ValueAnimator.java revision 9c38dbeb1d183ecd48bbf5d18a39f5e0508a1223
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.os.Handler; 20import android.os.Looper; 21import android.os.Message; 22import android.util.AndroidRuntimeException; 23import android.view.animation.AccelerateDecelerateInterpolator; 24import android.view.animation.AnimationUtils; 25import android.view.animation.LinearInterpolator; 26 27import java.util.ArrayList; 28import java.util.HashMap; 29 30/** 31 * This class provides a simple timing engine for running animations 32 * which calculate animated values and set them on target objects. 33 * 34 * <p>There is a single timing pulse that all animations use. It runs in a 35 * custom handler to ensure that property changes happen on the UI thread.</p> 36 * 37 * <p>By default, ValueAnimator uses non-linear time interpolation, via the 38 * {@link AccelerateDecelerateInterpolator} class, which accelerates into and decelerates 39 * out of an animation. This behavior can be changed by calling 40 * {@link ValueAnimator#setInterpolator(TimeInterpolator)}.</p> 41 */ 42public class ValueAnimator extends Animator { 43 44 /** 45 * Internal constants 46 */ 47 48 /* 49 * The default amount of time in ms between animation frames 50 */ 51 private static final long DEFAULT_FRAME_DELAY = 10; 52 53 /** 54 * Messages sent to timing handler: START is sent when an animation first begins, FRAME is sent 55 * by the handler to itself to process the next animation frame 56 */ 57 static final int ANIMATION_START = 0; 58 static final int ANIMATION_FRAME = 1; 59 60 /** 61 * Values used with internal variable mPlayingState to indicate the current state of an 62 * animation. 63 */ 64 static final int STOPPED = 0; // Not yet playing 65 static final int RUNNING = 1; // Playing normally 66 static final int SEEKED = 2; // Seeked to some time value 67 68 /** 69 * Internal variables 70 * NOTE: This object implements the clone() method, making a deep copy of any referenced 71 * objects. As other non-trivial fields are added to this class, make sure to add logic 72 * to clone() to make deep copies of them. 73 */ 74 75 // The first time that the animation's animateFrame() method is called. This time is used to 76 // determine elapsed time (and therefore the elapsed fraction) in subsequent calls 77 // to animateFrame() 78 long mStartTime; 79 80 /** 81 * Set when setCurrentPlayTime() is called. If negative, animation is not currently seeked 82 * to a value. 83 */ 84 long mSeekTime = -1; 85 86 // The static sAnimationHandler processes the internal timing loop on which all animations 87 // are based 88 private static ThreadLocal<AnimationHandler> sAnimationHandler = 89 new ThreadLocal<AnimationHandler>(); 90 91 // The time interpolator to be used if none is set on the animation 92 private static final TimeInterpolator sDefaultInterpolator = 93 new AccelerateDecelerateInterpolator(); 94 95 /** 96 * Used to indicate whether the animation is currently playing in reverse. This causes the 97 * elapsed fraction to be inverted to calculate the appropriate values. 98 */ 99 private boolean mPlayingBackwards = false; 100 101 /** 102 * This variable tracks the current iteration that is playing. When mCurrentIteration exceeds the 103 * repeatCount (if repeatCount!=INFINITE), the animation ends 104 */ 105 private int mCurrentIteration = 0; 106 107 /** 108 * Tracks current elapsed/eased fraction, for querying in getAnimatedFraction(). 109 */ 110 private float mCurrentFraction = 0f; 111 112 /** 113 * Tracks whether a startDelay'd animation has begun playing through the startDelay. 114 */ 115 private boolean mStartedDelay = false; 116 117 /** 118 * Tracks the time at which the animation began playing through its startDelay. This is 119 * different from the mStartTime variable, which is used to track when the animation became 120 * active (which is when the startDelay expired and the animation was added to the active 121 * animations list). 122 */ 123 private long mDelayStartTime; 124 125 /** 126 * Flag that represents the current state of the animation. Used to figure out when to start 127 * an animation (if state == STOPPED). Also used to end an animation that 128 * has been cancel()'d or end()'d since the last animation frame. Possible values are 129 * STOPPED, RUNNING, SEEKED. 130 */ 131 int mPlayingState = STOPPED; 132 133 /** 134 * Additional playing state to indicate whether an animator has been start()'d. There is 135 * some lag between a call to start() and the first animation frame. We should still note 136 * that the animation has been started, even if it's first animation frame has not yet 137 * happened, and reflect that state in isRunning(). 138 * Note that delayed animations are different: they are not started until their first 139 * animation frame, which occurs after their delay elapses. 140 */ 141 private boolean mRunning = false; 142 143 /** 144 * Additional playing state to indicate whether an animator has been start()'d, whether or 145 * not there is a nonzero startDelay. 146 */ 147 private boolean mStarted = false; 148 149 /** 150 * Flag that denotes whether the animation is set up and ready to go. Used to 151 * set up animation that has not yet been started. 152 */ 153 boolean mInitialized = false; 154 155 // 156 // Backing variables 157 // 158 159 // How long the animation should last in ms 160 private long mDuration = 300; 161 162 // The amount of time in ms to delay starting the animation after start() is called 163 private long mStartDelay = 0; 164 165 // The number of milliseconds between animation frames 166 private static long sFrameDelay = DEFAULT_FRAME_DELAY; 167 168 // The number of times the animation will repeat. The default is 0, which means the animation 169 // will play only once 170 private int mRepeatCount = 0; 171 172 /** 173 * The type of repetition that will occur when repeatMode is nonzero. RESTART means the 174 * animation will start from the beginning on every new cycle. REVERSE means the animation 175 * will reverse directions on each iteration. 