ValueAnimator.java revision 608fc3cbed6062f29cd512c08aacb8c1632a8851
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.view.animation.AccelerateDecelerateInterpolator; 23import android.view.animation.AnimationUtils; 24 25import java.util.ArrayList; 26import java.util.HashMap; 27 28/** 29 * This class provides a simple timing engine for running animations 30 * which calculate animated values and set them on target objects. 31 * 32 * <p>There is a single timing pulse that all animations use. It runs in a 33 * custom handler to ensure that property changes happen on the UI thread.</p> 34 * 35 * <p>By default, ValueAnimator uses non-linear time interpolation, via the 36 * {@link AccelerateDecelerateInterpolator} class, which accelerates into and decelerates 37 * out of an animation. This behavior can be changed by calling 38 * {@link ValueAnimator#setInterpolator(TimeInterpolator)}.</p> 39 */ 40public class ValueAnimator<T> extends Animator { 41 42 /** 43 * Internal constants 44 */ 45 46 /* 47 * The default amount of time in ms between animation frames 48 */ 49 private static final long DEFAULT_FRAME_DELAY = 10; 50 51 /** 52 * Messages sent to timing handler: START is sent when an animation first begins, FRAME is sent 53 * by the handler to itself to process the next animation frame 54 */ 55 private static final int ANIMATION_START = 0; 56 private static final int ANIMATION_FRAME = 1; 57 58 /** 59 * Values used with internal variable mPlayingState to indicate the current state of an 60 * animation. 61 */ 62 private static final int STOPPED = 0; // Not yet playing 63 private static final int RUNNING = 1; // Playing normally 64 private static final int CANCELED = 2; // cancel() called - need to end it 65 private static final int ENDED = 3; // end() called - need to end it 66 private static final int SEEKED = 4; // 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 private long mStartTime; 79 80 /** 81 * Set when setCurrentPlayTime() is called. If negative, animation is not currently seeked 82 * to a value. 83 */ 84 private long mSeekTime = -1; 85 86 // The static sAnimationHandler processes the internal timing loop on which all animations 87 // are based 88 private static AnimationHandler sAnimationHandler; 89 90 // The static list of all active animations 91 private static final ArrayList<ValueAnimator> sAnimations = new ArrayList<ValueAnimator>(); 92 93 // The set of animations to be started on the next animation frame 94 private static final ArrayList<ValueAnimator> sPendingAnimations = new ArrayList<ValueAnimator>(); 95 96 // The time interpolator to be used if none is set on the animation 97 private static final TimeInterpolator sDefaultInterpolator = 98 new AccelerateDecelerateInterpolator(); 99 100 // type evaluators for the three primitive types handled by this implementation 101 private static final TypeEvaluator sIntEvaluator = new IntEvaluator(); 102 private static final TypeEvaluator sFloatEvaluator = new FloatEvaluator(); 103 private static final TypeEvaluator sDoubleEvaluator = new DoubleEvaluator(); 104 105 /** 106 * Used to indicate whether the animation is currently playing in reverse. This causes the 107 * elapsed fraction to be inverted to calculate the appropriate values. 108 */ 109 private boolean mPlayingBackwards = false; 110 111 /** 112 * This variable tracks the current iteration that is playing. When mCurrentIteration exceeds the 113 * repeatCount (if repeatCount!=INFINITE), the animation ends 114 */ 115 private int mCurrentIteration = 0; 116 117 /** 118 * Tracks whether a startDelay'd animation has begun playing through the startDelay. 119 */ 120 private boolean mStartedDelay = false; 121 122 /** 123 * Tracks the time at which the animation began playing through its startDelay. This is 124 * different from the mStartTime variable, which is used to track when the animation became 125 * active (which is when the startDelay expired and the animation was added to the active 126 * animations list). 127 */ 128 private long mDelayStartTime; 129 130 /** 131 * Flag that represents the current state of the animation. Used to figure out when to start 132 * an animation (if state == STOPPED). Also used to end an animation that 133 * has been cancel()'d or end()'d since the last animation frame. Possible values are 134 * STOPPED, RUNNING, ENDED, CANCELED. 135 */ 136 private int mPlayingState = STOPPED; 137 138 /** 139 * Internal collections used to avoid set collisions as animations start and end while being 140 * processed. 