/* * Copyright (C) 2010 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.animation; import android.os.Looper; import android.os.Trace; import android.util.AndroidRuntimeException; import android.view.Choreographer; import android.view.animation.AccelerateDecelerateInterpolator; import android.view.animation.AnimationUtils; import android.view.animation.LinearInterpolator; import java.util.ArrayList; import java.util.HashMap; /** * This class provides a simple timing engine for running animations * which calculate animated values and set them on target objects. * *

There is a single timing pulse that all animations use. It runs in a * custom handler to ensure that property changes happen on the UI thread.

* *

By default, ValueAnimator uses non-linear time interpolation, via the * {@link AccelerateDecelerateInterpolator} class, which accelerates into and decelerates * out of an animation. This behavior can be changed by calling * {@link ValueAnimator#setInterpolator(TimeInterpolator)}.

* *
*

Developer Guides

*

For more information about animating with {@code ValueAnimator}, read the * Property * Animation developer guide.

*
*/ @SuppressWarnings("unchecked") public class ValueAnimator extends Animator { /** * Internal constants */ private static float sDurationScale = 1.0f; /** * Values used with internal variable mPlayingState to indicate the current state of an * animation. */ static final int STOPPED = 0; // Not yet playing static final int RUNNING = 1; // Playing normally static final int SEEKED = 2; // Seeked to some time value /** * Internal variables * NOTE: This object implements the clone() method, making a deep copy of any referenced * objects. As other non-trivial fields are added to this class, make sure to add logic * to clone() to make deep copies of them. */ // The first time that the animation's animateFrame() method is called. This time is used to // determine elapsed time (and therefore the elapsed fraction) in subsequent calls // to animateFrame() long mStartTime; /** * Set when setCurrentPlayTime() is called. If negative, animation is not currently seeked * to a value. */ long mSeekTime = -1; /** * Set on the next frame after pause() is called, used to calculate a new startTime * or delayStartTime which allows the animator to continue from the point at which * it was paused. If negative, has not yet been set. */ private long mPauseTime; /** * Set when an animator is resumed. This triggers logic in the next frame which * actually resumes the animator. */ private boolean mResumed = false; // The static sAnimationHandler processes the internal timing loop on which all animations // are based /** * @hide */ protected static ThreadLocal sAnimationHandler = new ThreadLocal(); // The time interpolator to be used if none is set on the animation private static final TimeInterpolator sDefaultInterpolator = new AccelerateDecelerateInterpolator(); /** * Used to indicate whether the animation is currently playing in reverse. This causes the * elapsed fraction to be inverted to calculate the appropriate values. */ private boolean mPlayingBackwards = false; /** * This variable tracks the current iteration that is playing. When mCurrentIteration exceeds the * repeatCount (if repeatCount!=INFINITE), the animation ends */ private int mCurrentIteration = 0; /** * Tracks current elapsed/eased fraction, for querying in getAnimatedFraction(). */ private float mCurrentFraction = 0f; /** * Tracks whether a startDelay'd animation has begun playing through the startDelay. */ private boolean mStartedDelay = false; /** * Tracks the time at which the animation began playing through its startDelay. This is * different from the mStartTime variable, which is used to track when the animation became * active (which is when the startDelay expired and the animation was added to the active * animations list). */ private long mDelayStartTime; /** * Flag that represents the current state of the animation. Used to figure out when to start * an animation (if state == STOPPED). Also used to end an animation that * has been cancel()'d or end()'d since the last animation frame. Possible values are * STOPPED, RUNNING, SEEKED. */ int mPlayingState = STOPPED; /** * Additional playing state to indicate whether an animator has been start()'d. There is * some lag between a call to start() and the first animation frame. We should still note * that the animation has been started, even if it's first animation frame has not yet * happened, and reflect that state in isRunning(). * Note that delayed animations are different: they are not started until their first * animation frame, which occurs after their delay elapses. */ private boolean mRunning = false; /** * Additional playing state to indicate whether an animator has been start()'d, whether or * not there is a nonzero startDelay. */ private boolean mStarted = false; /** * Tracks whether we've notified listeners of the onAnimationStart() event. This can be * complex to keep track of since we notify listeners at different times depending on * startDelay and whether start() was called before end(). */ private boolean mStartListenersCalled = false; /** * Flag that denotes whether the animation is set up and ready to go. Used to * set up animation that has not yet been started. */ boolean mInitialized = false; // // Backing variables // // How long the animation should last in ms private long mDuration = (long)(300 * sDurationScale); private long mUnscaledDuration = 300; // The amount of time in ms to delay starting the animation after start() is called private long mStartDelay = 0; private long mUnscaledStartDelay = 0; // The number of times the animation will repeat. The default is 0, which means the animation // will play only once private int mRepeatCount = 0; /** * The type of repetition that will occur when repeatMode is nonzero. RESTART means the * animation will start from the beginning on every new cycle. REVERSE means the animation * will reverse directions on each iteration. */ private int mRepeatMode = RESTART; /** * The time interpolator to be used. The elapsed fraction of the animation will be passed * through this interpolator to calculate the interpolated fraction, which is then used to * calculate the animated values. */ private TimeInterpolator mInterpolator = sDefaultInterpolator; /** * The set of listeners to be sent events through the life of an animation. */ ArrayList mUpdateListeners = null; /** * The property/value sets being animated. */ PropertyValuesHolder[] mValues; /** * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values * by property name during calls to getAnimatedValue(String). */ HashMap mValuesMap; /** * Public constants */ /** * When the animation reaches the end and repeatCount is INFINITE * or a positive value, the animation restarts from the beginning. */ public static final int RESTART = 1; /** * When the animation reaches the end and repeatCount is INFINITE * or a positive value, the animation reverses direction on every iteration. */ public static final int REVERSE = 2; /** * This value used used with the {@link #setRepeatCount(int)} property to repeat * the animation indefinitely. */ public static final int INFINITE = -1; /** * @hide */ public static void setDurationScale(float durationScale) { sDurationScale = durationScale; } /** * @hide */ public static float getDurationScale() { return sDurationScale; } /** * Creates a new ValueAnimator object. This default constructor is primarily for * use internally; the factory methods which take parameters are more generally * useful. */ public ValueAnimator() { } /** * Constructs and returns a ValueAnimator that animates between int values. A single * value implies that that value is the one being animated to. However, this is not typically * useful in a ValueAnimator object because there is no way for the object to determine the * starting value for the animation (unlike ObjectAnimator, which can derive that value * from the target object and property being animated). Therefore, there should typically * be two or more values. * * @param values A set of values that the animation will animate between over time. * @return A ValueAnimator object that is set up to animate between the given values. */ public static ValueAnimator ofInt(int... values) { ValueAnimator anim = new ValueAnimator(); anim.setIntValues(values); return anim; } /** * Constructs and returns a ValueAnimator that animates between color values. A single * value implies that that value is the one being animated to. However, this is not typically * useful in a ValueAnimator object because there is no way for the object to determine the * starting value for the animation (unlike ObjectAnimator, which can derive that value * from the target object and property being animated). Therefore, there should typically * be two or more values. * * @param values A set of values that the animation will animate between over time. * @return A ValueAnimator object that is set up to animate between the given values. */ public static ValueAnimator ofArgb(int... values) { ValueAnimator anim = new ValueAnimator(); anim.setIntValues(values); anim.setEvaluator(ArgbEvaluator.getInstance()); return anim; } /** * Constructs and returns a ValueAnimator that animates between float values. A single * value implies that that value is the one being animated to. However, this is not typically * useful in a ValueAnimator object because there is no way for the object to determine the * starting value for the animation (unlike ObjectAnimator, which can derive that value * from the target object and property being animated). Therefore, there should typically * be two or more values. * * @param values A set of values that the animation will animate between over time. * @return A ValueAnimator object that is set up to animate between the given values. */ public static ValueAnimator ofFloat(float... values) { ValueAnimator anim = new ValueAnimator(); anim.setFloatValues(values); return anim; } /** * Constructs and returns a ValueAnimator that animates between the values * specified in the PropertyValuesHolder objects. * * @param values A set of PropertyValuesHolder objects whose values will be animated * between over time. * @return A ValueAnimator object that is set up to animate between the given values. */ public static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values) { ValueAnimator anim = new ValueAnimator(); anim.setValues(values); return anim; } /** * Constructs and returns a ValueAnimator that animates between Object values. A single * value implies that that value is the one being animated to. However, this is not typically * useful in a ValueAnimator object because there is no way for the object to determine the * starting value for the animation (unlike ObjectAnimator, which can derive that value * from the target object and property being animated). Therefore, there should typically * be two or more values. * *

