chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsRecyclerView.java - chromium/src - Git at Google

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 package org.chromium.chrome.browser.suggestions;

 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.support.annotation.Nullable;
 import android.support.v4.view.ViewCompat;
 import android.support.v4.view.animation.FastOutLinearInInterpolator;
 import android.support.v7.view.ContextThemeWrapper;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.helper.ItemTouchHelper;
 import android.util.AttributeSet;
 import android.view.GestureDetector;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.animation.Interpolator;
 import android.view.inputmethod.EditorInfo;
 import android.view.inputmethod.InputConnection;

 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.native_page.ContextMenuManager;
 import org.chromium.chrome.browser.ntp.cards.CardViewHolder;
 import org.chromium.chrome.browser.ntp.cards.NewTabPageAdapter;
 import org.chromium.chrome.browser.ntp.cards.NewTabPageViewHolder;
 import org.chromium.chrome.browser.ntp.cards.ScrollToLoadListener;
 import org.chromium.chrome.browser.widget.displaystyle.UiConfig;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;

 /**
  * Simple wrapper on top of a RecyclerView that will acquire focus when tapped.  Ensures the
  * New Tab page receives focus when clicked.
  */
 public class SuggestionsRecyclerView extends RecyclerView {
     private static final Interpolator DISMISS_INTERPOLATOR = new FastOutLinearInInterpolator();
     private static final int DISMISS_ANIMATION_TIME_MS = 300;

     private final GestureDetector mGestureDetector;
     private final LinearLayoutManager mLayoutManager;

     // The ScrollToLoadListener triggers loading more content when the user is near the end.
     @Nullable private ScrollToLoadListener mScrollToLoadListener;

     /**
      * Total height of the items being dismissed.  Tracked to allow the bottom space to compensate
      * for their removal animation and avoid moving the scroll position.
      */
     private int mCompensationHeight;

     /**
      * Height compensation value for each item being dismissed. Since dismissals sometimes include
      * sibling elements, and these don't get the standard treatment, we track the total height
      * associated with the element the user interacted with.
      */
     private final Map<ViewHolder, Integer> mCompensationHeightMap = new HashMap<>();

     /**
      * Whether the {@link SuggestionsRecyclerView} and its children should react to touch events.
      */
     private boolean mTouchEnabled = true;

     /** The ui config for this view. */
     private UiConfig mUiConfig;

     /** The context menu manager for this view. */
     private ContextMenuManager mContextMenuManager;

     private boolean mIsCardBeingSwiped;

     public SuggestionsRecyclerView(Context context) {
         this(context, null);
     }

     @SuppressWarnings("RestrictTo")
     public SuggestionsRecyclerView(Context context, AttributeSet attrs) {
         super(new ContextThemeWrapper(context, R.style.NewTabPageRecyclerView), attrs);

         Resources res = getContext().getResources();
         setBackgroundColor(SuggestionsConfig.getBackgroundColor(res));
         setLayoutParams(new LayoutParams(
                 ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
         setFocusable(true);
         setFocusableInTouchMode(true);
         setContentDescription(res.getString(R.string.accessibility_new_tab_page));

         mGestureDetector =
                 new GestureDetector(getContext(), new GestureDetector.SimpleOnGestureListener() {
                     @Override
                     public boolean onSingleTapUp(MotionEvent e) {
                         boolean retVal = super.onSingleTapUp(e);
                         requestFocus();
                         return retVal;
                     }
                 });
         mLayoutManager = new LinearLayoutManager(getContext());
         setLayoutManager(mLayoutManager);
         setHasFixedSize(true);

         ItemTouchHelper helper = new ItemTouchHelper(new ItemTouchCallbacks());
         helper.attachToRecyclerView(this);

         addOnScrollListener(new SuggestionsMetrics.ScrollEventReporter());
     }

     public boolean isFirstItemVisible() {
         return mLayoutManager.findFirstVisibleItemPosition() == 0;
     }

