ValueAnimator.java revision a00f3865f55c5c9cb74510ee2b239d101230133c
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 private static final int ANIMATION_START = 0; 58 private 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 // TODO: We access the following ThreadLocal variables often, some of them on every update. 87 // If ThreadLocal access is significantly expensive, we may want to put all of these 88 // fields into a structure sot hat we just access ThreadLocal once to get the reference 89 // to that structure, then access the structure directly for each field. 90 91 // The static sAnimationHandler processes the internal timing loop on which all animations 92 // are based 93 private static ThreadLocal<AnimationHandler> sAnimationHandler = 94 new ThreadLocal<AnimationHandler>(); 95 96 // The per-thread list of all active animations 97 private static final ThreadLocal<ArrayList<ValueAnimator>> sAnimations = 98 new ThreadLocal<ArrayList<ValueAnimator>>() { 99 @Override 100 protected ArrayList<ValueAnimator> initialValue() { 101 return new ArrayList<ValueAnimator>(); 102 } 103 }; 104 105 // The per-thread set of animations to be started on the next animation frame 106 private static final ThreadLocal<ArrayList<ValueAnimator>> sPendingAnimations = 107 new ThreadLocal<ArrayList<ValueAnimator>>() { 108 @Override 109 protected ArrayList<ValueAnimator> initialValue() { 110 return new ArrayList<ValueAnimator>(); 111 } 112 }; 113 114 /** 115 * Internal per-thread collections used to avoid set collisions as animations start and end 116 * while being processed. 117 */ 118 private static final ThreadLocal<ArrayList<ValueAnimator>> sDelayedAnims = 119 new ThreadLocal<ArrayList<ValueAnimator>>() { 120 @Override 121 protected ArrayList<ValueAnimator> initialValue() { 122 return new ArrayList<ValueAnimator>(); 123 } 124 }; 125 126 private static final ThreadLocal<ArrayList<ValueAnimator>> sEndingAnims = 127 new ThreadLocal<ArrayList<ValueAnimator>>() { 128 @Override 129 protected ArrayList<ValueAnimator> initialValue() { 130 return new ArrayList<ValueAnimator>(); 131 } 132 }; 133 134 private static final ThreadLocal<ArrayList<ValueAnimator>> sReadyAnims = 135 new ThreadLocal<ArrayList<ValueAnimator>>() { 136 @Override 137 protected ArrayList<ValueAnimator> initialValue() { 138 return new ArrayList<ValueAnimator>(); 139 } 140 }; 141 142 // The time interpolator to be used if none is set on the animation 143 private static final TimeInterpolator sDefaultInterpolator = 144 new AccelerateDecelerateInterpolator(); 145 146 // type evaluators for the primitive types handled by this implementation 147 private static final TypeEvaluator sIntEvaluator = new IntEvaluator(); 148 private static final TypeEvaluator sFloatEvaluator = new FloatEvaluator(); 149 150 /** 151 * Used to indicate whether the animation is currently playing in reverse. This causes the 152 * elapsed fraction to be inverted to calculate the appropriate values. 153 */ 154 private boolean mPlayingBackwards = false; 155 156 /** 157 * This variable tracks the current iteration that is playing. When mCurrentIteration exceeds the 158 * repeatCount (if repeatCount!=INFINITE), the animation ends 159 */ 160 private int mCurrentIteration = 0; 161 162 /** 163 * Tracks current elapsed/eased fraction, for querying in getAnimatedFraction(). 164 */ 165 private float mCurrentFraction = 0f; 166 167 /** 168 * Tracks whether a startDelay'd animation has begun playing through the startDelay. 169 */ 170 private boolean mStartedDelay = false; 171 172 /** 173 * Tracks the time at which the animation began playing through its startDelay. This is 174 * different from the mStartTime variable, which is used to track when the animation became 175 * active (which is when the startDelay expired and the animation was added to the active 176 * animations list). 177 */ 178 private long mDelayStartTime; 179 180 /** 181 * Flag that represents the current state of the animation. Used to figure out when to start 182 * an animation (if state == STOPPED). Also used to end an animation that 183 * has been cancel()'d or end()'d since the last animation frame. Possible values are 184 * STOPPED, RUNNING, SEEKED. 185 */ 186 int mPlayingState = STOPPED; 187 188 /** 189 * Flag that denotes whether the animation is set up and ready to go. Used to 190 * set up animation that has not yet been started. 