176 */ 177 private int mRepeatMode = RESTART; 178 179 /** 180 * The time interpolator to be used. The elapsed fraction of the animation will be passed 181 * through this interpolator to calculate the interpolated fraction, which is then used to 182 * calculate the animated values. 183 */ 184 private TimeInterpolator mInterpolator = sDefaultInterpolator; 185 186 /** 187 * The set of listeners to be sent events through the life of an animation. 188 */ 189 private ArrayList<AnimatorUpdateListener> mUpdateListeners = null; 190 191 /** 192 * The property/value sets being animated. 193 */ 194 PropertyValuesHolder[] mValues; 195 196 /** 197 * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values 198 * by property name during calls to getAnimatedValue(String). 199 */ 200 HashMap<String, PropertyValuesHolder> mValuesMap; 201 202 /** 203 * Public constants 204 */ 205 206 /** 207 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 208 * or a positive value, the animation restarts from the beginning. 209 */ 210 public static final int RESTART = 1; 211 /** 212 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 213 * or a positive value, the animation reverses direction on every iteration. 214 */ 215 public static final int REVERSE = 2; 216 /** 217 * This value used used with the {@link #setRepeatCount(int)} property to repeat 218 * the animation indefinitely. 219 */ 220 public static final int INFINITE = -1; 221 222 /** 223 * Creates a new ValueAnimator object. This default constructor is primarily for 224 * use internally; the factory methods which take parameters are more generally 225 * useful. 226 */ 227 public ValueAnimator() { 228 } 229 230 /** 231 * Constructs and returns a ValueAnimator that animates between int values. A single 232 * value implies that that value is the one being animated to. However, this is not typically 233 * useful in a ValueAnimator object because there is no way for the object to determine the 234 * starting value for the animation (unlike ObjectAnimator, which can derive that value 235 * from the target object and property being animated). Therefore, there should typically 236 * be two or more values. 237 * 238 * @param values A set of values that the animation will animate between over time. 239 * @return A ValueAnimator object that is set up to animate between the given values. 240 */ 241 public static ValueAnimator ofInt(int... values) { 242 ValueAnimator anim = new ValueAnimator(); 243 anim.setIntValues(values); 244 return anim; 245 } 246 247 /** 248 * Constructs and returns a ValueAnimator that animates between float values. A single 249 * value implies that that value is the one being animated to. However, this is not typically 250 * useful in a ValueAnimator object because there is no way for the object to determine the 251 * starting value for the animation (unlike ObjectAnimator, which can derive that value 252 * from the target object and property being animated). Therefore, there should typically 253 * be two or more values. 254 * 255 * @param values A set of values that the animation will animate between over time. 256 * @return A ValueAnimator object that is set up to animate between the given values. 257 */ 258 public static ValueAnimator ofFloat(float... values) { 259 ValueAnimator anim = new ValueAnimator(); 260 anim.setFloatValues(values); 261 return anim; 262 } 263 264 /** 265 * Constructs and returns a ValueAnimator that animates between the values 266 * specified in the PropertyValuesHolder objects. 267 * 268 * @param values A set of PropertyValuesHolder objects whose values will be animated 269 * between over time. 270 * @return A ValueAnimator object that is set up to animate between the given values. 271 */ 272 public static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values) { 273 ValueAnimator anim = new ValueAnimator(); 274 anim.setValues(values); 275 return anim; 276 } 277 /** 278 * Constructs and returns a ValueAnimator that animates between Object values. A single 279 * value implies that that value is the one being animated to. However, this is not typically 280 * useful in a ValueAnimator object because there is no way for the object to determine the 281 * starting value for the animation (unlike ObjectAnimator, which can derive that value 282 * from the target object and property being animated). Therefore, there should typically 283 * be two or more values. 284 * 285 * <p>Since ValueAnimator does not know how to animate between arbitrary Objects, this 286 * factory method also takes a TypeEvaluator object that the ValueAnimator will use 287 * to perform that interpolation. 288 * 289 * @param evaluator A TypeEvaluator that will be called on each animation frame to 290 * provide the ncessry interpolation between the Object values to derive the animated 291 * value. 292 * @param values A set of values that the animation will animate between over time. 293 * @return A ValueAnimator object that is set up to animate between the given values. 294 */ 295 public static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values) { 296 ValueAnimator anim = new ValueAnimator(); 297 anim.setObjectValues(values); 298 anim.setEvaluator(evaluator); 299 return anim; 300 } 301 302 /** 303 * Sets int values that will be animated between. A single 304 * value implies that that value is the one being animated to. However, this is not typically 305 * useful in a ValueAnimator object because there is no way for the object to determine the 306 * starting value for the animation (unlike ObjectAnimator, which can derive that value 307 * from the target object and property being animated). Therefore, there should typically 308 * be two or more values. 