Java tutorial
/* * Copyright (C) 2013 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 android.transitions.everywhere; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.animation.TimeInterpolator; import android.annotation.TargetApi; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Path; import android.graphics.Rect; import android.os.Build; import android.support.v4.util.LongSparseArray; import android.transitions.everywhere.utils.AnimatorUtils; import android.transitions.everywhere.utils.ArrayMap; import android.transitions.everywhere.utils.Objects; import android.transitions.everywhere.utils.ViewUtils; import android.util.AttributeSet; import android.util.Log; import android.util.SparseArray; import android.view.InflateException; import android.view.SurfaceView; import android.view.TextureView; import android.view.View; import android.view.ViewGroup; import android.view.ViewOverlay; import android.view.animation.AnimationUtils; import android.widget.ListView; import android.widget.Spinner; import java.util.ArrayList; import java.util.List; import java.util.StringTokenizer; /** * A Transition holds information about animations that will be run on its * targets during a scene change. Subclasses of this abstract class may * choreograph several child transitions ({@link TransitionSet} or they may * perform custom animations themselves. Any Transition has two main jobs: * (1) capture property values, and (2) play animations based on changes to * captured property values. A custom transition knows what property values * on View objects are of interest to it, and also knows how to animate * changes to those values. For example, the {@link Fade} transition tracks * changes to visibility-related properties and is able to construct and run * animations that fade items in or out based on changes to those properties. * <p/> * <p>Note: Transitions may not work correctly with either {@link SurfaceView} * or {@link TextureView}, due to the way that these views are displayed * on the screen. For SurfaceView, the problem is that the view is updated from * a non-UI thread, so changes to the view due to transitions (such as moving * and resizing the view) may be out of sync with the display inside those bounds. * TextureView is more compatible with transitions in general, but some * specific transitions (such as {@link Fade}) may not be compatible * with TextureView because they rely on {@link ViewOverlay} functionality, * which does not currently work with TextureView.</p> * <p/> * <p>Transitions can be declared in XML resource files inside the <code>res/transition</code> * directory. Transition resources consist of a tag name for one of the Transition * subclasses along with attributes to define some of the attributes of that transition. * For example, here is a minimal resource file that declares a {@link ChangeBounds} transition:</p> * <p/> * {@sample development/samples/ApiDemos/res/transition/changebounds.xml ChangeBounds} * <p/> * <p>Note that attributes for the transition are not required, just as they are * optional when declared in code; Transitions created from XML resources will use * the same defaults as their code-created equivalents. Here is a slightly more * elaborate example which declares a {@link TransitionSet} transition with * {@link ChangeBounds} and {@link Fade} child transitions:</p> * <p/> * {@sample * development/samples/ApiDemos/res/transition/changebounds_fadeout_sequential.xml TransitionSet} * <p/> * <p>This TransitionSet contains {@link @hidden/Explode} for visibility, * {@link ChangeBounds}, {@link ChangeTransform}, * and {@link ChangeClipBounds} and * {@link ChangeImageTransform}:</p> * * {@sample development/samples/ApiDemos/res/transition/explode_move_together.xml MultipleTransform} * * <p>Custom transition classes may be instantiated with a <code>transition</code> tag:</p> * <pre><transition class="my.app.transition.CustomTransition"/></pre> * <p>Custom transition classes loaded from XML must have a public nullary (no argument) * constructor.</p> * <p/> * <p>In this example, the transitionOrdering attribute is used on the TransitionSet * object to change from the default {@link TransitionSet#ORDERING_TOGETHER} behavior * to be {@link TransitionSet#ORDERING_SEQUENTIAL} instead. Also, the {@link Fade} * transition uses a fadingMode of {@link Fade#OUT} instead of the default * out-in behavior. Finally, note the use of the <code>targets</code> sub-tag, which * takes a set of {@link android.transitions.everywhere.R.styleable#TransitionTarget target} tags, each * of which lists a specific <code>targetId</code>, <code>targetClass</code>, * <code>targetName</code>, <code>excludeId</code>, <code>excludeClass</code>, or * <code>excludeName</code>, which this transition acts upon. * Use of targets is optional, but can be used to either limit the time spent checking * attributes on unchanging views, or limiting the types of animations run on specific views. * In this case, we know that only the <code>grayscaleContainer</code> will be * disappearing, so we choose to limit the {@link Fade} transition to only that view.</p> * <p/> * Further information on XML resource descriptions for transitions can be found for * {@link android.transitions.everywhere.R.styleable#Transition}, {@link android.transitions.everywhere.R.styleable#TransitionSet}, * {@link android.transitions.everywhere.R.styleable#TransitionTarget}, and {@link android.transitions.everywhere.R.styleable#Fade}, * {@link android.transitions.everywhere.R.styleable#Slide}, and {@link android.transitions.everywhere.R.styleable#ChangeTransform}. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB) public abstract class Transition implements Cloneable { private static final String LOG_TAG = "Transition"; protected static final boolean DBG = false; /** * With {@link #setMatchOrder(int...)}, chooses to match by View instance. */ public static final int MATCH_INSTANCE = 0x1; private static final int MATCH_FIRST = MATCH_INSTANCE; /** * With {@link #setMatchOrder(int...)}, chooses to match by * {@link android.view.View#getTransitionName()}. Null names will not be matched. */ public static final int MATCH_NAME = 0x2; /** * With {@link #setMatchOrder(int...)}, chooses to match by * {@link android.view.View#getId()}. Negative IDs will not be matched. */ public static final int MATCH_ID = 0x3; /** * With {@link #setMatchOrder(int...)}, chooses to match by the {@link android.widget.Adapter} * item id. When {@link android.widget.Adapter#hasStableIds()} returns false, no match * will be made for items. */ public static final int MATCH_ITEM_ID = 0x4; private static final int MATCH_LAST = MATCH_ITEM_ID; private static final String MATCH_INSTANCE_STR = "instance"; private static final String MATCH_NAME_STR = "name"; /** To be removed before L release */ private static final String MATCH_VIEW_NAME_STR = "viewName"; private static final String MATCH_ID_STR = "id"; private static final String MATCH_ITEM_ID_STR = "itemId"; private static final int[] DEFAULT_MATCH_ORDER = { MATCH_NAME, MATCH_INSTANCE, MATCH_ID, MATCH_ITEM_ID, }; private static final PathMotion STRAIGHT_PATH_MOTION = new PathMotion() { @Override public Path getPath(float startX, float startY, float endX, float endY) { Path path = new Path(); path.moveTo(startX, startY); path.lineTo(endX, endY); return path; } }; private String mName = ((Object) this).getClass().getName(); long mStartDelay = -1; long mDuration = -1; TimeInterpolator mInterpolator = null; ArrayList<Integer> mTargetIds = new ArrayList<Integer>(); ArrayList<View> mTargets = new ArrayList<View>(); ArrayList<String> mTargetNames = null; ArrayList<Class> mTargetTypes = null; ArrayList<Integer> mTargetIdExcludes = null; ArrayList<View> mTargetExcludes = null; ArrayList<Class> mTargetTypeExcludes = null; ArrayList<String> mTargetNameExcludes = null; ArrayList<Integer> mTargetIdChildExcludes = null; ArrayList<View> mTargetChildExcludes = null; ArrayList<Class> mTargetTypeChildExcludes = null; private TransitionValuesMaps mStartValues = new TransitionValuesMaps(); private TransitionValuesMaps mEndValues = new TransitionValuesMaps(); TransitionSet mParent = null; private int[] mMatchOrder = DEFAULT_MATCH_ORDER; ArrayList<TransitionValues> mStartValuesList; // only valid after playTransition starts ArrayList<TransitionValues> mEndValuesList; // only valid after playTransitions starts // Per-animator information used for later canceling when future transitions overlap private static ThreadLocal<ArrayMap<Animator, AnimationInfo>> sRunningAnimators = new ThreadLocal<ArrayMap<Animator, AnimationInfo>>(); // Scene Root is set at createAnimator() time in the cloned Transition ViewGroup mSceneRoot = null; // Whether removing views from their parent is possible. This is only for views // in the start scene, which are no longer in the view hierarchy. This property // is determined by whether the previous Scene was created from a layout // resource, and thus the views from the exited scene are going away anyway // and can be removed as necessary to achieve a particular effect, such as // removing them from parents to add them to overlays. boolean mCanRemoveViews = false; // Track all animators in use in case the transition gets canceled and needs to // cancel running animators private ArrayList<Animator> mCurrentAnimators = new ArrayList<Animator>(); // Number of per-target instances of this Transition currently running. This count is // determined by calls to start() and end() int mNumInstances = 0; // Whether this transition is currently paused, due to a call to pause() boolean mPaused = false; // Whether this transition has ended. Used to avoid pause/resume on transitions // that have completed private boolean mEnded = false; // The set of listeners to be sent transition lifecycle events. ArrayList<TransitionListener> mListeners = null; // The set of animators collected from calls to createAnimator(), // to be run in runAnimators() ArrayList<Animator> mAnimators = new ArrayList<Animator>(); // The function for calculating the Animation start delay. TransitionPropagation mPropagation; // The rectangular region for Transitions like Explode and TransitionPropagations // like CircularPropagation EpicenterCallback mEpicenterCallback; // For Fragment shared element transitions, linking views explicitly by mismatching // transitionNames. ArrayMap<String, String> mNameOverrides; // The function used to interpolate along two-dimensional points. Typically used // for adding curves to x/y View motion. private PathMotion mPathMotion = STRAIGHT_PATH_MOTION; /** * Constructs a Transition