191 */ 192 boolean mInitialized = false; 193 194 // 195 // Backing variables 196 // 197 198 // How long the animation should last in ms 199 private long mDuration = 300; 200 201 // The amount of time in ms to delay starting the animation after start() is called 202 private long mStartDelay = 0; 203 204 // The number of milliseconds between animation frames 205 private static long sFrameDelay = DEFAULT_FRAME_DELAY; 206 207 // The number of times the animation will repeat. The default is 0, which means the animation 208 // will play only once 209 private int mRepeatCount = 0; 210 211 /** 212 * The type of repetition that will occur when repeatMode is nonzero. RESTART means the 213 * animation will start from the beginning on every new cycle. REVERSE means the animation 214 * will reverse directions on each iteration. 215 */ 216 private int mRepeatMode = RESTART; 217 218 /** 219 * The time interpolator to be used. The elapsed fraction of the animation will be passed 220 * through this interpolator to calculate the interpolated fraction, which is then used to 221 * calculate the animated values. 222 */ 223 private TimeInterpolator mInterpolator = sDefaultInterpolator; 224 225 /** 226 * The set of listeners to be sent events through the life of an animation. 227 */ 228 private ArrayList<AnimatorUpdateListener> mUpdateListeners = null; 229 230 /** 231 * The property/value sets being animated. 232 */ 233 PropertyValuesHolder[] mValues; 234 235 /** 236 * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values 237 * by property name during calls to getAnimatedValue(String). 238 */ 239 HashMap<String, PropertyValuesHolder> mValuesMap; 240 241 /** 242 * Public constants 243 */ 244 245 /** 246 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 247 * or a positive value, the animation restarts from the beginning. 248 */ 249 public static final int RESTART = 1; 250 /** 251 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 252 * or a positive value, the animation reverses direction on every iteration. 253 */ 254 public static final int REVERSE = 2; 255 /** 256 * This value used used with the {@link #setRepeatCount(int)} property to repeat 257 * the animation indefinitely. 258 */ 259 public static final int INFINITE = -1; 260 261 /** 262 * Creates a new ValueAnimator object. This default constructor is primarily for 263 * use internally; the factory methods which take parameters are more generally 264 * useful. 265 */ 266 public ValueAnimator() { 267 } 268 269 /** 270 * Constructs and returns a ValueAnimator that animates between int values. A single 271 * value implies that that value is the one being animated to. However, this is not typically 272 * useful in a ValueAnimator object because there is no way for the object to determine the 273 * starting value for the animation (unlike ObjectAnimator, which can derive that value 274 * from the target object and property being animated). Therefore, there should typically 275 * be two or more values. 276 * 277 * @param values A set of values that the animation will animate between over time. 278 * @return A ValueAnimator object that is set up to animate between the given values. 279 */ 280 public static ValueAnimator ofInt(int... values) { 281 ValueAnimator anim = new ValueAnimator(); 282 anim.setIntValues(values); 283 return anim; 284 } 285 286 /** 287 * Constructs and returns a ValueAnimator that animates between float values. A single 288 * value implies that that value is the one being animated to. However, this is not typically 289 * useful in a ValueAnimator object because there is no way for the object to determine the 290 * starting value for the animation (unlike ObjectAnimator, which can derive that value 291 * from the target object and property being animated). Therefore, there should typically 292 * be two or more values. 293 * 294 * @param values A set of values that the animation will animate between over time. 295 * @return A ValueAnimator object that is set up to animate between the given values. 296 */ 297 public static ValueAnimator ofFloat(float... values) { 298 ValueAnimator anim = new ValueAnimator(); 299 anim.setFloatValues(values); 300 return anim; 301 } 302 303 /** 304 * Constructs and returns a ValueAnimator that animates between the values 305 * specified in the PropertyValuesHolder objects. 306 * 307 * @param values A set of PropertyValuesHolder objects whose values will be animated 308 * between over time. 309 * @return A ValueAnimator object that is set up to animate between the given values. 310 */ 311 public static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values) { 312 ValueAnimator anim = new ValueAnimator(); 313 anim.setValues(values); 314 return anim; 315 } 316 /** 317 * Constructs and returns a ValueAnimator that animates between Object values. A single 318 * value implies that that value is the one being animated to. However, this is not typically 319 * useful in a ValueAnimator object because there is no way for the object to determine the 320 * starting value for the animation (unlike ObjectAnimator, which can derive that value 321 * from the target object and property being animated). Therefore, there should typically 322 * be two or more values. 