src/com/android/car/dialer/StrequentsItemAnimator.java - platform/packages/apps/Car/Dialer - Git at Google

 /*
  * Copyright (C) 2015 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.car.dialer;

 import android.support.v4.view.ViewCompat;
 import android.support.v4.view.ViewPropertyAnimatorCompat;
 import android.support.v4.view.ViewPropertyAnimatorListener;
 import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.support.v7.widget.SimpleItemAnimator;
 import android.view.View;

 import java.util.ArrayList;
 import java.util.List;

 /**
  * Branch from {@link android.support.v7.widget.DefaultItemAnimator} with changes on
  * {@link #animateAddImpl}, {@link #animateAdd} and {@link #animateRemoveImpl}.
  */
 public class StrequentsItemAnimator extends SimpleItemAnimator {
     private static final boolean DEBUG = false;

     private ArrayList<ViewHolder> mPendingRemovals = new ArrayList<>();
     private ArrayList<ViewHolder> mPendingAdditions = new ArrayList<>();
     private ArrayList<MoveInfo> mPendingMoves = new ArrayList<>();
     private ArrayList<ChangeInfo> mPendingChanges = new ArrayList<>();

     private ArrayList<ArrayList<ViewHolder>> mAdditionsList = new ArrayList<>();
     private ArrayList<ArrayList<MoveInfo>> mMovesList = new ArrayList<>();
     private ArrayList<ArrayList<ChangeInfo>> mChangesList = new ArrayList<>();

     private ArrayList<ViewHolder> mAddAnimations = new ArrayList<>();
     private ArrayList<ViewHolder> mMoveAnimations = new ArrayList<>();
     private ArrayList<ViewHolder> mRemoveAnimations = new ArrayList<>();
     private ArrayList<ViewHolder> mChangeAnimations = new ArrayList<>();

     private static class MoveInfo {
         public ViewHolder holder;
         public int fromX, fromY, toX, toY;

         private MoveInfo(ViewHolder holder, int fromX, int fromY, int toX, int toY) {
             this.holder = holder;
             this.fromX = fromX;
             this.fromY = fromY;
             this.toX = toX;
             this.toY = toY;
         }
     }

     private static class ChangeInfo {
         public ViewHolder oldHolder, newHolder;
         public int fromX, fromY, toX, toY;
         private ChangeInfo(ViewHolder oldHolder, ViewHolder newHolder) {
             this.oldHolder = oldHolder;
             this.newHolder = newHolder;
         }

         private ChangeInfo(ViewHolder oldHolder, ViewHolder newHolder,
                 int fromX, int fromY, int toX, int toY) {
             this(oldHolder, newHolder);
             this.fromX = fromX;
             this.fromY = fromY;
             this.toX = toX;
             this.toY = toY;
         }

         @Override
         public String toString() {
             return "ChangeInfo{" +
                     "oldHolder=" + oldHolder +
                     ", newHolder=" + newHolder +
                     ", fromX=" + fromX +
                     ", fromY=" + fromY +
                     ", toX=" + toX +
                     ", toY=" + toY +
                     '}';
         }
     }

     @Override
     public void runPendingAnimations() {
         boolean removalsPending = !mPendingRemovals.isEmpty();
         boolean movesPending = !mPendingMoves.isEmpty();
         boolean changesPending = !mPendingChanges.isEmpty();
         boolean additionsPending = !mPendingAdditions.isEmpty();
         if (!removalsPending && !movesPending && !additionsPending && !changesPending) {
             // nothing to animate
             return;
         }
         // First, remove stuff
         for (ViewHolder holder : mPendingRemovals) {
             animateRemoveImpl(holder);
         }
         mPendingRemovals.clear();
         // Next, move stuff
         if (movesPending) {
             final ArrayList<MoveInfo> moves = new ArrayList<MoveInfo>();
             moves.addAll(mPendingMoves);
             mMovesList.add(moves);
             mPendingMoves.clear();
             Runnable mover = new Runnable() {
                 @Override
                 public void run() {
                     for (MoveInfo moveInfo : moves) {
                         animateMoveImpl(moveInfo.holder, moveInfo.fromX, moveInfo.fromY,
                                 moveInfo.toX, moveInfo.toY);
                     }
                     moves.clear();
                     mMovesList.remove(moves);
                 }
             };
             if (removalsPending) {
                 View view = moves.get(0).holder.itemView;
                 ViewCompat.postOnAnimationDelayed(view, mover, getRemoveDuration());
             } else {
                 mover.run();
             }
         }
         // Next, change stuff, to run in parallel with move animations
         if (changesPending) {
             final ArrayList<ChangeInfo> changes = new ArrayList<ChangeInfo>();
             changes.addAll(mPendingChanges);
             mChangesList.add(changes);
             mPendingChanges.clear();
             Runnable changer = new Runnable() {
                 @Override
                 public void run() {
                     for (ChangeInfo change : changes) {
                         animateChangeImpl(change);
                     }
                     changes.clear();
                     mChangesList.remove(changes);
                 }
             };
             if (removalsPending) {
                 ViewHolder holder = changes.get(0).oldHolder;
                 ViewCompat.postOnAnimationDelayed(holder.itemView, changer, getRemoveDuration());
             } else {
                 changer.run();
             }
         }
         // Next, add stuff
         if (additionsPending) {
             final ArrayList<ViewHolder> additions = new ArrayList<ViewHolder>();
             additions.addAll(mPendingAdditions);
             mAdditionsList.add(additions);
             mPendingAdditions.clear();
             Runnable adder = new Runnable() {
                 public void run() {
                     for (ViewHolder holder : additions) {
                         animateAddImpl(holder);
                     }
                     additions.clear();
                     mAdditionsList.remove(additions);
                 }
             };
             if (removalsPending || movesPending || changesPending) {
                 long removeDuration = removalsPending ? getRemoveDuration() : 0;
                 long moveDuration = movesPending ? getMoveDuration() : 0;
                 long changeDuration = changesPending ? getChangeDuration() : 0;
                 long totalDelay = removeDuration + Math.max(moveDuration, changeDuration);
                 View view = additions.get(0).itemView;
                 ViewCompat.postOnAnimationDelayed(view, adder, totalDelay);
             } else {
                 adder.run();
             }
         }
     }