141 */ 142 private static final ArrayList<ValueAnimator> sEndingAnims = new ArrayList<ValueAnimator>(); 143 private static final ArrayList<ValueAnimator> sDelayedAnims = new ArrayList<ValueAnimator>(); 144 private static final ArrayList<ValueAnimator> sReadyAnims = new ArrayList<ValueAnimator>(); 145 146 /** 147 * Flag that denotes whether the animation is set up and ready to go. Used to 148 * set up animation that has not yet been started. 149 */ 150 boolean mInitialized = false; 151 152 // 153 // Backing variables 154 // 155 156 // How long the animation should last in ms 157 private long mDuration; 158 159 // The amount of time in ms to delay starting the animation after start() is called 160 private long mStartDelay = 0; 161 162 // The number of milliseconds between animation frames 163 private static long sFrameDelay = DEFAULT_FRAME_DELAY; 164 165 // The number of times the animation will repeat. The default is 0, which means the animation 166 // will play only once 167 private int mRepeatCount = 0; 168 169 /** 170 * The type of repetition that will occur when repeatMode is nonzero. RESTART means the 171 * animation will start from the beginning on every new cycle. REVERSE means the animation 172 * will reverse directions on each iteration. 173 */ 174 private int mRepeatMode = RESTART; 175 176 /** 177 * The time interpolator to be used. The elapsed fraction of the animation will be passed 178 * through this interpolator to calculate the interpolated fraction, which is then used to 179 * calculate the animated values. 180 */ 181 private TimeInterpolator mInterpolator = sDefaultInterpolator; 182 183 /** 184 * The set of listeners to be sent events through the life of an animation. 185 */ 186 private ArrayList<AnimatorUpdateListener> mUpdateListeners = null; 187 188 /** 189 * The property/value sets being animated. 190 */ 191 PropertyValuesHolder[] mValues; 192 193 /** 194 * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values 195 * by property name during calls to getAnimatedValue(String). 196 */ 197 HashMap<String, PropertyValuesHolder> mValuesMap; 198 199 /** 200 * Public constants 201 */ 202 203 /** 204 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 205 * or a positive value, the animation restarts from the beginning. 206 */ 207 public static final int RESTART = 1; 208 /** 209 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 210 * or a positive value, the animation reverses direction on every iteration. 211 */ 212 public static final int REVERSE = 2; 213 /** 214 * This value used used with the {@link #setRepeatCount(int)} property to repeat 215 * the animation indefinitely. 216 */ 217 public static final int INFINITE = -1; 218 219 /** 220 * Creates a new ValueAnimator object. This default constructor is primarily for 221 * use internally; the other constructors which take parameters are more generally 222 * useful. 223 */ 224 public ValueAnimator() { 225 } 226 227 /** 228 * Constructs an ValueAnimator object with the specified duration and set of 229 * values. If the values are a set of PropertyValuesHolder objects, then these objects 230 * define the potentially multiple properties being animated and the values the properties are 231 * animated between. Otherwise, the values define a single set of values animated between. 232 * 233 * @param duration The length of the animation, in milliseconds. 234 * @param values The set of values to animate between. If these values are not 235 * PropertyValuesHolder objects, then there should be more than one value, since the values 236 * determine the interval to animate between. 237 */ 238 public ValueAnimator(long duration, T...values) { 239 mDuration = duration; 240 if (values.length > 0) { 241 setValues(values); 242 } 243 } 244 245 /** 246 * Sets the values, per property, being animated between. This function is called internally 247 * by the constructors of ValueAnimator that take a list of values. But an ValueAnimator can 248 * be constructed without values and this method can be called to set the values manually 249 * instead. 250 * 251 * @param values The set of values, per property, being animated between. 252 */ 253 public void setValues(PropertyValuesHolder... values) { 254 int numValues = values.length; 255 mValues = values; 256 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 257 for (int i = 0; i < numValues; ++i) { 258 PropertyValuesHolder valuesHolder = (PropertyValuesHolder) values[i]; 259 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 260 } 261 // New property/values/target should cause re-initialization prior to starting 262 mInitialized = false; 263 } 264 265 /** 266 * Returns the values that this ValueAnimator animates between. These values are stored in 267 * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list 268 * of value objects instead. 