Since ValueAnimator does not know how to animate between arbitrary Objects, this * factory method also takes a TypeEvaluator object that the ValueAnimator will use * to perform that interpolation. * * @param evaluator A TypeEvaluator that will be called on each animation frame to * provide the ncessry interpolation between the Object values to derive the animated * value. * @param values A set of values that the animation will animate between over time. * @return A ValueAnimator object that is set up to animate between the given values. */ public static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values) { ValueAnimator anim = new ValueAnimator(); anim.setObjectValues(values); anim.setEvaluator(evaluator); return anim; } /** * Sets int values that will be animated between. A single * value implies that that value is the one being animated to. However, this is not typically * useful in a ValueAnimator object because there is no way for the object to determine the * starting value for the animation (unlike ObjectAnimator, which can derive that value * from the target object and property being animated). Therefore, there should typically * be two or more values. * *

If there are already multiple sets of values defined for this ValueAnimator via more * than one PropertyValuesHolder object, this method will set the values for the first * of those objects.

* * @param values A set of values that the animation will animate between over time. */ public void setIntValues(int... values) { if (values == null || values.length == 0) { return; } if (mValues == null || mValues.length == 0) { setValues(PropertyValuesHolder.ofInt("", values)); } else { PropertyValuesHolder valuesHolder = mValues[0]; valuesHolder.setIntValues(values); } // New property/values/target should cause re-initialization prior to starting mInitialized = false; } /** * Sets float values that will be animated between. A single * value implies that that value is the one being animated to. However, this is not typically * useful in a ValueAnimator object because there is no way for the object to determine the * starting value for the animation (unlike ObjectAnimator, which can derive that value * from the target object and property being animated). Therefore, there should typically * be two or more values. * *

If there are already multiple sets of values defined for this ValueAnimator via more * than one PropertyValuesHolder object, this method will set the values for the first * of those objects.

* * @param values A set of values that the animation will animate between over time. */ public void setFloatValues(float... values) { if (values == null || values.length == 0) { return; } if (mValues == null || mValues.length == 0) { setValues(PropertyValuesHolder.ofFloat("", values)); } else { PropertyValuesHolder valuesHolder = mValues[0]; valuesHolder.setFloatValues(values); } // New property/values/target should cause re-initialization prior to starting mInitialized = false; } /** * Sets the values to animate between for this animation. A single * value implies that that value is the one being animated to. However, this is not typically * useful in a ValueAnimator object because there is no way for the object to determine the * starting value for the animation (unlike ObjectAnimator, which can derive that value * from the target object and property being animated). Therefore, there should typically * be two or more values. * *

If there are already multiple sets of values defined for this ValueAnimator via more * than one PropertyValuesHolder object, this method will set the values for the first * of those objects.

* *

There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate * between these value objects. ValueAnimator only knows how to interpolate between the * primitive types specified in the other setValues() methods.

* * @param values The set of values to animate between. */ public void setObjectValues(Object... values) { if (values == null || values.length == 0) { return; } if (mValues == null || mValues.length == 0) { setValues(PropertyValuesHolder.ofObject("", null, values)); } else { PropertyValuesHolder valuesHolder = mValues[0]; valuesHolder.setObjectValues(values); } // New property/values/target should cause re-initialization prior to starting mInitialized = false; } /** * Sets the values, per property, being animated between. This function is called internally * by the constructors of ValueAnimator that take a list of values. But a ValueAnimator can * be constructed without values and this method can be called to set the values manually * instead. * * @param values The set of values, per property, being animated between. */ public void setValues(PropertyValuesHolder... values) { int numValues = values.length; mValues = values; mValuesMap = new HashMap(numValues); for (int i = 0; i < numValues; ++i) { PropertyValuesHolder valuesHolder = values[i]; mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); } // New property/values/target should cause re-initialization prior to starting mInitialized = false; } /** * Returns the values that this ValueAnimator animates between. These values are stored in * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list * of value objects instead. * * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the * values, per property, that define the animation. */ public PropertyValuesHolder[] getValues() { return mValues; } /** * This function is called immediately before processing the first animation * frame of an animation. If there is a nonzero startDelay, the * function is called after that delay ends. * It takes care of the final initialization steps for the * animation. * *

Overrides of this method should call the superclass method to ensure * that internal mechanisms for the animation are set up correctly.

