ValueAnimator.java revision d422dc358f0100106dc07d7b903201eb9b043b11
1/* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.animation; 18 19import android.content.res.ConfigurationBoundResourceCache; 20import android.os.Looper; 21import android.os.Trace; 22import android.util.AndroidRuntimeException; 23import android.view.Choreographer; 24import android.view.animation.AccelerateDecelerateInterpolator; 25import android.view.animation.AnimationUtils; 26import android.view.animation.LinearInterpolator; 27 28import java.util.ArrayList; 29import java.util.HashMap; 30 31/** 32 * This class provides a simple timing engine for running animations 33 * which calculate animated values and set them on target objects. 34 * 35 * <p>There is a single timing pulse that all animations use. It runs in a 36 * custom handler to ensure that property changes happen on the UI thread.</p> 37 * 38 * <p>By default, ValueAnimator uses non-linear time interpolation, via the 39 * {@link AccelerateDecelerateInterpolator} class, which accelerates into and decelerates 40 * out of an animation. This behavior can be changed by calling 41 * {@link ValueAnimator#setInterpolator(TimeInterpolator)}.</p> 42 * 43 * <div class="special reference"> 44 * <h3>Developer Guides</h3> 45 * <p>For more information about animating with {@code ValueAnimator}, read the 46 * <a href="{@docRoot}guide/topics/graphics/prop-animation.html#value-animator">Property 47 * Animation</a> developer guide.</p> 48 * </div> 49 */ 50@SuppressWarnings("unchecked") 51public class ValueAnimator extends Animator { 52 53 /** 54 * Internal constants 55 */ 56 private static float sDurationScale = 1.0f; 57 58 /** 59 * Values used with internal variable mPlayingState to indicate the current state of an 60 * animation. 61 */ 62 static final int STOPPED = 0; // Not yet playing 63 static final int RUNNING = 1; // Playing normally 64 static final int SEEKED = 2; // Seeked to some time value 65 66 /** 67 * Internal variables 68 * NOTE: This object implements the clone() method, making a deep copy of any referenced 69 * objects. As other non-trivial fields are added to this class, make sure to add logic 70 * to clone() to make deep copies of them. 71 */ 72 73 // The first time that the animation's animateFrame() method is called. This time is used to 74 // determine elapsed time (and therefore the elapsed fraction) in subsequent calls 75 // to animateFrame() 76 long mStartTime; 77 78 /** 79 * Set when setCurrentPlayTime() is called. If negative, animation is not currently seeked 80 * to a value. 81 */ 82 long mSeekTime = -1; 83 84 /** 85 * Set on the next frame after pause() is called, used to calculate a new startTime 86 * or delayStartTime which allows the animator to continue from the point at which 87 * it was paused. If negative, has not yet been set. 88 */ 89 private long mPauseTime; 90 91 /** 92 * Set when an animator is resumed. This triggers logic in the next frame which 93 * actually resumes the animator. 94 */ 95 private boolean mResumed = false; 96 97 98 // The static sAnimationHandler processes the internal timing loop on which all animations 99 // are based 100 /** 101 * @hide 102 */ 103 protected static ThreadLocal<AnimationHandler> sAnimationHandler = 104 new ThreadLocal<AnimationHandler>(); 105 106 // The time interpolator to be used if none is set on the animation 107 private static final TimeInterpolator sDefaultInterpolator = 108 new AccelerateDecelerateInterpolator(); 109 110 /** 111 * Used to indicate whether the animation is currently playing in reverse. This causes the 112 * elapsed fraction to be inverted to calculate the appropriate values. 113 */ 114 private boolean mPlayingBackwards = false; 115 116 /** 117 * This variable tracks the current iteration that is playing. When mCurrentIteration exceeds the 118 * repeatCount (if repeatCount!=INFINITE), the animation ends 119 */ 120 private int mCurrentIteration = 0; 121 122 /** 123 * Tracks current elapsed/eased fraction, for querying in getAnimatedFraction(). 124 */ 125 private float mCurrentFraction = 0f; 126 127 /** 128 * Tracks whether a startDelay'd animation has begun playing through the startDelay. 129 */ 130 private boolean mStartedDelay = false; 131 132 /** 133 * Tracks the time at which the animation began playing through its startDelay. This is 134 * different from the mStartTime variable, which is used to track when the animation became 135 * active (which is when the startDelay expired and the animation was added to the active 136 * animations list). 137 */ 138 private long mDelayStartTime; 139 140 /** 141 * Flag that represents the current state of the animation. Used to figure out when to start 142 * an animation (if state == STOPPED). Also used to end an animation that 143 * has been cancel()'d or end()'d since the last animation frame. Possible values are 144 * STOPPED, RUNNING, SEEKED. 145 */ 146 int mPlayingState = STOPPED; 147 148 /** 149 * Additional playing state to indicate whether an animator has been start()'d. There is 150 * some lag between a call to start() and the first animation frame. We should still note 151 * that the animation has been started, even if it's first animation frame has not yet 152 * happened, and reflect that state in isRunning(). 153 * Note that delayed animations are different: they are not started until their first 154 * animation frame, which occurs after their delay elapses. 155 */ 156 private boolean mRunning = false; 157 158 /** 159 * Additional playing state to indicate whether an animator has been start()'d, whether or 160 * not there is a nonzero startDelay. 161 */ 162 private boolean mStarted = false; 163 164 /** 165 * Tracks whether we've notified listeners of the onAnimationStart() event. This can be 166 * complex to keep track of since we notify listeners at different times depending on 167 * startDelay and whether start() was called before end(). 168 */ 169 private boolean mStartListenersCalled = false; 170 171 /** 172 * Flag that denotes whether the animation is set up and ready to go. Used to 173 * set up animation that has not yet been started. 174 */ 175 boolean mInitialized = false; 176 177 // 178 // Backing variables 179 // 180 181 // How long the animation should last in ms 182 private long mDuration = (long)(300 * sDurationScale); 183 private long mUnscaledDuration = 300; 184 185 // The amount of time in ms to delay starting the animation after start() is called 186 private long mStartDelay = 0; 187 private long mUnscaledStartDelay = 0; 188 189 // The number of times the animation will repeat. The default is 0, which means the animation 190 // will play only once 191 private int mRepeatCount = 0; 192 193 /** 194 * The type of repetition that will occur when repeatMode is nonzero. RESTART means the 195 * animation will start from the beginning on every new cycle. REVERSE means the animation 196 * will reverse directions on each iteration. 