Java tutorial
/* * Copyright (C) 2015 Simon Vig Therkildsen * * 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 net.simonvt.cathode.widget; import android.support.v4.view.ViewCompat; import android.support.v4.view.ViewPropertyAnimatorCompat; import android.support.v4.view.ViewPropertyAnimatorListener; import android.support.v7.widget.RecyclerView; import android.support.v7.widget.RecyclerView.ViewHolder; import android.view.View; import java.util.ArrayList; import java.util.List; import net.simonvt.cathode.BuildConfig; /** * This implementation of {@link android.support.v7.widget.RecyclerView.ItemAnimator} provides * basic * animations on remove, add, and move events that happen to the items in * a RecyclerView. RecyclerView uses a DefaultItemAnimator by default. * * @see android.support.v7.widget.RecyclerView#setItemAnimator(android.support.v7.widget.RecyclerView.ItemAnimator) */ public class ScalingItemAnimator extends RecyclerView.ItemAnimator { private static final boolean DEBUG = BuildConfig.DEBUG; private ArrayList<ViewHolder> pendingRemovals = new ArrayList<ViewHolder>(); private ArrayList<ViewHolder> pendingAdditions = new ArrayList<ViewHolder>(); private ArrayList<MoveInfo> pendingMoves = new ArrayList<MoveInfo>(); private ArrayList<ChangeInfo> pendingChanges = new ArrayList<ChangeInfo>(); private ArrayList<ArrayList<ViewHolder>> additionsList = new ArrayList<ArrayList<ViewHolder>>(); private ArrayList<ArrayList<MoveInfo>> movesList = new ArrayList<ArrayList<MoveInfo>>(); private ArrayList<ArrayList<ChangeInfo>> changesList = new ArrayList<ArrayList<ChangeInfo>>(); private ArrayList<ViewHolder> addAnimations = new ArrayList<ViewHolder>(); private ArrayList<ViewHolder> moveAnimations = new ArrayList<ViewHolder>(); private ArrayList<ViewHolder> removeAnimations = new ArrayList<ViewHolder>(); private ArrayList<ViewHolder> changeAnimations = new ArrayList<ViewHolder>(); 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 + '}'; } } public ScalingItemAnimator() { if (DEBUG) { setRemoveDuration(500); setMoveDuration(500); setAddDuration(500); setChangeDuration(500); } } @Override public void runPendingAnimations() { boolean removalsPending = !pendingRemovals.isEmpty(); boolean movesPending = !pendingMoves.isEmpty(); boolean changesPending = !pendingChanges.isEmpty(); boolean additionsPending = !pendingAdditions.isEmpty(); if (!removalsPending && !movesPending && !additionsPending && !changesPending) { // nothing to animate return; } // First, remove stuff for (ViewHolder holder : pendingRemovals) { animateRemoveImpl(holder); } pendingRemovals.clear(); // Next, move stuff if (movesPending) { final ArrayList<MoveInfo> moves = new ArrayList<MoveInfo>(); moves.addAll(pendingMoves); movesList.add(moves); pendingMoves.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(); movesList.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(pendingChanges); changesList.add(changes); pendingChanges.clear(); Runnable changer = new Runnable() { @Override public void run() { for (ChangeInfo change : changes) { animateChangeImpl(change); } changes.clear(); changesList.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(pendingAdditions); additionsList.add(additions); pendingAdditions.clear(); Runnable adder = new Runnable() { public void run() { for (ViewHolder holder : additions) { animateAddImpl(holder); } additions.clear(); additionsList.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); pendingRemovals.add(holder); return true; } private void animateRemoveImpl(final ViewHolder holder) { final View view = holder.itemView; final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view); animation.setDuration(getRemoveDuration()).alpha(0).scaleY(0.5f).setListener(new VpaListenerAdapter() { @Override public void onAnimationStart(View view) { dispatchRemoveStarting(holder); } @Override public void onAnimationEnd(View view) { animation.setListener(null); ViewCompat.setAlpha(view, 1); ViewCompat.setScaleY(view, 1); dispatchRemoveFinished(holder); removeAnimations.remove(holder); dispatchFinishedWhenDone(); } }).start(); removeAnimations.add(holder); } @Override public boolean animateAdd(final ViewHolder holder) { endAnimation(holder); ViewCompat.setAlpha(holder.itemView, 0); ViewCompat.setScaleY(holder.itemView, 0.5f); pendingAdditions.add(holder); return true; } private void animateAddImpl(final ViewHolder holder) { final View view = holder.itemView; addAnimations.add(holder); final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view); animation.alpha(1).scaleY(1).setDuration(getAddDuration()).setListener(new VpaListenerAdapter() { @Override public void onAnimationStart(View view) { dispatchAddStarting(holder); } @Override public void onAnimationCancel(View view) { ViewCompat.setAlpha(view, 1); ViewCompat.setScaleY(view, 1); } @Override public void onAnimationEnd(View view) { animation.setListener(null); dispatchAddFinished(holder); addAnimations.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); } pendingMoves.