content: /*
   * Copyright (C) 2012 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.android.launcher3;
  
  import android.animation.Animator;
  import android.animation.AnimatorListenerAdapter;
  import android.animation.LayoutTransition;
  import android.animation.ObjectAnimator;
  import android.animation.TimeInterpolator;
  import android.annotation.SuppressLint;
  import android.content.Context;
  import android.content.res.TypedArray;
  import android.graphics.Matrix;
  import android.graphics.Rect;
  import android.os.Bundle;
  import android.os.Parcel;
  import android.os.Parcelable;
  import android.util.AttributeSet;
  import android.util.DisplayMetrics;
  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.ViewDebug;
  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 com.android.launcher3.anim.PropertyListBuilder;
  import com.android.launcher3.pageindicators.PageIndicator;
  import com.android.launcher3.touch.OverScroll;
  import com.android.launcher3.util.Themes;
  import com.android.launcher3.util.Thunk;
  
  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;
  
      public static final int PAGE_SNAP_ANIMATION_DURATION = 750;
      protected static final int SLOW_PAGE_SNAP_ANIMATION_DURATION = 950;
  
      // OverScroll constants
      private final static int OVERSCROLL_PAGE_SNAP_ANIMATION_DURATION = 270;
  
      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;
  
      private static final float MAX_SCROLL_PROGRESS = 1.0f;
  
      // 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;
  
      public static final int INVALID_RESTORE_PAGE = -1001;
  
      private boolean mFreeScroll = false;
      private int mFreeScrollMinScrollX = -1;
      private int mFreeScrollMaxScrollX = -1;
  
      protected int mFlingThresholdVelocity;
      protected int mMinFlingVelocity;
      protected int mMinSnapVelocity;
  
      protected boolean mFirstLayout = true;
      private int mNormalChildHeight;
  
      @ViewDebug.ExportedProperty(category = "launcher")
      protected int mCurrentPage;
      private int mChildCountOnLastLayout;
  
      @ViewDebug.ExportedProperty(category = "launcher")
      protected int mNextPage = INVALID_PAGE;
      protected int mMaxScrollX;
      protected LauncherScroller mScroller;
      private Interpolator mDefaultInterpolator;
      private VelocityTracker mVelocityTracker;
      @Thunk int mPageSpacing = 0;
  
      private float mParentDownMotionX;
      private float mParentDownMotionY;
      private float mDownMotionX;
      private float mDownMotionY;
      private float mDownScrollX;
      private float mDragViewBaselineLeft;
      private float mLastMotionX;
      private float mLastMotionXRemainder;
      private float mLastMotionY;
      private float mTotalMotionX;
  
      private boolean mCancelTap;
  
      private int[] mPageScrolls;
  
      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 int TOUCH_STATE_REORDERING = 4;
  
      protected int mTouchState = TOUCH_STATE_REST;
  
      protected OnLongClickListener mLongClickListener;
  
      protected int mTouchSlop;
      private int mMaximumVelocity;
      protected boolean mAllowOverScroll = true;
      protected int[] mTempVisiblePagesRange = new int[2];
  
      protected static final int INVALID_POINTER = -1;
  
      protected int mActivePointerId = INVALID_POINTER;
  
      protected boolean mIsPageInTransition = false;
  
      protected boolean mWasInOverscroll = false;
  
      // 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;
  
      protected int mUnboundedScrollX;
  
      // Page Indicator
      @Thunk int mPageIndicatorViewId;
      protected PageIndicator mPageIndicator;
      // The viewport whether the pages are to be contained (the actual view may be larger than the
      // viewport)
      @ViewDebug.ExportedProperty(category = "launcher")
      private Rect mViewport = new Rect();
  
      // Reordering
      // We use the min scale to determine how much to expand the actually PagedView measured
      // dimensions such that when we are zoomed out, the view is not clipped
      private static int REORDERING_DROP_REPOSITION_DURATION = 200;
      @Thunk static int REORDERING_REORDER_REPOSITION_DURATION = 300;
      private static int REORDERING_SIDE_PAGE_HOVER_TIMEOUT = 80;
  
      private float mMinScale = 1f;
      private boolean mUseMinScale = false;
      @Thunk View mDragView;
      private Runnable mSidePageHoverRunnable;
      @Thunk int mSidePageHoverIndex = -1;
      // This variable's scope is only for the duration of startReordering() and endReordering()
      private boolean mReorderingStarted = false;
      // This variable's scope is for the duration of startReordering() and after the zoomIn()
      // animation after endReordering()
      private boolean mIsReordering;
      // The runnable that settles the page after snapToPage and animateDragViewToOriginalPosition
      private static final int NUM_ANIMATIONS_RUNNING_BEFORE_ZOOM_OUT = 2;
      private int mPostReorderingPreZoomInRemainingAnimationCount;
      private Runnable mPostReorderingPreZoomInRunnable;
  
      // Convenience/caching
      private static final Matrix sTmpInvMatrix = new Matrix();
      private static final float[] sTmpPoint = new float[2];
      private static final Rect sTmpRect = new Rect();
  
      protected final Rect mInsets = new Rect();
      protected final boolean mIsRtl;
  
      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);
          mPageIndicatorViewId = a.getResourceId(R.styleable.PagedView_pageIndicator, -1);
          a.recycle();
  
          setHapticFeedbackEnabled(false);
          mIsRtl = Utilities.isRtl(getResources());
          init();
      }
  
      /**
       * Initializes various states for this workspace.
       */
      protected void init() {
          mScroller = new LauncherScroller(getContext());
          setDefaultInterpolator(new ScrollInterpolator());
          mCurrentPage = 0;
  
          final ViewConfiguration configuration = ViewConfiguration.get(getContext());
          mTouchSlop = configuration.getScaledPagingTouchSlop();
          mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
  
          float density = getResources().getDisplayMetrics().density;
          mFlingThresholdVelocity = (int) (FLING_THRESHOLD_VELOCITY * density);
          mMinFlingVelocity = (int) (MIN_FLING_VELOCITY * density);
          mMinSnapVelocity = (int) (MIN_SNAP_VELOCITY * density);
          setOnHierarchyChangeListener(this);
          setWillNotDraw(false);
      }
  
      protected void setDefaultInterpolator(Interpolator interpolator) {
          mDefaultInterpolator = interpolator;
          mScroller.setInterpolator(mDefaultInterpolator);
      }
  
      public void initParentViews(View parent) {
          if (mPageIndicatorViewId > -1) {
              mPageIndicator = (PageIndicator) parent.findViewById(mPageIndicatorViewId);
              mPageIndicator.setMarkersCount(getChildCount());
              mPageIndicator.setContentDescription(getPageIndicatorDescription());
          }
      }
  