309 * 310 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 311 * than one PropertyValuesHolder object, this method will set the values for the first 312 * of those objects.</p> 313 * 314 * @param values A set of values that the animation will animate between over time. 315 */ 316 public void setIntValues(int... values) { 317 if (values == null || values.length == 0) { 318 return; 319 } 320 if (mValues == null || mValues.length == 0) { 321 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofInt("", values)}); 322 } else { 323 PropertyValuesHolder valuesHolder = mValues[0]; 324 valuesHolder.setIntValues(values); 325 } 326 // New property/values/target should cause re-initialization prior to starting 327 mInitialized = false; 328 } 329 330 /** 331 * Sets float values that will be animated between. A single 332 * value implies that that value is the one being animated to. However, this is not typically 333 * useful in a ValueAnimator object because there is no way for the object to determine the 334 * starting value for the animation (unlike ObjectAnimator, which can derive that value 335 * from the target object and property being animated). Therefore, there should typically 336 * be two or more values. 337 * 338 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 339 * than one PropertyValuesHolder object, this method will set the values for the first 340 * of those objects.</p> 341 * 342 * @param values A set of values that the animation will animate between over time. 343 */ 344 public void setFloatValues(float... values) { 345 if (values == null || values.length == 0) { 346 return; 347 } 348 if (mValues == null || mValues.length == 0) { 349 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofFloat("", values)}); 350 } else { 351 PropertyValuesHolder valuesHolder = mValues[0]; 352 valuesHolder.setFloatValues(values); 353 } 354 // New property/values/target should cause re-initialization prior to starting 355 mInitialized = false; 356 } 357 358 /** 359 * Sets the values to animate between for this animation. A single 360 * value implies that that value is the one being animated to. However, this is not typically 361 * useful in a ValueAnimator object because there is no way for the object to determine the 362 * starting value for the animation (unlike ObjectAnimator, which can derive that value 363 * from the target object and property being animated). Therefore, there should typically 364 * be two or more values. 365 * 366 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 367 * than one PropertyValuesHolder object, this method will set the values for the first 368 * of those objects.</p> 369 * 370 * <p>There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate 371 * between these value objects. ValueAnimator only knows how to interpolate between the 372 * primitive types specified in the other setValues() methods.</p> 373 * 374 * @param values The set of values to animate between. 375 */ 376 public void setObjectValues(Object... values) { 377 if (values == null || values.length == 0) { 378 return; 379 } 380 if (mValues == null || mValues.length == 0) { 381 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofObject("", 382 (TypeEvaluator)null, values)}); 383 } else { 384 PropertyValuesHolder valuesHolder = mValues[0]; 385 valuesHolder.setObjectValues(values); 386 } 387 // New property/values/target should cause re-initialization prior to starting 388 mInitialized = false; 389 } 390 391 /** 392 * Sets the values, per property, being animated between. This function is called internally 393 * by the constructors of ValueAnimator that take a list of values. But an ValueAnimator can 394 * be constructed without values and this method can be called to set the values manually 395 * instead. 396 * 397 * @param values The set of values, per property, being animated between. 398 */ 399 public void setValues(PropertyValuesHolder... values) { 400 int numValues = values.length; 401 mValues = values; 402 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 403 for (int i = 0; i < numValues; ++i) { 404 PropertyValuesHolder valuesHolder = (PropertyValuesHolder) values[i]; 405 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 406 } 407 // New property/values/target should cause re-initialization prior to starting 408 mInitialized = false; 409 } 410 411 /** 412 * Returns the values that this ValueAnimator animates between. These values are stored in 413 * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list 414 * of value objects instead. 415 * 416 * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the 417 * values, per property, that define the animation. 418 */ 419 public PropertyValuesHolder[] getValues() { 420 return mValues; 421 } 422 423 /** 424 * This function is called immediately before processing the first animation 425 * frame of an animation. If there is a nonzero <code>startDelay</code>, the 426 * function is called after that delay ends. 427 * It takes care of the final initialization steps for the 428 * animation. 429 * 430 * <p>Overrides of this method should call the superclass method to ensure 431 * that internal mechanisms for the animation are set up correctly.</p> 432 */ 433 void initAnimation() { 434 if (!mInitialized) { 435 int numValues = mValues.length; 436 for (int i = 0; i < numValues; ++i) { 437 mValues[i].init(); 438 } 439 mInitialized = true; 440 } 441 } 442 443 444 /** 445 * Sets the length of the animation. The default duration is 300 milliseconds. 446 * 447 * @param duration The length of the animation, in milliseconds. This value cannot 448 * be negative. 449 * @return ValueAnimator The object called with setDuration(). This return 450 * value makes it easier to compose statements together that construct and then set the 451 * duration, as in <code>ValueAnimator.ofInt(0, 10).setDuration(500).start()</code>. 