releaseVelocityTracker();
+            break;
+
+        case MotionEvent.ACTION_POINTER_UP:
+            onSecondaryPointerUp(ev);
+            break;
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean onGenericMotionEvent(MotionEvent event) {
+        if ((event.getSource() & InputDevice.SOURCE_CLASS_POINTER) != 0) {
+            switch (event.getAction()) {
+                case MotionEvent.ACTION_SCROLL: {
+                    // Handle mouse (or ext. device) by shifting the page depending on the scroll
+                    final float vscroll;
+                    final float hscroll;
+                    if ((event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0) {
+                        vscroll = 0;
+                        hscroll = event.getAxisValue(MotionEvent.AXIS_VSCROLL);
+                    } else {
+                        vscroll = -event.getAxisValue(MotionEvent.AXIS_VSCROLL);
+                        hscroll = event.getAxisValue(MotionEvent.AXIS_HSCROLL);
+                    }
+                    if (hscroll != 0 || vscroll != 0) {
+                        if (hscroll > 0 || vscroll > 0) {
+                            scrollRight();
+                        } else {
+                            scrollLeft();
+                        }
+                        return true;
+                    }
+                }
+            }
+        }
+        return super.onGenericMotionEvent(event);
+    }
+
+    private void acquireVelocityTrackerAndAddMovement(MotionEvent ev) {
+        if (mVelocityTracker == null) {
+            mVelocityTracker = VelocityTracker.obtain();
+        }
+        mVelocityTracker.addMovement(ev);
+    }
+
+    private void releaseVelocityTracker() {
+        if (mVelocityTracker != null) {
+            mVelocityTracker.recycle();
+            mVelocityTracker = null;
+        }
+    }
+
+    private void onSecondaryPointerUp(MotionEvent ev) {
+        final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >>
+                MotionEvent.ACTION_POINTER_INDEX_SHIFT;
+        final int pointerId = ev.getPointerId(pointerIndex);
+        if (pointerId == mActivePointerId) {
+            // This was our active pointer going up. Choose a new
+            // active pointer and adjust accordingly.
+            // TODO: Make this decision more intelligent.
+            final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
+            mLastMotionX = mDownMotionX = ev.getX(newPointerIndex);
+            mLastMotionY = ev.getY(newPointerIndex);
+            mLastMotionXRemainder = 0;
+            mActivePointerId = ev.getPointerId(newPointerIndex);
+            if (mVelocityTracker != null) {
+                mVelocityTracker.clear();
+            }
+        }
+    }
+
+    protected void onUnhandledTap(MotionEvent ev) {}
+
+    @Override
+    public void requestChildFocus(View child, View focused) {
+        super.requestChildFocus(child, focused);
+        int page = indexToPage(indexOfChild(child));
+        if (page >= 0 && page != getCurrentPage() && !isInTouchMode()) {
+            snapToPage(page);
+        }
+    }
+
+    protected int getChildIndexForRelativeOffset(int relativeOffset) {
+        final int childCount = getChildCount();
+        int left;
+        int right;
+        for (int i = 0; i < childCount; ++i) {
+            left = getRelativeChildOffset(i);
+            right = (left + getScaledMeasuredWidth(getPageAt(i)));
+            if (left <= relativeOffset && relativeOffset <= right) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    protected int getChildWidth(int index) {
+        // This functions are called enough times that it actually makes a difference in the
+        // profiler -- so just inline the max() here
+        final int measuredWidth = getPageAt(index).getMeasuredWidth();
+        final int minWidth = mMinimumWidth;
+        return (minWidth > measuredWidth) ? minWidth : measuredWidth;
+    }
+
+    int getPageNearestToCenterOfScreen() {
+        int minDistanceFromScreenCenter = Integer.MAX_VALUE;
+        int minDistanceFromScreenCenterIndex = -1;
+        int screenCenter = getScrollX() + (getMeasuredWidth() / 2);
+        final int childCount = getChildCount();
+        for (int i = 0; i < childCount; ++i) {
+            View layout = (View) getPageAt(i);
+            int childWidth = getScaledMeasuredWidth(layout);
+            int halfChildWidth = (childWidth / 2);
+            int childCenter = getChildOffset(i) + halfChildWidth;
+            int distanceFromScreenCenter = Math.abs(childCenter - screenCenter);
+            if (distanceFromScreenCenter < minDistanceFromScreenCenter) {
+                minDistanceFromScreenCenter = distanceFromScreenCenter;
+                minDistanceFromScreenCenterIndex = i;
+            }
+        }
+        return minDistanceFromScreenCenterIndex;
+    }
+
+    protected void snapToDestination() {
+        snapToPage(getPageNearestToCenterOfScreen(), PAGE_SNAP_ANIMATION_DURATION);
+    }
+
+    private static class ScrollInterpolator implements Interpolator {
+        public ScrollInterpolator() {
+        }
+
+        public float getInterpolation(float t) {
+            t -= 1.0f;
+            return t*t*t*t*t + 1;
+        }
+    }
+
+    // We want the duration of the page snap animation to be influenced by the distance that
+    // the screen has to travel, however, we don't want this duration to be effected in a
+    // purely linear fashion. Instead, we use this method to moderate the effect that the distance
+    // of travel has on the overall snap duration.