     @Override
     public boolean animateRemove(final ViewHolder holder) {
         endAnimation(holder);
         mPendingRemovals.add(holder);
         return true;
     }

     private void animateRemoveImpl(final ViewHolder holder) {
         // Animate on the content if it's CallLogViewHolder.
         final View view = holder instanceof CallLogViewHolder ?
                 ((CallLogViewHolder) holder).container : holder.itemView;
         final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view);
         mRemoveAnimations.add(holder);
         animation.setDuration(getRemoveDuration())
                 .alpha(0).setListener(new VpaListenerAdapter() {
             @Override
             public void onAnimationStart(View view) {
                 dispatchRemoveStarting(holder);
             }

             @Override
             public void onAnimationEnd(View view) {
                 animation.setListener(null);
                 ViewCompat.setAlpha(view, 1);
                 dispatchRemoveFinished(holder);
                 mRemoveAnimations.remove(holder);
                 dispatchFinishedWhenDone();
             }
         }).start();
     }

     @Override
     public boolean animateAdd(final ViewHolder holder) {
         endAnimation(holder);
         // for CallLogViewHolder, instead of fade out the whole card, fade out only the content.
         if (holder instanceof CallLogViewHolder) {
             ViewCompat.setAlpha(((CallLogViewHolder) holder).container, 0);
         } else {
             ViewCompat.setAlpha(holder.itemView, 0);
         }
         mPendingAdditions.add(holder);
         return true;
     }

     private void animateAddImpl(final ViewHolder holder) {
         // Animate on the content if it's CallLogViewHolder.
         final View view = holder instanceof CallLogViewHolder ?
                 ((CallLogViewHolder) holder).container : holder.itemView;
         final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view);
         mAddAnimations.add(holder);
         animation.alpha(1).setDuration(getAddDuration()).
                 setListener(new VpaListenerAdapter() {
                     @Override
                     public void onAnimationStart(View view) {
                         dispatchAddStarting(holder);
                     }
                     @Override
                     public void onAnimationCancel(View view) {
                         ViewCompat.setAlpha(view, 1);
                     }

                     @Override
                     public void onAnimationEnd(View view) {
                         animation.setListener(null);
                         dispatchAddFinished(holder);
                         mAddAnimations.remove(holder);
                         dispatchFinishedWhenDone();
                     }
                 }).start();
     }

     @Override
     public boolean animateMove(final ViewHolder holder, int fromX, int fromY,
             int toX, int toY) {
         final View view = holder.itemView;
         fromX += ViewCompat.getTranslationX(holder.itemView);
         fromY += ViewCompat.getTranslationY(holder.itemView);
         endAnimation(holder);
         int deltaX = toX - fromX;
         int deltaY = toY - fromY;
         if (deltaX == 0 && deltaY == 0) {
             dispatchMoveFinished(holder);
             return false;
         }
         if (deltaX != 0) {
             ViewCompat.setTranslationX(view, -deltaX);
         }
         if (deltaY != 0) {
             ViewCompat.setTranslationY(view, -deltaY);
         }
         mPendingMoves.add(new MoveInfo(holder, fromX, fromY, toX, toY));
         return true;
     }

     private void animateMoveImpl(final ViewHolder holder, int fromX, int fromY, int toX, int toY) {
         final View view = holder.itemView;
         final int deltaX = toX - fromX;
         final int deltaY = toY - fromY;
         if (deltaX != 0) {
             ViewCompat.animate(view).translationX(0);
         }
         if (deltaY != 0) {
             ViewCompat.animate(view).translationY(0);
         }
         // TODO: make EndActions end listeners instead, since end actions aren't called when
         // vpas are canceled (and can't end them. why?)
         // need listener functionality in VPACompat for this. Ick.
         final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view);
         mMoveAnimations.add(holder);
         animation.setDuration(getMoveDuration()).setListener(new VpaListenerAdapter() {
             @Override
             public void onAnimationStart(View view) {
                 dispatchMoveStarting(holder);
             }
             @Override
             public void onAnimationCancel(View view) {
                 if (deltaX != 0) {
                     ViewCompat.setTranslationX(view, 0);
                 }
                 if (deltaY != 0) {
                     ViewCompat.setTranslationY(view, 0);
                 }
             }
             @Override
             public void onAnimationEnd(View view) {
                 animation.setListener(null);
                 dispatchMoveFinished(holder);
                 mMoveAnimations.remove(holder);
                 dispatchFinishedWhenDone();
             }
         }).start();
     }