     /**
      * Sets whether the {@link SuggestionsRecyclerView} and its children should react to touch
      * events.
      */
     public void setTouchEnabled(boolean enabled) {
         mTouchEnabled = enabled;
     }

     /**
      * @return Whether the {@link SuggestionsRecyclerView} and its children should react to touch
      * events.
      */
     protected boolean getTouchEnabled() {
         return mTouchEnabled;
     }

     @Override
     public boolean onInterceptTouchEvent(MotionEvent ev) {
         mGestureDetector.onTouchEvent(ev);
         if (!getTouchEnabled()) return true;
         return super.onInterceptTouchEvent(ev);
     }

     @Override
     public boolean dispatchTouchEvent(MotionEvent ev) {
         if (ev.getActionMasked() == MotionEvent.ACTION_UP
                 || ev.getActionMasked() == MotionEvent.ACTION_CANCEL) {
             setLayoutFrozen(false);
         }
         return super.dispatchTouchEvent(ev);
     }

     @SuppressLint("ClickableViewAccessibility")
     @Override
     public boolean onTouchEvent(MotionEvent ev) {
         if (!getTouchEnabled()) return false;

         // Action down would already have been handled in onInterceptTouchEvent
         if (ev.getActionMasked() != MotionEvent.ACTION_DOWN) {
             mGestureDetector.onTouchEvent(ev);
         }
         return super.onTouchEvent(ev);
     }

     @Override
     public void focusableViewAvailable(View v) {
         // To avoid odd jumps during NTP animation transitions, we do not attempt to give focus
         // to child views if this scroll view already has focus.
         if (hasFocus()) return;
         super.focusableViewAvailable(v);
     }

     @Override
     public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
         // Fixes landscape transitions when unfocusing the URL bar: crbug.com/288546
         outAttrs.imeOptions = EditorInfo.IME_FLAG_NO_FULLSCREEN;
         return super.onCreateInputConnection(outAttrs);
     }

     @Override
     protected void onConfigurationChanged(Configuration newConfig) {
         super.onConfigurationChanged(newConfig);

         // When the viewport configuration changes, we want to update the display style so that the
         // observers are aware of the new available space. Another moment to do this update could
         // be through a OnLayoutChangeListener, but then we get notified of the change after the
         // layout pass, which means that the new style will only be visible after layout happens
         // again. We prefer updating here to avoid having to require that additional layout pass.
         if (mUiConfig != null) mUiConfig.updateDisplayStyle();

         // Close the Context Menu as it may have moved (https://crbug.com/642688).
         if (mContextMenuManager != null) mContextMenuManager.closeContextMenu();
     }

     @Override
     protected void onLayout(boolean changed, int l, int t, int r, int b) {
         int numberViews = getChildCount();
         for (int i = 0; i < numberViews; ++i) {
             View view = getChildAt(i);
             ((NewTabPageViewHolder) getChildViewHolder(view)).updateLayoutParams();
         }
         super.onLayout(changed, l, t, r, b);
     }

     public void init(UiConfig uiConfig, ContextMenuManager contextMenuManager) {
         mUiConfig = uiConfig;
         mContextMenuManager = contextMenuManager;
     }

     public NewTabPageAdapter getNewTabPageAdapter() {
         return (NewTabPageAdapter) getAdapter();
     }

     public LinearLayoutManager getLinearLayoutManager() {
         return mLayoutManager;
     }

     /** Called when an item is in the process of being removed from the view. */
     public void onItemDismissStarted(ViewHolder viewHolder) {
         assert !mCompensationHeightMap.containsKey(viewHolder);

         int dismissedHeight = 0;
         List<ViewHolder> siblings = getDismissalGroupViewHolders(viewHolder);
         for (ViewHolder siblingViewHolder : siblings) {
             dismissedHeight += siblingViewHolder.itemView.getHeight();
         }

         mCompensationHeightMap.put(viewHolder, dismissedHeight);
         mCompensationHeight += dismissedHeight;
     }