+    float distanceInfluenceForSnapDuration(float f) {
+        f -= 0.5f; // center the values about 0.
+        f *= 0.3f * Math.PI / 2.0f;
+        return (float) Math.sin(f);
+    }
+
+    protected void snapToPageWithVelocity(int whichPage, int velocity) {
+        whichPage = Math.max(0, Math.min(whichPage, getChildCount() - 1));
+        int halfScreenSize = getMeasuredWidth() / 2;
+
+        if (DEBUG) Log.d(TAG, "snapToPage.getChildOffset(): " + getChildOffset(whichPage));
+        if (DEBUG) Log.d(TAG, "snapToPageWithVelocity.getRelativeChildOffset(): "
+                + getMeasuredWidth() + ", " + getChildWidth(whichPage));
+        final int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage);
+        int delta = newX - mUnboundedScrollX;
+        int duration = 0;
+
+        if (Math.abs(velocity) < mMinFlingVelocity) {
+            // If the velocity is low enough, then treat this more as an automatic page advance
+            // as opposed to an apparent physical response to flinging
+            snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION);
+            return;
+        }
+
+        // Here we compute a "distance" that will be used in the computation of the overall
+        // snap duration. This is a function of the actual distance that needs to be traveled;
+        // we keep this value close to half screen size in order to reduce the variance in snap
+        // duration as a function of the distance the page needs to travel.
+        float distanceRatio = Math.min(1f, 1.0f * Math.abs(delta) / (2 * halfScreenSize));
+        float distance = halfScreenSize + halfScreenSize *
+                distanceInfluenceForSnapDuration(distanceRatio);
+
+        velocity = Math.abs(velocity);
+        velocity = Math.max(mMinSnapVelocity, velocity);
+
+        // we want the page's snap velocity to approximately match the velocity at which the
+        // user flings, so we scale the duration by a value near to the derivative of the scroll
+        // interpolator at zero, ie. 5. We use 4 to make it a little slower.
+        duration = 4 * Math.round(1000 * Math.abs(distance / velocity));
+        duration = Math.min(duration, MAX_PAGE_SNAP_DURATION);
+
+        snapToPage(whichPage, delta, duration);
+    }
+
+    protected void snapToPage(int whichPage) {
+        snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION);
+    }
+
+    protected void snapToPage(int whichPage, int duration) {
+        whichPage = Math.max(0, Math.min(whichPage, getPageCount() - 1));
+
+        if (DEBUG) Log.d(TAG, "snapToPage.getChildOffset(): " + getChildOffset(whichPage));
+        if (DEBUG) Log.d(TAG, "snapToPage.getRelativeChildOffset(): " + getMeasuredWidth() + ", "
+                + getChildWidth(whichPage));
+        int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage);
+        final int sX = mUnboundedScrollX;
+        final int delta = newX - sX;
+        snapToPage(whichPage, delta, duration);
+    }
+
+    protected void snapToPage(int whichPage, int delta, int duration) {
+        mNextPage = whichPage;
+
+        View focusedChild = getFocusedChild();
+        if (focusedChild != null && whichPage != mCurrentPage &&
+                focusedChild == getPageAt(mCurrentPage)) {
+            focusedChild.clearFocus();
+        }
+
+        pageBeginMoving();
+        awakenScrollBars(duration);
+        if (duration == 0) {
+            duration = Math.abs(delta);
+        }
+
+        if (!mScroller.isFinished()) mScroller.abortAnimation();
+        mScroller.startScroll(mUnboundedScrollX, 0, delta, 0, duration);
+
+        // Load associated pages immediately if someone else is handling the scroll, otherwise defer
+        // loading associated pages until the scroll settles
+        if (mDeferScrollUpdate) {
+            loadAssociatedPages(mNextPage);
+        } else {
+            mDeferLoadAssociatedPagesUntilScrollCompletes = true;
+        }
+        notifyPageSwitchListener();
+        invalidate();
+    }
+
+    public void scrollLeft() {
+        if (mScroller.isFinished()) {
+            if (mCurrentPage > 0) snapToPage(mCurrentPage - 1);
+        } else {
+            if (mNextPage > 0) snapToPage(mNextPage - 1);
+        }
+    }
+
+    public void scrollRight() {
+        if (mScroller.isFinished()) {