     @Override
     public boolean animateChange(ViewHolder oldHolder, ViewHolder newHolder,
             int fromX, int fromY, int toX, int toY) {
         final float prevTranslationX = ViewCompat.getTranslationX(oldHolder.itemView);
         final float prevTranslationY = ViewCompat.getTranslationY(oldHolder.itemView);
         final float prevAlpha = ViewCompat.getAlpha(oldHolder.itemView);
         endAnimation(oldHolder);
         int deltaX = (int) (toX - fromX - prevTranslationX);
         int deltaY = (int) (toY - fromY - prevTranslationY);
         // recover prev translation state after ending animation
         ViewCompat.setTranslationX(oldHolder.itemView, prevTranslationX);
         ViewCompat.setTranslationY(oldHolder.itemView, prevTranslationY);
         ViewCompat.setAlpha(oldHolder.itemView, prevAlpha);
         if (newHolder != null && newHolder.itemView != null) {
             // carry over translation values
             endAnimation(newHolder);
             ViewCompat.setTranslationX(newHolder.itemView, -deltaX);
             ViewCompat.setTranslationY(newHolder.itemView, -deltaY);
             ViewCompat.setAlpha(newHolder.itemView, 0);
         }
         mPendingChanges.add(new ChangeInfo(oldHolder, newHolder, fromX, fromY, toX, toY));
         return true;
     }

     private void animateChangeImpl(final ChangeInfo changeInfo) {
         final ViewHolder holder = changeInfo.oldHolder;
         final View view = holder == null ? null : holder.itemView;
         final ViewHolder newHolder = changeInfo.newHolder;
         final View newView = newHolder != null ? newHolder.itemView : null;
         if (view != null) {
             final ViewPropertyAnimatorCompat oldViewAnim = ViewCompat.animate(view).setDuration(
                     getChangeDuration());
             mChangeAnimations.add(changeInfo.oldHolder);
             oldViewAnim.translationX(changeInfo.toX - changeInfo.fromX);
             oldViewAnim.translationY(changeInfo.toY - changeInfo.fromY);
             oldViewAnim.alpha(0).setListener(new VpaListenerAdapter() {
                 @Override
                 public void onAnimationStart(View view) {
                     dispatchChangeStarting(changeInfo.oldHolder, true);
                 }

                 @Override
                 public void onAnimationEnd(View view) {
                     oldViewAnim.setListener(null);
                     ViewCompat.setAlpha(view, 1);
                     ViewCompat.setTranslationX(view, 0);
                     ViewCompat.setTranslationY(view, 0);
                     dispatchChangeFinished(changeInfo.oldHolder, true);
                     mChangeAnimations.remove(changeInfo.oldHolder);
                     dispatchFinishedWhenDone();
                 }
             }).start();
         }
         if (newView != null) {
             final ViewPropertyAnimatorCompat newViewAnimation = ViewCompat.animate(newView);
             mChangeAnimations.add(changeInfo.newHolder);
             newViewAnimation.translationX(0).translationY(0).setDuration(getChangeDuration()).
                     alpha(1).setListener(new VpaListenerAdapter() {
                 @Override
                 public void onAnimationStart(View view) {
                     dispatchChangeStarting(changeInfo.newHolder, false);
                 }
                 @Override
                 public void onAnimationEnd(View view) {
                     newViewAnimation.setListener(null);
                     ViewCompat.setAlpha(newView, 1);
                     ViewCompat.setTranslationX(newView, 0);
                     ViewCompat.setTranslationY(newView, 0);
                     dispatchChangeFinished(changeInfo.newHolder, false);
                     mChangeAnimations.remove(changeInfo.newHolder);
                     dispatchFinishedWhenDone();
                 }
             }).start();
         }
     }

     private void endChangeAnimation(List<ChangeInfo> infoList, ViewHolder item) {
         for (int i = infoList.size() - 1; i >= 0; i--) {
             ChangeInfo changeInfo = infoList.get(i);
             if (endChangeAnimationIfNecessary(changeInfo, item)) {
                 if (changeInfo.oldHolder == null && changeInfo.newHolder == null) {
                     infoList.remove(changeInfo);
                 }
             }
         }
     }

     private void endChangeAnimationIfNecessary(ChangeInfo changeInfo) {
         if (changeInfo.oldHolder != null) {
             endChangeAnimationIfNecessary(changeInfo, changeInfo.oldHolder);
         }
         if (changeInfo.newHolder != null) {
             endChangeAnimationIfNecessary(changeInfo, changeInfo.newHolder);
         }
     }
     private boolean endChangeAnimationIfNecessary(ChangeInfo changeInfo, ViewHolder item) {
         boolean oldItem = false;
         if (changeInfo.newHolder == item) {
             changeInfo.newHolder = null;
         } else if (changeInfo.oldHolder == item) {
             changeInfo.oldHolder = null;
             oldItem = true;
         } else {
             return false;
         }
         ViewCompat.setAlpha(item.itemView, 1);
         ViewCompat.setTranslationX(item.itemView, 0);
         ViewCompat.setTranslationY(item.itemView, 0);
         dispatchChangeFinished(item, oldItem);
         return true;
     }

     @Override
     public void endAnimation(ViewHolder item) {
         final View view = item.itemView;
         // this will trigger end callback which should set properties to their target values.
         ViewCompat.animate(view).cancel();
         // TODO if some other animations are chained to end, how do we cancel them as well?
         for (int i = mPendingMoves.size() - 1; i >= 0; i--) {
             MoveInfo moveInfo = mPendingMoves.get(i);
             if (moveInfo.holder == item) {
                 ViewCompat.setTranslationY(view, 0);
                 ViewCompat.setTranslationX(view, 0);
                 dispatchMoveFinished(item);
                 mPendingMoves.remove(i);
             }
         }
         endChangeAnimation(mPendingChanges, item);
         if (mPendingRemovals.remove(item)) {
             ViewCompat.setAlpha(view, 1);
             dispatchRemoveFinished(item);
         }
         if (mPendingAdditions.remove(item)) {
             ViewCompat.setAlpha(view, 1);
             dispatchAddFinished(item);
         }

         for (int i = mChangesList.size() - 1; i >= 0; i--) {
             ArrayList<ChangeInfo> changes = mChangesList.get(i);
             endChangeAnimation(changes, item);
             if (changes.isEmpty()) {
                 mChangesList.remove(i);
             }
         }
         for (int i = mMovesList.size() - 1; i >= 0; i--) {
             ArrayList<MoveInfo> moves = mMovesList.get(i);
             for (int j = moves.size() - 1; j >= 0; j--) {
                 MoveInfo moveInfo = moves.get(j);
                 if (moveInfo.holder == item) {
                     ViewCompat.setTranslationY(view, 0);
                     ViewCompat.setTranslationX(view, 0);
                     dispatchMoveFinished(item);
                     moves.remove(j);
                     if (moves.isEmpty()) {
                         mMovesList.remove(i);
                     }
                     break;
                 }
             }
         }
         for (int i = mAdditionsList.size() - 1; i >= 0; i--) {
             ArrayList<ViewHolder> additions = mAdditionsList.get(i);
             if (additions.remove(item)) {
                 ViewCompat.setAlpha(view, 1);
                 dispatchAddFinished(item);
                 if (additions.isEmpty()) {
                     mAdditionsList.remove(i);
                 }
             }
         }