object with no target objects. A transition with * no targets defaults to running on all target objects in the scene hierarchy * (if the transition is not contained in a TransitionSet), or all target * objects passed down from its parent (if it is in a TransitionSet). */ public Transition() { } /** * Perform inflation from XML and apply a class-specific base style from a * theme attribute or style resource. This constructor of Transition allows * subclasses to use their own base style when they are inflating. * * @param context The Context the transition is running in, through which it can * access the current theme, resources, etc. * @param attrs The attributes of the XML tag that is inflating the transition. */ public Transition(Context context, AttributeSet attrs) { TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.Transition); long duration = a.getInt(R.styleable.Transition_duration, -1); if (duration >= 0) { setDuration(duration); } else { duration = a.getInt(R.styleable.Transition_android_duration, -1); if (duration >= 0) { setDuration(duration); } } long startDelay = a.getInt(R.styleable.Transition_startDelay, -1); if (startDelay > 0) { setStartDelay(startDelay); } int resID = a.getResourceId(R.styleable.Transition_interpolator, 0); if (resID > 0) { setInterpolator(AnimationUtils.loadInterpolator(context, resID)); } else { resID = a.getResourceId(R.styleable.Transition_android_interpolator, 0); if (resID > 0) { setInterpolator(AnimationUtils.loadInterpolator(context, resID)); } } String matchOrder = a.getString(R.styleable.Transition_matchOrder); if (matchOrder != null) { setMatchOrder(parseMatchOrder(matchOrder)); } a.recycle(); } private static int[] parseMatchOrder(String matchOrderString) { StringTokenizer st = new StringTokenizer(matchOrderString, ","); int matches[] = new int[st.countTokens()]; int index = 0; while (st.hasMoreTokens()) { String token = st.nextToken().trim(); if (MATCH_ID_STR.equalsIgnoreCase(token)) { matches[index] = Transition.MATCH_ID; } else if (MATCH_INSTANCE_STR.equalsIgnoreCase(token)) { matches[index] = Transition.MATCH_INSTANCE; } else if (MATCH_NAME_STR.equalsIgnoreCase(token)) { matches[index] = Transition.MATCH_NAME; } else if (MATCH_VIEW_NAME_STR.equalsIgnoreCase(token)) { matches[index] = Transition.MATCH_NAME; } else if (MATCH_ITEM_ID_STR.equalsIgnoreCase(token)) { matches[index] = Transition.MATCH_ITEM_ID; } else if (token.isEmpty()) { int[] smallerMatches = new int[matches.length - 1]; System.arraycopy(matches, 0, smallerMatches, 0, index); matches = smallerMatches; index--; } else { throw new InflateException("Unknown match type in matchOrder: '" + token + "'"); } index++; } return matches; } /** * Sets the duration of this transition. By default, there is no duration * (indicated by a negative number), which means that the Animator created by * the transition will have its own specified duration. If the duration of a * Transition is set, that duration will override the Animator duration. * * @param duration The length of the animation, in milliseconds. * @return This transition object. * @attr ref android.R.styleable#Transition_duration */ public Transition setDuration(long duration) { mDuration = duration; return this; } /** * Returns the duration set on this transition. If no duration has been set, * the returned value will be negative, indicating that resulting animators will * retain their own durations. * * @return The duration set on this transition, in milliseconds, if one has been * set, otherwise returns a negative number. */ public long getDuration() { return mDuration; } /** * Sets the startDelay of this transition. By default, there is no delay * (indicated by a negative number), which means that the Animator created by * the transition will have its own specified startDelay. If the delay of a * Transition is set, that delay will override the Animator delay. * * @param startDelay The length of the delay, in milliseconds. * @return This transition object. * @attr ref android.R.styleable#Transition_startDelay */ public Transition setStartDelay(long startDelay) { mStartDelay = startDelay; return this; } /** * Returns the startDelay set on this transition. If no startDelay has been set, * the returned value will be negative, indicating that resulting animators will * retain their own startDelays. * * @return The startDelay set on this transition, in milliseconds, if one has * been set, otherwise returns a negative number. */ public long getStartDelay() { return mStartDelay; } /** * Sets the interpolator of this transition. By default, the interpolator * is null, which means that the Animator created by the transition * will have its own specified interpolator. If the interpolator of a * Transition is set, that interpolator will override the Animator interpolator. * * @param interpolator The time interpolator used by the transition * @return This transition object. * @attr ref android.R.styleable#Transition_interpolator */ public Transition setInterpolator(TimeInterpolator interpolator) { mInterpolator = interpolator; return this; } /** * Returns the interpolator set on this transition. If no interpolator has been set, * the returned value will be null, indicating that resulting animators will * retain their own interpolators. * * @return The interpolator set on this transition, if one has been set, otherwise * returns null. */ public TimeInterpolator getInterpolator() { return mInterpolator; } /** * Returns the set of property names used stored in the {@link TransitionValues} * object passed into {@link #captureStartValues(TransitionValues)} that * this transition cares about for the purposes of canceling overlapping animations. * When any transition is started on a given scene root, all transitions * currently running on that same scene root are checked to see whether the * properties on which they based their animations agree with the end values of * the same properties in the new transition. If the end values are not equal, * then the old animation is canceled since the new transition will start a new * animation to these new values. If the values are equal, the old animation is * allowed to continue and no new animation is started for that transition. * <p/> * <p>A transition does not need to override this method. However, not doing so * will mean that the cancellation logic outlined in the previous paragraph * will be skipped for that transition, possibly leading to artifacts as * old transitions and new transitions on the same targets run in parallel, * animating views toward potentially different end values.</p> * * @return An array of property names as described in the class documentation for * {@link TransitionValues}. The default implementation returns <code>null</code>. */ public String[] getTransitionProperties() { return null; } /** * This method creates an animation that will be run for this transition * given the information in the startValues and endValues structures captured * earlier for the start and end scenes. Subclasses of Transition should override * this method. The method should only be called by the transition system; it is * not intended to be called from external classes. * <p/> * <p>This method is called by the transition's parent (all the way up to the * topmost Transition in the hierarchy) with the sceneRoot and start/end * values that the transition may need to set up initial target values * and construct an appropriate animation. For example, if an overall * Transition is a {@link TransitionSet} consisting of several * child transitions in sequence, then some of the child transitions may * want to set initial values on target views prior to the overall * Transition commencing, to put them in an appropriate state for the * delay between that start and the child Transition start time. For * example, a transition that fades an item in may wish to set the starting * alpha value to 0, to avoid it blinking in prior to the transition * actually starting the animation. This is necessary because the scene * change that triggers the Transition will automatically set the end-scene * on all target views, so a Transition that wants to animate from a * different value should set that value prior to returning from this method.</p> * <p/> * <p>Additionally, a Transition can perform logic to determine whether * the transition needs to run on the given target and start/end values. * For example, a transition that resizes objects on the screen may wish * to avoid running for views which are not present in either the start * or end scenes.</p> * <p/> * <p>If there is an animator created and returned from this method, the * transition mechanism will apply any applicable duration, startDelay, * and interpolator to that animation and start it. A return value of * <code>null</code> indicates that no animation should run. The default * implementation returns null.</p> * <p/> * <p>The method is called for every applicable target object, which is * stored in the {@link TransitionValues#view} field.</p> * * @param sceneRoot The root of the transition hierarchy. * @param startValues The values for a specific target in the start scene. * @param endValues The values for the target in the end scene. * @return A Animator to be started at the appropriate time in the * overall transition for this scene change. A null value means no animation * should be run. */ public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues, TransitionValues endValues) { return null; } /** * Sets the order in which Transition matches View start and end values. * <p> * The default behavior is to match first by {@link android.view.View#getTransitionName()}, * then by View instance, then by {@link android.view.View#getId()} and finally * by its item ID if it is in a direct child of ListView. The caller can * choose to have only some or all of the values of {@link #MATCH_INSTANCE}, * {@link #MATCH_NAME}, {@link #MATCH_ITEM_ID}, and {@link #MATCH_ID}. Only * the match algorithms supplied will be used to determine whether Views are the * the same in both the start and end Scene. Views that do not match will be considered * as entering or leaving the Scene. * </p> * @param matches A list of zero or more of {@link #MATCH_INSTANCE}, * {@link #MATCH_NAME}, {@link #MATCH_ITEM_ID}, and {@link #MATCH_ID}. * If none are provided, then the default match order will be set. */ public void setMatchOrder(int... matches) { if (matches == null || matches.length == 0) { mMatchOrder = DEFAULT_MATCH_ORDER; } else { for (int i = 0; i < matches.length; i++) { int match = matches[i]; if (!isValidMatch(match)) { throw new