      // Convenience methods to map points from self to parent and vice versa
      private float[] mapPointFromViewToParent(View v, float x, float y) {
          sTmpPoint[0] = x;
          sTmpPoint[1] = y;
          v.getMatrix().mapPoints(sTmpPoint);
          sTmpPoint[0] += v.getLeft();
          sTmpPoint[1] += v.getTop();
          return sTmpPoint;
      }
      private float[] mapPointFromParentToView(View v, float x, float y) {
          sTmpPoint[0] = x - v.getLeft();
          sTmpPoint[1] = y - v.getTop();
          v.getMatrix().invert(sTmpInvMatrix);
          sTmpInvMatrix.mapPoints(sTmpPoint);
          return sTmpPoint;
      }
  
      private void updateDragViewTranslationDuringDrag() {
          if (mDragView != null) {
              float x = (mLastMotionX - mDownMotionX) + (getScrollX() - mDownScrollX) +
                      (mDragViewBaselineLeft - mDragView.getLeft());
              float y = mLastMotionY - mDownMotionY;
              mDragView.setTranslationX(x);
              mDragView.setTranslationY(y);
  
              if (DEBUG) Log.d(TAG, "PagedView.updateDragViewTranslationDuringDrag(): "
                      + x + ", " + y);
          }
      }
  
      public void setMinScale(float f) {
          mMinScale = f;
          mUseMinScale = true;
          requestLayout();
      }
  
      @Override
      public void setScaleX(float scaleX) {
          super.setScaleX(scaleX);
          if (isReordering(true)) {
              float[] p = mapPointFromParentToView(this, mParentDownMotionX, mParentDownMotionY);
              mLastMotionX = p[0];
              mLastMotionY = p[1];
              updateDragViewTranslationDuringDrag();
          }
      }
  
      // Convenience methods to get the actual width/height of the PagedView (since it is measured
      // to be larger to account for the minimum possible scale)
      int getViewportWidth() {
          return mViewport.width();
      }
      public int getViewportHeight() {
          return mViewport.height();
      }
  
      // Convenience methods to get the offset ASSUMING that we are centering the pages in the
      // PagedView both horizontally and vertically
      int getViewportOffsetX() {
          return (getMeasuredWidth() - getViewportWidth()) / 2;
      }
  
      int getViewportOffsetY() {
          return (getMeasuredHeight() - getViewportHeight()) / 2;
      }
  
      public PageIndicator getPageIndicator() {
          return mPageIndicator;
      }
  
      /**
       * Returns the index of the currently displayed page. When in free scroll mode, this is the page
       * that the user was on before entering free scroll mode (e.g. the home screen page they
       * long-pressed on to enter the overview). Try using {@link #getPageNearestToCenterOfScreen()}
       * to get the page the user is currently scrolling over.
       */
      public int getCurrentPage() {
          return mCurrentPage;
      }
  
      /**
       * Returns the index of page to be shown immediately afterwards.
       */
      public int getNextPage() {
          return (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage;
      }
  
      public int getPageCount() {
          return getChildCount();
      }
  
      public 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() {
          // If the current page is invalid, just reset the scroll position to zero
          int newX = 0;
          if (0 <= mCurrentPage && mCurrentPage < getPageCount()) {
              newX = getScrollForPage(mCurrentPage);
          }
          scrollTo(newX, 0);
          mScroller.setFinalX(newX);
          forceFinishScroller(true);
      }
  
      private void abortScrollerAnimation(boolean resetNextPage) {
          mScroller.abortAnimation();
          // We need to clean up the next page here to avoid computeScrollHelper from
          // updating current page on the pass.
          if (resetNextPage) {
              mNextPage = INVALID_PAGE;
          }
      }
  
      private void forceFinishScroller(boolean resetNextPage) {
          mScroller.forceFinished(true);
          // We need to clean up the next page here to avoid computeScrollHelper from
          // updating current page on the pass.
          if (resetNextPage) {
              mNextPage = INVALID_PAGE;
          }
      }
  
      private int validateNewPage(int newPage) {
          int validatedPage = newPage;
          // When in free scroll mode, we need to clamp to the free scroll page range.
          if (mFreeScroll) {
              getFreeScrollPageRange(mTempVisiblePagesRange);
              validatedPage = Math.max(mTempVisiblePagesRange[0],
                      Math.min(newPage, mTempVisiblePagesRange[1]));
          }
          // Ensure that it is clamped by the actual set of children in all cases
          validatedPage = Utilities.boundToRange(validatedPage, 0, getPageCount() - 1);
          return validatedPage;
      }
  
      /**
       * Sets the current page.
       */
      public void setCurrentPage(int currentPage) {
          if (!mScroller.isFinished()) {
              abortScrollerAnimation(true);
          }
          // don't introduce any checks like mCurrentPage == currentPage here-- if we change the
          // the default
          if (getChildCount() == 0) {
              return;
          }
          int prevPage = mCurrentPage;
          mCurrentPage = validateNewPage(currentPage);
          updateCurrentPageScroll();
          notifyPageSwitchListener(prevPage);
          invalidate();
      }
  
      /**
       * Should be called whenever the page changes. In the case of a scroll, we wait until the page
       * has settled.
       */
      protected void notifyPageSwitchListener(int prevPage) {
          updatePageIndicator();
      }
  
      private void updatePageIndicator() {
          // Update the page indicator (when we aren't reordering)
          if (mPageIndicator != null) {
              mPageIndicator.setContentDescription(getPageIndicatorDescription());
              if (!isReordering(false)) {
                  mPageIndicator.setActiveMarker(getNextPage());
              }
          }
      }
      protected void pageBeginTransition() {
          if (!mIsPageInTransition) {
              mIsPageInTransition = true;
              onPageBeginTransition();
          }
      }
  
      protected void pageEndTransition() {
          if (mIsPageInTransition) {
              mIsPageInTransition = false;
              onPageEndTransition();
          }
      }
  
      protected boolean isPageInTransition() {
          return mIsPageInTransition;
      }
  
      /**
       * Called when the page starts moving as part of the scroll. Subclasses can override this
       * to provide custom behavior during animation.
       */
      protected void onPageBeginTransition() {
      }
  
      /**
       * Called when the page ends moving as part of the scroll. Subclasses can override this
       * to provide custom behavior during animation.
       */
      protected void onPageEndTransition() {
          mWasInOverscroll = false;
      }
  
      /**
       * 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);
          }
          super.setOnLongClickListener(l);
      }
  
      protected int getUnboundedScrollX() {
          return mUnboundedScrollX;
      }
  
      @Override
      public void scrollBy(int x, int y) {
          scrollTo(getUnboundedScrollX() + x, getScrollY() + y);
      }
  
      @Override
      public void scrollTo(int x, int y) {
          // In free scroll mode, we clamp the scrollX
          if (mFreeScroll) {
              // If the scroller is trying to move to a location beyond the maximum allowed
              // in the free scroll mode, we make sure to end the scroll operation.
              if (!mScroller.isFinished() &&
                      (x > mFreeScrollMaxScrollX || x < mFreeScrollMinScrollX)) {
                  forceFinishScroller(false);
              }
  
              x = Math.min(x, mFreeScrollMaxScrollX);
              x = Math.max(x, mFreeScrollMinScrollX);
          }
  
          mUnboundedScrollX = x;
  
          boolean isXBeforeFirstPage = mIsRtl ? (x > mMaxScrollX) : (x < 0);
          boolean isXAfterLastPage = mIsRtl ? (x < 0) : (x > mMaxScrollX);
          if (isXBeforeFirstPage) {
              super.scrollTo(mIsRtl ? mMaxScrollX : 0, y);
              if (mAllowOverScroll) {
                  mWasInOverscroll = true;
                  if (mIsRtl) {
                      overScroll(x - mMaxScrollX);
                  } else {
                      overScroll(x);
                  }
              }
          } else if (isXAfterLastPage) {
              super.scrollTo(mIsRtl ? 0 : mMaxScrollX, y);
              if (mAllowOverScroll) {
                  mWasInOverscroll = true;
                  if (mIsRtl) {
                      overScroll(x);
                  } else {
                      overScroll(x - mMaxScrollX);
                  }
              }
          } else {
              if (mWasInOverscroll) {
                  overScroll(0);
                  mWasInOverscroll = false;
              }
              mOverScrollX = x;
              super.scrollTo(x, y);
          }
  