         // animations should be ended by the cancel above.
         if (mRemoveAnimations.remove(item) && DEBUG) {
             throw new IllegalStateException("after animation is cancelled, item should not be in "
                     + "mRemoveAnimations list");
         }

         if (mAddAnimations.remove(item) && DEBUG) {
             throw new IllegalStateException("after animation is cancelled, item should not be in "
                     + "mAddAnimations list");
         }

         if (mChangeAnimations.remove(item) && DEBUG) {
             throw new IllegalStateException("after animation is cancelled, item should not be in "
                     + "mChangeAnimations list");
         }

         if (mMoveAnimations.remove(item) && DEBUG) {
             throw new IllegalStateException("after animation is cancelled, item should not be in "
                     + "mMoveAnimations list");
         }
         dispatchFinishedWhenDone();
     }

     @Override
     public boolean isRunning() {
         return (!mPendingAdditions.isEmpty() ||
                 !mPendingChanges.isEmpty() ||
                 !mPendingMoves.isEmpty() ||
                 !mPendingRemovals.isEmpty() ||
                 !mMoveAnimations.isEmpty() ||
                 !mRemoveAnimations.isEmpty() ||
                 !mAddAnimations.isEmpty() ||
                 !mChangeAnimations.isEmpty() ||
                 !mMovesList.isEmpty() ||
                 !mAdditionsList.isEmpty() ||
                 !mChangesList.isEmpty());
     }

     /**
      * Check the state of currently pending and running animations. If there are none
      * pending/running, call {@link #dispatchAnimationsFinished()} to notify any
      * listeners.
      */
     private void dispatchFinishedWhenDone() {
         if (!isRunning()) {
             dispatchAnimationsFinished();
         }
     }

     @Override
     public void endAnimations() {
         int count = mPendingMoves.size();
         for (int i = count - 1; i >= 0; i--) {
             MoveInfo item = mPendingMoves.get(i);
             View view = item.holder.itemView;
             ViewCompat.setTranslationY(view, 0);
             ViewCompat.setTranslationX(view, 0);
             dispatchMoveFinished(item.holder);
             mPendingMoves.remove(i);
         }
         count = mPendingRemovals.size();
         for (int i = count - 1; i >= 0; i--) {
             ViewHolder item = mPendingRemovals.get(i);
             dispatchRemoveFinished(item);
             mPendingRemovals.remove(i);
         }
         count = mPendingAdditions.size();
         for (int i = count - 1; i >= 0; i--) {
             ViewHolder item = mPendingAdditions.get(i);
             View view = item.itemView;
             ViewCompat.setAlpha(view, 1);
             dispatchAddFinished(item);
             mPendingAdditions.remove(i);
         }
         count = mPendingChanges.size();
         for (int i = count - 1; i >= 0; i--) {
             endChangeAnimationIfNecessary(mPendingChanges.get(i));
         }
         mPendingChanges.clear();
         if (!isRunning()) {
             return;
         }

         int listCount = mMovesList.size();
         for (int i = listCount - 1; i >= 0; i--) {
             ArrayList<MoveInfo> moves = mMovesList.get(i);
             count = moves.size();
             for (int j = count - 1; j >= 0; j--) {
                 MoveInfo moveInfo = moves.get(j);
                 ViewHolder item = moveInfo.holder;
                 View view = item.itemView;
                 ViewCompat.setTranslationY(view, 0);
                 ViewCompat.setTranslationX(view, 0);
                 dispatchMoveFinished(moveInfo.holder);
                 moves.remove(j);
                 if (moves.isEmpty()) {
                     mMovesList.remove(moves);
                 }
             }
         }
         listCount = mAdditionsList.size();
         for (int i = listCount - 1; i >= 0; i--) {
             ArrayList<ViewHolder> additions = mAdditionsList.get(i);
             count = additions.size();
             for (int j = count - 1; j >= 0; j--) {
                 ViewHolder item = additions.get(j);
                 View view = item.itemView;
                 ViewCompat.setAlpha(view, 1);
                 dispatchAddFinished(item);
                 additions.remove(j);
                 if (additions.isEmpty()) {
                     mAdditionsList.remove(additions);
                 }
             }
         }
         listCount = mChangesList.size();
         for (int i = listCount - 1; i >= 0; i--) {
             ArrayList<ChangeInfo> changes = mChangesList.get(i);
             count = changes.size();
             for (int j = count - 1; j >= 0; j--) {
                 endChangeAnimationIfNecessary(changes.get(j));
                 if (changes.isEmpty()) {
                     mChangesList.remove(changes);
                 }
             }
         }

         cancelAll(mRemoveAnimations);
         cancelAll(mMoveAnimations);
         cancelAll(mAddAnimations);
         cancelAll(mChangeAnimations);

         dispatchAnimationsFinished();
     }

     void cancelAll(List<ViewHolder> viewHolders) {
         for (int i = viewHolders.size() - 1; i >= 0; i--) {
             ViewCompat.animate(viewHolders.get(i).itemView).cancel();
         }
     }

     private static class VpaListenerAdapter implements ViewPropertyAnimatorListener {
         @Override
         public void onAnimationStart(View view) {}