IllegalArgumentException("matches contains invalid value"); } if (alreadyContains(matches, i)) { throw new IllegalArgumentException("matches contains a duplicate value"); } } mMatchOrder = matches.clone(); } } private static boolean isValidMatch(int match) { return (match >= MATCH_FIRST && match <= MATCH_LAST); } private static boolean alreadyContains(int[] array, int searchIndex) { int value = array[searchIndex]; for (int i = 0; i < searchIndex; i++) { if (array[i] == value) { return true; } } return false; } /** * Match start/end values by View instance. Adds matched values to mStartValuesList * and mEndValuesList and removes them from unmatchedStart and unmatchedEnd. */ private void matchInstances(ArrayMap<View, TransitionValues> unmatchedStart, ArrayMap<View, TransitionValues> unmatchedEnd) { for (int i = unmatchedStart.size() - 1; i >= 0; i--) { View view = unmatchedStart.keyAt(i); TransitionValues end = unmatchedEnd.remove(view); if (end != null) { TransitionValues start = unmatchedStart.removeAt(i); mStartValuesList.add(start); mEndValuesList.add(end); } } } /** * Match start/end values by Adapter item ID. Adds matched values to mStartValuesList * and mEndValuesList and removes them from unmatchedStart and unmatchedEnd, using * startItemIds and endItemIds as a guide for which Views have unique item IDs. */ private void matchItemIds(ArrayMap<View, TransitionValues> unmatchedStart, ArrayMap<View, TransitionValues> unmatchedEnd, LongSparseArray<View> startItemIds, LongSparseArray<View> endItemIds) { int numStartIds = startItemIds.size(); for (int i = 0; i < numStartIds; i++) { View startView = startItemIds.valueAt(i); if (startView != null) { View endView = endItemIds.get(startItemIds.keyAt(i)); if (endView != null) { TransitionValues startValues = unmatchedStart.get(startView); TransitionValues endValues = unmatchedEnd.get(endView); if (startValues != null && endValues != null) { mStartValuesList.add(startValues); mEndValuesList.add(endValues); unmatchedStart.remove(startView); unmatchedEnd.remove(endView); } } } } } /** * Match start/end values by Adapter view ID. Adds matched values to mStartValuesList * and mEndValuesList and removes them from unmatchedStart and unmatchedEnd, using * startIds and endIds as a guide for which Views have unique IDs. */ private void matchIds(ArrayMap<View, TransitionValues> unmatchedStart, ArrayMap<View, TransitionValues> unmatchedEnd, SparseArray<View> startIds, SparseArray<View> endIds) { int numStartIds = startIds.size(); for (int i = 0; i < numStartIds; i++) { View startView = startIds.valueAt(i); if (startView != null && isValidTarget(startView)) { View endView = endIds.get(startIds.keyAt(i)); if (endView != null && isValidTarget(endView)) { TransitionValues startValues = unmatchedStart.get(startView); TransitionValues endValues = unmatchedEnd.get(endView); if (startValues != null && endValues != null) { mStartValuesList.add(startValues); mEndValuesList.add(endValues); unmatchedStart.remove(startView); unmatchedEnd.remove(endView); } } } } } /** * Match start/end values by Adapter transitionName. Adds matched values to mStartValuesList * and mEndValuesList and removes them from unmatchedStart and unmatchedEnd, using * startNames and endNames as a guide for which Views have unique transitionNames. */ private void matchNames(ArrayMap<View, TransitionValues> unmatchedStart, ArrayMap<View, TransitionValues> unmatchedEnd, ArrayMap<String, View> startNames, ArrayMap<String, View> endNames) { int numStartNames = startNames.size(); for (int i = 0; i < numStartNames; i++) { View startView = startNames.valueAt(i); if (startView != null && isValidTarget(startView)) { View endView = endNames.get(startNames.keyAt(i)); if (endView != null && isValidTarget(endView)) { TransitionValues startValues = unmatchedStart.get(startView); TransitionValues endValues = unmatchedEnd.get(endView); if (startValues != null && endValues != null) { mStartValuesList.add(startValues); mEndValuesList.add(endValues); unmatchedStart.remove(startView); unmatchedEnd.remove(endView); } } } } } /** * Adds all values from unmatchedStart and unmatchedEnd to mStartValuesList and mEndValuesList, * assuming that there is no match between values in the list. */ private void addUnmatched(ArrayMap<View, TransitionValues> unmatchedStart, ArrayMap<View, TransitionValues> unmatchedEnd) { // Views that only exist in the start Scene for (int i = 0; i < unmatchedStart.size(); i++) { mStartValuesList.add(unmatchedStart.valueAt(i)); mEndValuesList.add(null); } // Views that only exist in the end Scene for (int i = 0; i < unmatchedEnd.size(); i++) { mEndValuesList.add(unmatchedEnd.valueAt(i)); mStartValuesList.add(null); } } private void matchStartAndEnd(TransitionValuesMaps startValues, TransitionValuesMaps endValues) { ArrayMap<View, TransitionValues> unmatchedStart = new ArrayMap<View, TransitionValues>( startValues.viewValues); ArrayMap<View, TransitionValues> unmatchedEnd = new ArrayMap<View, TransitionValues>(endValues.viewValues); for (int i = 0; i < mMatchOrder.length; i++) { switch (mMatchOrder[i]) { case MATCH_INSTANCE: matchInstances(unmatchedStart, unmatchedEnd); break; case MATCH_NAME: matchNames(unmatchedStart, unmatchedEnd, startValues.nameValues, endValues.nameValues); break; case MATCH_ID: matchIds(unmatchedStart, unmatchedEnd, startValues.idValues, endValues.idValues); break; case MATCH_ITEM_ID: matchItemIds(unmatchedStart, unmatchedEnd, startValues.itemIdValues, endValues.itemIdValues); break; } } addUnmatched(unmatchedStart, unmatchedEnd); } /** * This method, essentially a wrapper around all calls to createAnimator for all * possible target views, is called with the entire set of start/end * values. The implementation in Transition iterates through these lists * and calls {@link #createAnimator(ViewGroup, TransitionValues, TransitionValues)} * with each set of start/end values on this transition. The * TransitionSet subclass overrides this method and delegates it to * each of its children in succession. * * @hide */ protected void createAnimators(ViewGroup sceneRoot, TransitionValuesMaps startValues, TransitionValuesMaps endValues, ArrayList<TransitionValues> startValuesList, ArrayList<TransitionValues> endValuesList) { if (DBG) { Log.d(LOG_TAG, "createAnimators() for " + this); } ArrayMap<Animator, AnimationInfo> runningAnimators = getRunningAnimators(); long minStartDelay = Long.MAX_VALUE; int minAnimator = mAnimators.size(); SparseArray<Long> startDelays = new SparseArray<Long>(); int startValuesListCount = startValuesList.size(); for (int i = 0; i < startValuesListCount; ++i) { TransitionValues start = startValuesList.get(i); TransitionValues end = endValuesList.get(i); if (start != null && !start.targetedTransitions.contains(this)) { start = null; } if (end != null && !end.targetedTransitions.contains(this)) { end = null; } if (start == null && end == null) { continue; } // Only bother trying to animate with values that differ between start/end boolean isChanged = start == null || end == null || areValuesChanged(start, end); if (isChanged) { if (DBG) { View view = (end != null) ? end.view : start.view; Log.d(LOG_TAG, " differing start/end values for view " + view); if (start == null || end == null) { Log.d(LOG_TAG, " " + ((start == null) ? "start null, end non-null" : "start non-null, end null")); } else { for (String key : start.values.keySet()) { Object startValue = start.values.get(key); Object endValue = end.values.get(key); if (startValue != endValue && !startValue.equals(endValue)) { Log.d(LOG_TAG, " " + key + ": start(" + startValue + "), end(" + endValue + ")"); } } } } // TODO: what to do about targetIds and itemIds? Animator animator = createAnimator(sceneRoot, start, end); if (animator != null) { // Save animation info for future cancellation purposes View view = null; TransitionValues infoValues = null; if (end != null) { view = end.view; String[] properties = getTransitionProperties(); if (view != null && properties != null && properties.length > 0) { infoValues = new TransitionValues(); infoValues.view = view; TransitionValues newValues = endValues.viewValues.get(view); if (newValues != null) { for (int j = 0; j < properties.length; ++j) { infoValues.values.put(properties[j], newValues.values.get(properties[j])); } } int numExistingAnims = runningAnimators.size(); for (int j = 0; j < numExistingAnims; ++j) { Animator anim = runningAnimators.keyAt(j); AnimationInfo info = runningAnimators.get(anim); if (info.values != null && info.view == view && ((info.name == null && getName() == null) || info.name.equals(getName()))) { if (info.values.equals(infoValues)) { // Favor the old animator animator = null; break; } } } } } else { view = (start != null) ? start.view : null; } if (animator != null) { if (mPropagation != null) { long delay = mPropagation.getStartDelay(sceneRoot, this, start, end); startDelays.put(mAnimators.size(), delay); minStartDelay = Math.min(delay, minStartDelay); } AnimationInfo info = new AnimationInfo(view, getName(), this, ViewUtils.getWindowId(sceneRoot), infoValues); runningAnimators.put(animator, info); mAnimators.add(animator); } } } } if (minStartDelay != 0) { for (int i = 0; i < startDelays.size(); i++) { int index = startDelays.keyAt(i); Animator animator = mAnimators.get(index); long delay = startDelays.valueAt(i) - minStartDelay + animator.getStartDelay(); animator.setStartDelay(delay); } } } /** * Internal utility method for checking whether a given view/id * is valid for this transition, where "valid" means that either * the Transition has no target/targetId list (the default, in which * cause the transition should act on all views in the hiearchy), or * the given view is in the target list or the view id is in the * targetId list. If the target parameter is null, then the target list * is not checked (this is in the case of ListView items, where the * views are ignored and only the ids are used). */ boolean isValidTarget(View target) { int targetId = target.getId(); if (mTargetIdExcludes != null && mTargetIdExcludes.contains(targetId)) { return false; } if (mTargetExcludes != null && mTargetExcludes.contains(target)) { return false; } if (mTargetTypeExcludes != null && target != null) { int numTypes = mTargetTypeExcludes.size(); for (int i = 0; i < numTypes; ++i) { Class type = mTargetTypeExcludes.get(i); if (type.isInstance(target)) { return false; } } } final String transitionName = ViewUtils.getTransitionName(target); if (mTargetNameExcludes != null && target != null && transitionName != null) { if (mTargetNameExcludes.contains(transitionName)) { return false; } } if (mTargetIds.size() == 0 && mTargets.size() == 0 && (mTargetTypes == null || mTargetTypes.isEmpty()) && (mTargetNames == null || mTargetNames.isEmpty())) { return true; } if (mTargetIds.contains(targetId) || mTargets.contains(target)) { return true; } if (mTargetNames != null && mTargetNames.contains(transitionName)) { return true; } if (mTargetTypes != null) { for (int i = 0; i < mTargetTypes.size(); ++i) { if (mTargetTypes.get(i).isInstance(target)) { return true; } } } return false; } private static ArrayMap<Animator, AnimationInfo> getRunningAnimators() { ArrayMap<Animator, AnimationInfo> runningAnimators = sRunningAnimators.get(); if (runningAnimators == null) { runningAnimators = new ArrayMap<Animator, AnimationInfo>(); sRunningAnimators.set(runningAnimators); } return runningAnimators; } /** * This is called internally once all animations have been set up by the * transition hierarchy. * * @hide */ protected void runAnimators() { if (DBG) { Log.d(LOG_TAG, "runAnimators() on " + this); } start(); ArrayMap<Animator, AnimationInfo> runningAnimators = getRunningAnimators(); // Now start every Animator that was previously created for this transition for (Animator anim : mAnimators) { if (DBG) { Log.d(LOG_TAG, " anim: " + anim); } if (runningAnimators.containsKey(anim)) { start(); runAnimator(anim, runningAnimators); } } mAnimators.clear(); end(); } private void runAnimator(Animator animator, final ArrayMap<Animator, AnimationInfo> runningAnimators) { if (animator != null) { // TODO: could be a single listener instance for all of them since it uses the param animator.