     /** Called when an item has finished being removed from the view. */
     public void onItemDismissFinished(ViewHolder viewHolder) {
         if (!mCompensationHeightMap.containsKey(viewHolder)) return;

         mCompensationHeight -= mCompensationHeightMap.remove(viewHolder);

         assert mCompensationHeight >= 0;
     }

     /**
      * Animates the card being swiped to the right as if the user had dismissed it. Any changes to
      * the animation here should be reflected also in {@link #updateViewStateForDismiss} and reset
      * in {@link CardViewHolder#onBindViewHolder()}.
      */
     public void dismissItemWithAnimation(final ViewHolder viewHolder) {
         List<ViewHolder> siblings = getDismissalGroupViewHolders(viewHolder);
         if (siblings.isEmpty()) return;

         List<Animator> animations = new ArrayList<>();
         for (ViewHolder dismissSibling : siblings) {
             addDismissalAnimators(animations, dismissSibling.itemView);
         }

         AnimatorSet animation = new AnimatorSet();
         animation.playTogether(animations);
         animation.setDuration(DISMISS_ANIMATION_TIME_MS);
         animation.setInterpolator(DISMISS_INTERPOLATOR);
         animation.addListener(new AnimatorListenerAdapter() {
             @Override
             public void onAnimationStart(Animator animation) {
                 SuggestionsRecyclerView.this.onItemDismissStarted(viewHolder);
             }

             @Override
             public void onAnimationEnd(Animator animation) {
                 // It is possible that by the time the animation ends, we navigated away from the
                 // container and it got destroyed. In that case, abort. (https://crbug.com/668945)
                 if (!ViewCompat.isAttachedToWindow(viewHolder.itemView)) return;

                 dismissItemInternal(viewHolder);
                 SuggestionsRecyclerView.this.onItemDismissFinished(viewHolder);
             }
         });
         animation.start();
     }

     private void dismissItemInternal(ViewHolder viewHolder) {
         // Re-check the position in case the adapter has changed.
         final int position = viewHolder.getAdapterPosition();
         if (position == RecyclerView.NO_POSITION) {
             // The item does not exist anymore, so ignore.
             return;
         }
         getNewTabPageAdapter().dismissItem(position, removedItemTitle -> {
             announceForAccessibility(getResources().getString(
                     R.string.ntp_accessibility_item_removed, removedItemTitle));
             if (mScrollToLoadListener != null) mScrollToLoadListener.onItemDismissed();
         });
     }

     /**
      * @param animations in/out list holding the animators to play.
      * @param view  view to animate.
      */
     private void addDismissalAnimators(List<Animator> animations, View view) {
         animations.add(ObjectAnimator.ofFloat(view, View.ALPHA, 0f));
         animations.add(ObjectAnimator.ofFloat(view, View.TRANSLATION_X, (float) view.getWidth()));
     }

     /**
      * Update the view's state as it is being swiped away. Any changes to the animation here should
      * be reflected also in {@link #dismissItemWithAnimation(ViewHolder)} and reset in
      * {@link CardViewHolder#onBindViewHolder()}.
      * @param dX The amount of horizontal displacement caused by user's action.
      * @param viewHolder The view holder containing the view to be updated.
      */
     private void updateViewStateForDismiss(float dX, ViewHolder viewHolder) {
         viewHolder.itemView.setTranslationX(dX);

         float input = Math.abs(dX) / viewHolder.itemView.getMeasuredWidth();
         float alpha = 1 - DISMISS_INTERPOLATOR.getInterpolation(input);
         viewHolder.itemView.setAlpha(alpha);
     }

     /**
      * Resets a card's properties affected by swipe to dismiss. Intended to be used as
      * {@link NewTabPageViewHolder.PartialBindCallback}
      */
     public static void resetForDismissCallback(NewTabPageViewHolder holder) {
         ((CardViewHolder) holder).getRecyclerView().updateViewStateForDismiss(0, holder);
     }