         @Override
         public void onAnimationEnd(View view) {}

         @Override
         public void onAnimationCancel(View view) {}
     };
 }
	/*
	* Copyright (C) 2015 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.car.dialer;

	import android.support.v4.view.ViewCompat;
	import android.support.v4.view.ViewPropertyAnimatorCompat;
	import android.support.v4.view.ViewPropertyAnimatorListener;
	import android.support.v7.widget.RecyclerView.ViewHolder;
	import android.support.v7.widget.SimpleItemAnimator;
	import android.view.View;

	import java.util.ArrayList;
	import java.util.List;

	/**
	* Branch from {@link android.support.v7.widget.DefaultItemAnimator} with changes on
	* {@link #animateAddImpl}, {@link #animateAdd} and {@link #animateRemoveImpl}.
	*/
	public class StrequentsItemAnimator extends SimpleItemAnimator {
	private static final boolean DEBUG = false;

	private ArrayList<ViewHolder> mPendingRemovals = new ArrayList<>();
	private ArrayList<ViewHolder> mPendingAdditions = new ArrayList<>();
	private ArrayList<MoveInfo> mPendingMoves = new ArrayList<>();
	private ArrayList<ChangeInfo> mPendingChanges = new ArrayList<>();

	private ArrayList<ArrayList<ViewHolder>> mAdditionsList = new ArrayList<>();
	private ArrayList<ArrayList<MoveInfo>> mMovesList = new ArrayList<>();
	private ArrayList<ArrayList<ChangeInfo>> mChangesList = new ArrayList<>();

	private ArrayList<ViewHolder> mAddAnimations = new ArrayList<>();
	private ArrayList<ViewHolder> mMoveAnimations = new ArrayList<>();
	private ArrayList<ViewHolder> mRemoveAnimations = new ArrayList<>();
	private ArrayList<ViewHolder> mChangeAnimations = new ArrayList<>();

	private static class MoveInfo {
	public ViewHolder holder;
	public int fromX, fromY, toX, toY;

	private MoveInfo(ViewHolder holder, int fromX, int fromY, int toX, int toY) {
	this.holder = holder;
	this.fromX = fromX;
	this.fromY = fromY;
	this.toX = toX;
	this.toY = toY;
	}
	}

	private static class ChangeInfo {
	public ViewHolder oldHolder, newHolder;
	public int fromX, fromY, toX, toY;
	private ChangeInfo(ViewHolder oldHolder, ViewHolder newHolder) {
	this.oldHolder = oldHolder;
	this.newHolder = newHolder;
	}

	private ChangeInfo(ViewHolder oldHolder, ViewHolder newHolder,
	int fromX, int fromY, int toX, int toY) {
	this(oldHolder, newHolder);
	this.fromX = fromX;
	this.fromY = fromY;
	this.toX = toX;
	this.toY = toY;
	}

	@Override
	public String toString() {
	return "ChangeInfo{" +
	"oldHolder=" + oldHolder +
	", newHolder=" + newHolder +
	", fromX=" + fromX +
	", fromY=" + fromY +
	", toX=" + toX +
	", toY=" + toY +
	'}';
	}
	}

	@Override
	public void runPendingAnimations() {
	boolean removalsPending = !mPendingRemovals.isEmpty();
	boolean movesPending = !mPendingMoves.isEmpty();
	boolean changesPending = !mPendingChanges.isEmpty();
	boolean additionsPending = !mPendingAdditions.isEmpty();
	if (!removalsPending && !movesPending && !additionsPending && !changesPending) {
	// nothing to animate
	return;
	}
	// First, remove stuff
	for (ViewHolder holder : mPendingRemovals) {
	animateRemoveImpl(holder);
	}
	mPendingRemovals.clear();
	// Next, move stuff
	if (movesPending) {
	final ArrayList<MoveInfo> moves = new ArrayList<MoveInfo>();
	moves.addAll(mPendingMoves);
	mMovesList.add(moves);
	mPendingMoves.clear();
	Runnable mover = new Runnable() {
	@Override
	public void run() {
	for (MoveInfo moveInfo : moves) {
	animateMoveImpl(moveInfo.holder, moveInfo.fromX, moveInfo.fromY,
	moveInfo.toX, moveInfo.toY);
	}
	moves.clear();
	mMovesList.remove(moves);
	}
	};
	if (removalsPending) {
	View view = moves.get(0).holder.itemView;
	ViewCompat.postOnAnimationDelayed(view, mover, getRemoveDuration());
	} else {
	mover.run();
	}
	}
	// Next, change stuff, to run in parallel with move animations
	if (changesPending) {
	final ArrayList<ChangeInfo> changes = new ArrayList<ChangeInfo>();
	changes.addAll(mPendingChanges);
	mChangesList.add(changes);
	mPendingChanges.clear();
	Runnable changer = new Runnable() {
	@Override
	public void run() {
	for (ChangeInfo change : changes) {
	animateChangeImpl(change);
	}
	changes.clear();
	mChangesList.remove(changes);
	}
	};
	if (removalsPending) {
	ViewHolder holder = changes.get(0).oldHolder;
	ViewCompat.postOnAnimationDelayed(holder.itemView, changer, getRemoveDuration());
	} else {
	changer.run();
	}
	}
	// Next, add stuff
	if (additionsPending) {
	final ArrayList<ViewHolder> additions = new ArrayList<ViewHolder>();
	additions.addAll(mPendingAdditions);
	mAdditionsList.add(additions);
	mPendingAdditions.clear();
	Runnable adder = new Runnable() {
	public void run() {
	for (ViewHolder holder : additions) {
	animateAddImpl(holder);
	}
	additions.clear();
	mAdditionsList.remove(additions);
	}
	};
	if (removalsPending \|\| movesPending \|\| changesPending) {
	long removeDuration = removalsPending ? getRemoveDuration() : 0;
	long moveDuration = movesPending ? getMoveDuration() : 0;
	long changeDuration = changesPending ? getChangeDuration() : 0;
	long totalDelay = removeDuration + Math.max(moveDuration, changeDuration);
	View view = additions.get(0).itemView;
	ViewCompat.postOnAnimationDelayed(view, adder, totalDelay);
	} else {
	adder.run();
	}
	}
	}