269 * 270 * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the 271 * values, per property, that define the animation. 272 */ 273 public PropertyValuesHolder[] getValues() { 274 return mValues; 275 } 276 277 /** 278 * Sets the values to animate between for this animation. If <code>values</code> is 279 * a set of PropertyValuesHolder objects, these objects will become the set of properties 280 * animated and the values that those properties are animated between. Otherwise, this method 281 * will set only one set of values for the ValueAnimator. Also, if the values are not 282 * PropertyValuesHolder objects and if there are already multiple sets of 283 * values defined for this ValueAnimator via 284 * more than one PropertyValuesHolder objects, this method will set the values for 285 * the first of those objects. 286 * 287 * @param values The set of values to animate between. 288 */ 289 public void setValues(T... values) { 290 if (mValues == null || mValues.length == 0) { 291 setValues(new PropertyValuesHolder[]{ 292 new PropertyValuesHolder("", (Object[])values)}); 293 } else { 294 PropertyValuesHolder valuesHolder = mValues[0]; 295 valuesHolder.setValues(values); 296 } 297 // New property/values/target should cause re-initialization prior to starting 298 mInitialized = false; 299 } 300 301 /** 302 * This function is called immediately before processing the first animation 303 * frame of an animation. If there is a nonzero <code>startDelay</code>, the 304 * function is called after that delay ends. 305 * It takes care of the final initialization steps for the 306 * animation. 307 * 308 * <p>Overrides of this method should call the superclass method to ensure 309 * that internal mechanisms for the animation are set up correctly.</p> 310 */ 311 void initAnimation() { 312 if (!mInitialized) { 313 int numValues = mValues.length; 314 for (int i = 0; i < numValues; ++i) { 315 mValues[i].init(); 316 } 317 mCurrentIteration = 0; 318 mInitialized = true; 319 } 320 } 321 322 323 /** 324 * Sets the length of the animation. 325 * 326 * @param duration The length of the animation, in milliseconds. 327 */ 328 public void setDuration(long duration) { 329 mDuration = duration; 330 } 331 332 /** 333 * Gets the length of the animation. 334 * 335 * @return The length of the animation, in milliseconds. 336 */ 337 public long getDuration() { 338 return mDuration; 339 } 340 341 /** 342 * Sets the position of the animation to the specified point in time. This time should 343 * be between 0 and the total duration of the animation, including any repetition. If 344 * the animation has not yet been started, then it will not advance forward after it is 345 * set to this time; it will simply set the time to this value and perform any appropriate 346 * actions based on that time. If the animation is already running, then setCurrentPlayTime() 347 * will set the current playing time to this value and continue playing from that point. 348 * 349 * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. 350 */ 351 public void setCurrentPlayTime(long playTime) { 352 initAnimation(); 353 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 354 if (mPlayingState != RUNNING) { 355 mSeekTime = playTime; 356 mPlayingState = SEEKED; 357 } 358 mStartTime = currentTime - playTime; 359 animationFrame(currentTime); 360 } 361 362 /** 363 * Gets the current position of the animation in time, which is equal to the current 364 * time minus the time that the animation started. An animation that is not yet started will 365 * return a value of zero. 366 * 367 * @return The current position in time of the animation. 368 */ 369 public long getCurrentPlayTime() { 370 if (!mInitialized || mPlayingState == STOPPED) { 371 return 0; 372 } 373 return AnimationUtils.currentAnimationTimeMillis() - mStartTime; 374 } 375 376 /** 377 * This custom, static handler handles the timing pulse that is shared by 378 * all active animations. This approach ensures that the setting of animation 379 * values will happen on the UI thread and that all animations will share 380 * the same times for calculating their values, which makes synchronizing 381 * animations possible. 