          // Update the last motion events when scrolling
          if (isReordering(true)) {
              float[] p = mapPointFromParentToView(this, mParentDownMotionX, mParentDownMotionY);
              mLastMotionX = p[0];
              mLastMotionY = p[1];
              updateDragViewTranslationDuringDrag();
          }
      }
  
      private void sendScrollAccessibilityEvent() {
          AccessibilityManager am =
                  (AccessibilityManager) getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
          if (am.isEnabled()) {
              if (mCurrentPage != getNextPage()) {
                  AccessibilityEvent ev =
                          AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_SCROLLED);
                  ev.setScrollable(true);
                  ev.setScrollX(getScrollX());
                  ev.setScrollY(getScrollY());
                  ev.setMaxScrollX(mMaxScrollX);
                  ev.setMaxScrollY(0);
  
                  sendAccessibilityEventUnchecked(ev);
              }
          }
      }
  
      // we moved this functionality to a helper function so SmoothPagedView can reuse it
      protected boolean computeScrollHelper() {
          return computeScrollHelper(true);
      }
  
      protected boolean computeScrollHelper(boolean shouldInvalidate) {
          if (mScroller.computeScrollOffset()) {
              // Don't bother scrolling if the page does not need to be moved
              if (getUnboundedScrollX() != mScroller.getCurrX()
                      || getScrollY() != mScroller.getCurrY()
                      || mOverScrollX != mScroller.getCurrX()) {
                  float scaleX = mFreeScroll ? getScaleX() : 1f;
                  int scrollX = (int) (mScroller.getCurrX() * (1 / scaleX));
                  scrollTo(scrollX, mScroller.getCurrY());
              }
              if (shouldInvalidate) {
                  invalidate();
              }
              return true;
          } else if (mNextPage != INVALID_PAGE && shouldInvalidate) {
              sendScrollAccessibilityEvent();
  
              int prevPage = mCurrentPage;
              mCurrentPage = validateNewPage(mNextPage);
              mNextPage = INVALID_PAGE;
              notifyPageSwitchListener(prevPage);
  
              // 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) {
                  pageEndTransition();
              }
  
              onPostReorderingAnimationCompleted();
              AccessibilityManager am = (AccessibilityManager)
                      getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
              if (am.isEnabled()) {
                  // Notify the user when the page changes
                  announceForAccessibility(getCurrentPageDescription());
              }
              return true;
          }
          return false;
      }
  
      @Override
      public void computeScroll() {
          computeScrollHelper();
      }
  
      public static class LayoutParams extends ViewGroup.LayoutParams {
          public boolean isFullScreenPage = false;
  
          // If true, the start edge of the page snaps to the start edge of the viewport.
          public boolean matchStartEdge = false;
  
          /**
           * {@inheritDoc}
           */
          public LayoutParams(int width, int height) {
              super(width, height);
          }
  
          public LayoutParams(Context context, AttributeSet attrs) {
              super(context, attrs);
          }
  
          public LayoutParams(ViewGroup.LayoutParams source) {
              super(source);
          }
      }
  
      @Override
      public LayoutParams generateLayoutParams(AttributeSet attrs) {
          return new LayoutParams(getContext(), attrs);
      }
  
      @Override
      protected LayoutParams generateDefaultLayoutParams() {
          return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
      }
  
      @Override
      protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
          return new LayoutParams(p);
      }
  
      @Override
      protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
          return p instanceof LayoutParams;
      }
  
      public void addFullScreenPage(View page) {
          LayoutParams lp = generateDefaultLayoutParams();
          lp.isFullScreenPage = true;
          super.addView(page, 0, lp);
      }
  
      public int getNormalChildHeight() {
          return mNormalChildHeight;
      }
  
      @Override
      protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
          if (getChildCount() == 0) {
              super.onMeasure(widthMeasureSpec, heightMeasureSpec);
              return;
          }
  
          // We measure the dimensions of the PagedView to be larger than the pages so that when we
          // zoom out (and scale down), the view is still contained in the parent
          int widthMode = MeasureSpec.getMode(widthMeasureSpec);
          int widthSize = MeasureSpec.getSize(widthMeasureSpec);
          int heightMode = MeasureSpec.getMode(heightMeasureSpec);
          int heightSize = MeasureSpec.getSize(heightMeasureSpec);
          // NOTE: We multiply by 2f to account for the fact that depending on the offset of the
          // viewport, we can be at most one and a half screens offset once we scale down
          DisplayMetrics dm = getResources().getDisplayMetrics();
          int maxSize = Math.max(dm.widthPixels + mInsets.left + mInsets.right,
                  dm.heightPixels + mInsets.top + mInsets.bottom);
  
          int parentWidthSize = (int) (2f * maxSize);
          int parentHeightSize = (int) (2f * maxSize);
          int scaledWidthSize, scaledHeightSize;
          if (mUseMinScale) {
              scaledWidthSize = (int) (parentWidthSize / mMinScale);
              scaledHeightSize = (int) (parentHeightSize / mMinScale);
          } else {
              scaledWidthSize = widthSize;
              scaledHeightSize = heightSize;
          }
          mViewport.set(0, 0, widthSize, heightSize);
  
          if (widthMode == MeasureSpec.UNSPECIFIED || heightMode == MeasureSpec.UNSPECIFIED) {
              super.onMeasure(widthMeasureSpec, heightMeasureSpec);
              return;
          }
  
