/* * 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.Handler; import android.os.Looper; import android.os.Message; import android.util.AndroidRuntimeException; 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)}.
*/ public class ValueAnimator extends Animator { /** * Internal constants */ /* * The default amount of time in ms between animation frames */ private static final long DEFAULT_FRAME_DELAY = 10; /** * Messages sent to timing handler: START is sent when an animation first begins, FRAME is sent * by the handler to itself to process the next animation frame */ private static final int ANIMATION_START = 0; private static final int ANIMATION_FRAME = 1; /** * 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; // TODO: We access the following ThreadLocal variables often, some of them on every update. // If ThreadLocal access is significantly expensive, we may want to put all of these // fields into a structure sot hat we just access ThreadLocal once to get the reference // to that structure, then access the structure directly for each field. // The static sAnimationHandler processes the internal timing loop on which all animations // are based private static ThreadLocalrepeatCount
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;
/**
* 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 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(new PropertyValuesHolder[]{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(new PropertyValuesHolder[]{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(new PropertyValuesHolder[]{PropertyValuesHolder.ofObject("", (TypeEvaluator)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 an 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 HashMapstartDelay
, 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 inValueAnimator.ofInt(0, 10).setDuration(500).start()
.
*/
public ValueAnimator setDuration(long duration) {
if (duration < 0) {
throw new IllegalArgumentException("Animators cannot have negative duration: " +
duration);
}
mDuration = duration;
return this;
}
/**
* Gets the length of the animation. The default duration is 300 milliseconds.
*
* @return The length of the animation, in milliseconds.
*/
public long getDuration() {
return mDuration;
}
/**
* 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;
animationFrame(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.
*
*/
private static class AnimationHandler extends Handler {
/**
* There are only two messages that we care about: ANIMATION_START and
* ANIMATION_FRAME. The START message is sent when an animation's start()
* method is called. It cannot start synchronously when start() is called
* because the call may be on the wrong thread, and it would also not be
* synchronized with other animations because it would not start on a common
* timing pulse. So each animation sends a START message to the handler, which
* causes the handler to place the animation on the active animations queue and
* start processing frames for that animation.
* The FRAME message is the one that is sent over and over while there are any
* active animations to process.
*/
@Override
public void handleMessage(Message msg) {
boolean callAgain = true;
ArrayListValueAnimator
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 ArrayListnull
* 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.
*/
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); } } /** * 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; mStartedDelay = false; sPendingAnimations.get().add(this); if (mStartDelay == 0) { // This sets the initial value of the animation, prior to actually starting it running setCurrentPlayTime(getCurrentPlayTime()); mPlayingState = STOPPED; if (mListeners != null) { ArrayListstartDelay
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;
} else {
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;
if (mPlayingState == STOPPED) {
mPlayingState = RUNNING;
if (mSeekTime < 0) {
mStartTime = currentTime;
} else {
mStartTime = currentTime - mSeekTime;
// Now that we're playing, reset the seek time
mSeekTime = -1;
}
}
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 ? false : true;
}
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;
}
/**
* 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) { ArrayListValueAnimator
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. Only * called on the main thread. * * @hide */ public static int getCurrentAnimationsCount() { return sAnimations.get().size(); } /** * Clear all animations on this thread, without canceling or ending them. * This should be used with caution. * * @hide */ public static void clearAllAnimations() { sAnimations.get().clear(); sPendingAnimations.get().clear(); sDelayedAnims.get().clear(); } @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; } }