382 * 383 */ 384 private static class AnimationHandler extends Handler { 385 /** 386 * There are only two messages that we care about: ANIMATION_START and 387 * ANIMATION_FRAME. The START message is sent when an animation's start() 388 * method is called. It cannot start synchronously when start() is called 389 * because the call may be on the wrong thread, and it would also not be 390 * synchronized with other animations because it would not start on a common 391 * timing pulse. So each animation sends a START message to the handler, which 392 * causes the handler to place the animation on the active animations queue and 393 * start processing frames for that animation. 394 * The FRAME message is the one that is sent over and over while there are any 395 * active animations to process. 396 */ 397 @Override 398 public void handleMessage(Message msg) { 399 boolean callAgain = true; 400 switch (msg.what) { 401 // TODO: should we avoid sending frame message when starting if we 402 // were already running? 403 case ANIMATION_START: 404 if (sAnimations.size() > 0 || sDelayedAnims.size() > 0) { 405 callAgain = false; 406 } 407 // pendingAnims holds any animations that have requested to be started 408 // We're going to clear sPendingAnimations, but starting animation may 409 // cause more to be added to the pending list (for example, if one animation 410 // starting triggers another starting). So we loop until sPendingAnimations 411 // is empty. 412 while (sPendingAnimations.size() > 0) { 413 ArrayList<ValueAnimator> pendingCopy = 414 (ArrayList<ValueAnimator>) sPendingAnimations.clone(); 415 sPendingAnimations.clear(); 416 int count = pendingCopy.size(); 417 for (int i = 0; i < count; ++i) { 418 ValueAnimator anim = pendingCopy.get(i); 419 // If the animation has a startDelay, place it on the delayed list 420 if (anim.mStartDelay == 0 || anim.mPlayingState == ENDED || 421 anim.mPlayingState == CANCELED) { 422 anim.startAnimation(); 423 } else { 424 sDelayedAnims.add(anim); 425 } 426 } 427 } 428 // fall through to process first frame of new animations 429 case ANIMATION_FRAME: 430 // currentTime holds the common time for all animations processed 431 // during this frame 432 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 433 434 // First, process animations currently sitting on the delayed queue, adding 435 // them to the active animations if they are ready 436 int numDelayedAnims = sDelayedAnims.size(); 437 for (int i = 0; i < numDelayedAnims; ++i) { 438 ValueAnimator anim = sDelayedAnims.get(i); 439 if (anim.delayedAnimationFrame(currentTime)) { 440 sReadyAnims.add(anim); 441 } 442 } 443 int numReadyAnims = sReadyAnims.size(); 444 if (numReadyAnims > 0) { 445 for (int i = 0; i < numReadyAnims; ++i) { 446 ValueAnimator anim = sReadyAnims.get(i); 447 anim.startAnimation(); 448 sDelayedAnims.remove(anim); 449 } 450 sReadyAnims.clear(); 451 } 452 453 // Now process all active animations. The return value from animationFrame() 454 // tells the handler whether it should now be ended 455 int numAnims = sAnimations.size(); 456 for (int i = 0; i < numAnims; ++i) { 457 ValueAnimator anim = sAnimations.get(i); 458 if (anim.animationFrame(currentTime)) { 459 sEndingAnims.add(anim); 460 } 461 } 462 if (sEndingAnims.size() > 0) { 463 for (int i = 0; i < sEndingAnims.size(); ++i) { 464 sEndingAnims.get(i).endAnimation(); 465 } 466 sEndingAnims.clear(); 467 } 468 469 // If there are still active or delayed animations, call the handler again 470 // after the frameDelay 471 if (callAgain && (!sAnimations.isEmpty() || !sDelayedAnims.isEmpty())) { 472 sendEmptyMessageDelayed(ANIMATION_FRAME, Math.max(0, sFrameDelay - 473- (AnimationUtils.currentAnimationTimeMillis() - currentTime))); 474 } 475 break; 476 } 477 } 478 } 479 480 /** 481 * The amount of time, in milliseconds, to delay starting the animation after 482 * {@link #start()} is called. 483 * 484 * @return the number of milliseconds to delay running the animation 485 */ 486 public long getStartDelay() { 487 return mStartDelay; 488 } 489 490 /** 491 * The amount of time, in milliseconds, to delay starting the animation after 492 * {@link #start()} is called. 