          // 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.
           */
          final int verticalPadding = getPaddingTop() + getPaddingBottom();
          final int horizontalPadding = getPaddingLeft() + getPaddingRight();
  
          int referenceChildWidth = 0;
          // 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);
          if (DEBUG) Log.d(TAG, "PagedView.scaledSize: " + scaledWidthSize + ", " + scaledHeightSize);
          if (DEBUG) Log.d(TAG, "PagedView.parentSize: " + parentWidthSize + ", " + parentHeightSize);
          if (DEBUG) Log.d(TAG, "PagedView.horizontalPadding: " + horizontalPadding);
          if (DEBUG) Log.d(TAG, "PagedView.verticalPadding: " + verticalPadding);
          final int childCount = getChildCount();
          for (int i = 0; i < childCount; i++) {
              // disallowing padding in paged view (just pass 0)
              final View child = getPageAt(i);
              if (child.getVisibility() != GONE) {
                  final LayoutParams lp = (LayoutParams) child.getLayoutParams();
  
                  int childWidthMode;
                  int childHeightMode;
                  int childWidth;
                  int childHeight;
  
                  if (!lp.isFullScreenPage) {
                      if (lp.width == LayoutParams.WRAP_CONTENT) {
                          childWidthMode = MeasureSpec.AT_MOST;
                      } else {
                          childWidthMode = MeasureSpec.EXACTLY;
                      }
  
                      if (lp.height == LayoutParams.WRAP_CONTENT) {
                          childHeightMode = MeasureSpec.AT_MOST;
                      } else {
                          childHeightMode = MeasureSpec.EXACTLY;
                      }
  
                      childWidth = getViewportWidth() - horizontalPadding
                              - mInsets.left - mInsets.right;
                      childHeight = getViewportHeight() - verticalPadding
                              - mInsets.top - mInsets.bottom;
                      mNormalChildHeight = childHeight;
                  } else {
                      childWidthMode = MeasureSpec.EXACTLY;
                      childHeightMode = MeasureSpec.EXACTLY;
  
                      childWidth = getViewportWidth();
                      childHeight = getViewportHeight();
                  }
                  if (referenceChildWidth == 0) {
                      referenceChildWidth = childWidth;
                  }
  
                  final int childWidthMeasureSpec =
                          MeasureSpec.makeMeasureSpec(childWidth, childWidthMode);
                      final int childHeightMeasureSpec =
                          MeasureSpec.makeMeasureSpec(childHeight, childHeightMode);
                  child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
              }
          }
          setMeasuredDimension(scaledWidthSize, scaledHeightSize);
      }
  
      @SuppressLint("DrawAllocation")
      @Override
      protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
          if (getChildCount() == 0) {
              return;
          }
  
          if (DEBUG) Log.d(TAG, "PagedView.onLayout()");
          final int childCount = getChildCount();
  
          int offsetX = getViewportOffsetX();
          int offsetY = getViewportOffsetY();
  
          // Update the viewport offsets
          mViewport.offset(offsetX, offsetY);
  
          final int startIndex = mIsRtl ? childCount - 1 : 0;
          final int endIndex = mIsRtl ? -1 : childCount;
          final int delta = mIsRtl ? -1 : 1;
  
          int verticalPadding = getPaddingTop() + getPaddingBottom();
  
          LayoutParams lp = (LayoutParams) getChildAt(startIndex).getLayoutParams();
          LayoutParams nextLp;
  
          int childLeft = offsetX + (lp.isFullScreenPage ? 0 : getPaddingLeft());
          if (mPageScrolls == null || childCount != mChildCountOnLastLayout) {
              mPageScrolls = new int[childCount];
          }
  
          for (int i = startIndex; i != endIndex; i += delta) {
              final View child = getPageAt(i);
              if (child.getVisibility() != View.GONE) {
                  lp = (LayoutParams) child.getLayoutParams();
                  int childTop;
                  if (lp.isFullScreenPage) {
                      childTop = offsetY;
                  } else {
                      childTop = offsetY + getPaddingTop() + mInsets.top;
                      childTop += (getViewportHeight() - mInsets.top - mInsets.bottom - verticalPadding - child.getMeasuredHeight()) / 2;
                  }
  
                  final int childWidth = child.getMeasuredWidth();
                  final int childHeight = child.getMeasuredHeight();
  
                  if (DEBUG) Log.d(TAG, "\tlayout-child" + i + ": " + childLeft + ", " + childTop);
                  child.layout(childLeft, childTop,
                          childLeft + child.getMeasuredWidth(), childTop + childHeight);
  
                  int scrollOffsetLeft = lp.isFullScreenPage ? 0 : getPaddingLeft();
                  mPageScrolls[i] = childLeft - scrollOffsetLeft - offsetX;
  
                  int pageGap = mPageSpacing;
                  int next = i + delta;
                  if (next != endIndex) {
                      nextLp = (LayoutParams) getPageAt(next).getLayoutParams();
                  } else {
                      nextLp = null;
                  }
  
                  // Prevent full screen pages from showing in the viewport
                  // when they are not the current page.
                  if (lp.isFullScreenPage) {
                      pageGap = getPaddingLeft();
                  } else if (nextLp != null && nextLp.isFullScreenPage) {
                      pageGap = getPaddingRight();
                  }
  
                  childLeft += childWidth + pageGap + getChildGap();
              }
          }
  
          final LayoutTransition transition = getLayoutTransition();
          // If the transition is running defer updating max scroll, as some empty pages could
          // still be present, and a max scroll change could cause sudden jumps in scroll.
          if (transition != null && transition.isRunning()) {
              transition.addTransitionListener(new LayoutTransition.TransitionListener() {
  
                  @Override
                  public void startTransition(LayoutTransition transition, ViewGroup container,
                          View view, int transitionType) { }
  
                  @Override
                  public void endTransition(LayoutTransition transition, ViewGroup container,
                          View view, int transitionType) {
                      // Wait until all transitions are complete.
                      if (!transition.isRunning()) {
                          transition.removeTransitionListener(this);
                          updateMaxScrollX();
                      }
                  }
              });
          } else {
              updateMaxScrollX();
          }
  
          if (mFirstLayout && mCurrentPage >= 0 && mCurrentPage < childCount) {
              updateCurrentPageScroll();
              mFirstLayout = false;
          }
  
          if (mScroller.isFinished() && mChildCountOnLastLayout != childCount) {
              setCurrentPage(getNextPage());
          }
          mChildCountOnLastLayout = childCount;
  
          if (isReordering(true)) {
              updateDragViewTranslationDuringDrag();
          }
      }
  
      protected int getChildGap() {
          return 0;
      }
  
      @Thunk void updateMaxScrollX() {
          mMaxScrollX = computeMaxScrollX();
      }
  
      protected int computeMaxScrollX() {
          int childCount = getChildCount();
          if (childCount > 0) {
              final int index = mIsRtl ? 0 : childCount - 1;
              return getScrollForPage(index);
          } else {
              return 0;
          }
      }
  
      public void setPageSpacing(int pageSpacing) {
          mPageSpacing = pageSpacing;
          requestLayout();
      }
  
      @Override
      public void onChildViewAdded(View parent, View child) {
          // Update the page indicator, we don't update the page indicator as we
          // add/remove pages
          if (mPageIndicator != null && !isReordering(false)) {
              mPageIndicator.addMarker();
          }
  
          // This ensures that when children are added, they get the correct transforms / alphas
          // in accordance with any scroll effects.
          updateFreescrollBounds();
          invalidate();
      }
  
      @Override
      public void onChildViewRemoved(View parent, View child) {
          updateFreescrollBounds();
          mCurrentPage = validateNewPage(mCurrentPage);
          invalidate();
      }
  
      private void removeMarkerForView() {
          // Update the page indicator, we don't update the page indicator as we
          // add/remove pages
          if (mPageIndicator != null && !isReordering(false)) {
              mPageIndicator.removeMarker();
          }
      }
  