	@Override
	public boolean animateRemove(final ViewHolder holder) {
	endAnimation(holder);
	mPendingRemovals.add(holder);
	return true;
	}

	private void animateRemoveImpl(final ViewHolder holder) {
	// Animate on the content if it's CallLogViewHolder.
	final View view = holder instanceof CallLogViewHolder ?
	((CallLogViewHolder) holder).container : holder.itemView;
	final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view);
	mRemoveAnimations.add(holder);
	animation.setDuration(getRemoveDuration())
	.alpha(0).setListener(new VpaListenerAdapter() {
	@Override
	public void onAnimationStart(View view) {
	dispatchRemoveStarting(holder);
	}

	@Override
	public void onAnimationEnd(View view) {
	animation.setListener(null);
	ViewCompat.setAlpha(view, 1);
	dispatchRemoveFinished(holder);
	mRemoveAnimations.remove(holder);
	dispatchFinishedWhenDone();
	}
	}).start();
	}

	@Override
	public boolean animateAdd(final ViewHolder holder) {
	endAnimation(holder);
	// for CallLogViewHolder, instead of fade out the whole card, fade out only the content.
	if (holder instanceof CallLogViewHolder) {
	ViewCompat.setAlpha(((CallLogViewHolder) holder).container, 0);
	} else {
	ViewCompat.setAlpha(holder.itemView, 0);
	}
	mPendingAdditions.add(holder);
	return true;
	}

	private void animateAddImpl(final ViewHolder holder) {
	// Animate on the content if it's CallLogViewHolder.
	final View view = holder instanceof CallLogViewHolder ?
	((CallLogViewHolder) holder).container : holder.itemView;
	final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view);
	mAddAnimations.add(holder);
	animation.alpha(1).setDuration(getAddDuration()).
	setListener(new VpaListenerAdapter() {
	@Override
	public void onAnimationStart(View view) {
	dispatchAddStarting(holder);
	}
	@Override
	public void onAnimationCancel(View view) {
	ViewCompat.setAlpha(view, 1);
	}

	@Override
	public void onAnimationEnd(View view) {
	animation.setListener(null);
	dispatchAddFinished(holder);
	mAddAnimations.remove(holder);
	dispatchFinishedWhenDone();
	}
	}).start();
	}

	@Override
	public boolean animateMove(final ViewHolder holder, int fromX, int fromY,
	int toX, int toY) {
	final View view = holder.itemView;
	fromX += ViewCompat.getTranslationX(holder.itemView);
	fromY += ViewCompat.getTranslationY(holder.itemView);
	endAnimation(holder);
	int deltaX = toX - fromX;
	int deltaY = toY - fromY;
	if (deltaX == 0 && deltaY == 0) {
	dispatchMoveFinished(holder);
	return false;
	}
	if (deltaX != 0) {
	ViewCompat.setTranslationX(view, -deltaX);
	}
	if (deltaY != 0) {
	ViewCompat.setTranslationY(view, -deltaY);
	}
	mPendingMoves.add(new MoveInfo(holder, fromX, fromY, toX, toY));
	return true;
	}

	private void animateMoveImpl(final ViewHolder holder, int fromX, int fromY, int toX, int toY) {
	final View view = holder.itemView;
	final int deltaX = toX - fromX;
	final int deltaY = toY - fromY;
	if (deltaX != 0) {
	ViewCompat.animate(view).translationX(0);
	}
	if (deltaY != 0) {
	ViewCompat.animate(view).translationY(0);
	}
	// TODO: make EndActions end listeners instead, since end actions aren't called when
	// vpas are canceled (and can't end them. why?)
	// need listener functionality in VPACompat for this. Ick.
	final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view);
	mMoveAnimations.add(holder);
	animation.setDuration(getMoveDuration()).setListener(new VpaListenerAdapter() {
	@Override
	public void onAnimationStart(View view) {
	dispatchMoveStarting(holder);
	}
	@Override
	public void onAnimationCancel(View view) {
	if (deltaX != 0) {
	ViewCompat.setTranslationX(view, 0);
	}
	if (deltaY != 0) {
	ViewCompat.setTranslationY(view, 0);
	}
	}
	@Override
	public void onAnimationEnd(View view) {
	animation.setListener(null);
	dispatchMoveFinished(holder);
	mMoveAnimations.remove(holder);
	dispatchFinishedWhenDone();
	}
	}).start();
	}

	@Override
	public boolean animateChange(ViewHolder oldHolder, ViewHolder newHolder,
	int fromX, int fromY, int toX, int toY) {
	final float prevTranslationX = ViewCompat.getTranslationX(oldHolder.itemView);
	final float prevTranslationY = ViewCompat.getTranslationY(oldHolder.itemView);
	final float prevAlpha = ViewCompat.getAlpha(oldHolder.itemView);
	endAnimation(oldHolder);
	int deltaX = (int) (toX - fromX - prevTranslationX);
	int deltaY = (int) (toY - fromY - prevTranslationY);
	// recover prev translation state after ending animation
	ViewCompat.setTranslationX(oldHolder.itemView, prevTranslationX);
	ViewCompat.setTranslationY(oldHolder.itemView, prevTranslationY);
	ViewCompat.setAlpha(oldHolder.itemView, prevAlpha);
	if (newHolder != null && newHolder.itemView != null) {
	// carry over translation values
	endAnimation(newHolder);
	ViewCompat.setTranslationX(newHolder.itemView, -deltaX);
	ViewCompat.setTranslationY(newHolder.itemView, -deltaY);
	ViewCompat.setAlpha(newHolder.itemView, 0);
	}
	mPendingChanges.add(new ChangeInfo(oldHolder, newHolder, fromX, fromY, toX, toY));
	return true;
	}