493 494 * @param startDelay The amount of the delay, in milliseconds 495 */ 496 public void setStartDelay(long startDelay) { 497 this.mStartDelay = startDelay; 498 } 499 500 /** 501 * The amount of time, in milliseconds, between each frame of the animation. This is a 502 * requested time that the animation will attempt to honor, but the actual delay between 503 * frames may be different, depending on system load and capabilities. This is a static 504 * function because the same delay will be applied to all animations, since they are all 505 * run off of a single timing loop. 506 * 507 * @return the requested time between frames, in milliseconds 508 */ 509 public static long getFrameDelay() { 510 return sFrameDelay; 511 } 512 513 /** 514 * The amount of time, in milliseconds, between each frame of the animation. This is a 515 * requested time that the animation will attempt to honor, but the actual delay between 516 * frames may be different, depending on system load and capabilities. This is a static 517 * function because the same delay will be applied to all animations, since they are all 518 * run off of a single timing loop. 519 * 520 * @param frameDelay the requested time between frames, in milliseconds 521 */ 522 public static void setFrameDelay(long frameDelay) { 523 sFrameDelay = frameDelay; 524 } 525 526 /** 527 * The most recent value calculated by this <code>ValueAnimator</code> when there is just one 528 * property being animated. This value is only sensible while the animation is running. The main 529 * purpose for this read-only property is to retrieve the value from the <code>ValueAnimator</code> 530 * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 531 * is called during each animation frame, immediately after the value is calculated. 532 * 533 * @return animatedValue The value most recently calculated by this <code>ValueAnimator</code> for 534 * the single property being animated. If there are several properties being animated 535 * (specified by several PropertyValuesHolder objects in the constructor), this function 536 * returns the animated value for the first of those objects. 537 */ 538 public Object getAnimatedValue() { 539 if (mValues != null && mValues.length > 0) { 540 return mValues[0].getAnimatedValue(); 541 } 542 // Shouldn't get here; should always have values unless ValueAnimator was set up wrong 543 return null; 544 } 545 546 /** 547 * The most recent value calculated by this <code>ValueAnimator</code> for <code>propertyName</code>. 548 * The main purpose for this read-only property is to retrieve the value from the 549 * <code>ValueAnimator</code> during a call to 550 * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 551 * is called during each animation frame, immediately after the value is calculated. 552 * 553 * @return animatedValue The value most recently calculated for the named property 554 * by this <code>ValueAnimator</code>. 555 */ 556 public Object getAnimatedValue(String propertyName) { 557 PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); 558 if (valuesHolder != null) { 559 return valuesHolder.getAnimatedValue(); 560 } else { 561 // At least avoid crashing if called with bogus propertyName 562 return null; 563 } 564 } 565 566 /** 567 * Sets how many times the animation should be repeated. If the repeat 568 * count is 0, the animation is never repeated. If the repeat count is 569 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken 570 * into account. The repeat count is 0 by default. 571 * 572 * @param value the number of times the animation should be repeated 573 */ 574 public void setRepeatCount(int value) { 575 mRepeatCount = value; 576 } 577 /** 578 * Defines how many times the animation should repeat. The default value 579 * is 0. 580 * 581 * @return the number of times the animation should repeat, or {@link #INFINITE} 582 */ 583 public int getRepeatCount() { 584 return mRepeatCount; 585 } 586 587 /** 588 * Defines what this animation should do when it reaches the end. This 589 * setting is applied only when the repeat count is either greater than 590 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 591 * 592 * @param value {@link #RESTART} or {@link #REVERSE} 593 */ 594 public void setRepeatMode(int value) { 595 mRepeatMode = value; 596 } 597 598 /** 599 * Defines what this animation should do when it reaches the end. 600 * 601 * @return either one of {@link #REVERSE} or {@link #RESTART} 602 */ 603 public int getRepeatMode() { 604 return mRepeatMode; 605 } 606 607 /** 608 * Adds a listener to the set of listeners that are sent update events through the life of 609 * an animation. This method is called on all listeners for every frame of the animation, 610 * after the values for the animation have been calculated. 611 * 612 * @param listener the listener to be added to the current set of listeners for this animation. 613 */ 614 public void addUpdateListener(AnimatorUpdateListener listener) { 615 if (mUpdateListeners == null) { 616 mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 617 } 618 mUpdateListeners.add(listener); 619 } 620 621 /** 622 * Removes all listeners from the set listening to frame updates for this animation. 