      @Override
      public void removeView(View v) {
          // XXX: We should find a better way to hook into this before the view
          // gets removed form its parent...
          removeMarkerForView();
          super.removeView(v);
      }
      @Override
      public void removeViewInLayout(View v) {
          // XXX: We should find a better way to hook into this before the view
          // gets removed form its parent...
          removeMarkerForView();
          super.removeViewInLayout(v);
      }
      @Override
      public void removeViewAt(int index) {
          // XXX: We should find a better way to hook into this before the view
          // gets removed form its parent...
          removeMarkerForView();
          super.removeViewAt(index);
      }
      @Override
      public void removeAllViewsInLayout() {
          // Update the page indicator, we don't update the page indicator as we
          // add/remove pages
          if (mPageIndicator != null) {
              mPageIndicator.setMarkersCount(0);
          }
  
          super.removeAllViewsInLayout();
      }
  
      protected int getChildOffset(int index) {
          if (index < 0 || index > getChildCount() - 1) return 0;
  
          int offset = getPageAt(index).getLeft() - getViewportOffsetX();
  
          return offset;
      }
  
      protected void getFreeScrollPageRange(int[] range) {
          range[0] = 0;
          range[1] = Math.max(0, getChildCount() - 1);
      }
  
      @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 (super.dispatchUnhandledMove(focused, direction)) {
              return true;
          }
  
          if (mIsRtl) {
              if (direction == View.FOCUS_LEFT) {
                  direction = View.FOCUS_RIGHT;
              } else if (direction == View.FOCUS_RIGHT) {
                  direction = View.FOCUS_LEFT;
              }
          }
          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 false;
      }
  
      @Override
      public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
          if (getDescendantFocusability() == FOCUS_BLOCK_DESCENDANTS) {
              return;
          }
  
          // XXX-RTL: This will be fixed in a future CL
          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) {
          if (mIsRtl) {
              return (x > (getViewportOffsetX() + getViewportWidth() -
                      getPaddingRight() - mPageSpacing));
          }
          return (x < getViewportOffsetX() + getPaddingLeft() + mPageSpacing);
      }
  
      /**
       * Return true if a tap at (x, y) should trigger a flip to the next page.
       */
      protected boolean hitsNextPage(float x, float y) {
          if (mIsRtl) {
              return (x < getViewportOffsetX() + getPaddingLeft() + mPageSpacing);
          }
          return  (x > (getViewportOffsetX() + getViewportWidth() -
                  getPaddingRight() - mPageSpacing));
      }
  
      /** Returns whether x and y originated within the buffered viewport */
      private boolean isTouchPointInViewportWithBuffer(int x, int y) {
          sTmpRect.set(mViewport.left - mViewport.width() / 2, mViewport.top,
                  mViewport.right + mViewport.width() / 2, mViewport.bottom);
          return sTmpRect.contains(x, y);
      }
  
      @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);
                  }
                  // 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)
                  break;
              }
  
              case MotionEvent.ACTION_DOWN: {
                  final float x = ev.getX();
                  final float y = ev.getY();
                  // Remember location of down touch
                  mDownMotionX = x;
                  mDownMotionY = y;
                  mDownScrollX = getScrollX();
                  mLastMotionX = x;
                  mLastMotionY = y;
                  float[] p = mapPointFromViewToParent(this, x, y);
                  mParentDownMotionX = p[0];
                  mParentDownMotionY = p[1];
                  mLastMotionXRemainder = 0;
                  mTotalMotionX = 0;
                  mActivePointerId = ev.getPointerId(0);
  
                  /*
                   * 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 / 3);
  
                  if (finishedScrolling) {
                      mTouchState = TOUCH_STATE_REST;
                      if (!mScroller.isFinished() && !mFreeScroll) {
                          setCurrentPage(getNextPage());
                          pageEndTransition();
                      }
                  } else {
                      if (isTouchPointInViewportWithBuffer((int) mDownMotionX, (int) mDownMotionY)) {
                          mTouchState = TOUCH_STATE_SCROLLING;
                      } else {
                          mTouchState = TOUCH_STATE_REST;
                      }
                  }
  
                  break;
              }
  
              case MotionEvent.ACTION_UP:
              case MotionEvent.ACTION_CANCEL:
                  resetTouchState();
                  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) {
          // Disallow scrolling if we don't have a valid pointer index
          final int pointerIndex = ev.findPointerIndex(mActivePointerId);
          if (pointerIndex == -1) return;
  
          // Disallow scrolling if we started the gesture from outside the viewport
          final float x = ev.getX(pointerIndex);
          final float y = ev.getY(pointerIndex);
          if (!isTouchPointInViewportWithBuffer((int) x, (int) y)) return;
  
          final int xDiff = (int) Math.abs(x - mLastMotionX);
  
          final int touchSlop = Math.round(touchSlopScale * mTouchSlop);
          boolean xMoved = xDiff > touchSlop;
  
          if (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;
              onScrollInteractionBegin();
              pageBeginTransition();
              // Stop listening for things like pinches.
              requestDisallowInterceptTouchEvent(true);
          }
      }
  
      protected void cancelCurrentPageLongPress() {
          // 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 = getViewportWidth() / 2;
  
          int delta = screenCenter - (getScrollForPage(page) + halfScreenSize);
          int count = getChildCount();
  
          final int totalDistance;
  
          int adjacentPage = page + 1;
          if ((delta < 0 && !mIsRtl) || (delta > 0 && mIsRtl)) {
              adjacentPage = page - 1;
          }
  
          if (adjacentPage < 0 || adjacentPage > count - 1) {
              totalDistance = v.getMeasuredWidth() + mPageSpacing;
          } else {
              totalDistance = Math.abs(getScrollForPage(adjacentPage) - getScrollForPage(page));
          }
  
          float scrollProgress = delta / (totalDistance * 1.0f);
          scrollProgress = Math.min(scrollProgress, MAX_SCROLL_PROGRESS);
          scrollProgress = Math.max(scrollProgress, - MAX_SCROLL_PROGRESS);
          return scrollProgress;
      }
  
      public int getScrollForPage(int index) {
          if (mPageScrolls == null || index >= mPageScrolls.length || index < 0) {
              return 0;
          } else {
              return mPageScrolls[index];
          }
      }
  
      // While layout transitions are occurring, a child's position may stray from its baseline
      // position. This method returns the magnitude of this stray at any given time.
      public int getLayoutTransitionOffsetForPage(int index) {
          if (mPageScrolls == null || index >= mPageScrolls.length || index < 0) {
              return 0;
          } else {
              View child = getChildAt(index);
  
              int scrollOffset = 0;
              LayoutParams lp = (LayoutParams) child.getLayoutParams();
              if (!lp.isFullScreenPage) {
                  scrollOffset = mIsRtl ? getPaddingRight() : getPaddingLeft();
              }
  
              int baselineX = mPageScrolls[index] + scrollOffset + getViewportOffsetX();
              return (int) (child.getX() - baselineX);
          }
      }
  
      protected void dampedOverScroll(float amount) {
          if (Float.compare(amount, 0f) == 0) return;
  
          int overScrollAmount = OverScroll.dampedScroll(amount, getViewportWidth());
          if (amount < 0) {
              mOverScrollX = overScrollAmount;
              super.scrollTo(mOverScrollX, getScrollY());
          } else {
              mOverScrollX = mMaxScrollX + overScrollAmount;
              super.scrollTo(mOverScrollX, getScrollY());
          }
          invalidate();
      }
  
      protected void overScroll(float amount) {
          dampedOverScroll(amount);
      }
  