323 * 324 * <p>Since ValueAnimator does not know how to animate between arbitrary Objects, this 325 * factory method also takes a TypeEvaluator object that the ValueAnimator will use 326 * to perform that interpolation. 327 * 328 * @param evaluator A TypeEvaluator that will be called on each animation frame to 329 * provide the ncessry interpolation between the Object values to derive the animated 330 * value. 331 * @param values A set of values that the animation will animate between over time. 332 * @return A ValueAnimator object that is set up to animate between the given values. 333 */ 334 public static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values) { 335 ValueAnimator anim = new ValueAnimator(); 336 anim.setObjectValues(values); 337 anim.setEvaluator(evaluator); 338 return anim; 339 } 340 341 /** 342 * Sets int values that will be animated between. A single 343 * value implies that that value is the one being animated to. However, this is not typically 344 * useful in a ValueAnimator object because there is no way for the object to determine the 345 * starting value for the animation (unlike ObjectAnimator, which can derive that value 346 * from the target object and property being animated). Therefore, there should typically 347 * be two or more values. 348 * 349 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 350 * than one PropertyValuesHolder object, this method will set the values for the first 351 * of those objects.</p> 352 * 353 * @param values A set of values that the animation will animate between over time. 354 */ 355 public void setIntValues(int... values) { 356 if (values == null || values.length == 0) { 357 return; 358 } 359 if (mValues == null || mValues.length == 0) { 360 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofInt("", values)}); 361 } else { 362 PropertyValuesHolder valuesHolder = mValues[0]; 363 valuesHolder.setIntValues(values); 364 } 365 // New property/values/target should cause re-initialization prior to starting 366 mInitialized = false; 367 } 368 369 /** 370 * Sets float values that will be animated between. A single 371 * value implies that that value is the one being animated to. However, this is not typically 372 * useful in a ValueAnimator object because there is no way for the object to determine the 373 * starting value for the animation (unlike ObjectAnimator, which can derive that value 374 * from the target object and property being animated). Therefore, there should typically 375 * be two or more values. 376 * 377 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 378 * than one PropertyValuesHolder object, this method will set the values for the first 379 * of those objects.</p> 380 * 381 * @param values A set of values that the animation will animate between over time. 382 */ 383 public void setFloatValues(float... values) { 384 if (values == null || values.length == 0) { 385 return; 386 } 387 if (mValues == null || mValues.length == 0) { 388 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofFloat("", values)}); 389 } else { 390 PropertyValuesHolder valuesHolder = mValues[0]; 391 valuesHolder.setFloatValues(values); 392 } 393 // New property/values/target should cause re-initialization prior to starting 394 mInitialized = false; 395 } 396 397 /** 398 * Sets the values to animate between for this animation. A single 399 * value implies that that value is the one being animated to. However, this is not typically 400 * useful in a ValueAnimator object because there is no way for the object to determine the 401 * starting value for the animation (unlike ObjectAnimator, which can derive that value 402 * from the target object and property being animated). Therefore, there should typically 403 * be two or more values. 404 * 405 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 406 * than one PropertyValuesHolder object, this method will set the values for the first 407 * of those objects.</p> 408 * 409 * <p>There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate 410 * between these value objects. ValueAnimator only knows how to interpolate between the 411 * primitive types specified in the other setValues() methods.</p> 412 * 413 * @param values The set of values to animate between. 