     /**
      * Sets the ScrollToLoadListener for the RecyclerView.
      */
     public void setScrollToLoadListener(@Nullable ScrollToLoadListener scrollToLoadListener) {
         mScrollToLoadListener = scrollToLoadListener;
         addOnScrollListener(mScrollToLoadListener);
     }

     /**
      * Clears the currently registered ScrollToLoadListener.
      */
     public void clearScrollToLoadListener() {
         if (mScrollToLoadListener == null) return;

         removeOnScrollListener(mScrollToLoadListener);
         mScrollToLoadListener = null;
     }

     private class ItemTouchCallbacks extends ItemTouchHelper.Callback {
         @Override
         public void onSwiped(ViewHolder viewHolder, int direction) {
             onItemDismissStarted(viewHolder);
             SuggestionsMetrics.recordCardSwipedAway();
             dismissItemInternal(viewHolder);
         }

         @Override
         public void clearView(RecyclerView recyclerView, ViewHolder viewHolder) {
             // clearView() is called when an interaction with the item is finished, which does
             // not mean that the user went all the way and dismissed the item before releasing it.
             // We need to check that the item has been removed.
             if (viewHolder.getAdapterPosition() == RecyclerView.NO_POSITION) {
                 onItemDismissFinished(viewHolder);
             }

             super.clearView(recyclerView, viewHolder);
         }

         @Override
         public boolean onMove(RecyclerView recyclerView, ViewHolder viewHolder, ViewHolder target) {
             assert false; // Drag and drop not supported, the method will never be called.
             return false;
         }

         @Override
         public int getMovementFlags(RecyclerView recyclerView, ViewHolder viewHolder) {
             int swipeFlags = 0;
             if (((NewTabPageViewHolder) viewHolder).isDismissable()) {
                 swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
             }

             return makeMovementFlags(0 /* dragFlags */, swipeFlags);
         }

         @Override
         public void onChildDraw(Canvas c, RecyclerView recyclerView, ViewHolder viewHolder,
                 float dX, float dY, int actionState, boolean isCurrentlyActive) {
             mIsCardBeingSwiped = isCurrentlyActive && dX != 0.f;

             // In some cases a removed child may call this method when unrelated items are
             // interacted with (https://crbug.com/664466, b/32900699), but in that case
             // getSiblingDismissalViewHolders() below will return an empty list.

             // We use our own implementation of the dismissal animation, so we don't call the
             // parent implementation. (by default it changes the translation-X and elevation)
             for (ViewHolder siblingViewHolder : getDismissalGroupViewHolders(viewHolder)) {
                 updateViewStateForDismiss(dX, siblingViewHolder);
             }
         }
     }

     /**
      * Tells if one of card views is being swiped now.
      * @return {@code true} if a card view is being swiped.
      */
     public boolean isCardBeingSwiped() {
         return mIsCardBeingSwiped;
     }

     private List<ViewHolder> getDismissalGroupViewHolders(ViewHolder viewHolder) {
         int position = viewHolder.getAdapterPosition();
         if (position == NO_POSITION) return Collections.emptyList();

         List<ViewHolder> viewHolders = new ArrayList<>();
         Set<Integer> dismissalRange = getNewTabPageAdapter().getItemDismissalGroup(position);
         for (int i : dismissalRange) {
             ViewHolder siblingViewHolder = findViewHolderForAdapterPosition(i);
             if (siblingViewHolder == null) continue;

             viewHolders.add(siblingViewHolder);
         }
         return viewHolders;
     }
 }
	// Copyright 2016 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	package org.chromium.chrome.browser.suggestions;