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationStart(Animator animation) { mCurrentAnimators.add(animation); } @Override public void onAnimationEnd(Animator animation) { runningAnimators.remove(animation); mCurrentAnimators.remove(animation); } }); animate(animator); } } /** * Captures the values in the start scene for the properties that this * transition monitors. These values are then passed as the startValues * structure in a later call to * {@link #createAnimator(ViewGroup, TransitionValues, TransitionValues)}. * The main concern for an implementation is what the * properties are that the transition cares about and what the values are * for all of those properties. The start and end values will be compared * later during the * {@link #createAnimator(android.view.ViewGroup, TransitionValues, TransitionValues)} * method to determine what, if any, animations, should be run. * <p/> * <p>Subclasses must implement this method. The method should only be called by the * transition system; it is not intended to be called from external classes.</p> * * @param transitionValues The holder for any values that the Transition * wishes to store. Values are stored in the <code>values</code> field * of this TransitionValues object and are keyed from * a String value. For example, to store a view's rotation value, * a transition might call * <code>transitionValues.values.put("appname:transitionname:rotation", * view.getRotation())</code>. The target view will already be stored in * the transitionValues structure when this method is called. * @see #captureEndValues(TransitionValues) * @see #createAnimator(ViewGroup, TransitionValues, TransitionValues) */ public abstract void captureStartValues(TransitionValues transitionValues); /** * Captures the values in the end scene for the properties that this * transition monitors. These values are then passed as the endValues * structure in a later call to * {@link #createAnimator(ViewGroup, TransitionValues, TransitionValues)}. * The main concern for an implementation is what the * properties are that the transition cares about and what the values are * for all of those properties. The start and end values will be compared * later during the * {@link #createAnimator(android.view.ViewGroup, TransitionValues, TransitionValues)} * method to determine what, if any, animations, should be run. * <p/> * <p>Subclasses must implement this method. The method should only be called by the * transition system; it is not intended to be called from external classes.</p> * * @param transitionValues The holder for any values that the Transition * wishes to store. Values are stored in the <code>values</code> field * of this TransitionValues object and are keyed from * a String value. For example, to store a view's rotation value, * a transition might call * <code>transitionValues.values.put("appname:transitionname:rotation", * view.getRotation())</code>. The target view will already be stored in * the transitionValues structure when this method is called. * @see #captureStartValues(TransitionValues) * @see #createAnimator(ViewGroup, TransitionValues, TransitionValues) */ public abstract void captureEndValues(TransitionValues transitionValues); /** * Adds the id of a target view that this Transition is interested in * animating. By default, there are no targetIds, and a Transition will * listen for changes on every view in the hierarchy below the sceneRoot * of the Scene being transitioned into. Setting targetIds constrains * the Transition to only listen for, and act on, views with these IDs. * Views with different IDs, or no IDs whatsoever, will be ignored. * <p/> * <p>Note that using ids to specify targets implies that ids should be unique * within the view hierarchy underneat the scene root.</p> * * @param targetId The id of a target view, must be a positive number. * @return The Transition to which the targetId is added. * Returning the same object makes it easier to chain calls during * construction, such as * <code>transitionSet.addTransitions(new Fade()).addTarget(someId);</code> * @see View#getId() */ public Transition addTarget(int targetId) { if (targetId > 0) { mTargetIds.add(targetId); } return this; } /** * Adds the transitionName of a target view that this Transition is interested in * animating. By default, there are no targetNames, and a Transition will * listen for changes on every view in the hierarchy below the sceneRoot * of the Scene being transitioned into. Setting targetNames constrains * the Transition to only listen for, and act on, views with these transitionNames. * Views with different transitionNames, or no transitionName whatsoever, will be ignored. * * <p>Note that transitionNames should be unique within the view hierarchy.</p> * * @see android.view.View#getTransitionName() * @param targetName The transitionName of a target view, must be non-null. * @return The Transition to which the target transitionName is added. * Returning the same object makes it easier to chain calls during * construction, such as * <code>transitionSet.addTransitions(new Fade()).addTarget(someName);</code> */ public Transition addTarget(String targetName) { if (targetName != null) { if (mTargetNames == null) { mTargetNames = new ArrayList<String>(); } mTargetNames.add(targetName); } return this; } /** * Adds the Class of a target view that this Transition is interested in * animating. By default, there are no targetTypes, and a Transition will * listen for changes on every view in the hierarchy below the sceneRoot * of the Scene being transitioned into. Setting targetTypes constrains * the Transition to only listen for, and act on, views with these classes. * Views with different classes will be ignored. * * <p>Note that any View that can be cast to targetType will be included, so * if targetType is <code>View.class</code>, all Views will be included.</p> * * @see #addTarget(int) * @see #addTarget(android.view.View) * @see #excludeTarget(Class, boolean) * @see #excludeChildren(Class, boolean) * * @param targetType The type to include when running this transition. * @return The Transition to which the target class was added. * Returning the same object makes it easier to chain calls during * construction, such as * <code>transitionSet.addTransitions(new Fade()).addTarget(ImageView.class);</code> */ public Transition addTarget(Class targetType) { if (targetType != null) { if (mTargetTypes == null) { mTargetTypes = new ArrayList<Class>(); } mTargetTypes.add(targetType); } return this; } /** * Removes the given targetName from the list of transitionNames that this Transition * is interested in animating. * * @param targetName The transitionName of a target view, must not be null. * @return The Transition from which the targetName is removed. * Returning the same object makes it easier to chain calls during * construction, such as * <code>transitionSet.addTransitions(new Fade()).removeTargetName(someName);</code> */ public Transition removeTarget(String targetName) { if (targetName != null && mTargetNames != null) { mTargetNames.remove(targetName); } return this; } /** * Removes the given targetId from the list of ids that this Transition * is interested in animating. * * @param targetId The id of a target view, must be a positive number. * @return The Transition from which the targetId is removed. * Returning the same object makes it easier to chain calls during * construction, such as * <code>transitionSet.addTransitions(new Fade()).removeTargetId(someId);</code> */ public Transition removeTarget(int targetId) { if (targetId > 0) { mTargetIds.remove(targetId); } return this; } /** * Whether to add the given id to the list of target ids to exclude from this * transition. The <code>exclude</code> parameter specifies whether the target * should be added to or removed from the excluded list. * <p/> * <p>Excluding targets is a general mechanism for allowing transitions to run on * a view hierarchy while skipping target views that should not be part of * the transition. For example, you may want to avoid animating children * of a specific ListView or Spinner. Views can be excluded either by their * id, or by their instance reference, or by the Class of that view * (eg, {@link Spinner}).</p> * * @param targetId The id of a target to ignore when running this transition. * @param exclude Whether to add the target to or remove the target from the * current list of excluded targets. * @return This transition object. * @see #excludeChildren(int, boolean) * @see #excludeTarget(View, boolean) * @see #excludeTarget(Class, boolean) */ public Transition excludeTarget(int targetId, boolean exclude) { if (targetId >= 0) { mTargetIdExcludes = excludeObject(mTargetIdExcludes, targetId, exclude); } return this; } /** * Whether to add the given transitionName to the list of target transitionNames to exclude * from this transition. The <code>exclude</code> parameter specifies whether the target * should be added to or removed from the excluded list. * * <p>Excluding targets is a general mechanism for allowing transitions to run on * a view hierarchy while skipping target views that should not be part of * the transition. For example, you may want to avoid animating children * of a specific ListView or Spinner. Views can be excluded by their * id, their instance reference, their transitionName, or by the Class of that view * (eg, {@link Spinner}).