414 */ 415 public void setObjectValues(Object... values) { 416 if (values == null || values.length == 0) { 417 return; 418 } 419 if (mValues == null || mValues.length == 0) { 420 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofObject("", 421 (TypeEvaluator)null, values)}); 422 } else { 423 PropertyValuesHolder valuesHolder = mValues[0]; 424 valuesHolder.setObjectValues(values); 425 } 426 // New property/values/target should cause re-initialization prior to starting 427 mInitialized = false; 428 } 429 430 /** 431 * Sets the values, per property, being animated between. This function is called internally 432 * by the constructors of ValueAnimator that take a list of values. But an ValueAnimator can 433 * be constructed without values and this method can be called to set the values manually 434 * instead. 435 * 436 * @param values The set of values, per property, being animated between. 437 */ 438 public void setValues(PropertyValuesHolder... values) { 439 int numValues = values.length; 440 mValues = values; 441 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 442 for (int i = 0; i < numValues; ++i) { 443 PropertyValuesHolder valuesHolder = (PropertyValuesHolder) values[i]; 444 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 445 } 446 // New property/values/target should cause re-initialization prior to starting 447 mInitialized = false; 448 } 449 450 /** 451 * Returns the values that this ValueAnimator animates between. These values are stored in 452 * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list 453 * of value objects instead. 454 * 455 * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the 456 * values, per property, that define the animation. 457 */ 458 public PropertyValuesHolder[] getValues() { 459 return mValues; 460 } 461 462 /** 463 * This function is called immediately before processing the first animation 464 * frame of an animation. If there is a nonzero <code>startDelay</code>, the 465 * function is called after that delay ends. 466 * It takes care of the final initialization steps for the 467 * animation. 468 * 469 * <p>Overrides of this method should call the superclass method to ensure 470 * that internal mechanisms for the animation are set up correctly.</p> 471 */ 472 void initAnimation() { 473 if (!mInitialized) { 474 int numValues = mValues.length; 475 for (int i = 0; i < numValues; ++i) { 476 mValues[i].init(); 477 } 478 mInitialized = true; 479 } 480 } 481 482 483 /** 484 * Sets the length of the animation. The default duration is 300 milliseconds. 485 * 486 * @param duration The length of the animation, in milliseconds. This value cannot 487 * be negative. 488 * @return ValueAnimator The object called with setDuration(). This return 489 * value makes it easier to compose statements together that construct and then set the 490 * duration, as in <code>ValueAnimator.ofInt(0, 10).setDuration(500).start()</code>. 491 */ 492 public ValueAnimator setDuration(long duration) { 493 if (duration < 0) { 494 throw new IllegalArgumentException("Animators cannot have negative duration: " + 495 duration); 496 } 497 mDuration = duration; 498 return this; 499 } 500 501 /** 502 * Gets the length of the animation. The default duration is 300 milliseconds. 503 * 504 * @return The length of the animation, in milliseconds. 505 */ 506 public long getDuration() { 507 return mDuration; 508 } 509 510 /** 511 * Sets the position of the animation to the specified point in time. This time should 512 * be between 0 and the total duration of the animation, including any repetition. If 513 * the animation has not yet been started, then it will not advance forward after it is 514 * set to this time; it will simply set the time to this value and perform any appropriate 515 * actions based on that time. If the animation is already running, then setCurrentPlayTime() 516 * will set the current playing time to this value and continue playing from that point. 517 * 518 * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. 519 */ 520 public void setCurrentPlayTime(long playTime) { 521 initAnimation(); 522 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 523 if (mPlayingState != RUNNING) { 524 mSeekTime = playTime; 525 mPlayingState = SEEKED; 526 } 527 mStartTime = currentTime - playTime; 528 animationFrame(currentTime); 529 } 530 531 /** 532 * Gets the current position of the animation in time, which is equal to the current 533 * time minus the time that the animation started. An animation that is not yet started will 534 * return a value of zero. 535 * 536 * @return The current position in time of the animation. 