+            if (mCurrentPage < getChildCount() -1) snapToPage(mCurrentPage + 1);
+        } else {
+            if (mNextPage < getChildCount() -1) snapToPage(mNextPage + 1);
+        }
+    }
+
+    public int getPageForView(View v) {
+        int result = -1;
+        if (v != null) {
+            ViewParent vp = v.getParent();
+            int count = getChildCount();
+            for (int i = 0; i < count; i++) {
+                if (vp == getPageAt(i)) {
+                    return i;
+                }
+            }
+        }
+        return result;
+    }
+
+    /**
+     * @return True is long presses are still allowed for the current touch
+     */
+    public boolean allowLongPress() {
+        return mAllowLongPress;
+    }
+
+    /**
+     * Set true to allow long-press events to be triggered, usually checked by
+     * {@link Launcher} to accept or block dpad-initiated long-presses.
+     */
+    public void setAllowLongPress(boolean allowLongPress) {
+        mAllowLongPress = allowLongPress;
+    }
+
+    public static class SavedState extends BaseSavedState {
+        int currentPage = -1;
+
+        SavedState(Parcelable superState) {
+            super(superState);
+        }
+
+        private SavedState(Parcel in) {
+            super(in);
+            currentPage = in.readInt();
+        }
+
+        @Override
+        public void writeToParcel(Parcel out, int flags) {
+            super.writeToParcel(out, flags);
+            out.writeInt(currentPage);
+        }
+
+        public static final Parcelable.Creator<SavedState> CREATOR =
+                new Parcelable.Creator<SavedState>() {
+            public SavedState createFromParcel(Parcel in) {
+                return new SavedState(in);
+            }
+
+            public SavedState[] newArray(int size) {
+                return new SavedState[size];
+            }
+        };
+    }
+
+    protected void loadAssociatedPages(int page) {
+        loadAssociatedPages(page, false);
+    }
+    protected void loadAssociatedPages(int page, boolean immediateAndOnly) {
+        if (mContentIsRefreshable) {
+            final int count = getChildCount();
+            if (page < count) {
+                int lowerPageBound = getAssociatedLowerPageBound(page);
+                int upperPageBound = getAssociatedUpperPageBound(page);
+                if (DEBUG) Log.d(TAG, "loadAssociatedPages: " + lowerPageBound + "/"
+                        + upperPageBound);
+                // First, clear any pages that should no longer be loaded
+                for (int i = 0; i < count; ++i) {
+                    Page layout = (Page) getPageAt(i);
+                    if ((i < lowerPageBound) || (i > upperPageBound)) {
+                        if (layout.getPageChildCount() > 0) {
+                            layout.removeAllViewsOnPage();
+                        }
+                        mDirtyPageContent.set(i, true);
+                    }
+                }
+                // Next, load any new pages
+                for (int i = 0; i < count; ++i) {
+                    if ((i != page) && immediateAndOnly) {
+                        continue;
+                    }
+                    if (lowerPageBound <= i && i <= upperPageBound) {
+                        if (mDirtyPageContent.get(i)) {
+                            syncPageItems(i, (i == page) && immediateAndOnly);
+                            mDirtyPageContent.set(i, false);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    protected int getAssociatedLowerPageBound(int page) {
+        return Math.max(0, page - 1);
+    }
+    protected int getAssociatedUpperPageBound(int page) {
+        final int count = getChildCount();
+        return Math.min(page + 1, count - 1);
+    }
+
+    /**
+     * This method is called ONLY to synchronize the number of pages that the paged view has.
+     * To actually fill the pages with information, implement syncPageItems() below.  It is
+     * guaranteed that syncPageItems() will be called for a particular page before it is shown,
+     * and therefore, individual page items do not need to be updated in this method.
+     */
+    public abstract void syncPages();
+
+    /**
+     * This method is called to synchronize the items that are on a particular page.  If views on
+     * the page can be reused, then they should be updated within this method.