      /**
       * return true if freescroll has been enabled, false otherwise
       */
      public boolean enableFreeScroll() {
          setEnableFreeScroll(true);
          return true;
      }
  
      public void disableFreeScroll() {
          setEnableFreeScroll(false);
      }
  
      void updateFreescrollBounds() {
          getFreeScrollPageRange(mTempVisiblePagesRange);
          if (mIsRtl) {
              mFreeScrollMinScrollX = getScrollForPage(mTempVisiblePagesRange[1]);
              mFreeScrollMaxScrollX = getScrollForPage(mTempVisiblePagesRange[0]);
          } else {
              mFreeScrollMinScrollX = getScrollForPage(mTempVisiblePagesRange[0]);
              mFreeScrollMaxScrollX = getScrollForPage(mTempVisiblePagesRange[1]);
          }
      }
  
      private void setEnableFreeScroll(boolean freeScroll) {
          boolean wasFreeScroll = mFreeScroll;
          mFreeScroll = freeScroll;
  
          if (mFreeScroll) {
              updateFreescrollBounds();
              getFreeScrollPageRange(mTempVisiblePagesRange);
              if (getCurrentPage() < mTempVisiblePagesRange[0]) {
                  setCurrentPage(mTempVisiblePagesRange[0]);
              } else if (getCurrentPage() > mTempVisiblePagesRange[1]) {
                  setCurrentPage(mTempVisiblePagesRange[1]);
              }
          } else if (wasFreeScroll) {
              snapToPage(getNextPage());
          }
  
          setEnableOverscroll(!freeScroll);
      }
  
      protected void setEnableOverscroll(boolean enable) {
          mAllowOverScroll = enable;
      }
  
      private int getNearestHoverOverPageIndex() {
          if (mDragView != null) {
              int dragX = (int) (mDragView.getLeft() + (mDragView.getMeasuredWidth() / 2)
                      + mDragView.getTranslationX());
              getFreeScrollPageRange(mTempVisiblePagesRange);
              int minDistance = Integer.MAX_VALUE;
              int minIndex = indexOfChild(mDragView);
              for (int i = mTempVisiblePagesRange[0]; i <= mTempVisiblePagesRange[1]; i++) {
                  View page = getPageAt(i);
                  int pageX = (int) (page.getLeft() + page.getMeasuredWidth() / 2);
                  int d = Math.abs(dragX - pageX);
                  if (d < minDistance) {
                      minIndex = i;
                      minDistance = d;
                  }
              }
              return minIndex;
          }
          return -1;
      }
  
      @Override
      public boolean onTouchEvent(MotionEvent ev) {
          super.onTouchEvent(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()) {
                  abortScrollerAnimation(false);
              }
  
              // Remember where the motion event started
              mDownMotionX = mLastMotionX = ev.getX();
              mDownMotionY = mLastMotionY = ev.getY();
              mDownScrollX = getScrollX();
              float[] p = mapPointFromViewToParent(this, mLastMotionX, mLastMotionY);
              mParentDownMotionX = p[0];
              mParentDownMotionY = p[1];
              mLastMotionXRemainder = 0;
              mTotalMotionX = 0;
              mActivePointerId = ev.getPointerId(0);
  
              if (mTouchState == TOUCH_STATE_SCROLLING) {
                  onScrollInteractionBegin();
                  pageBeginTransition();
              }
              break;
  
          case MotionEvent.ACTION_MOVE:
              if (mTouchState == TOUCH_STATE_SCROLLING) {
                  // Scroll to follow the motion event
                  final int pointerIndex = ev.findPointerIndex(mActivePointerId);
  
                  if (pointerIndex == -1) return true;
  
                  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) {
                      scrollBy((int) deltaX, 0);
                      mLastMotionX = x;
                      mLastMotionXRemainder = deltaX - (int) deltaX;
                  } else {
                      awakenScrollBars();
                  }
              } else if (mTouchState == TOUCH_STATE_REORDERING) {
                  // Update the last motion position
                  mLastMotionX = ev.getX();
                  mLastMotionY = ev.getY();
  
                  // Update the parent down so that our zoom animations take this new movement into
                  // account
                  float[] pt = mapPointFromViewToParent(this, mLastMotionX, mLastMotionY);
                  mParentDownMotionX = pt[0];
                  mParentDownMotionY = pt[1];
                  updateDragViewTranslationDuringDrag();
  
                  // Find the closest page to the touch point
                  final int dragViewIndex = indexOfChild(mDragView);
  
                  if (DEBUG) Log.d(TAG, "mLastMotionX: " + mLastMotionX);
                  if (DEBUG) Log.d(TAG, "mLastMotionY: " + mLastMotionY);
                  if (DEBUG) Log.d(TAG, "mParentDownMotionX: " + mParentDownMotionX);
                  if (DEBUG) Log.d(TAG, "mParentDownMotionY: " + mParentDownMotionY);
  
                  final int pageUnderPointIndex = getNearestHoverOverPageIndex();
                  // Do not allow any page to be moved to 0th position.
                  if (pageUnderPointIndex > 0 && pageUnderPointIndex != indexOfChild(mDragView)) {
                      mTempVisiblePagesRange[0] = 0;
                      mTempVisiblePagesRange[1] = getPageCount() - 1;
                      getFreeScrollPageRange(mTempVisiblePagesRange);
                      if (mTempVisiblePagesRange[0] <= pageUnderPointIndex &&
                              pageUnderPointIndex <= mTempVisiblePagesRange[1] &&
                              pageUnderPointIndex != mSidePageHoverIndex && mScroller.isFinished()) {
                          mSidePageHoverIndex = pageUnderPointIndex;
                          mSidePageHoverRunnable = new Runnable() {
                              @Override
                              public void run() {
                                  // Setup the scroll to the correct page before we swap the views
                                  snapToPage(pageUnderPointIndex);
  
                                  // For each of the pages between the paged view and the drag view,
                                  // animate them from the previous position to the new position in
                                  // the layout (as a result of the drag view moving in the layout)
                                  int shiftDelta = (dragViewIndex < pageUnderPointIndex) ? -1 : 1;
                                  int lowerIndex = (dragViewIndex < pageUnderPointIndex) ?
                                          dragViewIndex + 1 : pageUnderPointIndex;
                                  int upperIndex = (dragViewIndex > pageUnderPointIndex) ?
                                          dragViewIndex - 1 : pageUnderPointIndex;
                                  for (int i = lowerIndex; i <= upperIndex; ++i) {
                                      View v = getChildAt(i);
                                      // dragViewIndex < pageUnderPointIndex, so after we remove the
                                      // drag view all subsequent views to pageUnderPointIndex will
                                      // shift down.
                                      int oldX = getViewportOffsetX() + getChildOffset(i);
                                      int newX = getViewportOffsetX() + getChildOffset(i + shiftDelta);
  
                                      // Animate the view translation from its old position to its new
                                      // position
                                      ObjectAnimator anim = (ObjectAnimator) v.getTag();
                                      if (anim != null) {
                                          anim.cancel();
                                      }
  