</p> * * @see #excludeTarget(View, boolean) * @see #excludeTarget(int, boolean) * @see #excludeTarget(Class, boolean) * * @param targetName The name of a target to ignore when running this transition. * @param exclude Whether to add the target to or remove the target from the * current list of excluded targets. * @return This transition object. */ public Transition excludeTarget(String targetName, boolean exclude) { mTargetNameExcludes = excludeObject(mTargetNameExcludes, targetName, exclude); return this; } /** * Whether to add the children of the given id to the list of targets to exclude * from this transition. The <code>exclude</code> parameter specifies whether * the children of the target should be added to or removed from the excluded list. * Excluding children in this way provides a simple mechanism for excluding all * children of specific targets, rather than individually excluding each * child individually. * <p/> * <p>Excluding targets is a general mechanism for allowing transitions to run on * a view hierarchy while skipping target views that should not be part of * the transition. For example, you may want to avoid animating children * of a specific ListView or Spinner. Views can be excluded either by their * id, or by their instance reference, or by the Class of that view * (eg, {@link Spinner}).</p> * * @param targetId The id of a target whose children should be ignored when running * this transition. * @param exclude Whether to add the target to or remove the target from the * current list of excluded-child targets. * @return This transition object. * @see #excludeTarget(int, boolean) * @see #excludeChildren(View, boolean) * @see #excludeChildren(Class, boolean) */ public Transition excludeChildren(int targetId, boolean exclude) { if (targetId >= 0) { mTargetIdChildExcludes = excludeObject(mTargetIdChildExcludes, targetId, exclude); } return this; } /** * Whether to add the given target to the list of targets to exclude from this * transition. The <code>exclude</code> parameter specifies whether the target * should be added to or removed from the excluded list. * <p/> * <p>Excluding targets is a general mechanism for allowing transitions to run on * a view hierarchy while skipping target views that should not be part of * the transition. For example, you may want to avoid animating children * of a specific ListView or Spinner. Views can be excluded either by their * id, or by their instance reference, or by the Class of that view * (eg, {@link Spinner}).</p> * * @param target The target to ignore when running this transition. * @param exclude Whether to add the target to or remove the target from the * current list of excluded targets. * @return This transition object. * @see #excludeChildren(View, boolean) * @see #excludeTarget(int, boolean) * @see #excludeTarget(Class, boolean) */ public Transition excludeTarget(View target, boolean exclude) { mTargetExcludes = excludeObject(mTargetExcludes, target, exclude); return this; } /** * Whether to add the children of given target to the list of target children * to exclude from this transition. The <code>exclude</code> parameter specifies * whether the target should be added to or removed from the excluded list. * <p/> * <p>Excluding targets is a general mechanism for allowing transitions to run on * a view hierarchy while skipping target views that should not be part of * the transition. For example, you may want to avoid animating children * of a specific ListView or Spinner. Views can be excluded either by their * id, or by their instance reference, or by the Class of that view * (eg, {@link Spinner}).</p> * * @param target The target to ignore when running this transition. * @param exclude Whether to add the target to or remove the target from the * current list of excluded targets. * @return This transition object. * @see #excludeTarget(View, boolean) * @see #excludeChildren(int, boolean) * @see #excludeChildren(Class, boolean) */ public Transition excludeChildren(View target, boolean exclude) { mTargetChildExcludes = excludeObject(mTargetChildExcludes, target, exclude); return this; } /** * Utility method to manage the boilerplate code that is the same whether we * are excluding targets or their children. */ private static <T> ArrayList<T> excludeObject(ArrayList<T> list, T target, boolean exclude) { if (target != null) { if (exclude) { list = ArrayListManager.add(list, target); } else { list = ArrayListManager.remove(list, target); } } return list; } /** * Whether to add the given type to the list of types to exclude from this * transition. The <code>exclude</code> parameter specifies whether the target * type should be added to or removed from the excluded list. * <p/> * <p>Excluding targets is a general mechanism for allowing transitions to run on * a view hierarchy while skipping target views that should not be part of * the transition. For example, you may want to avoid animating children * of a specific ListView or Spinner. Views can be excluded either by their * id, or by their instance reference, or by the Class of that view * (eg, {@link Spinner}).</p> * * @param type The type to ignore when running this transition. * @param exclude Whether to add the target type to or remove it from the * current list of excluded target types. * @return This transition object. * @see #excludeChildren(Class, boolean) * @see #excludeTarget(int, boolean) * @see #excludeTarget(View, boolean) */ public Transition excludeTarget(Class type, boolean exclude) { mTargetTypeExcludes = excludeObject(mTargetTypeExcludes, type, exclude); return this; } /** * Whether to add the given type to the list of types whose children should * be excluded from this transition. The <code>exclude</code> parameter * specifies whether the target type should be added to or removed from * the excluded list. * <p/> * <p>Excluding targets is a general mechanism for allowing transitions to run on * a view hierarchy while skipping target views that should not be part of * the transition. For example, you may want to avoid animating children * of a specific ListView or Spinner. Views can be excluded either by their * id, or by their instance reference, or by the Class of that view * (eg, {@link Spinner}).</p> * * @param type The type to ignore when running this transition. * @param exclude Whether to add the target type to or remove it from the * current list of excluded target types. * @return This transition object. * @see #excludeTarget(Class, boolean) * @see #excludeChildren(int, boolean) * @see #excludeChildren(View, boolean) */ public Transition excludeChildren(Class type, boolean exclude) { mTargetTypeChildExcludes = excludeObject(mTargetTypeChildExcludes, type, exclude); return this; } /** * Sets the target view instances that this Transition is interested in * animating. By default, there are no targets, and a Transition will * listen for changes on every view in the hierarchy below the sceneRoot * of the Scene being transitioned into. Setting targets constrains * the Transition to only listen for, and act on, these views. * All other views will be ignored. * <p/> * <p>The target list is like the {@link #addTarget(int) targetId} * list except this list specifies the actual View instances, not the ids * of the views. This is an important distinction when scene changes involve * view hierarchies which have been inflated separately; different views may * share the same id but not actually be the same instance. If the transition * should treat those views as the same, then {@link #addTarget(int)} should be used * instead of {@link #addTarget(View)}. If, on the other hand, scene changes involve * changes all within the same view hierarchy, among views which do not * necessarily have ids set on them, then the target list of views may be more * convenient.</p> * * @param target A View on which the Transition will act, must be non-null. * @return The Transition to which the target is added. * Returning the same object makes it easier to chain calls during * construction, such as * <code>transitionSet.addTransitions(new Fade()).addTarget(someView);</code> * @see #addTarget(int) */ public Transition addTarget(View target) { mTargets.add(target); return this; } /** * Removes the given target from the list of targets that this Transition * is interested in animating. * * @param target The target view, must be non-null. * @return Transition The Transition from which the target is removed. * Returning the same object makes it easier to chain calls during * construction, such as * <code>transitionSet.addTransitions(new Fade()).removeTarget(someView);</code> */ public Transition removeTarget(View target) { if (target != null) { mTargets.remove(target); } return this; } /** * Removes the given target from the list of targets that this Transition * is interested in animating. * * @param target The type of the target view, must be non-null. * @return Transition The Transition from which the target is removed. * Returning the same object makes it easier to chain calls during * construction, such as * <code>transitionSet.addTransitions(new Fade()).removeTarget(someType);</code> */ public Transition removeTarget(Class target) { if (target != null) { mTargetTypes.remove(target); } return this; } /** * Returns the list of target IDs that this transition limits itself to * tracking and animating. If the list is null or empty for * {@link #getTargetIds()}, {@link #getTargets()}, {@link #getTargetNames()}, and * {@link #getTargetTypes()} then this transition is * not limited to specific views, and will handle changes to any views * in the hierarchy of a scene change. * * @return the list of target IDs */ public List<Integer> getTargetIds() { return mTargetIds; } /** * Returns the list of target views that this transition limits itself to * tracking and animating. If the list is null or empty for * {@link #getTargetIds()}, {@link #getTargets()}, {@link #getTargetNames()}, and * {@link #getTargetTypes()} then this transition is * not limited to specific views, and will handle changes to any views * in the hierarchy of a scene change. * * @return the list of target views */ public List<View> getTargets() { return mTargets; } /** * Returns the list of target transitionNames that this