*/ void initAnimation() { if (!mInitialized) { int numValues = mValues.length; for (int i = 0; i < numValues; ++i) { mValues[i].init(); } mInitialized = true; } } /** * Sets the length of the animation. The default duration is 300 milliseconds. * * @param duration The length of the animation, in milliseconds. This value cannot * be negative. * @return ValueAnimator The object called with setDuration(). This return * value makes it easier to compose statements together that construct and then set the * duration, as in ValueAnimator.ofInt(0, 10).setDuration(500).start(). */ public ValueAnimator setDuration(long duration) { if (duration < 0) { throw new IllegalArgumentException("Animators cannot have negative duration: " + duration); } mUnscaledDuration = duration; updateScaledDuration(); return this; } private void updateScaledDuration() { mDuration = (long)(mUnscaledDuration * sDurationScale); } /** * Gets the length of the animation. The default duration is 300 milliseconds. * * @return The length of the animation, in milliseconds. */ public long getDuration() { return mUnscaledDuration; } /** * Sets the position of the animation to the specified point in time. This time should * be between 0 and the total duration of the animation, including any repetition. If * the animation has not yet been started, then it will not advance forward after it is * set to this time; it will simply set the time to this value and perform any appropriate * actions based on that time. If the animation is already running, then setCurrentPlayTime() * will set the current playing time to this value and continue playing from that point. * * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. */ public void setCurrentPlayTime(long playTime) { initAnimation(); long currentTime = AnimationUtils.currentAnimationTimeMillis(); if (mPlayingState != RUNNING) { mSeekTime = playTime; mPlayingState = SEEKED; } mStartTime = currentTime - playTime; doAnimationFrame(currentTime); } /** * Gets the current position of the animation in time, which is equal to the current * time minus the time that the animation started. An animation that is not yet started will * return a value of zero. * * @return The current position in time of the animation. */ public long getCurrentPlayTime() { if (!mInitialized || mPlayingState == STOPPED) { return 0; } return AnimationUtils.currentAnimationTimeMillis() - mStartTime; } /** * This custom, static handler handles the timing pulse that is shared by * all active animations. This approach ensures that the setting of animation * values will happen on the UI thread and that all animations will share * the same times for calculating their values, which makes synchronizing * animations possible. * * The handler uses the Choreographer for executing periodic callbacks. * * @hide */ @SuppressWarnings("unchecked") protected static class AnimationHandler implements Runnable { // The per-thread list of all active animations /** @hide */ protected final ArrayList mAnimations = new ArrayList(); // Used in doAnimationFrame() to avoid concurrent modifications of mAnimations private final ArrayList mTmpAnimations = new ArrayList(); // The per-thread set of animations to be started on the next animation frame /** @hide */ protected final ArrayList mPendingAnimations = new ArrayList(); /** * Internal per-thread collections used to avoid set collisions as animations start and end * while being processed. * @hide */ protected final ArrayList mDelayedAnims = new ArrayList(); private final ArrayList mEndingAnims = new ArrayList(); private final ArrayList mReadyAnims = new ArrayList(); private final Choreographer mChoreographer; private boolean mAnimationScheduled; private AnimationHandler() { mChoreographer = Choreographer.getInstance(); } /** * Start animating on the next frame. */ public void start() { scheduleAnimation(); } private void doAnimationFrame(long frameTime) { // mPendingAnimations holds any animations that have requested to be started // We're going to clear mPendingAnimations, but starting animation may // cause more to be added to the pending list (for example, if one animation // starting triggers another starting). So we loop until mPendingAnimations // is empty. while (mPendingAnimations.size() > 0) { ArrayList pendingCopy = (ArrayList) mPendingAnimations.clone(); mPendingAnimations.clear(); int count = pendingCopy.size(); for (int i = 0; i < count; ++i) { ValueAnimator anim = pendingCopy.get(i); // If the animation has a startDelay, place it on the delayed list if (anim.mStartDelay == 0) { anim.startAnimation(this); } else { mDelayedAnims.add(anim); } } } // Next, process animations currently sitting on the delayed queue, adding // them to the active animations if they are ready int numDelayedAnims = mDelayedAnims.size(); for (int i = 0; i < numDelayedAnims; ++i) { ValueAnimator anim = mDelayedAnims.get(i); if (anim.delayedAnimationFrame(frameTime)) { mReadyAnims.add(anim); } } int numReadyAnims = mReadyAnims.size(); if (numReadyAnims > 0) { for (int i = 0; i < numReadyAnims; ++i) { ValueAnimator anim = mReadyAnims.get(i); anim.startAnimation(this); anim.mRunning = true; mDelayedAnims.remove(anim); } mReadyAnims.clear(); } // Now process all active animations. The return value from animationFrame() // tells the handler whether it should now be ended int numAnims = mAnimations.size(); for (int i = 0; i < numAnims; ++i) { mTmpAnimations.add(mAnimations.get(i)); } for (int i = 0; i < numAnims; ++i) { ValueAnimator anim = mTmpAnimations.get(i); if (mAnimations.contains(anim) && anim.doAnimationFrame(frameTime)) { mEndingAnims.add(anim); } } mTmpAnimations.clear(); if (mEndingAnims.size() > 0) { for (int i = 0; i < mEndingAnims.size(); ++i) { mEndingAnims.get(i).endAnimation(this); } mEndingAnims.clear(); } // If there are still active or delayed animations, schedule a future call to // onAnimate to process the next frame of the animations. if (!mAnimations.isEmpty() || !mDelayedAnims.isEmpty()) { scheduleAnimation(); } } // Called by the Choreographer. @Override public void run() { mAnimationScheduled = false; doAnimationFrame(mChoreographer.getFrameTime()); } private void scheduleAnimation() { if (!mAnimationScheduled) { mChoreographer.postCallback(Choreographer.CALLBACK_ANIMATION, this, null); mAnimationScheduled = true; } } } /** * The amount of time, in milliseconds, to delay starting the animation after * {@link #start()} is called. * * @return the number of milliseconds to delay running the animation */ public long getStartDelay() { return mUnscaledStartDelay; } /** * The amount of time, in milliseconds, to delay starting the animation after * {@link #start()} is called. * @param startDelay The amount of the delay, in milliseconds */ public void setStartDelay(long startDelay) { this.mStartDelay = (long)(startDelay * sDurationScale); mUnscaledStartDelay = startDelay; } /** * The amount of time, in milliseconds, between each frame of the animation. This is a * requested time that the animation will attempt to honor, but the actual delay between * frames may be different, depending on system load and capabilities. This is a static * function because the same delay will be applied to all animations, since they are all * run off of a single timing loop. * * The frame delay may be ignored when the animation system uses an external timing * source, such as the display refresh rate (vsync), to govern animations. * * @return the requested time between frames, in milliseconds */ public static long getFrameDelay() { return Choreographer.getFrameDelay(); } /** * The amount of time, in milliseconds, between each frame of the animation. This is a * requested time that the animation will attempt to honor, but the actual delay between * frames may be different, depending on system load and capabilities. This is a static * function because the same delay will be applied to all animations, since they are all * run off of a single timing loop. * * The frame delay may be ignored when the animation system uses an external timing * source, such as the display refresh rate (vsync), to govern animations. * * @param frameDelay the requested time between frames, in milliseconds */ public static void setFrameDelay(long frameDelay) { Choreographer.setFrameDelay(frameDelay); } /** * The most recent value calculated by this ValueAnimator when there is just one * property being animated. This value is only sensible while the animation is running. The main * purpose for this read-only property is to retrieve the value from the ValueAnimator * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which * is called during each animation frame, immediately after the value is calculated. * * @return animatedValue The value most recently calculated by this ValueAnimator for * the single property being animated. If there are several properties being animated * (specified by several PropertyValuesHolder objects in the constructor), this function * returns the animated value for the first of those objects. */ public Object getAnimatedValue() { if (mValues != null && mValues.length > 0) { return mValues[0].getAnimatedValue(); } // Shouldn't get here; should always have values unless ValueAnimator was set up wrong return null; } /** * The most recent value calculated by this ValueAnimator for propertyName. * The main purpose for this read-only property is to retrieve the value from the * ValueAnimator during a call to * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which * is called during each animation frame, immediately after the value is calculated. * * @return animatedValue The value most recently calculated for the named property * by this ValueAnimator. */ public Object getAnimatedValue(String propertyName) { PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); if (valuesHolder != null) { return valuesHolder.getAnimatedValue(); } else { // At least avoid crashing if called with bogus propertyName return null; } } /** * Sets how many times the animation should be repeated. If the repeat * count is 0, the animation is never repeated. If the repeat count is * greater than 0 or {@link #INFINITE}, the repeat mode will be taken * into account. The repeat count is 0 by default. * * @param value the number of times the animation should be repeated */ public void setRepeatCount(int value) { mRepeatCount = value; } /** * Defines how many times the animation should repeat. The default value * is 0. * * @return the number of times the animation should repeat, or {@link #INFINITE} */ public int getRepeatCount() { return mRepeatCount; } /** * Defines what this animation should do when it reaches the end. This * setting is applied only when the repeat count is either greater than * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. * * @param value {@link #RESTART} or {@link #REVERSE} */ public void setRepeatMode(int value) { mRepeatMode = value; } /** * Defines what this animation should do when it reaches the end. * * @return either one of {@link #REVERSE} or {@link #RESTART} */ public int getRepeatMode() { return mRepeatMode; } /** * Adds a listener to the set of listeners that are sent update events through the life of * an animation. This method is called on all listeners for every frame of the animation, * after the values for the animation have been calculated. * * @param listener the listener to be added to the current set of listeners for this animation. */ public void addUpdateListener(AnimatorUpdateListener listener) { if (mUpdateListeners == null) { mUpdateListeners = new ArrayList(); } mUpdateListeners.add(listener); } /** * Removes all listeners from the set listening to frame updates for this animation. */ public void removeAllUpdateListeners() { if (mUpdateListeners == null) { return; } mUpdateListeners.clear(); mUpdateListeners = null; } /** * Removes a listener from the set listening to frame updates for this animation. * * @param listener the listener to be removed from the current set of update listeners * for this animation. */ public void removeUpdateListener(AnimatorUpdateListener listener) { if (mUpdateListeners == null) { return; } mUpdateListeners.remove(listener); if (mUpdateListeners.size() == 0) { mUpdateListeners = null; } } /** * The time interpolator used in calculating the elapsed fraction of this animation. The * interpolator determines whether the animation runs with linear or non-linear motion, * such as acceleration and deceleration. The default value is * {@link android.view.animation.AccelerateDecelerateInterpolator} * * @param value the interpolator to be used by this animation. A value of null * will result in linear interpolation. */ @Override public void setInterpolator(TimeInterpolator value) { if (value != null) { mInterpolator = value; } else { mInterpolator = new LinearInterpolator(); } } /** * Returns the timing interpolator that this ValueAnimator uses. * * @return The timing interpolator for this ValueAnimator. */ @Override public TimeInterpolator getInterpolator() { return mInterpolator; } /** * The type evaluator to be used when calculating the animated values of this animation. * The system will automatically assign a float or int evaluator based on the type * of startValue and endValue in the constructor. But if these values * are not one of these primitive types, or if different evaluation is desired (such as is * necessary with int values that represent colors), a custom evaluator needs to be assigned. * For example, when running an animation on color values, the {@link ArgbEvaluator} * should be used to get correct RGB color interpolation. * *