+     */
+    public abstract void syncPageItems(int page, boolean immediate);
+
+    protected void invalidatePageData() {
+        invalidatePageData(-1, false);
+    }
+    protected void invalidatePageData(int currentPage) {
+        invalidatePageData(currentPage, false);
+    }
+    protected void invalidatePageData(int currentPage, boolean immediateAndOnly) {
+        if (!mIsDataReady) {
+            return;
+        }
+
+        if (mContentIsRefreshable) {
+            // Force all scrolling-related behavior to end
+            mScroller.forceFinished(true);
+            mNextPage = INVALID_PAGE;
+
+            // Update all the pages
+            syncPages();
+
+            // We must force a measure after we've loaded the pages to update the content width and
+            // to determine the full scroll width
+            measure(MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY),
+                    MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.EXACTLY));
+
+            // Set a new page as the current page if necessary
+            if (currentPage > -1) {
+                setCurrentPage(Math.min(getPageCount() - 1, currentPage));
+            }
+
+            // Mark each of the pages as dirty
+            final int count = getChildCount();
+            mDirtyPageContent.clear();
+            for (int i = 0; i < count; ++i) {
+                mDirtyPageContent.add(true);
+            }
+
+            // Load any pages that are necessary for the current window of views
+            loadAssociatedPages(mCurrentPage, immediateAndOnly);
+            requestLayout();
+        }
+    }
+
+    protected View getScrollingIndicator() {
+        // We use mHasScrollIndicator to prevent future lookups if there is no sibling indicator
+        // found
+        if (mHasScrollIndicator && mScrollIndicator == null) {
+            ViewGroup parent = (ViewGroup) getParent();
+            if (parent != null) {
+                mScrollIndicator = (View) (parent.findViewById(R.id.paged_view_indicator));
+                mHasScrollIndicator = mScrollIndicator != null;
+                if (mHasScrollIndicator) {
+                    mScrollIndicator.setVisibility(View.VISIBLE);
+                }
+            }
+        }
+        return mScrollIndicator;
+    }
+
+    protected boolean isScrollingIndicatorEnabled() {
+        return true;
+    }
+
+    Runnable hideScrollingIndicatorRunnable = new Runnable() {
+        @Override
+        public void run() {
+            hideScrollingIndicator(false);
+        }
+    };
+    protected void flashScrollingIndicator(boolean animated) {
+        removeCallbacks(hideScrollingIndicatorRunnable);
+        showScrollingIndicator(!animated);
+        postDelayed(hideScrollingIndicatorRunnable, sScrollIndicatorFlashDuration);
+    }
+
+    protected void showScrollingIndicator(boolean immediately) {
+        mShouldShowScrollIndicator = true;
+        mShouldShowScrollIndicatorImmediately = true;
+        if (getChildCount() <= 1) return;
+        if (!isScrollingIndicatorEnabled()) return;
+
+        mShouldShowScrollIndicator = false;
+        getScrollingIndicator();
+        if (mScrollIndicator != null) {
+            // Fade the indicator in
+            updateScrollingIndicatorPosition();
+            mScrollIndicator.setVisibility(View.VISIBLE);
+            cancelScrollingIndicatorAnimations();
+            if (immediately || mScrollingPaused) {
+                mScrollIndicator.setAlpha(1f);
+            } else {
+                mScrollIndicatorAnimator = LauncherAnimUtils.ofFloat(mScrollIndicator, "alpha", 1f);
+                mScrollIndicatorAnimator.setDuration(sScrollIndicatorFadeInDuration);
+                mScrollIndicatorAnimator.start();
+            }
+        }
+    }
+
+    protected void cancelScrollingIndicatorAnimations() {
+        if (mScrollIndicatorAnimator != null) {
+            mScrollIndicatorAnimator.cancel();
+        }
+    }
+
+    protected void hideScrollingIndicator(boolean immediately) {
+        if (getChildCount() <= 1) return;
+        if (!isScrollingIndicatorEnabled()) return;
+
+        getScrollingIndicator();
+        if (mScrollIndicator != null) {
+            // Fade the indicator out
+            updateScrollingIndicatorPosition();
+            cancelScrollingIndicatorAnimations();
+            if (immediately || mScrollingPaused) {
+                mScrollIndicator.setVisibility(View.INVISIBLE);
+                mScrollIndicator.setAlpha(0f);
+            } else {
+                mScrollIndicatorAnimator = LauncherAnimUtils.ofFloat(mScrollIndicator, "alpha", 0f);
+                mScrollIndicatorAnimator.setDuration(sScrollIndicatorFadeOutDuration);
+                mScrollIndicatorAnimator.addListener(new AnimatorListenerAdapter() {
+                    private boolean cancelled = false;
+                    @Override
+                    public void onAnimationCancel(android.animation.Animator animation) {
+                        cancelled = true;
+                    }
+                    @Override
+                    public void onAnimationEnd(Animator animation) {
+                        if (!cancelled) {
+                            mScrollIndicator.setVisibility(View.INVISIBLE);
+                        }
+                    }
+                });
+                mScrollIndicatorAnimator.start();
+            }
+        }
+    }
+
+    /**
+     * To be overridden by subclasses to determine whether the scroll indicator should stretch to
+     * fill its space on the track or not.