transition limits itself to * tracking and animating. If the list is null or empty for * {@link #getTargetIds()}, {@link #getTargets()}, {@link #getTargetNames()}, and * {@link #getTargetTypes()} then this transition is * not limited to specific views, and will handle changes to any views * in the hierarchy of a scene change. * * @return the list of target transitionNames */ public List<String> getTargetNames() { return mTargetNames; } /** * To be removed before L release. * @hide */ public List<String> getTargetViewNames() { return mTargetNames; } /** * Returns the list of target transitionNames that this transition limits itself to * tracking and animating. If the list is null or empty for * {@link #getTargetIds()}, {@link #getTargets()}, {@link #getTargetNames()}, and * {@link #getTargetTypes()} then this transition is * not limited to specific views, and will handle changes to any views * in the hierarchy of a scene change. * * @return the list of target Types */ public List<Class> getTargetTypes() { return mTargetTypes; } /** * Recursive method that captures values for the given view and the * hierarchy underneath it. * @param sceneRoot The root of the view hierarchy being captured * @param start true if this capture is happening before the scene change, * false otherwise */ void captureValues(ViewGroup sceneRoot, boolean start) { clearValues(start); if ((mTargetIds.size() > 0 || mTargets.size() > 0) && (mTargetNames == null || mTargetNames.isEmpty()) && (mTargetTypes == null || mTargetTypes.isEmpty())) { for (int i = 0; i < mTargetIds.size(); ++i) { int id = mTargetIds.get(i); View view = sceneRoot.findViewById(id); if (view != null) { TransitionValues values = new TransitionValues(); values.view = view; if (start) { captureStartValues(values); } else { captureEndValues(values); } values.targetedTransitions.add(this); capturePropagationValues(values); if (start) { addViewValues(mStartValues, view, values); } else { addViewValues(mEndValues, view, values); } } } for (int i = 0; i < mTargets.size(); ++i) { View view = mTargets.get(i); TransitionValues values = new TransitionValues(); values.view = view; if (start) { captureStartValues(values); } else { captureEndValues(values); } values.targetedTransitions.add(this); capturePropagationValues(values); if (start) { addViewValues(mStartValues, view, values); } else { addViewValues(mEndValues, view, values); } } } else { captureHierarchy(sceneRoot, start); } if (!start && mNameOverrides != null) { int numOverrides = mNameOverrides.size(); ArrayList<View> overriddenViews = new ArrayList<View>(numOverrides); for (int i = 0; i < numOverrides; i++) { String fromName = mNameOverrides.keyAt(i); overriddenViews.add(mStartValues.nameValues.remove(fromName)); } for (int i = 0; i < numOverrides; i++) { View view = overriddenViews.get(i); if (view != null) { String toName = mNameOverrides.valueAt(i); mStartValues.nameValues.put(toName, view); } } } } static void addViewValues(TransitionValuesMaps transitionValuesMaps, View view, TransitionValues transitionValues) { transitionValuesMaps.viewValues.put(view, transitionValues); int id = view.getId(); if (id >= 0) { if (transitionValuesMaps.idValues.indexOfKey(id) >= 0) { // Duplicate IDs cannot match by ID. transitionValuesMaps.idValues.put(id, null); } else { transitionValuesMaps.idValues.put(id, view); } } String name = ViewUtils.getTransitionName(view); if (name != null) { if (transitionValuesMaps.nameValues.containsKey(name)) { // Duplicate transitionNames: cannot match by transitionName. transitionValuesMaps.nameValues.put(name, null); } else { transitionValuesMaps.nameValues.put(name, view); } } if (view.getParent() instanceof ListView) { ListView listview = (ListView) view.getParent(); if (listview.getAdapter().hasStableIds()) { int position = listview.getPositionForView(view); long itemId = listview.getItemIdAtPosition(position); if (transitionValuesMaps.itemIdValues.indexOfKey(itemId) >= 0) { // Duplicate item IDs: cannot match by item ID. View alreadyMatched = transitionValuesMaps.itemIdValues.get(itemId); if (alreadyMatched != null) { android.support.v4.view.ViewCompat.setHasTransientState(alreadyMatched, false); transitionValuesMaps.itemIdValues.put(itemId, null); } } else { android.support.v4.view.ViewCompat.setHasTransientState(view, true); transitionValuesMaps.itemIdValues.put(itemId, view); } } } } /** * Clear valuesMaps for specified start/end state * * @param start true if the start values should be cleared, false otherwise */ void clearValues(boolean start) { if (start) { mStartValues.viewValues.clear(); mStartValues.idValues.clear(); mStartValues.itemIdValues.clear(); mStartValues.nameValues.clear(); mStartValuesList = null; } else { mEndValues.viewValues.clear(); mEndValues.idValues.clear(); mEndValues.itemIdValues.clear(); mEndValues.nameValues.clear(); mEndValuesList = null; } } /** * Recursive method which captures values for an entire view hierarchy, * starting at some root view. Transitions without targetIDs will use this * method to capture values for all possible views. * * @param view The view for which to capture values. Children of this View * will also be captured, recursively down to the leaf nodes. * @param start true if values are being captured in the start scene, false * otherwise. */ private void captureHierarchy(View view, boolean start) { if (view == null) { return; } int id = view.getId(); if (mTargetIdExcludes != null && mTargetIdExcludes.contains(id)) { return; } if (mTargetExcludes != null && mTargetExcludes.contains(view)) { return; } if (mTargetTypeExcludes != null && view != null) { int numTypes = mTargetTypeExcludes.size(); for (int i = 0; i < numTypes; ++i) { if (mTargetTypeExcludes.get(i).isInstance(view)) { return; } } } if (view.getParent() instanceof ViewGroup) { TransitionValues values = new TransitionValues(); values.view = view; if (start) { captureStartValues(values); } else { captureEndValues(values); } values.targetedTransitions.add(this); capturePropagationValues(values); if (start) { addViewValues(mStartValues, view, values); } else { addViewValues(mEndValues, view, values); } } if (view instanceof ViewGroup) { // Don't traverse child hierarchy if there are any child-excludes on this view if (mTargetIdChildExcludes != null && mTargetIdChildExcludes.contains(id)) { return; } if (mTargetChildExcludes != null && mTargetChildExcludes.contains(view)) { return; } if (mTargetTypeChildExcludes != null) { int numTypes = mTargetTypeChildExcludes.size(); for (int i = 0; i < numTypes; ++i) { if (mTargetTypeChildExcludes.get(i).isInstance(view)) { return; } } } ViewGroup parent = (ViewGroup) view; for (int i = 0; i < parent.getChildCount(); ++i) { captureHierarchy(parent.getChildAt(i), start); } } } /** * This method can be called by transitions to get the TransitionValues for * any particular view during the transition-playing process. This might be * necessary, for example, to query the before/after state of related views * for a given transition. */ public TransitionValues getTransitionValues(View view, boolean start) { if (mParent != null) { return mParent.getTransitionValues(view, start); } TransitionValuesMaps valuesMaps = start ? mStartValues : mEndValues; return valuesMaps.viewValues.get(view); } /** * Find the matched start or end value for a given View. This is only valid * after playTransition starts. For example, it will be valid in * {@link #createAnimator(android.view.ViewGroup, TransitionValues, TransitionValues)}, but not * in {@link #captureStartValues(TransitionValues)}. * * @param view The view to find the match for. * @param viewInStart Is View from the start values or end values. * @return The matching TransitionValues for view in either start or end values, depending * on viewInStart or null if there is no match for the given view. */ TransitionValues getMatchedTransitionValues(View view, boolean viewInStart) { if (mParent != null) { return mParent.getMatchedTransitionValues(view, viewInStart); } ArrayList<TransitionValues> lookIn = viewInStart ? mStartValuesList : mEndValuesList; if (lookIn == null) { return null; } int count = lookIn.size(); int index = -1; for (int i = 0; i < count; i++) { TransitionValues values = lookIn.get(i); if (values == null) { return null; } if (values.view == view) { index = i; break; } } TransitionValues values = null; if (index >= 0) { ArrayList<TransitionValues> matchIn = viewInStart ? mEndValuesList : mStartValuesList; values = matchIn.get(index); } return values; } /** * Pauses this transition, sending out calls to {@link * TransitionListener#onTransitionPause(Transition)} to all listeners * and pausing all running animators started by this transition. * * @hide */ public void pause(View sceneRoot) { if (!mEnded) { ArrayMap<Animator, AnimationInfo> runningAnimators = getRunningAnimators(); int numOldAnims = runningAnimators.size(); if (sceneRoot != null) { Object windowId = ViewUtils.getWindowId(sceneRoot); for (int i = numOldAnims - 1; i >= 0; i--) { AnimationInfo info = runningAnimators.valueAt(i); if (info.view != null && windowId != null && Objects.equal(windowId, info.windowId)) { Animator anim = runningAnimators.keyAt(i); AnimatorUtils.pause(anim); } } } if (mListeners != null && mListeners.size() > 0) { ArrayList<TransitionListener> tmpListeners = (ArrayList<TransitionListener>) mListeners.clone(); int numListeners = tmpListeners.size(); for (int i = 0; i < numListeners; ++i) { tmpListeners.get(i).onTransitionPause(this); } } mPaused = true; } } /** * Resumes this transition, sending out calls to {@link * TransitionListener#onTransitionPause(Transition)} to all listeners * and pausing all running animators started by this transition. * * @hide */ public void resume(View sceneRoot) { if (mPaused) { if (!mEnded) { ArrayMap<Animator, AnimationInfo> runningAnimators = getRunningAnimators(); int numOldAnims = runningAnimators.size(); Object windowId = ViewUtils.getWindowId(sceneRoot); for (int i = numOldAnims - 1; i >= 0; i--) { AnimationInfo info = runningAnimators.valueAt(i); if (info.view != null && windowId != null && Objects.equal(windowId, info.windowId)) { Animator anim = runningAnimators.keyAt(i); AnimatorUtils.resume(anim); } } if (mListeners != null && mListeners.size() > 0) { ArrayList<TransitionListener> tmpListeners = (ArrayList<TransitionListener>) mListeners.clone(); int numListeners = tmpListeners.size(); for (int i = 0; i < numListeners; ++i) { tmpListeners.get(i).onTransitionResume(this); } } } mPaused = false; } } /** * Called by TransitionManager to play the transition. This calls * createAnimators() to set things up and create