	import android.animation.Animator;
	import android.animation.AnimatorListenerAdapter;
	import android.animation.AnimatorSet;
	import android.animation.ObjectAnimator;
	import android.annotation.SuppressLint;
	import android.content.Context;
	import android.content.res.Configuration;
	import android.content.res.Resources;
	import android.graphics.Canvas;
	import android.support.annotation.Nullable;
	import android.support.v4.view.ViewCompat;
	import android.support.v4.view.animation.FastOutLinearInInterpolator;
	import android.support.v7.view.ContextThemeWrapper;
	import android.support.v7.widget.LinearLayoutManager;
	import android.support.v7.widget.RecyclerView;
	import android.support.v7.widget.helper.ItemTouchHelper;
	import android.util.AttributeSet;
	import android.view.GestureDetector;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.ViewGroup;
	import android.view.animation.Interpolator;
	import android.view.inputmethod.EditorInfo;
	import android.view.inputmethod.InputConnection;

	import org.chromium.chrome.R;
	import org.chromium.chrome.browser.native_page.ContextMenuManager;
	import org.chromium.chrome.browser.ntp.cards.CardViewHolder;
	import org.chromium.chrome.browser.ntp.cards.NewTabPageAdapter;
	import org.chromium.chrome.browser.ntp.cards.NewTabPageViewHolder;
	import org.chromium.chrome.browser.ntp.cards.ScrollToLoadListener;
	import org.chromium.chrome.browser.widget.displaystyle.UiConfig;

	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;

	/**
	* Simple wrapper on top of a RecyclerView that will acquire focus when tapped. Ensures the
	* New Tab page receives focus when clicked.
	*/
	public class SuggestionsRecyclerView extends RecyclerView {
	private static final Interpolator DISMISS_INTERPOLATOR = new FastOutLinearInInterpolator();
	private static final int DISMISS_ANIMATION_TIME_MS = 300;

	private final GestureDetector mGestureDetector;
	private final LinearLayoutManager mLayoutManager;

	// The ScrollToLoadListener triggers loading more content when the user is near the end.
	@Nullable private ScrollToLoadListener mScrollToLoadListener;

	/**
	* Total height of the items being dismissed. Tracked to allow the bottom space to compensate
	* for their removal animation and avoid moving the scroll position.
	*/
	private int mCompensationHeight;

	/**
	* Height compensation value for each item being dismissed. Since dismissals sometimes include
	* sibling elements, and these don't get the standard treatment, we track the total height
	* associated with the element the user interacted with.
	*/
	private final Map<ViewHolder, Integer> mCompensationHeightMap = new HashMap<>();

	/**
	* Whether the {@link SuggestionsRecyclerView} and its children should react to touch events.
	*/
	private boolean mTouchEnabled = true;

	/** The ui config for this view. */
	private UiConfig mUiConfig;

	/** The context menu manager for this view. */
	private ContextMenuManager mContextMenuManager;

	private boolean mIsCardBeingSwiped;

	public SuggestionsRecyclerView(Context context) {
	this(context, null);
	}

	@SuppressWarnings("RestrictTo")
	public SuggestionsRecyclerView(Context context, AttributeSet attrs) {
	super(new ContextThemeWrapper(context, R.style.NewTabPageRecyclerView), attrs);

	Resources res = getContext().getResources();
	setBackgroundColor(SuggestionsConfig.getBackgroundColor(res));
	setLayoutParams(new LayoutParams(
	ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
	setFocusable(true);
	setFocusableInTouchMode(true);
	setContentDescription(res.getString(R.string.accessibility_new_tab_page));

	mGestureDetector =
	new GestureDetector(getContext(), new GestureDetector.SimpleOnGestureListener() {
	@Override
	public boolean onSingleTapUp(MotionEvent e) {
	boolean retVal = super.onSingleTapUp(e);
	requestFocus();
	return retVal;
	}
	});
	mLayoutManager = new LinearLayoutManager(getContext());
	setLayoutManager(mLayoutManager);
	setHasFixedSize(true);