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. moveAnimations.add(holder); final ViewPropertyAnimatorCompat animation = ViewCompat.animate(view); 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); moveAnimations.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); } pendingChanges.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.itemView; final ViewHolder newHolder = changeInfo.newHolder; final View newView = newHolder != null ? newHolder.itemView : null; changeAnimations.add(changeInfo.oldHolder); final ViewPropertyAnimatorCompat oldViewAnim = ViewCompat.animate(view).setDuration(getChangeDuration()); 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); changeAnimations.remove(changeInfo.oldHolder); dispatchFinishedWhenDone(); } }).start(); if (newView != null) { changeAnimations.add(changeInfo.newHolder); final ViewPropertyAnimatorCompat newViewAnimation = ViewCompat.animate(newView); 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); changeAnimations.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 = pendingMoves.size() - 1; i >= 0; i--) { MoveInfo moveInfo = pendingMoves.get(i); if (moveInfo.holder == item) { ViewCompat.setTranslationY(view, 0); ViewCompat.setTranslationX(view, 0); dispatchMoveFinished(item); pendingMoves.remove(item); } } endChangeAnimation(pendingChanges, item); if (pendingRemovals.remove(item)) { ViewCompat.setAlpha(view, 1); dispatchRemoveFinished(item); } if (pendingAdditions.remove(item)) { ViewCompat.setAlpha(view, 1); dispatchAddFinished(item); } for (int i = changesList.size() - 1; i >= 0; i--) { ArrayList<ChangeInfo> changes = changesList.get(i); endChangeAnimation(changes, item); if (changes.isEmpty()) { changesList.remove(changes); } } for (int i = movesList.size() - 1; i >= 0; i--) { ArrayList<MoveInfo> moves = movesList.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()) { movesList.remove(moves); } break; } } } for (int i = additionsList.size() - 1; i >= 0; i--) { ArrayList<ViewHolder> additions = additionsList.get(i); if (additions.remove(item)) { ViewCompat.setAlpha(view, 1); dispatchAddFinished(item); if (additions.isEmpty()) { additionsList.remove(additions); } } } // animations should be ended by the cancel above. if (removeAnimations.remove(item) && DEBUG) { throw new IllegalStateException( "after animation is cancelled, item should not be in " + "removeAnimations list"); } if (addAnimations.remove(item) && DEBUG) { throw new IllegalStateException( "after animation is cancelled, item should not be in " + "addAnimations list"); } if (changeAnimations.remove(item) && DEBUG) { throw new IllegalStateException( "after animation is cancelled, item should not be in " + "changeAnimations list"); } if (moveAnimations.remove(item) && DEBUG) { throw new IllegalStateException( "after animation is cancelled, item should not be in " + "moveAnimations list"); } dispatchFinishedWhenDone(); } @Override public boolean isRunning() { return (!pendingAdditions.isEmpty() || !pendingChanges.isEmpty() || !pendingMoves.isEmpty() || !pendingRemovals.isEmpty() || !moveAnimations.isEmpty() || !removeAnimations.isEmpty() || !addAnimations.isEmpty() || !changeAnimations.isEmpty() || !movesList.isEmpty() || !additionsList.isEmpty() || !changesList.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 = pendingMoves.size(); for (int i = count - 1; i >= 0; i--) { MoveInfo item = pendingMoves.get(i); View view = item.holder.itemView; ViewCompat.setTranslationY(view, 0); ViewCompat.setTranslationX(view, 0); dispatchMoveFinished(item.holder); pendingMoves.remove(i); } count = pendingRemovals.size(); for (int i = count - 1; i >= 0; i--) { ViewHolder item = pendingRemovals.get(i); dispatchRemoveFinished(item); pendingRemovals.remove(i); } count = pendingAdditions.size(); for (int i = count - 1; i >= 0; i--) { ViewHolder item = pendingAdditions.get(i); View view = item.itemView; ViewCompat.setAlpha(view, 1); dispatchAddFinished(item); pendingAdditions.remove(i); } count = pendingChanges.size(); for (int i = count - 1; i >= 0; i--) { endChangeAnimationIfNecessary(pendingChanges.get(i)); } pendingChanges.clear(); if (!isRunning()) { return; } int listCount = movesList.size(); for (int i = listCount - 1; i >= 0; i--) { ArrayList<MoveInfo> moves = movesList.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()) { movesList.remove(moves); } } } listCount = additionsList.size(); for (int i = listCount - 1; i >= 0; i--) { ArrayList<ViewHolder> additions = additionsList.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()) { additionsList.remove(additions); } } } listCount = changesList.size(); for (int i = listCount - 1; i >= 0; i--) { ArrayList<ChangeInfo> changes = changesList.get(i); count = changes.size(); for (int j = count - 1; j >= 0; j--) { endChangeAnimationIfNecessary(changes.get(j)); if (changes.isEmpty()) { changesList.remove(changes); } } } cancelAll(removeAnimations); cancelAll(moveAnimations); cancelAll(addAnimations); cancelAll(changeAnimations); 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) { } } }