                                      v.setTranslationX(oldX - newX);
                                      anim = LauncherAnimUtils.ofFloat(v, View.TRANSLATION_X, 0);
                                      anim.setDuration(REORDERING_REORDER_REPOSITION_DURATION);
                                      anim.start();
                                      v.setTag(anim);
                                  }
  
                                  removeView(mDragView);
                                  addView(mDragView, pageUnderPointIndex);
                                  mSidePageHoverIndex = -1;
                                  if (mPageIndicator != null) {
                                      mPageIndicator.setActiveMarker(getNextPage());
                                  }
                              }
                          };
                          postDelayed(mSidePageHoverRunnable, REORDERING_SIDE_PAGE_HOVER_TIMEOUT);
                      }
                  } else {
                      removeCallbacks(mSidePageHoverRunnable);
                      mSidePageHoverIndex = -1;
                  }
              } 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 = getPageAt(mCurrentPage).getMeasuredWidth();
                  boolean isSignificantMove = Math.abs(deltaX) > pageWidth *
                          SIGNIFICANT_MOVE_THRESHOLD;
  
                  mTotalMotionX += Math.abs(mLastMotionX + mLastMotionXRemainder - x);
  
                  boolean isFling = mTotalMotionX > MIN_LENGTH_FOR_FLING &&
                          shouldFlingForVelocity(velocityX);
  
                  if (!mFreeScroll) {
                      // 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.
                      boolean isDeltaXLeft = mIsRtl ? deltaX > 0 : deltaX < 0;
                      boolean isVelocityXLeft = mIsRtl ? velocityX > 0 : velocityX < 0;
                      if (((isSignificantMove && !isDeltaXLeft && !isFling) ||
                              (isFling && !isVelocityXLeft)) && mCurrentPage > 0) {
                          finalPage = returnToOriginalPage ? mCurrentPage : mCurrentPage - 1;
                          snapToPageWithVelocity(finalPage, velocityX);
                      } else if (((isSignificantMove && isDeltaXLeft && !isFling) ||
                              (isFling && isVelocityXLeft)) &&
                              mCurrentPage < getChildCount() - 1) {
                          finalPage = returnToOriginalPage ? mCurrentPage : mCurrentPage + 1;
                          snapToPageWithVelocity(finalPage, velocityX);
                      } else {
                          snapToDestination();
                      }
                  } else {
                      if (!mScroller.isFinished()) {
                          abortScrollerAnimation(true);
                      }
  
                      float scaleX = getScaleX();
                      int vX = (int) (-velocityX * scaleX);
                      int initialScrollX = (int) (getScrollX() * scaleX);
  
                      mScroller.setInterpolator(mDefaultInterpolator);
                      mScroller.fling(initialScrollX,
                              getScrollY(), vX, 0, Integer.MIN_VALUE, Integer.MAX_VALUE, 0, 0);
                      mNextPage = getPageNearestToCenterOfScreen((int) (mScroller.getFinalX() / scaleX));
                      invalidate();
                  }
                  onScrollInteractionEnd();
              } 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 if (mTouchState == TOUCH_STATE_REORDERING) {
                  // Update the last motion position
                  mLastMotionX = ev.getX();
                  mLastMotionY = ev.getY();
  
                  // Update the parent down so that our zoom animations take this new movement into
                  // account
                  float[] pt = mapPointFromViewToParent(this, mLastMotionX, mLastMotionY);
                  mParentDownMotionX = pt[0];
                  mParentDownMotionY = pt[1];
                  updateDragViewTranslationDuringDrag();
              } else {
                  if (!mCancelTap) {
                      onUnhandledTap(ev);
                  }
              }
  
              // Remove the callback to wait for the side page hover timeout
              removeCallbacks(mSidePageHoverRunnable);
              // End any intermediate reordering states
              resetTouchState();
              break;
  
          case MotionEvent.ACTION_CANCEL:
              if (mTouchState == TOUCH_STATE_SCROLLING) {
                  snapToDestination();
                  onScrollInteractionEnd();
              }
              resetTouchState();
              break;
  
          case MotionEvent.ACTION_POINTER_UP:
              onSecondaryPointerUp(ev);
              releaseVelocityTracker();
              break;
          }
  
          return true;
      }
  
      protected boolean shouldFlingForVelocity(int velocityX) {
          return Math.abs(velocityX) > mFlingThresholdVelocity;
      }
  
      private void resetTouchState() {
          releaseVelocityTracker();
          endReordering();
          mCancelTap = false;
          mTouchState = TOUCH_STATE_REST;
          mActivePointerId = INVALID_POINTER;
      }
  
      /**
       * Triggered by scrolling via touch
       */
      protected void onScrollInteractionBegin() {
      }
  
      protected void onScrollInteractionEnd() {
      }
  
      protected void onUnhandledTap(MotionEvent ev) {
          Launcher.getLauncher(getContext()).onClick(this);
      }
  
      @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) {
                          boolean isForwardScroll = mIsRtl ? (hscroll < 0 || vscroll < 0)
                                                           : (hscroll > 0 || vscroll > 0);
                          if (isForwardScroll) {
                              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.clear();
              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();
              }
          }
      }
  
      @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);
          }
      }
  
      int getPageNearestToCenterOfScreen() {
          return getPageNearestToCenterOfScreen(getScrollX());
      }
  
      private int getPageNearestToCenterOfScreen(int scaledScrollX) {
          int screenCenter = getViewportOffsetX() + scaledScrollX + (getViewportWidth() / 2);
          int minDistanceFromScreenCenter = Integer.MAX_VALUE;
          int minDistanceFromScreenCenterIndex = -1;
          final int childCount = getChildCount();
          for (int i = 0; i < childCount; ++i) {
              View layout = (View) getPageAt(i);
              int childWidth = layout.getMeasuredWidth();
              int halfChildWidth = (childWidth / 2);
              int childCenter = getViewportOffsetX() + getChildOffset(i) + halfChildWidth;
              int distanceFromScreenCenter = Math.abs(childCenter - screenCenter);
              if (distanceFromScreenCenter < minDistanceFromScreenCenter) {
                  minDistanceFromScreenCenter = distanceFromScreenCenter;
                  minDistanceFromScreenCenterIndex = i;
              }
          }
          return minDistanceFromScreenCenterIndex;
      }
  
      protected void snapToDestination() {
          snapToPage(getPageNearestToCenterOfScreen(), getPageSnapDuration());
      }
  
      protected boolean isInOverScroll() {
          return (mOverScrollX > mMaxScrollX || mOverScrollX < 0);
      }
  
      protected int getPageSnapDuration() {
          if (isInOverScroll()) {
              return OVERSCROLL_PAGE_SNAP_ANIMATION_DURATION;
          }
          return PAGE_SNAP_ANIMATION_DURATION;
      }
  
      public 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.
      private 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 = validateNewPage(whichPage);
          int halfScreenSize = getViewportWidth() / 2;
  
          final int newX = getScrollForPage(whichPage);
          int delta = newX - getUnboundedScrollX();
          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));
  