197 */ 198 private int mRepeatMode = RESTART; 199 200 /** 201 * The time interpolator to be used. The elapsed fraction of the animation will be passed 202 * through this interpolator to calculate the interpolated fraction, which is then used to 203 * calculate the animated values. 204 */ 205 private TimeInterpolator mInterpolator = sDefaultInterpolator; 206 207 /** 208 * The set of listeners to be sent events through the life of an animation. 209 */ 210 ArrayList<AnimatorUpdateListener> mUpdateListeners = null; 211 212 /** 213 * The property/value sets being animated. 214 */ 215 PropertyValuesHolder[] mValues; 216 217 /** 218 * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values 219 * by property name during calls to getAnimatedValue(String). 220 */ 221 HashMap<String, PropertyValuesHolder> mValuesMap; 222 223 /** 224 * Public constants 225 */ 226 227 /** 228 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 229 * or a positive value, the animation restarts from the beginning. 230 */ 231 public static final int RESTART = 1; 232 /** 233 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 234 * or a positive value, the animation reverses direction on every iteration. 235 */ 236 public static final int REVERSE = 2; 237 /** 238 * This value used used with the {@link #setRepeatCount(int)} property to repeat 239 * the animation indefinitely. 240 */ 241 public static final int INFINITE = -1; 242 243 244 /** 245 * @hide 246 */ 247 public static void setDurationScale(float durationScale) { 248 sDurationScale = durationScale; 249 } 250 251 /** 252 * @hide 253 */ 254 public static float getDurationScale() { 255 return sDurationScale; 256 } 257 258 /** 259 * Creates a new ValueAnimator object. This default constructor is primarily for 260 * use internally; the factory methods which take parameters are more generally 261 * useful. 262 */ 263 public ValueAnimator() { 264 } 265 266 /** 267 * Constructs and returns a ValueAnimator that animates between int values. A single 268 * value implies that that value is the one being animated to. However, this is not typically 269 * useful in a ValueAnimator object because there is no way for the object to determine the 270 * starting value for the animation (unlike ObjectAnimator, which can derive that value 271 * from the target object and property being animated). Therefore, there should typically 272 * be two or more values. 273 * 274 * @param values A set of values that the animation will animate between over time. 275 * @return A ValueAnimator object that is set up to animate between the given values. 276 */ 277 public static ValueAnimator ofInt(int... values) { 278 ValueAnimator anim = new ValueAnimator(); 279 anim.setIntValues(values); 280 return anim; 281 } 282 283 /** 284 * Constructs and returns a ValueAnimator that animates between color values. A single 285 * value implies that that value is the one being animated to. However, this is not typically 286 * useful in a ValueAnimator object because there is no way for the object to determine the 287 * starting value for the animation (unlike ObjectAnimator, which can derive that value 288 * from the target object and property being animated). Therefore, there should typically 289 * be two or more values. 290 * 291 * @param values A set of values that the animation will animate between over time. 292 * @return A ValueAnimator object that is set up to animate between the given values. 293 */ 294 public static ValueAnimator ofArgb(int... values) { 295 ValueAnimator anim = new ValueAnimator(); 296 anim.setIntValues(values); 297 anim.setEvaluator(ArgbEvaluator.getInstance()); 298 return anim; 299 } 300 301 /** 302 * Constructs and returns a ValueAnimator that animates between float values. A single 303 * value implies that that value is the one being animated to. However, this is not typically 304 * useful in a ValueAnimator object because there is no way for the object to determine the 305 * starting value for the animation (unlike ObjectAnimator, which can derive that value 306 * from the target object and property being animated). Therefore, there should typically 307 * be two or more values. 308 * 309 * @param values A set of values that the animation will animate between over time. 310 * @return A ValueAnimator object that is set up to animate between the given values. 311 */ 312 public static ValueAnimator ofFloat(float... values) { 313 ValueAnimator anim = new ValueAnimator(); 314 anim.setFloatValues(values); 315 return anim; 316 } 317 318 /** 319 * Constructs and returns a ValueAnimator that animates between the values 320 * specified in the PropertyValuesHolder objects. 321 * 322 * @param values A set of PropertyValuesHolder objects whose values will be animated 323 * between over time. 324 * @return A ValueAnimator object that is set up to animate between the given values. 325 */ 326 public static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values) { 327 ValueAnimator anim = new ValueAnimator(); 328 anim.setValues(values); 329 return anim; 330 } 331 /** 332 * Constructs and returns a ValueAnimator that animates between Object values. A single 333 * value implies that that value is the one being animated to. However, this is not typically 334 * useful in a ValueAnimator object because there is no way for the object to determine the 335 * starting value for the animation (unlike ObjectAnimator, which can derive that value 336 * from the target object and property being animated). Therefore, there should typically 337 * be two or more values. 338 * 339 * <p>Since ValueAnimator does not know how to animate between arbitrary Objects, this 340 * factory method also takes a TypeEvaluator object that the ValueAnimator will use 341 * to perform that interpolation. 342 * 343 * @param evaluator A TypeEvaluator that will be called on each animation frame to 344 * provide the ncessry interpolation between the Object values to derive the animated 345 * value. 346 * @param values A set of values that the animation will animate between over time. 347 * @return A ValueAnimator object that is set up to animate between the given values. 