If this ValueAnimator has only one set of values being animated between, this evaluator * will be used for that set. If there are several sets of values being animated, which is * the case if PropertyValuesHolder objects were set on the ValueAnimator, then the evaluator * is assigned just to the first PropertyValuesHolder object.

* * @param value the evaluator to be used this animation */ public void setEvaluator(TypeEvaluator value) { if (value != null && mValues != null && mValues.length > 0) { mValues[0].setEvaluator(value); } } private void notifyStartListeners() { if (mListeners != null && !mStartListenersCalled) { ArrayList tmpListeners = (ArrayList) mListeners.clone(); int numListeners = tmpListeners.size(); for (int i = 0; i < numListeners; ++i) { tmpListeners.get(i).onAnimationStart(this); } } mStartListenersCalled = true; } /** * Start the animation playing. This version of start() takes a boolean flag that indicates * whether the animation should play in reverse. The flag is usually false, but may be set * to true if called from the reverse() method. * *

The animation started by calling this method will be run on the thread that called * this method. This thread should have a Looper on it (a runtime exception will be thrown if * this is not the case). Also, if the animation will animate * properties of objects in the view hierarchy, then the calling thread should be the UI * thread for that view hierarchy.

* * @param playBackwards Whether the ValueAnimator should start playing in reverse. */ private void start(boolean playBackwards) { if (Looper.myLooper() == null) { throw new AndroidRuntimeException("Animators may only be run on Looper threads"); } mPlayingBackwards = playBackwards; mCurrentIteration = 0; mPlayingState = STOPPED; mStarted = true; mStartedDelay = false; mPaused = false; updateScaledDuration(); // in case the scale factor has changed since creation time AnimationHandler animationHandler = getOrCreateAnimationHandler(); animationHandler.mPendingAnimations.add(this); if (mStartDelay == 0) { // This sets the initial value of the animation, prior to actually starting it running setCurrentPlayTime(0); mPlayingState = STOPPED; mRunning = true; notifyStartListeners(); } animationHandler.start(); } @Override public void start() { start(false); } @Override public void cancel() { // Only cancel if the animation is actually running or has been started and is about // to run AnimationHandler handler = getOrCreateAnimationHandler(); if (mPlayingState != STOPPED || handler.mPendingAnimations.contains(this) || handler.mDelayedAnims.contains(this)) { // Only notify listeners if the animator has actually started if ((mStarted || mRunning) && mListeners != null) { if (!mRunning) { // If it's not yet running, then start listeners weren't called. Call them now. notifyStartListeners(); } ArrayList tmpListeners = (ArrayList) mListeners.clone(); for (AnimatorListener listener : tmpListeners) { listener.onAnimationCancel(this); } } endAnimation(handler); } } @Override public void end() { AnimationHandler handler = getOrCreateAnimationHandler(); if (!handler.mAnimations.contains(this) && !handler.mPendingAnimations.contains(this)) { // Special case if the animation has not yet started; get it ready for ending mStartedDelay = false; startAnimation(handler); mStarted = true; } else if (!mInitialized) { initAnimation(); } animateValue(mPlayingBackwards ? 0f : 1f); endAnimation(handler); } @Override public void resume() { if (mPaused) { mResumed = true; } super.resume(); } @Override public void pause() { boolean previouslyPaused = mPaused; super.pause(); if (!previouslyPaused && mPaused) { mPauseTime = -1; mResumed = false; } } @Override public boolean isRunning() { return (mPlayingState == RUNNING || mRunning); } @Override public boolean isStarted() { return mStarted; } /** * Plays the ValueAnimator in reverse. If the animation is already running, * it will stop itself and play backwards from the point reached when reverse was called. * If the animation is not currently running, then it will start from the end and * play backwards. This behavior is only set for the current animation; future playing * of the animation will use the default behavior of playing forward. */ @Override public void reverse() { mPlayingBackwards = !mPlayingBackwards; if (mPlayingState == RUNNING) { long currentTime = AnimationUtils.currentAnimationTimeMillis(); long currentPlayTime = currentTime - mStartTime; long timeLeft = mDuration - currentPlayTime; mStartTime = currentTime - timeLeft; } else if (mStarted) { end(); } else { start(true); } } /** * @hide */ @Override public boolean canReverse() { return true; } /** * Called internally to end an animation by removing it from the animations list. Must be * called on the UI thread. * @hide */ protected void endAnimation(AnimationHandler handler) { handler.mAnimations.remove(this); handler.mPendingAnimations.remove(this); handler.mDelayedAnims.remove(this); mPlayingState = STOPPED; mPaused = false; if ((mStarted || mRunning) && mListeners != null) { if (!mRunning) { // If it's not yet running, then start listeners weren't called. Call them now. notifyStartListeners(); } ArrayList tmpListeners = (ArrayList) mListeners.clone(); int numListeners = tmpListeners.size(); for (int i = 0; i < numListeners; ++i) { tmpListeners.get(i).onAnimationEnd(this); } } mRunning = false; mStarted = false; mStartListenersCalled = false; mPlayingBackwards = false; if (Trace.isTagEnabled(Trace.TRACE_TAG_VIEW)) { Trace.asyncTraceEnd(Trace.TRACE_TAG_VIEW, getNameForTrace(), System.identityHashCode(this)); } } /** * Called internally to start an animation by adding it to the active animations list. Must be * called on the UI thread. */ private void startAnimation(AnimationHandler handler) { if (Trace.isTagEnabled(Trace.TRACE_TAG_VIEW)) { Trace.asyncTraceBegin(Trace.TRACE_TAG_VIEW, getNameForTrace(), System.identityHashCode(this)); } initAnimation(); handler.mAnimations.add(this); if (mStartDelay > 0 && mListeners != null) { // Listeners were already notified in start() if startDelay is 0; this is // just for delayed animations notifyStartListeners(); } } /** * Returns the name of this animator for debugging purposes. */ String getNameForTrace() { return "animator"; } /** * Internal function called to process an animation frame on an animation that is currently * sleeping through its startDelay phase. The return value indicates whether it * should be woken up and put on the active animations queue. * * @param currentTime The current animation time, used to calculate whether the animation * has exceeded its startDelay and should be started. * @return True if the animation's startDelay has been exceeded and the animation * should be added to the set of active animations. */ private boolean delayedAnimationFrame(long currentTime) { if (!mStartedDelay) { mStartedDelay = true; mDelayStartTime = currentTime; } if (mPaused) { if (mPauseTime < 0) { mPauseTime = currentTime; } return false; } else if (mResumed) { mResumed = false; if (mPauseTime > 0) { // Offset by the duration that the animation was paused mDelayStartTime += (currentTime - mPauseTime); } } long deltaTime = currentTime - mDelayStartTime; if (deltaTime > mStartDelay) { // startDelay ended - start the anim and record the // mStartTime appropriately mStartTime = currentTime - (deltaTime - mStartDelay); mPlayingState = RUNNING; return true; } return false; } /** * This internal function processes a single animation frame for a given animation. The * currentTime parameter is the timing pulse sent by the handler, used to calculate the * elapsed duration, and therefore * the elapsed fraction, of the animation. The return value indicates whether the animation * should be ended (which happens when the elapsed time of the animation exceeds the * animation's duration, including the repeatCount). * * @param currentTime The current time, as tracked by the static timing handler * @return true if the animation's duration, including any repetitions due to * repeatCount, has been exceeded and the animation should be ended. */ boolean animationFrame(long currentTime) { boolean done = false; switch (mPlayingState) { case RUNNING: case SEEKED: float fraction = mDuration > 0 ? (float)(currentTime - mStartTime) / mDuration : 1f; if (fraction >= 1f) { if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { // Time to repeat if (mListeners != null) { int numListeners = mListeners.size(); for (int i = 0; i < numListeners; ++i) { mListeners.get(i).onAnimationRepeat(this); } } if (mRepeatMode == REVERSE) { mPlayingBackwards = !mPlayingBackwards; } mCurrentIteration += (int)fraction; fraction = fraction % 1f; mStartTime += mDuration; } else { done = true; fraction = Math.min(fraction, 1.0f); } } if (mPlayingBackwards) { fraction = 1f - fraction; } animateValue(fraction); break; } return done; } /** * Processes a frame of the animation, adjusting the start time if needed. * * @param frameTime The frame time. * @return true if the animation has ended. */ final boolean doAnimationFrame(long frameTime) { if (mPlayingState == STOPPED) { mPlayingState = RUNNING; if (mSeekTime < 0) { mStartTime = frameTime; } else { mStartTime = frameTime - mSeekTime; // Now that we're playing, reset the seek time mSeekTime = -1; } } if (mPaused) { if (mPauseTime < 0) { mPauseTime = frameTime; } return false; } else if (mResumed) { mResumed = false; if (mPauseTime > 0) { // Offset by the duration that the animation was paused mStartTime += (frameTime - mPauseTime); } } // The frame time might be before the start time during the first frame of // an animation. The "current time" must always be on or after the start // time to avoid animating frames at negative time intervals. In practice, this // is very rare and only happens when seeking backwards. final long currentTime = Math.max(frameTime, mStartTime); return animationFrame(currentTime); } /** * Returns the current animation fraction, which is the elapsed/interpolated fraction used in * the most recent frame update on the animation. * * @return Elapsed/interpolated fraction of the animation. */ public float getAnimatedFraction() { return mCurrentFraction; } /** * This method is called with the elapsed fraction of the animation during every * animation frame. This function turns the elapsed fraction into an interpolated fraction * and then into an animated value (from the evaluator. The function is called mostly during * animation updates, but it is also called when the end() * function is called, to set the final value on the property. * *

Overrides of this method must call the superclass to perform the calculation * of the animated value.