452 */ 453 public ValueAnimator setDuration(long duration) { 454 if (duration < 0) { 455 throw new IllegalArgumentException("Animators cannot have negative duration: " + 456 duration); 457 } 458 mDuration = duration; 459 return this; 460 } 461 462 /** 463 * Gets the length of the animation. The default duration is 300 milliseconds. 464 * 465 * @return The length of the animation, in milliseconds. 466 */ 467 public long getDuration() { 468 return mDuration; 469 } 470 471 /** 472 * Sets the position of the animation to the specified point in time. This time should 473 * be between 0 and the total duration of the animation, including any repetition. If 474 * the animation has not yet been started, then it will not advance forward after it is 475 * set to this time; it will simply set the time to this value and perform any appropriate 476 * actions based on that time. If the animation is already running, then setCurrentPlayTime() 477 * will set the current playing time to this value and continue playing from that point. 478 * 479 * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. 480 */ 481 public void setCurrentPlayTime(long playTime) { 482 initAnimation(); 483 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 484 if (mPlayingState != RUNNING) { 485 mSeekTime = playTime; 486 mPlayingState = SEEKED; 487 } 488 mStartTime = currentTime - playTime; 489 animationFrame(currentTime); 490 } 491 492 /** 493 * Gets the current position of the animation in time, which is equal to the current 494 * time minus the time that the animation started. An animation that is not yet started will 495 * return a value of zero. 496 * 497 * @return The current position in time of the animation. 498 */ 499 public long getCurrentPlayTime() { 500 if (!mInitialized || mPlayingState == STOPPED) { 501 return 0; 502 } 503 return AnimationUtils.currentAnimationTimeMillis() - mStartTime; 504 } 505 506 /** 507 * This custom, static handler handles the timing pulse that is shared by 508 * all active animations. This approach ensures that the setting of animation 509 * values will happen on the UI thread and that all animations will share 510 * the same times for calculating their values, which makes synchronizing 511 * animations possible. 512 * 513 */ 514 private static class AnimationHandler extends Handler { 515 // The per-thread list of all active animations 516 private final ArrayList<ValueAnimator> mAnimations = new ArrayList<ValueAnimator>(); 517 518 // The per-thread set of animations to be started on the next animation frame 519 private final ArrayList<ValueAnimator> mPendingAnimations = new ArrayList<ValueAnimator>(); 520 521 /** 522 * Internal per-thread collections used to avoid set collisions as animations start and end 523 * while being processed. 524 */ 525 private final ArrayList<ValueAnimator> mDelayedAnims = new ArrayList<ValueAnimator>(); 526 private final ArrayList<ValueAnimator> mEndingAnims = new ArrayList<ValueAnimator>(); 527 private final ArrayList<ValueAnimator> mReadyAnims = new ArrayList<ValueAnimator>(); 528 529 /** 530 * There are only two messages that we care about: ANIMATION_START and 531 * ANIMATION_FRAME. The START message is sent when an animation's start() 532 * method is called. It cannot start synchronously when start() is called 533 * because the call may be on the wrong thread, and it would also not be 534 * synchronized with other animations because it would not start on a common 535 * timing pulse. So each animation sends a START message to the handler, which 536 * causes the handler to place the animation on the active animations queue and 537 * start processing frames for that animation. 538 * The FRAME message is the one that is sent over and over while there are any 539 * active animations to process. 540 */ 541 @Override 542 public void handleMessage(Message msg) { 543 boolean callAgain = true; 544 ArrayList<ValueAnimator> animations = mAnimations; 545 ArrayList<ValueAnimator> delayedAnims = mDelayedAnims; 546 switch (msg.what) { 547 // TODO: should we avoid sending frame message when starting if we 548 // were already running? 549 case ANIMATION_START: 550 ArrayList<ValueAnimator> pendingAnimations = mPendingAnimations; 551 if (animations.size() > 0 || delayedAnims.size() > 0) { 552 callAgain = false; 553 } 554 // pendingAnims holds any animations that have requested to be started 555 // We're going to clear sPendingAnimations, but starting animation may 556 // cause more to be added to the pending list (for example, if one animation 557 // starting triggers another starting). So we loop until sPendingAnimations 558 // is empty. 559 while (pendingAnimations.size() > 0) { 560 ArrayList<ValueAnimator> pendingCopy = 561 (ArrayList<ValueAnimator>) pendingAnimations.clone(); 562 pendingAnimations.clear(); 563 int count = pendingCopy.size(); 564 for (int i = 0; i < count; ++i) { 565 ValueAnimator anim = pendingCopy.get(i); 566 // If the animation has a startDelay, place it on the delayed list 567 if (anim.mStartDelay == 0) { 568 anim.startAnimation(this); 569 } else { 570 delayedAnims.add(anim); 571 } 572 } 573 } 574 // fall through to process first frame of new animations 575 case ANIMATION_FRAME: 576 // currentTime holds the common time for all animations processed 577 // during this frame 578 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 579 ArrayList<ValueAnimator> readyAnims = mReadyAnims; 580 ArrayList<ValueAnimator> endingAnims = mEndingAnims; 581 582 // First, process animations currently sitting on the delayed queue, adding 583 // them to the active animations if they are ready 584 int numDelayedAnims = delayedAnims.size(); 585 for (int i = 0; i < numDelayedAnims; ++i) { 586 ValueAnimator anim = delayedAnims.get(i); 587 if (anim.delayedAnimationFrame(currentTime)) { 588 readyAnims.add(anim); 589 } 590 } 591 int numReadyAnims = readyAnims.size(); 592 if (numReadyAnims > 0) { 593 for (int i = 0; i < numReadyAnims; ++i) { 594 ValueAnimator anim = readyAnims.get(i); 595 anim.startAnimation(this); 596 anim.mRunning = true; 597 delayedAnims.remove(anim); 598 } 599 readyAnims.clear(); 600 } 601 602 // Now process all active animations. The return value from animationFrame() 603 // tells the handler whether it should now be ended 604 int numAnims = animations.size(); 605 int i = 0; 606 while (i < numAnims) { 607 ValueAnimator anim = animations.get(i); 608 if (anim.animationFrame(currentTime)) { 609 endingAnims.add(anim); 610 } 611 if (animations.size() == numAnims) { 612 ++i; 613 } else { 614 // An animation might be canceled or ended by client code 615 // during the animation frame. Check to see if this happened by 616 // seeing whether the current index is the same as it was before 617 // calling animationFrame(). Another approach would be to copy 618 // animations to a temporary list and process that list instead, 619 // but that entails garbage and processing overhead that would 620 // be nice to avoid. 621 --numAnims; 622 endingAnims.remove(anim); 623 } 624 } 625 if (endingAnims.size() > 0) { 626 for (i = 0; i < endingAnims.size(); ++i) { 627 endingAnims.get(i).endAnimation(this); 628 } 629 endingAnims.clear(); 630 } 631 632 // If there are still active or delayed animations, call the handler again 633 // after the frameDelay 634 if (callAgain && (!animations.isEmpty() || !delayedAnims.isEmpty())) { 635 sendEmptyMessageDelayed(ANIMATION_FRAME, Math.max(0, sFrameDelay - 636 (AnimationUtils.currentAnimationTimeMillis() - currentTime))); 637 } 638 break; 639 } 640 } 641 } 642 643 /** 644 * The amount of time, in milliseconds, to delay starting the animation after 645 * {@link #start()} is called. 646 * 647 * @return the number of milliseconds to delay running the animation 648 */ 649 public long getStartDelay() { 650 return mStartDelay; 651 } 652 653 /** 654 * The amount of time, in milliseconds, to delay starting the animation after 655 * {@link #start()} is called. 656 657 * @param startDelay The amount of the delay, in milliseconds 658 */ 659 public void setStartDelay(long startDelay) { 660 this.mStartDelay = startDelay; 661 } 662 663 /** 664 * The amount of time, in milliseconds, between each frame of the animation. This is a 665 * requested time that the animation will attempt to honor, but the actual delay between 666 * frames may be different, depending on system load and capabilities. This is a static 667 * function because the same delay will be applied to all animations, since they are all 668 * run off of a single timing loop. 669 * 670 * @return the requested time between frames, in milliseconds 671 */ 672 public static long getFrameDelay() { 673 return sFrameDelay; 674 } 675 676 /** 677 * The amount of time, in milliseconds, between each frame of the animation. This is a 678 * requested time that the animation will attempt to honor, but the actual delay between 679 * frames may be different, depending on system load and capabilities. This is a static 680 * function because the same delay will be applied to all animations, since they are all 681 * run off of a single timing loop. 682 * 683 * @param frameDelay the requested time between frames, in milliseconds 684 */ 685 public static void setFrameDelay(long frameDelay) { 686 sFrameDelay = frameDelay; 687 } 688 689 /** 690 * The most recent value calculated by this <code>ValueAnimator</code> when there is just one 691 * property being animated. This value is only sensible while the animation is running. The main 692 * purpose for this read-only property is to retrieve the value from the <code>ValueAnimator</code> 693 * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 694 * is called during each animation frame, immediately after the value is calculated. 695 * 696 * @return animatedValue The value most recently calculated by this <code>ValueAnimator</code> for 697 * the single property being animated. If there are several properties being animated 698 * (specified by several PropertyValuesHolder objects in the constructor), this function 699 * returns the animated value for the first of those objects. 700 */ 701 public Object getAnimatedValue() { 702 if (mValues != null && mValues.length > 0) { 703 return mValues[0].getAnimatedValue(); 704 } 705 // Shouldn't get here; should always have values unless ValueAnimator was set up wrong 706 return null; 707 } 708 709 /** 710 * The most recent value calculated by this <code>ValueAnimator</code> for <code>propertyName</code>. 711 * The main purpose for this read-only property is to retrieve the value from the 712 * <code>ValueAnimator</code> during a call to 713 * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 714 * is called during each animation frame, immediately after the value is calculated. 715 * 716 * @return animatedValue The value most recently calculated for the named property 717 * by this <code>ValueAnimator</code>. 718 */ 719 public Object getAnimatedValue(String propertyName) { 720 PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); 721 if (valuesHolder != null) { 722 return valuesHolder.getAnimatedValue(); 723 } else { 724 // At least avoid crashing if called with bogus propertyName 725 return null; 726 } 727 } 728 729 /** 730 * Sets how many times the animation should be repeated. If the repeat 731 * count is 0, the animation is never repeated. If the repeat count is 732 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken 733 * into account. The repeat count is 0 by default. 734 * 735 * @param value the number of times the animation should be repeated 736 */ 737 public void setRepeatCount(int value) { 738 mRepeatCount = value; 739 } 740 /** 741 * Defines how many times the animation should repeat. The default value 742 * is 0. 