348 */ 349 public static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values) { 350 ValueAnimator anim = new ValueAnimator(); 351 anim.setObjectValues(values); 352 anim.setEvaluator(evaluator); 353 return anim; 354 } 355 356 /** 357 * Sets int values that will be animated between. A single 358 * value implies that that value is the one being animated to. However, this is not typically 359 * useful in a ValueAnimator object because there is no way for the object to determine the 360 * starting value for the animation (unlike ObjectAnimator, which can derive that value 361 * from the target object and property being animated). Therefore, there should typically 362 * be two or more values. 363 * 364 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 365 * than one PropertyValuesHolder object, this method will set the values for the first 366 * of those objects.</p> 367 * 368 * @param values A set of values that the animation will animate between over time. 369 */ 370 public void setIntValues(int... values) { 371 if (values == null || values.length == 0) { 372 return; 373 } 374 if (mValues == null || mValues.length == 0) { 375 setValues(PropertyValuesHolder.ofInt("", values)); 376 } else { 377 PropertyValuesHolder valuesHolder = mValues[0]; 378 valuesHolder.setIntValues(values); 379 } 380 // New property/values/target should cause re-initialization prior to starting 381 mInitialized = false; 382 } 383 384 /** 385 * Sets float values that will be animated between. A single 386 * value implies that that value is the one being animated to. However, this is not typically 387 * useful in a ValueAnimator object because there is no way for the object to determine the 388 * starting value for the animation (unlike ObjectAnimator, which can derive that value 389 * from the target object and property being animated). Therefore, there should typically 390 * be two or more values. 391 * 392 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 393 * than one PropertyValuesHolder object, this method will set the values for the first 394 * of those objects.</p> 395 * 396 * @param values A set of values that the animation will animate between over time. 397 */ 398 public void setFloatValues(float... values) { 399 if (values == null || values.length == 0) { 400 return; 401 } 402 if (mValues == null || mValues.length == 0) { 403 setValues(PropertyValuesHolder.ofFloat("", values)); 404 } else { 405 PropertyValuesHolder valuesHolder = mValues[0]; 406 valuesHolder.setFloatValues(values); 407 } 408 // New property/values/target should cause re-initialization prior to starting 409 mInitialized = false; 410 } 411 412 /** 413 * Sets the values to animate between for this animation. A single 414 * value implies that that value is the one being animated to. However, this is not typically 415 * useful in a ValueAnimator object because there is no way for the object to determine the 416 * starting value for the animation (unlike ObjectAnimator, which can derive that value 417 * from the target object and property being animated). Therefore, there should typically 418 * be two or more values. 419 * 420 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 421 * than one PropertyValuesHolder object, this method will set the values for the first 422 * of those objects.</p> 423 * 424 * <p>There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate 425 * between these value objects. ValueAnimator only knows how to interpolate between the 426 * primitive types specified in the other setValues() methods.</p> 427 * 428 * @param values The set of values to animate between. 429 */ 430 public void setObjectValues(Object... values) { 431 if (values == null || values.length == 0) { 432 return; 433 } 434 if (mValues == null || mValues.length == 0) { 435 setValues(PropertyValuesHolder.ofObject("", null, values)); 436 } else { 437 PropertyValuesHolder valuesHolder = mValues[0]; 438 valuesHolder.setObjectValues(values); 439 } 440 // New property/values/target should cause re-initialization prior to starting 441 mInitialized = false; 442 } 443 444 /** 445 * Sets the values, per property, being animated between. This function is called internally 446 * by the constructors of ValueAnimator that take a list of values. But a ValueAnimator can 447 * be constructed without values and this method can be called to set the values manually 448 * instead. 449 * 450 * @param values The set of values, per property, being animated between. 451 */ 452 public void setValues(PropertyValuesHolder... values) { 453 int numValues = values.length; 454 mValues = values; 455 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 456 for (int i = 0; i < numValues; ++i) { 457 PropertyValuesHolder valuesHolder = values[i]; 458 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 459 } 460 // New property/values/target should cause re-initialization prior to starting 461 mInitialized = false; 462 } 463 464 /** 465 * Returns the values that this ValueAnimator animates between. These values are stored in 466 * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list 467 * of value objects instead. 468 * 469 * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the 470 * values, per property, that define the animation. 471 */ 472 public PropertyValuesHolder[] getValues() { 473 return mValues; 474 } 475 476 /** 477 * This function is called immediately before processing the first animation 478 * frame of an animation. If there is a nonzero <code>startDelay</code>, the 479 * function is called after that delay ends. 480 * It takes care of the final initialization steps for the 481 * animation. 482 * 483 * <p>Overrides of this method should call the superclass method to ensure 484 * that internal mechanisms for the animation are set up correctly.</p> 485 */ 486 void initAnimation() { 487 if (!mInitialized) { 488 int numValues = mValues.length; 489 for (int i = 0; i < numValues; ++i) { 490 mValues[i].init(); 491 } 492 mInitialized = true; 493 } 494 } 495 496 497 /** 498 * Sets the length of the animation. The default duration is 300 milliseconds. 499 * 500 * @param duration The length of the animation, in milliseconds. This value cannot 501 * be negative. 502 * @return ValueAnimator The object called with setDuration(). This return 503 * value makes it easier to compose statements together that construct and then set the 504 * duration, as in <code>ValueAnimator.ofInt(0, 10).setDuration(500).start()</code>. 505 */ 506 public ValueAnimator setDuration(long duration) { 507 if (duration < 0) { 508 throw new IllegalArgumentException("Animators cannot have negative duration: " + 509 duration); 510 } 511 mUnscaledDuration = duration; 512 updateScaledDuration(); 513 return this; 514 } 515 516 private void updateScaledDuration() { 517 mDuration = (long)(mUnscaledDuration * sDurationScale); 518 } 519 520 /** 521 * Gets the length of the animation. The default duration is 300 milliseconds. 