          snapToPage(whichPage, delta, duration);
      }
  
      public void snapToPage(int whichPage) {
          snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION);
      }
  
      public void snapToPageImmediately(int whichPage) {
          snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION, true, null);
      }
  
      protected void snapToPage(int whichPage, int duration) {
          snapToPage(whichPage, duration, false, null);
      }
  
      protected void snapToPage(int whichPage, int duration, TimeInterpolator interpolator) {
          snapToPage(whichPage, duration, false, interpolator);
      }
  
      protected void snapToPage(int whichPage, int duration, boolean immediate,
              TimeInterpolator interpolator) {
          whichPage = validateNewPage(whichPage);
  
          int newX = getScrollForPage(whichPage);
          final int delta = newX - getUnboundedScrollX();
          snapToPage(whichPage, delta, duration, immediate, interpolator);
      }
  
      protected void snapToPage(int whichPage, int delta, int duration) {
          snapToPage(whichPage, delta, duration, false, null);
      }
  
      protected void snapToPage(int whichPage, int delta, int duration, boolean immediate,
              TimeInterpolator interpolator) {
          whichPage = validateNewPage(whichPage);
  
          mNextPage = whichPage;
  
          awakenScrollBars(duration);
          if (immediate) {
              duration = 0;
          } else if (duration == 0) {
              duration = Math.abs(delta);
          }
  
          if (duration != 0) {
              pageBeginTransition();
          }
  
          if (!mScroller.isFinished()) {
              abortScrollerAnimation(false);
          }
  
          if (interpolator != null) {
              mScroller.setInterpolator(interpolator);
          } else {
              mScroller.setInterpolator(mDefaultInterpolator);
          }
  
          mScroller.startScroll(getUnboundedScrollX(), 0, delta, 0, duration);
  
          updatePageIndicator();
  
          // Trigger a compute() to finish switching pages if necessary
          if (immediate) {
              computeScroll();
              pageEndTransition();
          }
  
          invalidate();
      }
  
      public void scrollLeft() {
          if (getNextPage() > 0) snapToPage(getNextPage() - 1);
      }
  
      public void scrollRight() {
          if (getNextPage() < getChildCount() -1) snapToPage(getNextPage() + 1);
      }
  
      @Override
      public boolean performLongClick() {
          mCancelTap = true;
          return super.performLongClick();
      }
  
      public static class SavedState extends BaseSavedState {
          int currentPage = -1;
  
          SavedState(Parcelable superState) {
              super(superState);
          }
  
          @Thunk 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];
              }
          };
      }
  
      // Animate the drag view back to the original position
      private void animateDragViewToOriginalPosition() {
          if (mDragView != null) {
              Animator anim = LauncherAnimUtils.ofPropertyValuesHolder(mDragView,
                      new PropertyListBuilder()
                              .scale(1)
                              .translationX(0)
                              .translationY(0)
                              .build())
                      .setDuration(REORDERING_DROP_REPOSITION_DURATION);
              anim.addListener(new AnimatorListenerAdapter() {
                  @Override
                  public void onAnimationEnd(Animator animation) {
                      onPostReorderingAnimationCompleted();
                  }
              });
              anim.start();
          }
      }
  
      public void onStartReordering() {
          // Set the touch state to reordering (allows snapping to pages, dragging a child, etc.)
          mTouchState = TOUCH_STATE_REORDERING;
          mIsReordering = true;
  
          // We must invalidate to trigger a redraw to update the layers such that the drag view
          // is always drawn on top
          invalidate();
      }
  
      @Thunk void onPostReorderingAnimationCompleted() {
          // Trigger the callback when reordering has settled
          --mPostReorderingPreZoomInRemainingAnimationCount;
          if (mPostReorderingPreZoomInRunnable != null &&
                  mPostReorderingPreZoomInRemainingAnimationCount == 0) {
              mPostReorderingPreZoomInRunnable.run();
              mPostReorderingPreZoomInRunnable = null;
          }
      }
  
      public void onEndReordering() {
          mIsReordering = false;
      }
  
      public boolean startReordering(View v) {
          int dragViewIndex = indexOfChild(v);
  
          // Do not allow the first page to be moved around
          if (mTouchState != TOUCH_STATE_REST || dragViewIndex <= 0) return false;
  
          mTempVisiblePagesRange[0] = 0;
          mTempVisiblePagesRange[1] = getPageCount() - 1;
          getFreeScrollPageRange(mTempVisiblePagesRange);
          mReorderingStarted = true;
  
          // Check if we are within the reordering range
          if (mTempVisiblePagesRange[0] <= dragViewIndex &&
              dragViewIndex <= mTempVisiblePagesRange[1]) {
              // Find the drag view under the pointer
              mDragView = getChildAt(dragViewIndex);
              mDragView.animate().scaleX(1.15f).scaleY(1.15f).setDuration(100).start();
              mDragViewBaselineLeft = mDragView.getLeft();
              snapToPage(getPageNearestToCenterOfScreen());
              disableFreeScroll();
              onStartReordering();
              return true;
          }
          return false;
      }
  
      boolean isReordering(boolean testTouchState) {
          boolean state = mIsReordering;
          if (testTouchState) {
              state &= (mTouchState == TOUCH_STATE_REORDERING);
          }
          return state;
      }
      void endReordering() {
          // For simplicity, we call endReordering sometimes even if reordering was never started.
          // In that case, we don't want to do anything.
          if (!mReorderingStarted) return;
          mReorderingStarted = false;
  
          mPostReorderingPreZoomInRunnable = new Runnable() {
              public void run() {
                  // If we haven't flung-to-delete the current child,
                  // then we just animate the drag view back into position
                  onEndReordering();
  
                  enableFreeScroll();
              }
          };
  
          mPostReorderingPreZoomInRemainingAnimationCount =
                  NUM_ANIMATIONS_RUNNING_BEFORE_ZOOM_OUT;
          // Snap to the current page
          snapToPage(indexOfChild(mDragView), 0);
          // Animate the drag view back to the front position
          animateDragViewToOriginalPosition();
      }
  
      /* Accessibility */
      @SuppressWarnings("deprecation")
      @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);
          }
          info.setClassName(getClass().getName());
  
          // Accessibility-wise, PagedView doesn't support long click, so disabling it.
          // Besides disabling the accessibility long-click, this also prevents this view from getting
          // accessibility focus.
          info.setLongClickable(false);
          info.removeAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_LONG_CLICK);
      }
  
      @Override
      public void sendAccessibilityEvent(int eventType) {
          // Don't let the view send real scroll events.
          if (eventType != AccessibilityEvent.TYPE_VIEW_SCROLLED) {
              super.sendAccessibilityEvent(eventType);
          }
      }
  
      @Override
      public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
          super.onInitializeAccessibilityEvent(event);
          event.setScrollable(getPageCount() > 1);
      }
  
      @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 getPageIndicatorDescription() {
          return getCurrentPageDescription();
      }
  
      protected String getCurrentPageDescription() {
          return getContext().getString(R.string.default_scroll_format,
                  getNextPage() + 1, getChildCount());
      }
  
      @Override
      public boolean onHoverEvent(android.view.MotionEvent event) {
          return true;
      }
  }
  