	ItemTouchHelper helper = new ItemTouchHelper(new ItemTouchCallbacks());
	helper.attachToRecyclerView(this);

	addOnScrollListener(new SuggestionsMetrics.ScrollEventReporter());
	}

	public boolean isFirstItemVisible() {
	return mLayoutManager.findFirstVisibleItemPosition() == 0;
	}

	/**
	* Sets whether the {@link SuggestionsRecyclerView} and its children should react to touch
	* events.
	*/
	public void setTouchEnabled(boolean enabled) {
	mTouchEnabled = enabled;
	}

	/**
	* @return Whether the {@link SuggestionsRecyclerView} and its children should react to touch
	* events.
	*/
	protected boolean getTouchEnabled() {
	return mTouchEnabled;
	}

	@Override
	public boolean onInterceptTouchEvent(MotionEvent ev) {
	mGestureDetector.onTouchEvent(ev);
	if (!getTouchEnabled()) return true;
	return super.onInterceptTouchEvent(ev);
	}

	@Override
	public boolean dispatchTouchEvent(MotionEvent ev) {
	if (ev.getActionMasked() == MotionEvent.ACTION_UP
	\|\| ev.getActionMasked() == MotionEvent.ACTION_CANCEL) {
	setLayoutFrozen(false);
	}
	return super.dispatchTouchEvent(ev);
	}

	@SuppressLint("ClickableViewAccessibility")
	@Override
	public boolean onTouchEvent(MotionEvent ev) {
	if (!getTouchEnabled()) return false;

	// Action down would already have been handled in onInterceptTouchEvent
	if (ev.getActionMasked() != MotionEvent.ACTION_DOWN) {
	mGestureDetector.onTouchEvent(ev);
	}
	return super.onTouchEvent(ev);
	}

	@Override
	public void focusableViewAvailable(View v) {
	// To avoid odd jumps during NTP animation transitions, we do not attempt to give focus
	// to child views if this scroll view already has focus.
	if (hasFocus()) return;
	super.focusableViewAvailable(v);
	}

	@Override
	public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
	// Fixes landscape transitions when unfocusing the URL bar: crbug.com/288546
	outAttrs.imeOptions = EditorInfo.IME_FLAG_NO_FULLSCREEN;
	return super.onCreateInputConnection(outAttrs);
	}

	@Override
	protected void onConfigurationChanged(Configuration newConfig) {
	super.onConfigurationChanged(newConfig);

	// When the viewport configuration changes, we want to update the display style so that the
	// observers are aware of the new available space. Another moment to do this update could
	// be through a OnLayoutChangeListener, but then we get notified of the change after the
	// layout pass, which means that the new style will only be visible after layout happens
	// again. We prefer updating here to avoid having to require that additional layout pass.
	if (mUiConfig != null) mUiConfig.updateDisplayStyle();

	// Close the Context Menu as it may have moved (https://crbug.com/642688).
	if (mContextMenuManager != null) mContextMenuManager.closeContextMenu();
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
	int numberViews = getChildCount();
	for (int i = 0; i < numberViews; ++i) {
	View view = getChildAt(i);
	((NewTabPageViewHolder) getChildViewHolder(view)).updateLayoutParams();
	}
	super.onLayout(changed, l, t, r, b);
	}

	public void init(UiConfig uiConfig, ContextMenuManager contextMenuManager) {
	mUiConfig = uiConfig;
	mContextMenuManager = contextMenuManager;
	}

	public NewTabPageAdapter getNewTabPageAdapter() {
	return (NewTabPageAdapter) getAdapter();
	}

	public LinearLayoutManager getLinearLayoutManager() {
	return mLayoutManager;
	}

	/** Called when an item is in the process of being removed from the view. */
	public void onItemDismissStarted(ViewHolder viewHolder) {
	assert !mCompensationHeightMap.containsKey(viewHolder);

	int dismissedHeight = 0;
	List<ViewHolder> siblings = getDismissalGroupViewHolders(viewHolder);
	for (ViewHolder siblingViewHolder : siblings) {
	dismissedHeight += siblingViewHolder.itemView.getHeight();
	}

	mCompensationHeightMap.put(viewHolder, dismissedHeight);
	mCompensationHeight += dismissedHeight;
	}