522 * 523 * @return The length of the animation, in milliseconds. 524 */ 525 public long getDuration() { 526 return mUnscaledDuration; 527 } 528 529 /** 530 * Sets the position of the animation to the specified point in time. This time should 531 * be between 0 and the total duration of the animation, including any repetition. If 532 * the animation has not yet been started, then it will not advance forward after it is 533 * set to this time; it will simply set the time to this value and perform any appropriate 534 * actions based on that time. If the animation is already running, then setCurrentPlayTime() 535 * will set the current playing time to this value and continue playing from that point. 536 * 537 * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. 538 */ 539 public void setCurrentPlayTime(long playTime) { 540 initAnimation(); 541 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 542 if (mPlayingState != RUNNING) { 543 mSeekTime = playTime; 544 mPlayingState = SEEKED; 545 } 546 mStartTime = currentTime - playTime; 547 doAnimationFrame(currentTime); 548 } 549 550 /** 551 * Gets the current position of the animation in time, which is equal to the current 552 * time minus the time that the animation started. An animation that is not yet started will 553 * return a value of zero. 554 * 555 * @return The current position in time of the animation. 556 */ 557 public long getCurrentPlayTime() { 558 if (!mInitialized || mPlayingState == STOPPED) { 559 return 0; 560 } 561 return AnimationUtils.currentAnimationTimeMillis() - mStartTime; 562 } 563 564 /** 565 * This custom, static handler handles the timing pulse that is shared by 566 * all active animations. This approach ensures that the setting of animation 567 * values will happen on the UI thread and that all animations will share 568 * the same times for calculating their values, which makes synchronizing 569 * animations possible. 570 * 571 * The handler uses the Choreographer for executing periodic callbacks. 572 * 573 * @hide 574 */ 575 @SuppressWarnings("unchecked") 576 protected static class AnimationHandler implements Runnable { 577 // The per-thread list of all active animations 578 /** @hide */ 579 protected final ArrayList<ValueAnimator> mAnimations = new ArrayList<ValueAnimator>(); 580 581 // Used in doAnimationFrame() to avoid concurrent modifications of mAnimations 582 private final ArrayList<ValueAnimator> mTmpAnimations = new ArrayList<ValueAnimator>(); 583 584 // The per-thread set of animations to be started on the next animation frame 585 /** @hide */ 586 protected final ArrayList<ValueAnimator> mPendingAnimations = new ArrayList<ValueAnimator>(); 587 588 /** 589 * Internal per-thread collections used to avoid set collisions as animations start and end 590 * while being processed. 591 * @hide 592 */ 593 protected final ArrayList<ValueAnimator> mDelayedAnims = new ArrayList<ValueAnimator>(); 594 private final ArrayList<ValueAnimator> mEndingAnims = new ArrayList<ValueAnimator>(); 595 private final ArrayList<ValueAnimator> mReadyAnims = new ArrayList<ValueAnimator>(); 596 597 private final Choreographer mChoreographer; 598 private boolean mAnimationScheduled; 599 600 private AnimationHandler() { 601 mChoreographer = Choreographer.getInstance(); 602 } 603 604 /** 605 * Start animating on the next frame. 606 */ 607 public void start() { 608 scheduleAnimation(); 609 } 610 611 private void doAnimationFrame(long frameTime) { 612 // mPendingAnimations holds any animations that have requested to be started 613 // We're going to clear mPendingAnimations, but starting animation may 614 // cause more to be added to the pending list (for example, if one animation 615 // starting triggers another starting). So we loop until mPendingAnimations 616 // is empty. 617 while (mPendingAnimations.size() > 0) { 618 ArrayList<ValueAnimator> pendingCopy = 619 (ArrayList<ValueAnimator>) mPendingAnimations.clone(); 620 mPendingAnimations.clear(); 621 int count = pendingCopy.size(); 622 for (int i = 0; i < count; ++i) { 623 ValueAnimator anim = pendingCopy.get(i); 624 // If the animation has a startDelay, place it on the delayed list 625 if (anim.mStartDelay == 0) { 626 anim.startAnimation(this); 627 } else { 628 mDelayedAnims.add(anim); 629 } 630 } 631 } 632 // Next, process animations currently sitting on the delayed queue, adding 633 // them to the active animations if they are ready 634 int numDelayedAnims = mDelayedAnims.size(); 635 for (int i = 0; i < numDelayedAnims; ++i) { 636 ValueAnimator anim = mDelayedAnims.get(i); 637 if (anim.delayedAnimationFrame(frameTime)) { 638 mReadyAnims.add(anim); 639 } 640 } 641 int numReadyAnims = mReadyAnims.size(); 642 if (numReadyAnims > 0) { 643 for (int i = 0; i < numReadyAnims; ++i) { 644 ValueAnimator anim = mReadyAnims.get(i); 645 anim.startAnimation(this); 646 anim.mRunning = true; 647 mDelayedAnims.remove(anim); 648 } 649 mReadyAnims.clear(); 650 } 651 652 // Now process all active animations. The return value from animationFrame() 653 // tells the handler whether it should now be ended 654 int numAnims = mAnimations.size(); 655 for (int i = 0; i < numAnims; ++i) { 656 mTmpAnimations.add(mAnimations.get(i)); 657 } 658 for (int i = 0; i < numAnims; ++i) { 659 ValueAnimator anim = mTmpAnimations.get(i); 660 if (mAnimations.contains(anim) && anim.doAnimationFrame(frameTime)) { 661 mEndingAnims.add(anim); 662 } 663 } 664 mTmpAnimations.clear(); 665 if (mEndingAnims.size() > 0) { 666 for (int i = 0; i < mEndingAnims.size(); ++i) { 667 mEndingAnims.get(i).endAnimation(this); 668 } 669 mEndingAnims.clear(); 670 } 671 672 // If there are still active or delayed animations, schedule a future call to 673 // onAnimate to process the next frame of the animations. 674 if (!mAnimations.isEmpty() || !mDelayedAnims.isEmpty()) { 675 scheduleAnimation(); 676 } 677 } 678 679 // Called by the Choreographer. 680 @Override 681 public void run() { 682 mAnimationScheduled = false; 683 doAnimationFrame(mChoreographer.getFrameTime()); 684 } 685 686 private void scheduleAnimation() { 687 if (!mAnimationScheduled) { 688 mChoreographer.postCallback(Choreographer.CALLBACK_ANIMATION, this, null); 689 mAnimationScheduled = true; 690 } 691 } 692 } 693 694 /** 695 * The amount of time, in milliseconds, to delay starting the animation after 696 * {@link #start()} is called. 