743 * 744 * @return the number of times the animation should repeat, or {@link #INFINITE} 745 */ 746 public int getRepeatCount() { 747 return mRepeatCount; 748 } 749 750 /** 751 * Defines what this animation should do when it reaches the end. This 752 * setting is applied only when the repeat count is either greater than 753 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 754 * 755 * @param value {@link #RESTART} or {@link #REVERSE} 756 */ 757 public void setRepeatMode(int value) { 758 mRepeatMode = value; 759 } 760 761 /** 762 * Defines what this animation should do when it reaches the end. 763 * 764 * @return either one of {@link #REVERSE} or {@link #RESTART} 765 */ 766 public int getRepeatMode() { 767 return mRepeatMode; 768 } 769 770 /** 771 * Adds a listener to the set of listeners that are sent update events through the life of 772 * an animation. This method is called on all listeners for every frame of the animation, 773 * after the values for the animation have been calculated. 774 * 775 * @param listener the listener to be added to the current set of listeners for this animation. 776 */ 777 public void addUpdateListener(AnimatorUpdateListener listener) { 778 if (mUpdateListeners == null) { 779 mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 780 } 781 mUpdateListeners.add(listener); 782 } 783 784 /** 785 * Removes all listeners from the set listening to frame updates for this animation. 786 */ 787 public void removeAllUpdateListeners() { 788 if (mUpdateListeners == null) { 789 return; 790 } 791 mUpdateListeners.clear(); 792 mUpdateListeners = null; 793 } 794 795 /** 796 * Removes a listener from the set listening to frame updates for this animation. 797 * 798 * @param listener the listener to be removed from the current set of update listeners 799 * for this animation. 800 */ 801 public void removeUpdateListener(AnimatorUpdateListener listener) { 802 if (mUpdateListeners == null) { 803 return; 804 } 805 mUpdateListeners.remove(listener); 806 if (mUpdateListeners.size() == 0) { 807 mUpdateListeners = null; 808 } 809 } 810 811 812 /** 813 * The time interpolator used in calculating the elapsed fraction of this animation. The 814 * interpolator determines whether the animation runs with linear or non-linear motion, 815 * such as acceleration and deceleration. The default value is 816 * {@link android.view.animation.AccelerateDecelerateInterpolator} 817 * 818 * @param value the interpolator to be used by this animation. A value of <code>null</code> 819 * will result in linear interpolation. 820 */ 821 @Override 822 public void setInterpolator(TimeInterpolator value) { 823 if (value != null) { 824 mInterpolator = value; 825 } else { 826 mInterpolator = new LinearInterpolator(); 827 } 828 } 829 830 /** 831 * Returns the timing interpolator that this ValueAnimator uses. 832 * 833 * @return The timing interpolator for this ValueAnimator. 834 */ 835 public TimeInterpolator getInterpolator() { 836 return mInterpolator; 837 } 838 839 /** 840 * The type evaluator to be used when calculating the animated values of this animation. 841 * The system will automatically assign a float or int evaluator based on the type 842 * of <code>startValue</code> and <code>endValue</code> in the constructor. But if these values 843 * are not one of these primitive types, or if different evaluation is desired (such as is 844 * necessary with int values that represent colors), a custom evaluator needs to be assigned. 845 * For example, when running an animation on color values, the {@link ArgbEvaluator} 846 * should be used to get correct RGB color interpolation. 847 * 848 * <p>If this ValueAnimator has only one set of values being animated between, this evaluator 849 * will be used for that set. If there are several sets of values being animated, which is 850 * the case if PropertyValuesHOlder objects were set on the ValueAnimator, then the evaluator 851 * is assigned just to the first PropertyValuesHolder object.</p> 852 * 853 * @param value the evaluator to be used this animation 854 */ 855 public void setEvaluator(TypeEvaluator value) { 856 if (value != null && mValues != null && mValues.length > 0) { 857 mValues[0].setEvaluator(value); 858 } 859 } 860 861 /** 862 * Start the animation playing. This version of start() takes a boolean flag that indicates 863 * whether the animation should play in reverse. The flag is usually false, but may be set 864 * to true if called from the reverse() method. 865 * 866 * <p>The animation started by calling this method will be run on the thread that called 867 * this method. This thread should have a Looper on it (a runtime exception will be thrown if 868 * this is not the case). Also, if the animation will animate 869 * properties of objects in the view hierarchy, then the calling thread should be the UI 870 * thread for that view hierarchy.</p> 871 * 872 * @param playBackwards Whether the ValueAnimator should start playing in reverse. 