	private void animateChangeImpl(final ChangeInfo changeInfo) {
	final ViewHolder holder = changeInfo.oldHolder;
	final View view = holder == null ? null : holder.itemView;
	final ViewHolder newHolder = changeInfo.newHolder;
	final View newView = newHolder != null ? newHolder.itemView : null;
	if (view != null) {
	final ViewPropertyAnimatorCompat oldViewAnim = ViewCompat.animate(view).setDuration(
	getChangeDuration());
	mChangeAnimations.add(changeInfo.oldHolder);
	oldViewAnim.translationX(changeInfo.toX - changeInfo.fromX);
	oldViewAnim.translationY(changeInfo.toY - changeInfo.fromY);
	oldViewAnim.alpha(0).setListener(new VpaListenerAdapter() {
	@Override
	public void onAnimationStart(View view) {
	dispatchChangeStarting(changeInfo.oldHolder, true);
	}

	@Override
	public void onAnimationEnd(View view) {
	oldViewAnim.setListener(null);
	ViewCompat.setAlpha(view, 1);
	ViewCompat.setTranslationX(view, 0);
	ViewCompat.setTranslationY(view, 0);
	dispatchChangeFinished(changeInfo.oldHolder, true);
	mChangeAnimations.remove(changeInfo.oldHolder);
	dispatchFinishedWhenDone();
	}
	}).start();
	}
	if (newView != null) {
	final ViewPropertyAnimatorCompat newViewAnimation = ViewCompat.animate(newView);
	mChangeAnimations.add(changeInfo.newHolder);
	newViewAnimation.translationX(0).translationY(0).setDuration(getChangeDuration()).
	alpha(1).setListener(new VpaListenerAdapter() {
	@Override
	public void onAnimationStart(View view) {
	dispatchChangeStarting(changeInfo.newHolder, false);
	}
	@Override
	public void onAnimationEnd(View view) {
	newViewAnimation.setListener(null);
	ViewCompat.setAlpha(newView, 1);
	ViewCompat.setTranslationX(newView, 0);
	ViewCompat.setTranslationY(newView, 0);
	dispatchChangeFinished(changeInfo.newHolder, false);
	mChangeAnimations.remove(changeInfo.newHolder);
	dispatchFinishedWhenDone();
	}
	}).start();
	}
	}

	private void endChangeAnimation(List<ChangeInfo> infoList, ViewHolder item) {
	for (int i = infoList.size() - 1; i >= 0; i--) {
	ChangeInfo changeInfo = infoList.get(i);
	if (endChangeAnimationIfNecessary(changeInfo, item)) {
	if (changeInfo.oldHolder == null && changeInfo.newHolder == null) {
	infoList.remove(changeInfo);
	}
	}
	}
	}

	private void endChangeAnimationIfNecessary(ChangeInfo changeInfo) {
	if (changeInfo.oldHolder != null) {
	endChangeAnimationIfNecessary(changeInfo, changeInfo.oldHolder);
	}
	if (changeInfo.newHolder != null) {
	endChangeAnimationIfNecessary(changeInfo, changeInfo.newHolder);
	}
	}
	private boolean endChangeAnimationIfNecessary(ChangeInfo changeInfo, ViewHolder item) {
	boolean oldItem = false;
	if (changeInfo.newHolder == item) {
	changeInfo.newHolder = null;
	} else if (changeInfo.oldHolder == item) {
	changeInfo.oldHolder = null;
	oldItem = true;
	} else {
	return false;
	}
	ViewCompat.setAlpha(item.itemView, 1);
	ViewCompat.setTranslationX(item.itemView, 0);
	ViewCompat.setTranslationY(item.itemView, 0);
	dispatchChangeFinished(item, oldItem);
	return true;
	}

	@Override
	public void endAnimation(ViewHolder item) {
	final View view = item.itemView;
	// this will trigger end callback which should set properties to their target values.
	ViewCompat.animate(view).cancel();
	// TODO if some other animations are chained to end, how do we cancel them as well?
	for (int i = mPendingMoves.size() - 1; i >= 0; i--) {
	MoveInfo moveInfo = mPendingMoves.get(i);
	if (moveInfo.holder == item) {
	ViewCompat.setTranslationY(view, 0);
	ViewCompat.setTranslationX(view, 0);
	dispatchMoveFinished(item);
	mPendingMoves.remove(i);
	}
	}
	endChangeAnimation(mPendingChanges, item);
	if (mPendingRemovals.remove(item)) {
	ViewCompat.setAlpha(view, 1);
	dispatchRemoveFinished(item);
	}
	if (mPendingAdditions.remove(item)) {
	ViewCompat.setAlpha(view, 1);
	dispatchAddFinished(item);
	}

	for (int i = mChangesList.size() - 1; i >= 0; i--) {
	ArrayList<ChangeInfo> changes = mChangesList.get(i);
	endChangeAnimation(changes, item);
	if (changes.isEmpty()) {
	mChangesList.remove(i);
	}
	}
	for (int i = mMovesList.size() - 1; i >= 0; i--) {
	ArrayList<MoveInfo> moves = mMovesList.get(i);
	for (int j = moves.size() - 1; j >= 0; j--) {
	MoveInfo moveInfo = moves.get(j);
	if (moveInfo.holder == item) {
	ViewCompat.setTranslationY(view, 0);
	ViewCompat.setTranslationX(view, 0);
	dispatchMoveFinished(item);
	moves.remove(j);
	if (moves.isEmpty()) {
	mMovesList.remove(i);
	}
	break;
	}
	}
	}
	for (int i = mAdditionsList.size() - 1; i >= 0; i--) {
	ArrayList<ViewHolder> additions = mAdditionsList.get(i);
	if (additions.remove(item)) {
	ViewCompat.setAlpha(view, 1);
	dispatchAddFinished(item);
	if (additions.isEmpty()) {
	mAdditionsList.remove(i);
	}
	}
	}