697 * 698 * @return the number of milliseconds to delay running the animation 699 */ 700 public long getStartDelay() { 701 return mUnscaledStartDelay; 702 } 703 704 /** 705 * The amount of time, in milliseconds, to delay starting the animation after 706 * {@link #start()} is called. 707 708 * @param startDelay The amount of the delay, in milliseconds 709 */ 710 public void setStartDelay(long startDelay) { 711 this.mStartDelay = (long)(startDelay * sDurationScale); 712 mUnscaledStartDelay = startDelay; 713 } 714 715 /** 716 * The amount of time, in milliseconds, between each frame of the animation. This is a 717 * requested time that the animation will attempt to honor, but the actual delay between 718 * frames may be different, depending on system load and capabilities. This is a static 719 * function because the same delay will be applied to all animations, since they are all 720 * run off of a single timing loop. 721 * 722 * The frame delay may be ignored when the animation system uses an external timing 723 * source, such as the display refresh rate (vsync), to govern animations. 724 * 725 * @return the requested time between frames, in milliseconds 726 */ 727 public static long getFrameDelay() { 728 return Choreographer.getFrameDelay(); 729 } 730 731 /** 732 * The amount of time, in milliseconds, between each frame of the animation. This is a 733 * requested time that the animation will attempt to honor, but the actual delay between 734 * frames may be different, depending on system load and capabilities. This is a static 735 * function because the same delay will be applied to all animations, since they are all 736 * run off of a single timing loop. 737 * 738 * The frame delay may be ignored when the animation system uses an external timing 739 * source, such as the display refresh rate (vsync), to govern animations. 740 * 741 * @param frameDelay the requested time between frames, in milliseconds 742 */ 743 public static void setFrameDelay(long frameDelay) { 744 Choreographer.setFrameDelay(frameDelay); 745 } 746 747 /** 748 * The most recent value calculated by this <code>ValueAnimator</code> when there is just one 749 * property being animated. This value is only sensible while the animation is running. The main 750 * purpose for this read-only property is to retrieve the value from the <code>ValueAnimator</code> 751 * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 752 * is called during each animation frame, immediately after the value is calculated. 753 * 754 * @return animatedValue The value most recently calculated by this <code>ValueAnimator</code> for 755 * the single property being animated. If there are several properties being animated 756 * (specified by several PropertyValuesHolder objects in the constructor), this function 757 * returns the animated value for the first of those objects. 758 */ 759 public Object getAnimatedValue() { 760 if (mValues != null && mValues.length > 0) { 761 return mValues[0].getAnimatedValue(); 762 } 763 // Shouldn't get here; should always have values unless ValueAnimator was set up wrong 764 return null; 765 } 766 767 /** 768 * The most recent value calculated by this <code>ValueAnimator</code> for <code>propertyName</code>. 769 * The main purpose for this read-only property is to retrieve the value from the 770 * <code>ValueAnimator</code> during a call to 771 * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 772 * is called during each animation frame, immediately after the value is calculated. 773 * 774 * @return animatedValue The value most recently calculated for the named property 775 * by this <code>ValueAnimator</code>. 776 */ 777 public Object getAnimatedValue(String propertyName) { 778 PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); 779 if (valuesHolder != null) { 780 return valuesHolder.getAnimatedValue(); 781 } else { 782 // At least avoid crashing if called with bogus propertyName 783 return null; 784 } 785 } 786 787 /** 788 * Sets how many times the animation should be repeated. If the repeat 789 * count is 0, the animation is never repeated. If the repeat count is 790 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken 791 * into account. The repeat count is 0 by default. 792 * 793 * @param value the number of times the animation should be repeated 794 */ 795 public void setRepeatCount(int value) { 796 mRepeatCount = value; 797 } 798 /** 799 * Defines how many times the animation should repeat. The default value 800 * is 0. 801 * 802 * @return the number of times the animation should repeat, or {@link #INFINITE} 803 */ 804 public int getRepeatCount() { 805 return mRepeatCount; 806 } 807 808 /** 809 * Defines what this animation should do when it reaches the end. This 810 * setting is applied only when the repeat count is either greater than 811 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 812 * 813 * @param value {@link #RESTART} or {@link #REVERSE} 814 */ 815 public void setRepeatMode(int value) { 816 mRepeatMode = value; 817 } 818 819 /** 820 * Defines what this animation should do when it reaches the end. 821 * 822 * @return either one of {@link #REVERSE} or {@link #RESTART} 823 */ 824 public int getRepeatMode() { 825 return mRepeatMode; 826 } 827 828 /** 829 * Adds a listener to the set of listeners that are sent update events through the life of 830 * an animation. This method is called on all listeners for every frame of the animation, 831 * after the values for the animation have been calculated. 832 * 833 * @param listener the listener to be added to the current set of listeners for this animation. 834 */ 835 public void addUpdateListener(AnimatorUpdateListener listener) { 836 if (mUpdateListeners == null) { 837 mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 838 } 839 mUpdateListeners.add(listener); 840 } 841 842 /** 843 * Removes all listeners from the set listening to frame updates for this animation. 844 */ 845 public void removeAllUpdateListeners() { 846 if (mUpdateListeners == null) { 847 return; 848 } 849 mUpdateListeners.clear(); 850 mUpdateListeners = null; 851 } 852 853 /** 854 * Removes a listener from the set listening to frame updates for this animation. 855 * 856 * @param listener the listener to be removed from the current set of update listeners 857 * for this animation. 