873 */ 874 private void start(boolean playBackwards) { 875 if (Looper.myLooper() == null) { 876 throw new AndroidRuntimeException("Animators may only be run on Looper threads"); 877 } 878 mPlayingBackwards = playBackwards; 879 mCurrentIteration = 0; 880 mPlayingState = STOPPED; 881 mStarted = true; 882 mStartedDelay = false; 883 AnimationHandler animationHandler = getOrCreateAnimationHandler(); 884 animationHandler.mPendingAnimations.add(this); 885 if (mStartDelay == 0) { 886 // This sets the initial value of the animation, prior to actually starting it running 887 setCurrentPlayTime(getCurrentPlayTime()); 888 mPlayingState = STOPPED; 889 mRunning = true; 890 891 if (mListeners != null) { 892 ArrayList<AnimatorListener> tmpListeners = 893 (ArrayList<AnimatorListener>) mListeners.clone(); 894 int numListeners = tmpListeners.size(); 895 for (int i = 0; i < numListeners; ++i) { 896 tmpListeners.get(i).onAnimationStart(this); 897 } 898 } 899 } 900 animationHandler.sendEmptyMessage(ANIMATION_START); 901 } 902 903 @Override 904 public void start() { 905 start(false); 906 } 907 908 @Override 909 public void cancel() { 910 // Only cancel if the animation is actually running or has been started and is about 911 // to run 912 AnimationHandler handler = getOrCreateAnimationHandler(); 913 if (mPlayingState != STOPPED 914 || handler.mPendingAnimations.contains(this) 915 || handler.mDelayedAnims.contains(this)) { 916 // Only notify listeners if the animator has actually started 917 if (mRunning && mListeners != null) { 918 ArrayList<AnimatorListener> tmpListeners = 919 (ArrayList<AnimatorListener>) mListeners.clone(); 920 for (AnimatorListener listener : tmpListeners) { 921 listener.onAnimationCancel(this); 922 } 923 } 924 endAnimation(handler); 925 } 926 } 927 928 @Override 929 public void end() { 930 AnimationHandler handler = getOrCreateAnimationHandler(); 931 if (!handler.mAnimations.contains(this) && !handler.mPendingAnimations.contains(this)) { 932 // Special case if the animation has not yet started; get it ready for ending 933 mStartedDelay = false; 934 startAnimation(handler); 935 } else if (!mInitialized) { 936 initAnimation(); 937 } 938 // The final value set on the target varies, depending on whether the animation 939 // was supposed to repeat an odd number of times 940 if (mRepeatCount > 0 && (mRepeatCount & 0x01) == 1) { 941 animateValue(0f); 942 } else { 943 animateValue(1f); 944 } 945 endAnimation(handler); 946 } 947 948 @Override 949 public boolean isRunning() { 950 return (mPlayingState == RUNNING || mRunning); 951 } 952 953 @Override 954 public boolean isStarted() { 955 return mStarted; 956 } 957 958 /** 959 * Plays the ValueAnimator in reverse. If the animation is already running, 960 * it will stop itself and play backwards from the point reached when reverse was called. 961 * If the animation is not currently running, then it will start from the end and 962 * play backwards. This behavior is only set for the current animation; future playing 963 * of the animation will use the default behavior of playing forward. 964 */ 965 public void reverse() { 966 mPlayingBackwards = !mPlayingBackwards; 967 if (mPlayingState == RUNNING) { 968 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 969 long currentPlayTime = currentTime - mStartTime; 970 long timeLeft = mDuration - currentPlayTime; 971 mStartTime = currentTime - timeLeft; 972 } else { 973 start(true); 974 } 975 } 976 977 /** 978 * Called internally to end an animation by removing it from the animations list. Must be 979 * called on the UI thread. 980 */ 981 private void endAnimation(AnimationHandler handler) { 982 handler.mAnimations.remove(this); 983 handler.mPendingAnimations.remove(this); 984 handler.mDelayedAnims.remove(this); 985 mPlayingState = STOPPED; 986 if (mRunning && mListeners != null) { 987 ArrayList<AnimatorListener> tmpListeners = 988 (ArrayList<AnimatorListener>) mListeners.clone(); 989 int numListeners = tmpListeners.size(); 990 for (int i = 0; i < numListeners; ++i) { 991 tmpListeners.get(i).onAnimationEnd(this); 992 } 993 } 994 mRunning = false; 995 mStarted = false; 996 } 997 998 /** 999 * Called internally to start an animation by adding it to the active animations list. Must be 1000 * called on the UI thread. 1001 */ 1002 private void startAnimation(AnimationHandler handler) { 1003 initAnimation(); 1004 handler.mAnimations.add(this); 1005 if (mStartDelay > 0 && mListeners != null) { 1006 // Listeners were already notified in start() if startDelay is 0; this is 1007 // just for delayed animations 1008 ArrayList<AnimatorListener> tmpListeners = 1009 (ArrayList<AnimatorListener>) mListeners.clone(); 1010 int numListeners = tmpListeners.size(); 1011 for (int i = 0; i < numListeners; ++i) { 1012 tmpListeners.get(i).onAnimationStart(this); 1013 } 1014 } 1015 } 1016 1017 /** 1018 * Internal function called to process an animation frame on an animation that is currently 1019 * sleeping through its <code>startDelay</code> phase. The return value indicates whether it 1020 * should be woken up and put on the active animations queue. 1021 * 1022 * @param currentTime The current animation time, used to calculate whether the animation 1023 * has exceeded its <code>startDelay</code> and should be started. 1024 * @return True if the animation's <code>startDelay</code> has been exceeded and the animation 1025 * should be added to the set of active animations. 1026 */ 1027 private boolean delayedAnimationFrame(long currentTime) { 1028 if (!mStartedDelay) { 1029 mStartedDelay = true; 1030 mDelayStartTime = currentTime; 1031 } else { 1032 long deltaTime = currentTime - mDelayStartTime; 1033 if (deltaTime > mStartDelay) { 1034 // startDelay ended - start the anim and record the 1035 // mStartTime appropriately 1036 mStartTime = currentTime - (deltaTime - mStartDelay); 1037 mPlayingState = RUNNING; 1038 return true; 1039 } 1040 } 1041 return false; 1042 } 1043 1044 /** 1045 * This internal function processes a single animation frame for a given animation. The 1046 * currentTime parameter is the timing pulse sent by the handler, used to calculate the 1047 * elapsed duration, and therefore 1048 * the elapsed fraction, of the animation. The return value indicates whether the animation 1049 * should be ended (which happens when the elapsed time of the animation exceeds the 1050 * animation's duration, including the repeatCount). 1051 * 1052 * @param currentTime The current time, as tracked by the static timing handler 1053 * @return true if the animation's duration, including any repetitions due to 1054 * <code>repeatCount</code> has been exceeded and the animation should be ended. 