623 */ 624 public void removeAllUpdateListeners() { 625 if (mUpdateListeners == null) { 626 return; 627 } 628 mUpdateListeners.clear(); 629 mUpdateListeners = null; 630 } 631 632 /** 633 * Removes a listener from the set listening to frame updates for this animation. 634 * 635 * @param listener the listener to be removed from the current set of update listeners 636 * for this animation. 637 */ 638 public void removeUpdateListener(AnimatorUpdateListener listener) { 639 if (mUpdateListeners == null) { 640 return; 641 } 642 mUpdateListeners.remove(listener); 643 if (mUpdateListeners.size() == 0) { 644 mUpdateListeners = null; 645 } 646 } 647 648 649 /** 650 * The time interpolator used in calculating the elapsed fraction of this animation. The 651 * interpolator determines whether the animation runs with linear or non-linear motion, 652 * such as acceleration and deceleration. The default value is 653 * {@link android.view.animation.AccelerateDecelerateInterpolator} 654 * 655 * @param value the interpolator to be used by this animation 656 */ 657 @Override 658 public void setInterpolator(TimeInterpolator value) { 659 if (value != null) { 660 mInterpolator = value; 661 } 662 } 663 664 /** 665 * Returns the timing interpolator that this ValueAnimator uses. 666 * 667 * @return The timing interpolator for this ValueAnimator. 668 */ 669 public TimeInterpolator getInterpolator() { 670 return mInterpolator; 671 } 672 673 /** 674 * The type evaluator to be used when calculating the animated values of this animation. 675 * The system will automatically assign a float, int, or double evaluator based on the type 676 * of <code>startValue</code> and <code>endValue</code> in the constructor. But if these values 677 * are not one of these primitive types, or if different evaluation is desired (such as is 678 * necessary with int values that represent colors), a custom evaluator needs to be assigned. 679 * For example, when running an animation on color values, the {@link RGBEvaluator} 680 * should be used to get correct RGB color interpolation. 681 * 682 * <p>If this ValueAnimator has only one set of values being animated between, this evaluator 683 * will be used for that set. If there are several sets of values being animated, which is 684 * the case if PropertyValuesHOlder objects were set on the ValueAnimator, then the evaluator 685 * is assigned just to the first PropertyValuesHolder object.</p> 686 * 687 * @param value the evaluator to be used this animation 688 */ 689 public void setEvaluator(TypeEvaluator value) { 690 if (value != null && mValues != null && mValues.length > 0) { 691 mValues[0].setEvaluator(value); 692 } 693 } 694 695 /** 696 * Start the animation playing. This version of start() takes a boolean flag that indicates 697 * whether the animation should play in reverse. The flag is usually false, but may be set 698 * to true if called from the reverse() method/ 699 * 700 * @param playBackwards Whether the ValueAnimator should start playing in reverse. 701 */ 702 private void start(boolean playBackwards) { 703 mPlayingBackwards = playBackwards; 704 Looper looper = Looper.getMainLooper(); 705 final boolean isUiThread; 706 if (looper != null) { 707 isUiThread = Thread.currentThread() == looper.getThread(); 708 } else { 709 // ignore check if we don't have a Looper (this isn't an Activity) 710 isUiThread = true; 711 } 712 if ((mStartDelay == 0) && isUiThread) { 713 if (mListeners != null) { 714 ArrayList<AnimatorListener> tmpListeners = 715 (ArrayList<AnimatorListener>) mListeners.clone(); 716 for (AnimatorListener listener : tmpListeners) { 717 listener.onAnimationStart(this); 718 } 719 } 720 // This sets the initial value of the animation, prior to actually starting it running 721 setCurrentPlayTime(getCurrentPlayTime()); 722 } 723 mPlayingState = STOPPED; 724 mStartedDelay = false; 725 sPendingAnimations.add(this); 726 if (sAnimationHandler == null) { 727 sAnimationHandler = new AnimationHandler(); 728 } 729 // TODO: does this put too many messages on the queue if the handler 730 // is already running? 731 sAnimationHandler.sendEmptyMessage(ANIMATION_START); 732 } 733 734 @Override 735 public void start() { 736 start(false); 737 } 738 739 @Override 740 public void cancel() { 741 if (mListeners != null) { 742 ArrayList<AnimatorListener> tmpListeners = 743 (ArrayList<AnimatorListener>) mListeners.clone(); 744 for (AnimatorListener listener : tmpListeners) { 745 listener.onAnimationCancel(this); 746 } 747 } 748 // Just set the CANCELED flag - this causes the animation to end the next time a frame 749 // is processed. 