858 */ 859 public void removeUpdateListener(AnimatorUpdateListener listener) { 860 if (mUpdateListeners == null) { 861 return; 862 } 863 mUpdateListeners.remove(listener); 864 if (mUpdateListeners.size() == 0) { 865 mUpdateListeners = null; 866 } 867 } 868 869 870 /** 871 * The time interpolator used in calculating the elapsed fraction of this animation. The 872 * interpolator determines whether the animation runs with linear or non-linear motion, 873 * such as acceleration and deceleration. The default value is 874 * {@link android.view.animation.AccelerateDecelerateInterpolator} 875 * 876 * @param value the interpolator to be used by this animation. A value of <code>null</code> 877 * will result in linear interpolation. 878 */ 879 @Override 880 public void setInterpolator(TimeInterpolator value) { 881 if (value != null) { 882 mInterpolator = value; 883 } else { 884 mInterpolator = new LinearInterpolator(); 885 } 886 } 887 888 /** 889 * Returns the timing interpolator that this ValueAnimator uses. 890 * 891 * @return The timing interpolator for this ValueAnimator. 892 */ 893 @Override 894 public TimeInterpolator getInterpolator() { 895 return mInterpolator; 896 } 897 898 /** 899 * The type evaluator to be used when calculating the animated values of this animation. 900 * The system will automatically assign a float or int evaluator based on the type 901 * of <code>startValue</code> and <code>endValue</code> in the constructor. But if these values 902 * are not one of these primitive types, or if different evaluation is desired (such as is 903 * necessary with int values that represent colors), a custom evaluator needs to be assigned. 904 * For example, when running an animation on color values, the {@link ArgbEvaluator} 905 * should be used to get correct RGB color interpolation. 906 * 907 * <p>If this ValueAnimator has only one set of values being animated between, this evaluator 908 * will be used for that set. If there are several sets of values being animated, which is 909 * the case if PropertyValuesHolder objects were set on the ValueAnimator, then the evaluator 910 * is assigned just to the first PropertyValuesHolder object.</p> 911 * 912 * @param value the evaluator to be used this animation 913 */ 914 public void setEvaluator(TypeEvaluator value) { 915 if (value != null && mValues != null && mValues.length > 0) { 916 mValues[0].setEvaluator(value); 917 } 918 } 919 920 private void notifyStartListeners() { 921 if (mListeners != null && !mStartListenersCalled) { 922 ArrayList<AnimatorListener> tmpListeners = 923 (ArrayList<AnimatorListener>) mListeners.clone(); 924 int numListeners = tmpListeners.size(); 925 for (int i = 0; i < numListeners; ++i) { 926 tmpListeners.get(i).onAnimationStart(this); 927 } 928 } 929 mStartListenersCalled = true; 930 } 931 932 /** 933 * Start the animation playing. This version of start() takes a boolean flag that indicates 934 * whether the animation should play in reverse. The flag is usually false, but may be set 935 * to true if called from the reverse() method. 936 * 937 * <p>The animation started by calling this method will be run on the thread that called 938 * this method. This thread should have a Looper on it (a runtime exception will be thrown if 939 * this is not the case). Also, if the animation will animate 940 * properties of objects in the view hierarchy, then the calling thread should be the UI 941 * thread for that view hierarchy.</p> 942 * 943 * @param playBackwards Whether the ValueAnimator should start playing in reverse. 944 */ 945 private void start(boolean playBackwards) { 946 if (Looper.myLooper() == null) { 947 throw new AndroidRuntimeException("Animators may only be run on Looper threads"); 948 } 949 mPlayingBackwards = playBackwards; 950 mCurrentIteration = 0; 951 mPlayingState = STOPPED; 952 mStarted = true; 953 mStartedDelay = false; 954 mPaused = false; 955 updateScaledDuration(); // in case the scale factor has changed since creation time 956 AnimationHandler animationHandler = getOrCreateAnimationHandler(); 957 animationHandler.mPendingAnimations.add(this); 958 if (mStartDelay == 0) { 959 // This sets the initial value of the animation, prior to actually starting it running 960 setCurrentPlayTime(0); 961 mPlayingState = STOPPED; 962 mRunning = true; 963 notifyStartListeners(); 964 } 965 animationHandler.start(); 966 } 967 968 @Override 969 public void start() { 970 start(false); 971 } 972 973 @Override 974 public void cancel() { 975 // Only cancel if the animation is actually running or has been started and is about 976 // to run 977 AnimationHandler handler = getOrCreateAnimationHandler(); 978 if (mPlayingState != STOPPED 979 || handler.mPendingAnimations.contains(this) 980 || handler.mDelayedAnims.contains(this)) { 981 // Only notify listeners if the animator has actually started 982 if ((mStarted || mRunning) && mListeners != null) { 983 if (!mRunning) { 984 // If it's not yet running, then start listeners weren't called. Call them now. 985 notifyStartListeners(); 986 } 987 ArrayList<AnimatorListener> tmpListeners = 988 (ArrayList<AnimatorListener>) mListeners.clone(); 989 for (AnimatorListener listener : tmpListeners) { 990 listener.onAnimationCancel(this); 991 } 992 } 993 endAnimation(handler); 994 } 995 } 996 997 @Override 998 public void end() { 999 AnimationHandler handler = getOrCreateAnimationHandler(); 1000 if (!handler.mAnimations.contains(this) && !handler.mPendingAnimations.contains(this)) { 1001 // Special case if the animation has not yet started; get it ready for ending 1002 mStartedDelay = false; 1003 startAnimation(handler); 1004 mStarted = true; 1005 } else if (!mInitialized) { 1006 initAnimation(); 1007 } 1008 animateValue(mPlayingBackwards ? 0f : 1f); 1009 endAnimation(handler); 1010 } 1011 1012 @Override 1013 public void resume() { 1014 if (mPaused) { 1015 mResumed = true; 1016 } 1017 super.resume(); 1018 } 1019 1020 @Override 1021 public void pause() { 1022 boolean previouslyPaused = mPaused; 1023 super.pause(); 1024 if (!previouslyPaused && mPaused) { 1025 mPauseTime = -1; 1026 mResumed = false; 1027 } 1028 } 1029 1030 @Override 1031 public boolean isRunning() { 1032 return (mPlayingState == RUNNING || mRunning); 1033 } 1034 1035 @Override 1036 public boolean isStarted() { 1037 return mStarted; 1038 } 1039 1040 /** 1041 * Plays the ValueAnimator in reverse. If the animation is already running, 1042 * it will stop itself and play backwards from the point reached when reverse was called. 1043 * If the animation is not currently running, then it will start from the end and 1044 * play backwards. This behavior is only set for the current animation; future playing 1045 * of the animation will use the default behavior of playing forward. 