	// animations should be ended by the cancel above.
	if (mRemoveAnimations.remove(item) && DEBUG) {
	throw new IllegalStateException("after animation is cancelled, item should not be in "
	+ "mRemoveAnimations list");
	}

	if (mAddAnimations.remove(item) && DEBUG) {
	throw new IllegalStateException("after animation is cancelled, item should not be in "
	+ "mAddAnimations list");
	}

	if (mChangeAnimations.remove(item) && DEBUG) {
	throw new IllegalStateException("after animation is cancelled, item should not be in "
	+ "mChangeAnimations list");
	}

	if (mMoveAnimations.remove(item) && DEBUG) {
	throw new IllegalStateException("after animation is cancelled, item should not be in "
	+ "mMoveAnimations list");
	}
	dispatchFinishedWhenDone();
	}

	@Override
	public boolean isRunning() {
	return (!mPendingAdditions.isEmpty() \|\|
	!mPendingChanges.isEmpty() \|\|
	!mPendingMoves.isEmpty() \|\|
	!mPendingRemovals.isEmpty() \|\|
	!mMoveAnimations.isEmpty() \|\|
	!mRemoveAnimations.isEmpty() \|\|
	!mAddAnimations.isEmpty() \|\|
	!mChangeAnimations.isEmpty() \|\|
	!mMovesList.isEmpty() \|\|
	!mAdditionsList.isEmpty() \|\|
	!mChangesList.isEmpty());
	}

	/**
	* Check the state of currently pending and running animations. If there are none
	* pending/running, call {@link #dispatchAnimationsFinished()} to notify any
	* listeners.
	*/
	private void dispatchFinishedWhenDone() {
	if (!isRunning()) {
	dispatchAnimationsFinished();
	}
	}

	@Override
	public void endAnimations() {
	int count = mPendingMoves.size();
	for (int i = count - 1; i >= 0; i--) {
	MoveInfo item = mPendingMoves.get(i);
	View view = item.holder.itemView;
	ViewCompat.setTranslationY(view, 0);
	ViewCompat.setTranslationX(view, 0);
	dispatchMoveFinished(item.holder);
	mPendingMoves.remove(i);
	}
	count = mPendingRemovals.size();
	for (int i = count - 1; i >= 0; i--) {
	ViewHolder item = mPendingRemovals.get(i);
	dispatchRemoveFinished(item);
	mPendingRemovals.remove(i);
	}
	count = mPendingAdditions.size();
	for (int i = count - 1; i >= 0; i--) {
	ViewHolder item = mPendingAdditions.get(i);
	View view = item.itemView;
	ViewCompat.setAlpha(view, 1);
	dispatchAddFinished(item);
	mPendingAdditions.remove(i);
	}
	count = mPendingChanges.size();
	for (int i = count - 1; i >= 0; i--) {
	endChangeAnimationIfNecessary(mPendingChanges.get(i));
	}
	mPendingChanges.clear();
	if (!isRunning()) {
	return;
	}

	int listCount = mMovesList.size();
	for (int i = listCount - 1; i >= 0; i--) {
	ArrayList<MoveInfo> moves = mMovesList.get(i);
	count = moves.size();
	for (int j = count - 1; j >= 0; j--) {
	MoveInfo moveInfo = moves.get(j);
	ViewHolder item = moveInfo.holder;
	View view = item.itemView;
	ViewCompat.setTranslationY(view, 0);
	ViewCompat.setTranslationX(view, 0);
	dispatchMoveFinished(moveInfo.holder);
	moves.remove(j);
	if (moves.isEmpty()) {
	mMovesList.remove(moves);
	}
	}
	}
	listCount = mAdditionsList.size();
	for (int i = listCount - 1; i >= 0; i--) {
	ArrayList<ViewHolder> additions = mAdditionsList.get(i);
	count = additions.size();
	for (int j = count - 1; j >= 0; j--) {
	ViewHolder item = additions.get(j);
	View view = item.itemView;
	ViewCompat.setAlpha(view, 1);
	dispatchAddFinished(item);
	additions.remove(j);
	if (additions.isEmpty()) {
	mAdditionsList.remove(additions);
	}
	}
	}
	listCount = mChangesList.size();
	for (int i = listCount - 1; i >= 0; i--) {
	ArrayList<ChangeInfo> changes = mChangesList.get(i);
	count = changes.size();
	for (int j = count - 1; j >= 0; j--) {
	endChangeAnimationIfNecessary(changes.get(j));
	if (changes.isEmpty()) {
	mChangesList.remove(changes);
	}
	}
	}

	cancelAll(mRemoveAnimations);
	cancelAll(mMoveAnimations);
	cancelAll(mAddAnimations);
	cancelAll(mChangeAnimations);

	dispatchAnimationsFinished();
	}

	void cancelAll(List<ViewHolder> viewHolders) {
	for (int i = viewHolders.size() - 1; i >= 0; i--) {
	ViewCompat.animate(viewHolders.get(i).itemView).cancel();
	}
	}

	private static class VpaListenerAdapter implements ViewPropertyAnimatorListener {
	@Override
	public void onAnimationStart(View view) {}

	@Override
	public void onAnimationEnd(View view) {}

	@Override
	public void onAnimationCancel(View view) {}
	};
	}