	/** Called when an item has finished being removed from the view. */
	public void onItemDismissFinished(ViewHolder viewHolder) {
	if (!mCompensationHeightMap.containsKey(viewHolder)) return;

	mCompensationHeight -= mCompensationHeightMap.remove(viewHolder);

	assert mCompensationHeight >= 0;
	}

	/**
	* Animates the card being swiped to the right as if the user had dismissed it. Any changes to
	* the animation here should be reflected also in {@link #updateViewStateForDismiss} and reset
	* in {@link CardViewHolder#onBindViewHolder()}.
	*/
	public void dismissItemWithAnimation(final ViewHolder viewHolder) {
	List<ViewHolder> siblings = getDismissalGroupViewHolders(viewHolder);
	if (siblings.isEmpty()) return;

	List<Animator> animations = new ArrayList<>();
	for (ViewHolder dismissSibling : siblings) {
	addDismissalAnimators(animations, dismissSibling.itemView);
	}

	AnimatorSet animation = new AnimatorSet();
	animation.playTogether(animations);
	animation.setDuration(DISMISS_ANIMATION_TIME_MS);
	animation.setInterpolator(DISMISS_INTERPOLATOR);
	animation.addListener(new AnimatorListenerAdapter() {
	@Override
	public void onAnimationStart(Animator animation) {
	SuggestionsRecyclerView.this.onItemDismissStarted(viewHolder);
	}

	@Override
	public void onAnimationEnd(Animator animation) {
	// It is possible that by the time the animation ends, we navigated away from the
	// container and it got destroyed. In that case, abort. (https://crbug.com/668945)
	if (!ViewCompat.isAttachedToWindow(viewHolder.itemView)) return;

	dismissItemInternal(viewHolder);
	SuggestionsRecyclerView.this.onItemDismissFinished(viewHolder);
	}
	});
	animation.start();
	}

	private void dismissItemInternal(ViewHolder viewHolder) {
	// Re-check the position in case the adapter has changed.
	final int position = viewHolder.getAdapterPosition();
	if (position == RecyclerView.NO_POSITION) {
	// The item does not exist anymore, so ignore.
	return;
	}
	getNewTabPageAdapter().dismissItem(position, removedItemTitle -> {
	announceForAccessibility(getResources().getString(
	R.string.ntp_accessibility_item_removed, removedItemTitle));
	if (mScrollToLoadListener != null) mScrollToLoadListener.onItemDismissed();
	});
	}

	/**
	* @param animations in/out list holding the animators to play.
	* @param view view to animate.
	*/
	private void addDismissalAnimators(List<Animator> animations, View view) {
	animations.add(ObjectAnimator.ofFloat(view, View.ALPHA, 0f));
	animations.add(ObjectAnimator.ofFloat(view, View.TRANSLATION_X, (float) view.getWidth()));
	}

	/**
	* Update the view's state as it is being swiped away. Any changes to the animation here should
	* be reflected also in {@link #dismissItemWithAnimation(ViewHolder)} and reset in
	* {@link CardViewHolder#onBindViewHolder()}.
	* @param dX The amount of horizontal displacement caused by user's action.
	* @param viewHolder The view holder containing the view to be updated.
	*/
	private void updateViewStateForDismiss(float dX, ViewHolder viewHolder) {
	viewHolder.itemView.setTranslationX(dX);

	float input = Math.abs(dX) / viewHolder.itemView.getMeasuredWidth();
	float alpha = 1 - DISMISS_INTERPOLATOR.getInterpolation(input);
	viewHolder.itemView.setAlpha(alpha);
	}