1046 */ 1047 @Override 1048 public void reverse() { 1049 mPlayingBackwards = !mPlayingBackwards; 1050 if (mPlayingState == RUNNING) { 1051 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 1052 long currentPlayTime = currentTime - mStartTime; 1053 long timeLeft = mDuration - currentPlayTime; 1054 mStartTime = currentTime - timeLeft; 1055 } else if (mStarted) { 1056 end(); 1057 } else { 1058 start(true); 1059 } 1060 } 1061 1062 /** 1063 * @hide 1064 */ 1065 @Override 1066 public boolean canReverse() { 1067 return true; 1068 } 1069 1070 /** 1071 * Called internally to end an animation by removing it from the animations list. Must be 1072 * called on the UI thread. 1073 * @hide 1074 */ 1075 protected void endAnimation(AnimationHandler handler) { 1076 handler.mAnimations.remove(this); 1077 handler.mPendingAnimations.remove(this); 1078 handler.mDelayedAnims.remove(this); 1079 mPlayingState = STOPPED; 1080 mPaused = false; 1081 if ((mStarted || mRunning) && mListeners != null) { 1082 if (!mRunning) { 1083 // If it's not yet running, then start listeners weren't called. Call them now. 1084 notifyStartListeners(); 1085 } 1086 ArrayList<AnimatorListener> tmpListeners = 1087 (ArrayList<AnimatorListener>) mListeners.clone(); 1088 int numListeners = tmpListeners.size(); 1089 for (int i = 0; i < numListeners; ++i) { 1090 tmpListeners.get(i).onAnimationEnd(this); 1091 } 1092 } 1093 mRunning = false; 1094 mStarted = false; 1095 mStartListenersCalled = false; 1096 mPlayingBackwards = false; 1097 if (Trace.isTagEnabled(Trace.TRACE_TAG_VIEW)) { 1098 Trace.asyncTraceEnd(Trace.TRACE_TAG_VIEW, getNameForTrace(), 1099 System.identityHashCode(this)); 1100 } 1101 } 1102 1103 /** 1104 * Called internally to start an animation by adding it to the active animations list. Must be 1105 * called on the UI thread. 1106 */ 1107 private void startAnimation(AnimationHandler handler) { 1108 if (Trace.isTagEnabled(Trace.TRACE_TAG_VIEW)) { 1109 Trace.asyncTraceBegin(Trace.TRACE_TAG_VIEW, getNameForTrace(), 1110 System.identityHashCode(this)); 1111 } 1112 initAnimation(); 1113 handler.mAnimations.add(this); 1114 if (mStartDelay > 0 && mListeners != null) { 1115 // Listeners were already notified in start() if startDelay is 0; this is 1116 // just for delayed animations 1117 notifyStartListeners(); 1118 } 1119 } 1120 1121 /** 1122 * Returns the name of this animator for debugging purposes. 1123 */ 1124 String getNameForTrace() { 1125 return "animator"; 1126 } 1127 1128 1129 /** 1130 * Internal function called to process an animation frame on an animation that is currently 1131 * sleeping through its <code>startDelay</code> phase. The return value indicates whether it 1132 * should be woken up and put on the active animations queue. 1133 * 1134 * @param currentTime The current animation time, used to calculate whether the animation 1135 * has exceeded its <code>startDelay</code> and should be started. 1136 * @return True if the animation's <code>startDelay</code> has been exceeded and the animation 1137 * should be added to the set of active animations. 1138 */ 1139 private boolean delayedAnimationFrame(long currentTime) { 1140 if (!mStartedDelay) { 1141 mStartedDelay = true; 1142 mDelayStartTime = currentTime; 1143 } 1144 if (mPaused) { 1145 if (mPauseTime < 0) { 1146 mPauseTime = currentTime; 1147 } 1148 return false; 1149 } else if (mResumed) { 1150 mResumed = false; 1151 if (mPauseTime > 0) { 1152 // Offset by the duration that the animation was paused 1153 mDelayStartTime += (currentTime - mPauseTime); 1154 } 1155 } 1156 long deltaTime = currentTime - mDelayStartTime; 1157 if (deltaTime > mStartDelay) { 1158 // startDelay ended - start the anim and record the 1159 // mStartTime appropriately 1160 mStartTime = currentTime - (deltaTime - mStartDelay); 1161 mPlayingState = RUNNING; 1162 return true; 1163 } 1164 return false; 1165 } 1166 1167 /** 1168 * This internal function processes a single animation frame for a given animation. The 1169 * currentTime parameter is the timing pulse sent by the handler, used to calculate the 1170 * elapsed duration, and therefore 1171 * the elapsed fraction, of the animation. The return value indicates whether the animation 1172 * should be ended (which happens when the elapsed time of the animation exceeds the 1173 * animation's duration, including the repeatCount). 1174 * 1175 * @param currentTime The current time, as tracked by the static timing handler 1176 * @return true if the animation's duration, including any repetitions due to 1177 * <code>repeatCount</code>, has been exceeded and the animation should be ended. 1178 */ 1179 boolean animationFrame(long currentTime) { 1180 boolean done = false; 1181 switch (mPlayingState) { 1182 case RUNNING: 1183 case SEEKED: 1184 float fraction = mDuration > 0 ? (float)(currentTime - mStartTime) / mDuration : 1f; 1185 if (fraction >= 1f) { 1186 if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { 1187 // Time to repeat 1188 if (mListeners != null) { 1189 int numListeners = mListeners.size(); 1190 for (int i = 0; i < numListeners; ++i) { 1191 mListeners.get(i).onAnimationRepeat(this); 1192 } 1193 } 1194 if (mRepeatMode == REVERSE) { 1195 mPlayingBackwards = !mPlayingBackwards; 1196 } 1197 mCurrentIteration += (int)fraction; 1198 fraction = fraction % 1f; 1199 mStartTime += mDuration; 1200 } else { 1201 done = true; 1202 fraction = Math.min(fraction, 1.0f); 1203 } 1204 } 1205 if (mPlayingBackwards) { 1206 fraction = 1f - fraction; 1207 } 1208 animateValue(fraction); 1209 break; 1210 } 1211 1212 return done; 1213 } 1214 1215 /** 1216 * Processes a frame of the animation, adjusting the start time if needed. 1217 * 1218 * @param frameTime The frame time. 1219 * @return true if the animation has ended. 1220 */ 1221 final boolean doAnimationFrame(long frameTime) { 1222 if (mPlayingState == STOPPED) { 1223 mPlayingState = RUNNING; 1224 if (mSeekTime < 0) { 1225 mStartTime = frameTime; 1226 } else { 1227 mStartTime = frameTime - mSeekTime; 1228 // Now that we're playing, reset the seek time 1229 mSeekTime = -1; 1230 } 1231 } 1232 if (mPaused) { 1233 if (mPauseTime < 0) { 1234 mPauseTime = frameTime; 1235 } 1236 return false; 1237 } else if (mResumed) { 1238 mResumed = false; 1239 if (mPauseTime > 0) { 1240 // Offset by the duration that the animation was paused 1241 mStartTime += (frameTime - mPauseTime); 1242 } 1243 } 1244 // The frame time might be before the start time during the first frame of 1245 // an animation. The "current time" must always be on or after the start 1246 // time to avoid animating frames at negative time intervals. In practice, this 1247 // is very rare and only happens when seeking backwards. 