* * @param fraction The elapsed fraction of the animation. */ void animateValue(float fraction) { fraction = mInterpolator.getInterpolation(fraction); mCurrentFraction = fraction; int numValues = mValues.length; for (int i = 0; i < numValues; ++i) { mValues[i].calculateValue(fraction); } if (mUpdateListeners != null) { int numListeners = mUpdateListeners.size(); for (int i = 0; i < numListeners; ++i) { mUpdateListeners.get(i).onAnimationUpdate(this); } } } @Override public ValueAnimator clone() { final ValueAnimator anim = (ValueAnimator) super.clone(); if (mUpdateListeners != null) { ArrayList oldListeners = mUpdateListeners; anim.mUpdateListeners = new ArrayList(); int numListeners = oldListeners.size(); for (int i = 0; i < numListeners; ++i) { anim.mUpdateListeners.add(oldListeners.get(i)); } } anim.mSeekTime = -1; anim.mPlayingBackwards = false; anim.mCurrentIteration = 0; anim.mInitialized = false; anim.mPlayingState = STOPPED; anim.mStartedDelay = false; PropertyValuesHolder[] oldValues = mValues; if (oldValues != null) { int numValues = oldValues.length; anim.mValues = new PropertyValuesHolder[numValues]; anim.mValuesMap = new HashMap(numValues); for (int i = 0; i < numValues; ++i) { PropertyValuesHolder newValuesHolder = oldValues[i].clone(); anim.mValues[i] = newValuesHolder; anim.mValuesMap.put(newValuesHolder.getPropertyName(), newValuesHolder); } } return anim; } /** * Implementors of this interface can add themselves as update listeners * to an ValueAnimator instance to receive callbacks on every animation * frame, after the current frame's values have been calculated for that * ValueAnimator. */ public static interface AnimatorUpdateListener { /** *

Notifies the occurrence of another frame of the animation.

* * @param animation The animation which was repeated. */ void onAnimationUpdate(ValueAnimator animation); } /** * Return the number of animations currently running. * * Used by StrictMode internally to annotate violations. * May be called on arbitrary threads! * * @hide */ public static int getCurrentAnimationsCount() { AnimationHandler handler = sAnimationHandler.get(); return handler != null ? handler.mAnimations.size() : 0; } /** * Clear all animations on this thread, without canceling or ending them. * This should be used with caution. * * @hide */ public static void clearAllAnimations() { AnimationHandler handler = sAnimationHandler.get(); if (handler != null) { handler.mAnimations.clear(); handler.mPendingAnimations.clear(); handler.mDelayedAnims.clear(); } } private static AnimationHandler getOrCreateAnimationHandler() { AnimationHandler handler = sAnimationHandler.get(); if (handler == null) { handler = new AnimationHandler(); sAnimationHandler.set(handler); } return handler; } @Override public String toString() { String returnVal = "ValueAnimator@" + Integer.toHexString(hashCode()); if (mValues != null) { for (int i = 0; i < mValues.length; ++i) { returnVal += "\n " + mValues[i].toString(); } } return returnVal; } /** *

Whether or not the ValueAnimator is allowed to run asynchronously off of * the UI thread. This is a hint that informs the ValueAnimator that it is * OK to run the animation off-thread, however ValueAnimator may decide * that it must run the animation on the UI thread anyway. For example if there * is an {@link AnimatorUpdateListener} the animation will run on the UI thread, * regardless of the value of this hint.

* *

Regardless of whether or not the animation runs asynchronously, all * listener callbacks will be called on the UI thread.

* *

To be able to use this hint the following must be true:

*
    *
  1. {@link #getAnimatedFraction()} is not needed (it will return undefined values).
  2. *
  3. The animator is immutable while {@link #isStarted()} is true. Requests * to change values, duration, delay, etc... may be ignored.
  4. *
  5. Lifecycle callback events may be asynchronous. Events such as * {@link Animator.AnimatorListener#onAnimationEnd(Animator)} or * {@link Animator.AnimatorListener#onAnimationRepeat(Animator)} may end up delayed * as they must be posted back to the UI thread, and any actions performed * by those callbacks (such as starting new animations) will not happen * in the same frame.
  6. *
  7. State change requests ({@link #cancel()}, {@link #end()}, {@link #reverse()}, etc...) * may be asynchronous. It is guaranteed that all state changes that are * performed on the UI thread in the same frame will be applied as a single * atomic update, however that frame may be the current frame, * the next frame, or some future frame. This will also impact the observed * state of the Animator. For example, {@link #isStarted()} may still return true * after a call to {@link #end()}. Using the lifecycle callbacks is preferred over * queries to {@link #isStarted()}, {@link #isRunning()}, and {@link #isPaused()} * for this reason.
  8. *
* @hide */ @Override public void setAllowRunningAsynchronously(boolean mayRunAsync) { // It is up to subclasses to support this, if they can. } }