+     */
+    protected boolean hasElasticScrollIndicator() {
+        return true;
+    }
+
+    private void updateScrollingIndicator() {
+        if (getChildCount() <= 1) return;
+        if (!isScrollingIndicatorEnabled()) return;
+
+        getScrollingIndicator();
+        if (mScrollIndicator != null) {
+            updateScrollingIndicatorPosition();
+        }
+        if (mShouldShowScrollIndicator) {
+            showScrollingIndicator(mShouldShowScrollIndicatorImmediately);
+        }
+    }
+
+    private void updateScrollingIndicatorPosition() {
+        if (!isScrollingIndicatorEnabled()) return;
+        if (mScrollIndicator == null) return;
+        int numPages = getChildCount();
+        int pageWidth = getMeasuredWidth();
+        int lastChildIndex = Math.max(0, getChildCount() - 1);
+        int maxScrollX = getChildOffset(lastChildIndex) - getRelativeChildOffset(lastChildIndex);
+        int trackWidth = pageWidth - mScrollIndicatorPaddingLeft - mScrollIndicatorPaddingRight;
+        int indicatorWidth = mScrollIndicator.getMeasuredWidth() -
+                mScrollIndicator.getPaddingLeft() - mScrollIndicator.getPaddingRight();
+
+        float offset = Math.max(0f, Math.min(1f, (float) getScrollX() / maxScrollX));
+        int indicatorSpace = trackWidth / numPages;
+        int indicatorPos = (int) (offset * (trackWidth - indicatorSpace)) + mScrollIndicatorPaddingLeft;
+        if (hasElasticScrollIndicator()) {
+            if (mScrollIndicator.getMeasuredWidth() != indicatorSpace) {
+                mScrollIndicator.getLayoutParams().width = indicatorSpace;
+                mScrollIndicator.requestLayout();
+            }
+        } else {
+            int indicatorCenterOffset = indicatorSpace / 2 - indicatorWidth / 2;
+            indicatorPos += indicatorCenterOffset;
+        }
+        mScrollIndicator.setTranslationX(indicatorPos);
+    }
+
+    public void showScrollIndicatorTrack() {
+    }
+
+    public void hideScrollIndicatorTrack() {
+    }
+
+    /* Accessibility */
+    @Override
+    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
+        super.onInitializeAccessibilityNodeInfo(info);
+        info.setScrollable(getPageCount() > 1);
+        if (getCurrentPage() < getPageCount() - 1) {
+            info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD);
+        }
+        if (getCurrentPage() > 0) {
+            info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD);
+        }
+    }
+
+    @Override
+    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
+        super.onInitializeAccessibilityEvent(event);
+        event.setScrollable(true);
+        if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
+            event.setFromIndex(mCurrentPage);
+            event.setToIndex(mCurrentPage);
+            event.setItemCount(getChildCount());
+        }
+    }
+
+    @Override
+    public boolean performAccessibilityAction(int action, Bundle arguments) {
+        if (super.performAccessibilityAction(action, arguments)) {
+            return true;
+        }
+        switch (action) {
+            case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: {
+                if (getCurrentPage() < getPageCount() - 1) {
+                    scrollRight();
+                    return true;
+                }
+            } break;
+            case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: {
+                if (getCurrentPage() > 0) {
+                    scrollLeft();
+                    return true;
+                }
+            } break;
+        }
+        return false;
+    }
+
+    protected String getCurrentPageDescription() {
+        return String.format(getContext().getString(R.string.default_scroll_format),
+                 getNextPage() + 1, getChildCount());
+    }
+
+    @Override
+    public boolean onHoverEvent(android.view.MotionEvent event) {
+        return true;
+    }
+}