1248 final long currentTime = Math.max(frameTime, mStartTime); 1249 return animationFrame(currentTime); 1250 } 1251 1252 /** 1253 * Returns the current animation fraction, which is the elapsed/interpolated fraction used in 1254 * the most recent frame update on the animation. 1255 * 1256 * @return Elapsed/interpolated fraction of the animation. 1257 */ 1258 public float getAnimatedFraction() { 1259 return mCurrentFraction; 1260 } 1261 1262 /** 1263 * This method is called with the elapsed fraction of the animation during every 1264 * animation frame. This function turns the elapsed fraction into an interpolated fraction 1265 * and then into an animated value (from the evaluator. The function is called mostly during 1266 * animation updates, but it is also called when the <code>end()</code> 1267 * function is called, to set the final value on the property. 1268 * 1269 * <p>Overrides of this method must call the superclass to perform the calculation 1270 * of the animated value.</p> 1271 * 1272 * @param fraction The elapsed fraction of the animation. 1273 */ 1274 void animateValue(float fraction) { 1275 fraction = mInterpolator.getInterpolation(fraction); 1276 mCurrentFraction = fraction; 1277 int numValues = mValues.length; 1278 for (int i = 0; i < numValues; ++i) { 1279 mValues[i].calculateValue(fraction); 1280 } 1281 if (mUpdateListeners != null) { 1282 int numListeners = mUpdateListeners.size(); 1283 for (int i = 0; i < numListeners; ++i) { 1284 mUpdateListeners.get(i).onAnimationUpdate(this); 1285 } 1286 } 1287 } 1288 1289 @Override 1290 public ValueAnimator clone() { 1291 final ValueAnimator anim = (ValueAnimator) super.clone(); 1292 if (mUpdateListeners != null) { 1293 anim.mUpdateListeners = new ArrayList<AnimatorUpdateListener>(mUpdateListeners); 1294 } 1295 anim.mSeekTime = -1; 1296 anim.mPlayingBackwards = false; 1297 anim.mCurrentIteration = 0; 1298 anim.mInitialized = false; 1299 anim.mPlayingState = STOPPED; 1300 anim.mStartedDelay = false; 1301 PropertyValuesHolder[] oldValues = mValues; 1302 if (oldValues != null) { 1303 int numValues = oldValues.length; 1304 anim.mValues = new PropertyValuesHolder[numValues]; 1305 anim.mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 1306 for (int i = 0; i < numValues; ++i) { 1307 PropertyValuesHolder newValuesHolder = oldValues[i].clone(); 1308 anim.mValues[i] = newValuesHolder; 1309 anim.mValuesMap.put(newValuesHolder.getPropertyName(), newValuesHolder); 1310 } 1311 } 1312 return anim; 1313 } 1314 1315 /** 1316 * Implementors of this interface can add themselves as update listeners 1317 * to an <code>ValueAnimator</code> instance to receive callbacks on every animation 1318 * frame, after the current frame's values have been calculated for that 1319 * <code>ValueAnimator</code>. 1320 */ 1321 public static interface AnimatorUpdateListener { 1322 /** 1323 * <p>Notifies the occurrence of another frame of the animation.</p> 1324 * 1325 * @param animation The animation which was repeated. 1326 */ 1327 void onAnimationUpdate(ValueAnimator animation); 1328 1329 } 1330 1331 /** 1332 * Return the number of animations currently running. 1333 * 1334 * Used by StrictMode internally to annotate violations. 1335 * May be called on arbitrary threads! 1336 * 1337 * @hide 1338 */ 1339 public static int getCurrentAnimationsCount() { 1340 AnimationHandler handler = sAnimationHandler.get(); 1341 return handler != null ? handler.mAnimations.size() : 0; 1342 } 1343 1344 /** 1345 * Clear all animations on this thread, without canceling or ending them. 1346 * This should be used with caution. 1347 * 1348 * @hide 1349 */ 1350 public static void clearAllAnimations() { 1351 AnimationHandler handler = sAnimationHandler.get(); 1352 if (handler != null) { 1353 handler.mAnimations.clear(); 1354 handler.mPendingAnimations.clear(); 1355 handler.mDelayedAnims.clear(); 1356 } 1357 } 1358 1359 private static AnimationHandler getOrCreateAnimationHandler() { 1360 AnimationHandler handler = sAnimationHandler.get(); 1361 if (handler == null) { 1362 handler = new AnimationHandler(); 1363 sAnimationHandler.set(handler); 1364 } 1365 return handler; 1366 } 1367 1368 @Override 1369 public String toString() { 1370 String returnVal = "ValueAnimator@" + Integer.toHexString(hashCode()); 1371 if (mValues != null) { 1372 for (int i = 0; i < mValues.length; ++i) { 1373 returnVal += "\n " + mValues[i].toString(); 1374 } 1375 } 1376 return returnVal; 1377 } 1378 1379 /** 1380 * <p>Whether or not the ValueAnimator is allowed to run asynchronously off of 1381 * the UI thread. This is a hint that informs the ValueAnimator that it is 1382 * OK to run the animation off-thread, however ValueAnimator may decide 1383 * that it must run the animation on the UI thread anyway. For example if there 1384 * is an {@link AnimatorUpdateListener} the animation will run on the UI thread, 1385 * regardless of the value of this hint.</p> 1386 * 1387 * <p>Regardless of whether or not the animation runs asynchronously, all 1388 * listener callbacks will be called on the UI thread.</p> 1389 * 1390 * <p>To be able to use this hint the following must be true:</p> 1391 * <ol> 1392 * <li>{@link #getAnimatedFraction()} is not needed (it will return undefined values).</li> 1393 * <li>The animator is immutable while {@link #isStarted()} is true. Requests 1394 * to change values, duration, delay, etc... may be ignored.</li> 1395 * <li>Lifecycle callback events may be asynchronous. Events such as 1396 * {@link Animator.AnimatorListener#onAnimationEnd(Animator)} or 1397 * {@link Animator.AnimatorListener#onAnimationRepeat(Animator)} may end up delayed 1398 * as they must be posted back to the UI thread, and any actions performed 1399 * by those callbacks (such as starting new animations) will not happen 1400 * in the same frame.</li> 1401 * <li>State change requests ({@link #cancel()}, {@link #end()}, {@link #reverse()}, etc...) 1402 * may be asynchronous. It is guaranteed that all state changes that are 1403 * performed on the UI thread in the same frame will be applied as a single 1404 * atomic update, however that frame may be the current frame, 1405 * the next frame, or some future frame. This will also impact the observed 1406 * state of the Animator. For example, {@link #isStarted()} may still return true 1407 * after a call to {@link #end()}. Using the lifecycle callbacks is preferred over 1408 * queries to {@link #isStarted()}, {@link #isRunning()}, and {@link #isPaused()} 1409 * for this reason.</li> 1410 * </ol> 1411 * @hide 1412 */ 1413 @Override 1414 public void setAllowRunningAsynchronously(boolean mayRunAsync) { 1415 // It is up to subclasses to support this, if they can. 1416 } 1417} 1418