750 mPlayingState = CANCELED; 751 } 752 753 @Override 754 public void end() { 755 if (!sAnimations.contains(this) && !sPendingAnimations.contains(this)) { 756 // Special case if the animation has not yet started; get it ready for ending 757 mStartedDelay = false; 758 sPendingAnimations.add(this); 759 if (sAnimationHandler == null) { 760 sAnimationHandler = new AnimationHandler(); 761 } 762 sAnimationHandler.sendEmptyMessage(ANIMATION_START); 763 } 764 // Just set the ENDED flag - this causes the animation to end the next time a frame 765 // is processed. 766 mPlayingState = ENDED; 767 } 768 769 @Override 770 public boolean isRunning() { 771 // ENDED or CANCELED indicate that it has been ended or canceled, but not processed yet 772 return (mPlayingState == RUNNING || mPlayingState == ENDED || mPlayingState == CANCELED); 773 } 774 775 /** 776 * Plays the ValueAnimator in reverse. If the animation is already running, 777 * it will stop itself and play backwards from the point reached when reverse was called. 778 * If the animation is not currently running, then it will start from the end and 779 * play backwards. This behavior is only set for the current animation; future playing 780 * of the animation will use the default behavior of playing forward. 781 */ 782 public void reverse() { 783 mPlayingBackwards = !mPlayingBackwards; 784 if (mPlayingState == RUNNING) { 785 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 786 long currentPlayTime = currentTime - mStartTime; 787 long timeLeft = mDuration - currentPlayTime; 788 mStartTime = currentTime - timeLeft; 789 } else { 790 start(true); 791 } 792 } 793 794 /** 795 * Called internally to end an animation by removing it from the animations list. Must be 796 * called on the UI thread. 797 */ 798 private void endAnimation() { 799 sAnimations.remove(this); 800 mPlayingState = STOPPED; 801 if (mListeners != null) { 802 ArrayList<AnimatorListener> tmpListeners = 803 (ArrayList<AnimatorListener>) mListeners.clone(); 804 for (AnimatorListener listener : tmpListeners) { 805 listener.onAnimationEnd(this); 806 } 807 } 808 } 809 810 /** 811 * Called internally to start an animation by adding it to the active animations list. Must be 812 * called on the UI thread. 813 */ 814 private void startAnimation() { 815 initAnimation(); 816 sAnimations.add(this); 817 if (mStartDelay > 0 && mListeners != null) { 818 // Listeners were already notified in start() if startDelay is 0; this is 819 // just for delayed animations 820 ArrayList<AnimatorListener> tmpListeners = 821 (ArrayList<AnimatorListener>) mListeners.clone(); 822 for (AnimatorListener listener : tmpListeners) { 823 listener.onAnimationStart(this); 824 } 825 } 826 } 827 828 /** 829 * Internal function called to process an animation frame on an animation that is currently 830 * sleeping through its <code>startDelay</code> phase. The return value indicates whether it 831 * should be woken up and put on the active animations queue. 832 * 833 * @param currentTime The current animation time, used to calculate whether the animation 834 * has exceeded its <code>startDelay</code> and should be started. 835 * @return True if the animation's <code>startDelay</code> has been exceeded and the animation 836 * should be added to the set of active animations. 837 */ 838 private boolean delayedAnimationFrame(long currentTime) { 839 if (mPlayingState == CANCELED || mPlayingState == ENDED) { 840 // end the delay, process an animation frame to actually cancel it 841 return true; 842 } 843 if (!mStartedDelay) { 844 mStartedDelay = true; 845 mDelayStartTime = currentTime; 846 } else { 847 long deltaTime = currentTime - mDelayStartTime; 848 if (deltaTime > mStartDelay) { 849 // startDelay ended - start the anim and record the 850 // mStartTime appropriately 851 mStartTime = currentTime - (deltaTime - mStartDelay); 852 mPlayingState = RUNNING; 853 return true; 854 } 855 } 856 return false; 857 } 858 859 /** 860 * This internal function processes a single animation frame for a given animation. The 861 * currentTime parameter is the timing pulse sent by the handler, used to calculate the 862 * elapsed duration, and therefore 863 * the elapsed fraction, of the animation. The return value indicates whether the animation 864 * should be ended (which happens when the elapsed time of the animation exceeds the 865 * animation's duration, including the repeatCount). 