1055 */ 1056 boolean animationFrame(long currentTime) { 1057 boolean done = false; 1058 1059 if (mPlayingState == STOPPED) { 1060 mPlayingState = RUNNING; 1061 if (mSeekTime < 0) { 1062 mStartTime = currentTime; 1063 } else { 1064 mStartTime = currentTime - mSeekTime; 1065 // Now that we're playing, reset the seek time 1066 mSeekTime = -1; 1067 } 1068 } 1069 switch (mPlayingState) { 1070 case RUNNING: 1071 case SEEKED: 1072 float fraction = mDuration > 0 ? (float)(currentTime - mStartTime) / mDuration : 1f; 1073 if (fraction >= 1f) { 1074 if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { 1075 // Time to repeat 1076 if (mListeners != null) { 1077 int numListeners = mListeners.size(); 1078 for (int i = 0; i < numListeners; ++i) { 1079 mListeners.get(i).onAnimationRepeat(this); 1080 } 1081 } 1082 if (mRepeatMode == REVERSE) { 1083 mPlayingBackwards = mPlayingBackwards ? false : true; 1084 } 1085 mCurrentIteration += (int)fraction; 1086 fraction = fraction % 1f; 1087 mStartTime += mDuration; 1088 } else { 1089 done = true; 1090 fraction = Math.min(fraction, 1.0f); 1091 } 1092 } 1093 if (mPlayingBackwards) { 1094 fraction = 1f - fraction; 1095 } 1096 animateValue(fraction); 1097 break; 1098 } 1099 1100 return done; 1101 } 1102 1103 /** 1104 * Returns the current animation fraction, which is the elapsed/interpolated fraction used in 1105 * the most recent frame update on the animation. 1106 * 1107 * @return Elapsed/interpolated fraction of the animation. 1108 */ 1109 public float getAnimatedFraction() { 1110 return mCurrentFraction; 1111 } 1112 1113 /** 1114 * This method is called with the elapsed fraction of the animation during every 1115 * animation frame. This function turns the elapsed fraction into an interpolated fraction 1116 * and then into an animated value (from the evaluator. The function is called mostly during 1117 * animation updates, but it is also called when the <code>end()</code> 1118 * function is called, to set the final value on the property. 1119 * 1120 * <p>Overrides of this method must call the superclass to perform the calculation 1121 * of the animated value.</p> 1122 * 1123 * @param fraction The elapsed fraction of the animation. 1124 */ 1125 void animateValue(float fraction) { 1126 fraction = mInterpolator.getInterpolation(fraction); 1127 mCurrentFraction = fraction; 1128 int numValues = mValues.length; 1129 for (int i = 0; i < numValues; ++i) { 1130 mValues[i].calculateValue(fraction); 1131 } 1132 if (mUpdateListeners != null) { 1133 int numListeners = mUpdateListeners.size(); 1134 for (int i = 0; i < numListeners; ++i) { 1135 mUpdateListeners.get(i).onAnimationUpdate(this); 1136 } 1137 } 1138 } 1139 1140 @Override 1141 public ValueAnimator clone() { 1142 final ValueAnimator anim = (ValueAnimator) super.clone(); 1143 if (mUpdateListeners != null) { 1144 ArrayList<AnimatorUpdateListener> oldListeners = mUpdateListeners; 1145 anim.mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 1146 int numListeners = oldListeners.size(); 1147 for (int i = 0; i < numListeners; ++i) { 1148 anim.mUpdateListeners.add(oldListeners.get(i)); 1149 } 1150 } 1151 anim.mSeekTime = -1; 1152 anim.mPlayingBackwards = false; 1153 anim.mCurrentIteration = 0; 1154 anim.mInitialized = false; 1155 anim.mPlayingState = STOPPED; 1156 anim.mStartedDelay = false; 1157 PropertyValuesHolder[] oldValues = mValues; 1158 if (oldValues != null) { 1159 int numValues = oldValues.length; 1160 anim.mValues = new PropertyValuesHolder[numValues]; 1161 anim.mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 1162 for (int i = 0; i < numValues; ++i) { 1163 PropertyValuesHolder newValuesHolder = oldValues[i].clone(); 1164 anim.mValues[i] = newValuesHolder; 1165 anim.mValuesMap.put(newValuesHolder.getPropertyName(), newValuesHolder); 1166 } 1167 } 1168 return anim; 1169 } 1170 1171 /** 1172 * Implementors of this interface can add themselves as update listeners 1173 * to an <code>ValueAnimator</code> instance to receive callbacks on every animation 1174 * frame, after the current frame's values have been calculated for that 1175 * <code>ValueAnimator</code>. 1176 */ 1177 public static interface AnimatorUpdateListener { 1178 /** 1179 * <p>Notifies the occurrence of another frame of the animation.</p> 1180 * 1181 * @param animation The animation which was repeated. 1182 */ 1183 void onAnimationUpdate(ValueAnimator animation); 1184 1185 } 1186 1187 /** 1188 * Return the number of animations currently running. 1189 * 1190 * Used by StrictMode internally to annotate violations. 1191 * May be called on arbitrary threads! 1192 * 1193 * @hide 1194 */ 1195 public static int getCurrentAnimationsCount() { 1196 AnimationHandler handler = sAnimationHandler.get(); 1197 return handler != null ? handler.mAnimations.size() : 0; 1198 } 1199 1200 /** 1201 * Clear all animations on this thread, without canceling or ending them. 1202 * This should be used with caution. 1203 * 1204 * @hide 1205 */ 1206 public static void clearAllAnimations() { 1207 AnimationHandler handler = sAnimationHandler.get(); 1208 if (handler != null) { 1209 handler.mAnimations.clear(); 1210 handler.mPendingAnimations.clear(); 1211 handler.mDelayedAnims.clear(); 1212 } 1213 } 1214 1215 private AnimationHandler getOrCreateAnimationHandler() { 1216 AnimationHandler handler = sAnimationHandler.get(); 1217 if (handler == null) { 1218 handler = new AnimationHandler(); 1219 sAnimationHandler.set(handler); 1220 } 1221 return handler; 1222 } 1223 1224 @Override 1225 public String toString() { 1226 String returnVal = "ValueAnimator@" + Integer.toHexString(hashCode()); 1227 if (mValues != null) { 1228 for (int i = 0; i < mValues.length; ++i) { 1229 returnVal += "\n " + mValues[i].toString(); 1230 } 1231 } 1232 return returnVal; 1233 } 1234} 1235