	/**
	* Resets a card's properties affected by swipe to dismiss. Intended to be used as
	* {@link NewTabPageViewHolder.PartialBindCallback}
	*/
	public static void resetForDismissCallback(NewTabPageViewHolder holder) {
	((CardViewHolder) holder).getRecyclerView().updateViewStateForDismiss(0, holder);
	}

	/**
	* Sets the ScrollToLoadListener for the RecyclerView.
	*/
	public void setScrollToLoadListener(@Nullable ScrollToLoadListener scrollToLoadListener) {
	mScrollToLoadListener = scrollToLoadListener;
	addOnScrollListener(mScrollToLoadListener);
	}

	/**
	* Clears the currently registered ScrollToLoadListener.
	*/
	public void clearScrollToLoadListener() {
	if (mScrollToLoadListener == null) return;

	removeOnScrollListener(mScrollToLoadListener);
	mScrollToLoadListener = null;
	}

	private class ItemTouchCallbacks extends ItemTouchHelper.Callback {
	@Override
	public void onSwiped(ViewHolder viewHolder, int direction) {
	onItemDismissStarted(viewHolder);
	SuggestionsMetrics.recordCardSwipedAway();
	dismissItemInternal(viewHolder);
	}

	@Override
	public void clearView(RecyclerView recyclerView, ViewHolder viewHolder) {
	// clearView() is called when an interaction with the item is finished, which does
	// not mean that the user went all the way and dismissed the item before releasing it.
	// We need to check that the item has been removed.
	if (viewHolder.getAdapterPosition() == RecyclerView.NO_POSITION) {
	onItemDismissFinished(viewHolder);
	}

	super.clearView(recyclerView, viewHolder);
	}

	@Override
	public boolean onMove(RecyclerView recyclerView, ViewHolder viewHolder, ViewHolder target) {
	assert false; // Drag and drop not supported, the method will never be called.
	return false;
	}

	@Override
	public int getMovementFlags(RecyclerView recyclerView, ViewHolder viewHolder) {
	int swipeFlags = 0;
	if (((NewTabPageViewHolder) viewHolder).isDismissable()) {
	swipeFlags = ItemTouchHelper.START \| ItemTouchHelper.END;
	}

	return makeMovementFlags(0 /* dragFlags */, swipeFlags);
	}

	@Override
	public void onChildDraw(Canvas c, RecyclerView recyclerView, ViewHolder viewHolder,
	float dX, float dY, int actionState, boolean isCurrentlyActive) {
	mIsCardBeingSwiped = isCurrentlyActive && dX != 0.f;

	// In some cases a removed child may call this method when unrelated items are
	// interacted with (https://crbug.com/664466, b/32900699), but in that case
	// getSiblingDismissalViewHolders() below will return an empty list.

	// We use our own implementation of the dismissal animation, so we don't call the
	// parent implementation. (by default it changes the translation-X and elevation)
	for (ViewHolder siblingViewHolder : getDismissalGroupViewHolders(viewHolder)) {
	updateViewStateForDismiss(dX, siblingViewHolder);
	}
	}
	}

	/**
	* Tells if one of card views is being swiped now.
	* @return {@code true} if a card view is being swiped.
	*/
	public boolean isCardBeingSwiped() {
	return mIsCardBeingSwiped;
	}

	private List<ViewHolder> getDismissalGroupViewHolders(ViewHolder viewHolder) {
	int position = viewHolder.getAdapterPosition();
	if (position == NO_POSITION) return Collections.emptyList();

	List<ViewHolder> viewHolders = new ArrayList<>();
	Set<Integer> dismissalRange = getNewTabPageAdapter().getItemDismissalGroup(position);
	for (int i : dismissalRange) {
	ViewHolder siblingViewHolder = findViewHolderForAdapterPosition(i);
	if (siblingViewHolder == null) continue;

	viewHolders.add(siblingViewHolder);
	}
	return viewHolders;
	}
	}