866 * 867 * @param currentTime The current time, as tracked by the static timing handler 868 * @return true if the animation's duration, including any repetitions due to 869 * <code>repeatCount</code> has been exceeded and the animation should be ended. 870 */ 871 private boolean animationFrame(long currentTime) { 872 boolean done = false; 873 874 if (mPlayingState == STOPPED) { 875 mPlayingState = RUNNING; 876 if (mSeekTime < 0) { 877 mStartTime = currentTime; 878 } else { 879 mStartTime = currentTime - mSeekTime; 880 // Now that we're playing, reset the seek time 881 mSeekTime = -1; 882 } 883 } 884 switch (mPlayingState) { 885 case RUNNING: 886 case SEEKED: 887 float fraction = (float)(currentTime - mStartTime) / mDuration; 888 if (fraction >= 1f) { 889 if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { 890 // Time to repeat 891 if (mListeners != null) { 892 for (AnimatorListener listener : mListeners) { 893 listener.onAnimationRepeat(this); 894 } 895 } 896 ++mCurrentIteration; 897 if (mRepeatMode == REVERSE) { 898 mPlayingBackwards = mPlayingBackwards ? false : true; 899 } 900 // TODO: doesn't account for fraction going Wayyyyy over 1, like 2+ 901 fraction = fraction - 1f; 902 mStartTime += mDuration; 903 } else { 904 done = true; 905 fraction = Math.min(fraction, 1.0f); 906 } 907 } 908 if (mPlayingBackwards) { 909 fraction = 1f - fraction; 910 } 911 animateValue(fraction); 912 break; 913 case ENDED: 914 // The final value set on the target varies, depending on whether the animation 915 // was supposed to repeat an odd number of times 916 if (mRepeatCount > 0 && (mRepeatCount & 0x01) == 1) { 917 animateValue(0f); 918 } else { 919 animateValue(1f); 920 } 921 // Fall through to set done flag 922 case CANCELED: 923 done = true; 924 mPlayingState = STOPPED; 925 break; 926 } 927 928 return done; 929 } 930 931 /** 932 * This method is called with the elapsed fraction of the animation during every 933 * animation frame. This function turns the elapsed fraction into an interpolated fraction 934 * and then into an animated value (from the evaluator. The function is called mostly during 935 * animation updates, but it is also called when the <code>end()</code> 936 * function is called, to set the final value on the property. 937 * 938 * <p>Overrides of this method must call the superclass to perform the calculation 939 * of the animated value.</p> 940 * 941 * @param fraction The elapsed fraction of the animation. 942 */ 943 void animateValue(float fraction) { 944 fraction = mInterpolator.getInterpolation(fraction); 945 int numValues = mValues.length; 946 for (int i = 0; i < numValues; ++i) { 947 mValues[i].calculateValue(fraction); 948 } 949 if (mUpdateListeners != null) { 950 int numListeners = mUpdateListeners.size(); 951 for (int i = 0; i < numListeners; ++i) { 952 mUpdateListeners.get(i).onAnimationUpdate(this); 953 } 954 } 955 } 956 957 @Override 958 public ValueAnimator clone() { 959 final ValueAnimator anim = (ValueAnimator) super.clone(); 960 if (mUpdateListeners != null) { 961 ArrayList<AnimatorUpdateListener> oldListeners = mUpdateListeners; 962 anim.mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 963 int numListeners = oldListeners.size(); 964 for (int i = 0; i < numListeners; ++i) { 965 anim.mUpdateListeners.add(oldListeners.get(i)); 966 } 967 } 968 anim.mSeekTime = -1; 969 anim.mPlayingBackwards = false; 970 anim.mCurrentIteration = 0; 971 anim.mInitialized = false; 972 anim.mPlayingState = STOPPED; 973 anim.mStartedDelay = false; 974 PropertyValuesHolder[] oldValues = mValues; 975 if (oldValues != null) { 976 int numValues = oldValues.length; 977 anim.mValues = new PropertyValuesHolder[numValues]; 978 for (int i = 0; i < numValues; ++i) { 979 anim.mValues[i] = oldValues[i].clone(); 980 } 981 anim.mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 982 for (int i = 0; i < numValues; ++i) { 983 PropertyValuesHolder valuesHolder = mValues[i]; 984 anim.mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 985 } 986 } 987 return anim; 988 } 989 990 /** 991 * Implementors of this interface can add themselves as update listeners 992 * to an <code>ValueAnimator</code> instance to receive callbacks on every animation 993 * frame, after the current frame's values have been calculated for that 994 * <code>ValueAnimator</code>. 995 */ 996 public static interface AnimatorUpdateListener { 997 /** 998 * <p>Notifies the occurrence of another frame of the animation.</p> 999 * 1000 * @param animation The animation which was repeated. 1001 */ 1002 void onAnimationUpdate(ValueAnimator animation); 1003 1004 } 1005}