all of the animations and then * runAnimations() to actually start the animations. */ void playTransition(ViewGroup sceneRoot) { mStartValuesList = new ArrayList<TransitionValues>(); mEndValuesList = new ArrayList<TransitionValues>(); matchStartAndEnd(mStartValues, mEndValues); ArrayMap<Animator, AnimationInfo> runningAnimators = getRunningAnimators(); int numOldAnims = runningAnimators.size(); Object windowId = ViewUtils.getWindowId(sceneRoot); for (int i = numOldAnims - 1; i >= 0; i--) { Animator anim = runningAnimators.keyAt(i); if (anim != null) { AnimationInfo oldInfo = runningAnimators.get(anim); if (oldInfo != null && oldInfo.view != null && oldInfo.windowId == windowId) { TransitionValues oldValues = oldInfo.values; View oldView = oldInfo.view; TransitionValues startValues = getTransitionValues(oldView, true); TransitionValues endValues = getMatchedTransitionValues(oldView, true); boolean cancel = (startValues != null || endValues != null) && oldInfo.transition.areValuesChanged(oldValues, endValues); if (cancel) { if (anim.isRunning() || AnimatorUtils.isAnimatorStarted(anim)) { if (DBG) { Log.d(LOG_TAG, "Canceling anim " + anim); } anim.cancel(); } else { if (DBG) { Log.d(LOG_TAG, "removing anim from info list: " + anim); } runningAnimators.remove(anim); } } } } } createAnimators(sceneRoot, mStartValues, mEndValues, mStartValuesList, mEndValuesList); runAnimators(); } boolean areValuesChanged(TransitionValues oldValues, TransitionValues newValues) { boolean valuesChanged = false; // if oldValues null, then transition didn't care to stash values, // and won't get canceled if (oldValues != null && newValues != null) { String[] properties = getTransitionProperties(); if (properties != null) { int count = properties.length; for (int i = 0; i < count; i++) { if (isValueChanged(oldValues, newValues, properties[i])) { valuesChanged = true; break; } } } else { for (String key : oldValues.values.keySet()) { if (isValueChanged(oldValues, newValues, key)) { valuesChanged = true; break; } } } } return valuesChanged; } private static boolean isValueChanged(TransitionValues oldValues, TransitionValues newValues, String key) { Object oldValue = oldValues.values.get(key); Object newValue = newValues.values.get(key); boolean changed; if (oldValue == null && newValue == null) { // both are null changed = false; } else if (oldValue == null || newValue == null) { // one is null changed = true; } else { // neither is null changed = !oldValue.equals(newValue); } if (DBG && changed) { Log.d(LOG_TAG, "Transition.playTransition: " + "oldValue != newValue for " + key + ": old, new = " + oldValue + ", " + newValue); } return changed; } /** * This is a utility method used by subclasses to handle standard parts of * setting up and running an Animator: it sets the {@link #getDuration() * duration} and the {@link #getStartDelay() startDelay}, starts the * animation, and, when the animator ends, calls {@link #end()}. * * @param animator The Animator to be run during this transition. * @hide */ protected void animate(Animator animator) { // TODO: maybe pass auto-end as a boolean parameter? if (animator == null) { end(); } else { if (getDuration() >= 0) { animator.setDuration(getDuration()); } if (getStartDelay() >= 0) { animator.setStartDelay(getStartDelay() + animator.getStartDelay()); } if (getInterpolator() != null) { animator.setInterpolator(getInterpolator()); } animator.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { end(); animation.removeListener(this); } }); animator.start(); } } /** * This method is called automatically by the transition and * TransitionSet classes prior to a Transition subclass starting; * subclasses should not need to call it directly. * * @hide */ protected void start() { if (mNumInstances == 0) { if (mListeners != null && mListeners.size() > 0) { ArrayList<TransitionListener> tmpListeners = (ArrayList<TransitionListener>) mListeners.clone(); int numListeners = tmpListeners.size(); for (int i = 0; i < numListeners; ++i) { tmpListeners.get(i).onTransitionStart(this); } } mEnded = false; } mNumInstances++; } /** * This method is called automatically by the Transition and * TransitionSet classes when a transition finishes, either because * a transition did nothing (returned a null Animator from * {@link android.transitions.everywhere.Transition#createAnimator(ViewGroup, TransitionValues, * TransitionValues)}) or because the transition returned a valid * Animator and end() was called in the onAnimationEnd() * callback of the AnimatorListener. * * @hide */ protected void end() { --mNumInstances; if (mNumInstances == 0) { if (mListeners != null && mListeners.size() > 0) { ArrayList<TransitionListener> tmpListeners = (ArrayList<TransitionListener>) mListeners.clone(); int numListeners = tmpListeners.size(); for (int i = 0; i < numListeners; ++i) { tmpListeners.get(i).onTransitionEnd(this); } } for (int i = 0; i < mStartValues.itemIdValues.size(); ++i) { View view = mStartValues.itemIdValues.valueAt(i); if (android.support.v4.view.ViewCompat.hasTransientState(view)) { android.support.v4.view.ViewCompat.setHasTransientState(view, false); } } for (int i = 0; i < mEndValues.itemIdValues.size(); ++i) { View view = mEndValues.itemIdValues.valueAt(i); if (android.support.v4.view.ViewCompat.hasTransientState(view)) { android.support.v4.view.ViewCompat.setHasTransientState(view, false); } } mEnded = true; } } void onEndOfAllTransitions() { // do nothing } /** * This method cancels a transition that is currently running. * * @hide */ protected void cancel() { int numAnimators = mCurrentAnimators.size(); for (int i = numAnimators - 1; i >= 0; i--) { Animator animator = mCurrentAnimators.get(i); animator.cancel(); } if (mListeners != null && mListeners.size() > 0) { ArrayList<TransitionListener> tmpListeners = (ArrayList<TransitionListener>) mListeners.clone(); int numListeners = tmpListeners.size(); for (int i = 0; i < numListeners; ++i) { tmpListeners.get(i).onTransitionCancel(this); } } } /** * Adds a listener to the set of listeners that are sent events through the * life of an animation, such as start, repeat, and end. * * @param listener the listener to be added to the current set of listeners * for this animation. * @return This transition object. */ public Transition addListener(TransitionListener listener) { if (mListeners == null) { mListeners = new ArrayList<TransitionListener>(); } mListeners.add(listener); return this; } /** * Removes a listener from the set listening to this animation. * * @param listener the listener to be removed from the current set of * listeners for this transition. * @return This transition object. */ public Transition removeListener(TransitionListener listener) { if (mListeners == null) { return this; } mListeners.remove(listener); if (mListeners.size() == 0) { mListeners = null; } return this; } /** * Sets the callback to use to find the epicenter of a Transition. A null value indicates * that there is no epicenter in the Transition and onGetEpicenter() will return null. * Transitions like {@link Explode} use a point or Rect to orient * the direction of travel. This is called the epicenter of the Transition and is * typically centered on a touched View. The * {@link Transition.EpicenterCallback} allows a Transition to * dynamically retrieve the epicenter during a Transition. * @param epicenterCallback The callback to use to find the epicenter of the Transition. */ public void setEpicenterCallback(EpicenterCallback epicenterCallback) { mEpicenterCallback = epicenterCallback; } /** * Returns the callback used to find the epicenter of the Transition. * Transitions like {@link Explode} use a point or Rect to orient * the direction of travel. This is called the epicenter of the Transition and is * typically centered on a touched View. The * {@link Transition.EpicenterCallback} allows a Transition to * dynamically retrieve the epicenter during a Transition. * @return the callback used to find the epicenter of the Transition. */ public EpicenterCallback getEpicenterCallback() { return mEpicenterCallback; } /** * Returns the epicenter as specified by the * {@link Transition.EpicenterCallback} or null if no callback exists. * @return the epicenter as specified by the * {@link Transition.EpicenterCallback} or null if no callback exists. * @see #setEpicenterCallback(Transition.EpicenterCallback) */ public Rect getEpicenter() { if (mEpicenterCallback == null) { return null; } return mEpicenterCallback.onGetEpicenter(this); } /** * Sets the algorithm used to calculate two-dimensional interpolation. * <p> * Transitions such as {@link ChangeBounds} move Views, typically * in a straight path between the start and end positions. Applications that desire to * have these motions move in a curve can change how Views interpolate in two dimensions * by extending PathMotion and implementing * {@link PathMotion#getPath(float, float, float, float)}. * </p> * <p> * When describing in XML, use a nested XML tag for the path motion. It can be one of * the built-in tags <code>arcMotion</code> or <code>patternPathMotion</code> or it can * be a custom PathMotion using <code>pathMotion</code> with the <code>class</code> * attributed with the fully-described class name. For example:</p> * <pre> * {@code * <changeBounds> * <pathMotion class="my.app.transition.MyPathMotion"/> * </changeBounds> * } * </pre> * <p>or</p> * <pre> * {@code * <changeBounds> * <arcMotion android:minimumHorizontalAngle="15" * android:minimumVerticalAngle="0" android:maximumAngle="90"/> * </changeBounds> * } * </pre> * * @param pathMotion Algorithm object to use for determining how to interpolate in two * dimensions. If null, a straight-path algorithm will be used. * @see ArcMotion * @see PatternPathMotion * @see PathMotion */ public void setPathMotion(PathMotion pathMotion) { if (pathMotion == null) { mPathMotion = STRAIGHT_PATH_MOTION; } else { mPathMotion = pathMotion; } } /** * Returns the algorithm object used to interpolate along two dimensions. This is typically * used to determine the View motion between two points. * * <p> * When describing in XML, use a nested XML tag for the path motion. It can be one of * the built-in tags <code>arcMotion</code> or <code>patternPathMotion</code> or it can * be a custom PathMotion using <code>pathMotion</code> with the <code>class</code> * attributed with the fully-described class name. For example:</p> * <pre> * {@code * <changeBounds> * <pathMotion class="my.app.transition.MyPathMotion"/> * </changeBounds>} * </pre> * <p>or</p> * <pre> * {@code * <changeBounds> * <arcMotion android:minimumHorizontalAngle="15" * android:minimumVerticalAngle="0" * android:maximumAngle="90"/> * </changeBounds>} * </pre> * * @return The algorithm object used to interpolate along two dimensions. * @see ArcMotion * @see PatternPathMotion * @see PathMotion */ public PathMotion getPathMotion() { return mPathMotion; } /** * Sets the method for determining Animator start delays. * When a Transition affects several Views like {@link Explode} or * {@link Slide}, there may be a desire to have a "wave-front" effect * such that the Animator start delay depends on position of the View. The * TransitionPropagation specifies how the start delays are calculated. * @param transitionPropagation The class used to determine the start delay of * Animators created by this Transition. A null value * indicates that no delay should be used. */ public void setPropagation(TransitionPropagation transitionPropagation) { mPropagation = transitionPropagation; } /** * Returns the {@link TransitionPropagation} used to calculate Animator start * delays. * When a Transition affects several Views like {@link Explode} or * {@link Slide}, there may be a desire to have a "wave-front" effect * such that the Animator start delay depends on position of the View. The * TransitionPropagation specifies how the start delays are calculated. * @return the {@link TransitionPropagation} used to calculate Animator start * delays. This is null by default. */ public TransitionPropagation getPropagation() { return mPropagation; } /** * Captures TransitionPropagation values for the given view and the * hierarchy underneath it. */ void capturePropagationValues(TransitionValues transitionValues) { if (mPropagation != null && !transitionValues.values.isEmpty()) { String[] propertyNames = mPropagation.getPropagationProperties(); if (propertyNames == null) { return; } boolean containsAll = true; for (int i = 0; i < propertyNames.length; i++) { if (!transitionValues.values.containsKey(propertyNames[i])) { containsAll = false; break; } } if (!containsAll) { mPropagation.captureValues(transitionValues); } } } Transition setSceneRoot(ViewGroup sceneRoot) { mSceneRoot = sceneRoot; return this; } void setCanRemoveViews(boolean canRemoveViews) { mCanRemoveViews = canRemoveViews; } public boolean canRemoveViews() { return mCanRemoveViews; } /** * Sets the shared element names -- a mapping from a name at the start state to * a different name at the end state. * @hide */ public void setNameOverrides(ArrayMap<String, String> overrides) { mNameOverrides = overrides; } /** @hide */ public ArrayMap<String, String> getNameOverrides() { return mNameOverrides; } /** @hide */ public void forceVisibility(int visibility, boolean isStartValue) { } @Override public String toString() { return toString(""); } @Override public Transition clone() { Transition clone = null; try { clone = (Transition) super.clone(); clone.mAnimators = new ArrayList<Animator>(); clone.mStartValues = new TransitionValuesMaps(); clone.mEndValues = new TransitionValuesMaps(); clone.mStartValuesList = null; clone.mEndValuesList = null; } catch (CloneNotSupportedException e) { } return clone; } /** * Returns the name of this Transition. This name is used internally to distinguish * between different transitions to determine when interrupting transitions overlap. * For example, a ChangeBounds running on the same target view as another ChangeBounds * should determine whether the old transition is animating to different end values * and should be canceled in favor of the new transition. * <p/> * <p>By default, a Transition's name is simply the value of {@link Class#getName()}, * but subclasses are free to override and return something different.</p> * * @return The name of this transition. */ public String getName() { return mName; } String toString(String indent) { String result = indent + ((Object) this).getClass().getSimpleName() + "@" + Integer.toHexString(((Object) this).hashCode()) + ": "; if (mDuration != -1) { result += "dur(" + mDuration + ") "; } if (mStartDelay != -1) { result += "dly(" + mStartDelay + ") "; } if (mInterpolator != null) { result += "interp(" + mInterpolator + ") "; } if (mTargetIds.size() > 0 || mTargets.size() > 0) { result += "tgts("; if (mTargetIds.size() > 0) { for (int i = 0; i < mTargetIds.size(); ++i) { if (i > 0) { result += ", "; } result += mTargetIds.get(i); } } if (mTargets.size() > 0) { for (int i = 0; i < mTargets.size(); ++i) { if (i > 0) { result += ", "; } result += mTargets.get(i); } } result += ")"; } return result; } /** * A transition listener receives notifications from a transition. * Notifications indicate transition lifecycle events. */ public static interface TransitionListener { /** * Notification about the start of the transition. * * @param transition The started transition. */ void onTransitionStart(Transition transition); /** * Notification about the end of the transition. Canceled transitions * will always notify listeners of both the cancellation and end * events. That is, {@link #onTransitionEnd(android.transitions.everywhere.Transition)} is always called, * regardless of whether the transition was canceled or played * through to completion. * * @param transition The transition which reached its end. */ void onTransitionEnd(Transition transition); /** * Notification about the cancellation of the transition. * Note that cancel may be called by a parent {@link TransitionSet} on * a child transition which has not yet started. This allows the child * transition to restore state on target objects which was set at * {@link #createAnimator(android.view.ViewGroup, TransitionValues, TransitionValues) * createAnimator()} time. * * @param transition The transition which was canceled. */ void onTransitionCancel(Transition transition); /** * Notification when a transition is paused. * Note that createAnimator() may be called by a parent {@link TransitionSet} on * a child transition which has not yet started. This allows the child * transition to restore state on target objects which was set at * {@link #createAnimator(android.view.ViewGroup, TransitionValues, TransitionValues) * createAnimator()} time. * * @param transition The transition which was paused. */ void onTransitionPause(Transition transition); /** * Notification when a transition is resumed. * Note that resume() may be called by a parent {@link TransitionSet} on * a child transition which has not yet started. This allows the child * transition to restore state which may have changed in an earlier call * to {@link #onTransitionPause(android.transitions.everywhere.Transition)}. * * @param transition The transition which was resumed. */ void onTransitionResume(Transition transition); } /** * Utility adapter class to avoid having to override all three methods * whenever someone just wants to listen for a single event. * * @hide */ public static class TransitionListenerAdapter implements TransitionListener { @Override public void onTransitionStart(Transition transition) { } @Override public void onTransitionEnd(Transition transition) { } @Override public void onTransitionCancel(Transition transition) { } @Override public void onTransitionPause(Transition transition) { } @Override public void onTransitionResume(Transition transition) { } } /** * Holds information about each animator used when a new transition starts * while other transitions are still running to determine whether a running * animation should be canceled or a new animation noop'd. The structure holds * information about the state that an animation is going to, to be compared to * end state of a new animation. * @hide */ public static class AnimationInfo { public View view; String name; TransitionValues values; Object windowId; Transition transition; AnimationInfo(View view, String name, Transition transition, Object windowId, TransitionValues values) { this.view = view; this.name = name; this.values = values; this.windowId = windowId; this.transition = transition; } } /** * Utility class for managing typed ArrayLists efficiently. In particular, this * can be useful for lists that we don't expect to be used often (eg, the exclude * lists), so we'd like to keep them nulled out by default. This causes the code to * become tedious, with constant null checks, code to allocate when necessary, * and code to null out the reference when the list is empty. This class encapsulates * all of that functionality into simple add()/remove() methods which perform the * necessary checks, allocation/null-out as appropriate, and return the * resulting list. */ private static class ArrayListManager { /** * Add the specified item to the list, returning the resulting list. * The returned list can either the be same list passed in or, if that * list was null, the new list that was created. * <p/> * Note that the list holds unique items; if the item already exists in the * list, the list is not modified. */ static <T> ArrayList<T> add(ArrayList<T> list, T item) { if (list == null) { list = new ArrayList<T>(); } if (!list.contains(item)) { list.add(item); } return list; } /** * Remove the specified item from the list, returning the resulting list. * The returned list can either the be same list passed in or, if that * list becomes empty as a result of the remove(), the new list was created. */ static <T> ArrayList<T> remove(ArrayList<T> list, T item) { if (list != null) { list.remove(item); if (list.isEmpty()) { list = null; } } return list; } } /** * Class to get the epicenter of Transition. Use * {@link #setEpicenterCallback(android.transitions.everywhere.Transition.EpicenterCallback)} to * set the callback used to calculate the epicenter of the Transition. Override * {@link #getEpicenter()} to return the rectangular region in screen coordinates of * the epicenter of the transition. * @see #setEpicenterCallback(android.transitions.everywhere.Transition.EpicenterCallback) */ public static abstract class EpicenterCallback { /** * Implementers must override to return the epicenter of the Transition in screen * coordinates. Transitions like {@link android.transitions.everywhere.Explode} depend upon * an epicenter for the Transition. In Explode, Views move toward or away from the * center of the epicenter Rect along the vector between the epicenter and the center * of the View appearing and disappearing. Some Transitions, such as * {@link android.transitions.everywhere.Fade} pay no attention to the epicenter. * * @param transition The transition for which the epicenter applies. * @return The Rect region of the epicenter of <code>transition</code> or null if * there is no epicenter. */ public abstract Rect onGetEpicenter(Transition transition); } }