537 */ 538 public long getCurrentPlayTime() { 539 if (!mInitialized || mPlayingState == STOPPED) { 540 return 0; 541 } 542 return AnimationUtils.currentAnimationTimeMillis() - mStartTime; 543 } 544 545 /** 546 * This custom, static handler handles the timing pulse that is shared by 547 * all active animations. This approach ensures that the setting of animation 548 * values will happen on the UI thread and that all animations will share 549 * the same times for calculating their values, which makes synchronizing 550 * animations possible. 551 * 552 */ 553 private static class AnimationHandler extends Handler { 554 /** 555 * There are only two messages that we care about: ANIMATION_START and 556 * ANIMATION_FRAME. The START message is sent when an animation's start() 557 * method is called. It cannot start synchronously when start() is called 558 * because the call may be on the wrong thread, and it would also not be 559 * synchronized with other animations because it would not start on a common 560 * timing pulse. So each animation sends a START message to the handler, which 561 * causes the handler to place the animation on the active animations queue and 562 * start processing frames for that animation. 563 * The FRAME message is the one that is sent over and over while there are any 564 * active animations to process. 565 */ 566 @Override 567 public void handleMessage(Message msg) { 568 boolean callAgain = true; 569 ArrayList<ValueAnimator> animations = sAnimations.get(); 570 ArrayList<ValueAnimator> delayedAnims = sDelayedAnims.get(); 571 switch (msg.what) { 572 // TODO: should we avoid sending frame message when starting if we 573 // were already running? 574 case ANIMATION_START: 575 ArrayList<ValueAnimator> pendingAnimations = sPendingAnimations.get(); 576 if (animations.size() > 0 || delayedAnims.size() > 0) { 577 callAgain = false; 578 } 579 // pendingAnims holds any animations that have requested to be started 580 // We're going to clear sPendingAnimations, but starting animation may 581 // cause more to be added to the pending list (for example, if one animation 582 // starting triggers another starting). So we loop until sPendingAnimations 583 // is empty. 584 while (pendingAnimations.size() > 0) { 585 ArrayList<ValueAnimator> pendingCopy = 586 (ArrayList<ValueAnimator>) pendingAnimations.clone(); 587 pendingAnimations.clear(); 588 int count = pendingCopy.size(); 589 for (int i = 0; i < count; ++i) { 590 ValueAnimator anim = pendingCopy.get(i); 591 // If the animation has a startDelay, place it on the delayed list 592 if (anim.mStartDelay == 0) { 593 anim.startAnimation(); 594 } else { 595 delayedAnims.add(anim); 596 } 597 } 598 } 599 // fall through to process first frame of new animations 600 case ANIMATION_FRAME: 601 // currentTime holds the common time for all animations processed 602 // during this frame 603 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 604 ArrayList<ValueAnimator> readyAnims = sReadyAnims.get(); 605 ArrayList<ValueAnimator> endingAnims = sEndingAnims.get(); 606 607 // First, process animations currently sitting on the delayed queue, adding 608 // them to the active animations if they are ready 609 int numDelayedAnims = delayedAnims.size(); 610 for (int i = 0; i < numDelayedAnims; ++i) { 611 ValueAnimator anim = delayedAnims.get(i); 612 if (anim.delayedAnimationFrame(currentTime)) { 613 readyAnims.add(anim); 614 } 615 } 616 int numReadyAnims = readyAnims.size(); 617 if (numReadyAnims > 0) { 618 for (int i = 0; i < numReadyAnims; ++i) { 619 ValueAnimator anim = readyAnims.get(i); 620 anim.startAnimation(); 621 delayedAnims.remove(anim); 622 } 623 readyAnims.clear(); 624 } 625 626 // Now process all active animations. The return value from animationFrame() 627 // tells the handler whether it should now be ended 628 int numAnims = animations.size(); 629 int i = 0; 630 while (i < numAnims) { 631 ValueAnimator anim = animations.get(i); 632 if (anim.animationFrame(currentTime)) { 633 endingAnims.add(anim); 634 } 635 if (animations.size() == numAnims) { 636 ++i; 637 } else { 638 // An animation might be canceled or ended by client code 639 // during the animation frame. Check to see if this happened by 640 // seeing whether the current index is the same as it was before 641 // calling animationFrame(). Another approach would be to copy 642 // animations to a temporary list and process that list instead, 643 // but that entails garbage and processing overhead that would 644 // be nice to avoid. 645 --numAnims; 646 endingAnims.remove(anim); 647 } 648 } 649 if (endingAnims.size() > 0) { 650 for (i = 0; i < endingAnims.size(); ++i) { 651 endingAnims.get(i).endAnimation(); 652 } 653 endingAnims.clear(); 654 } 655 656 // If there are still active or delayed animations, call the handler again 657 // after the frameDelay 658 if (callAgain && (!animations.isEmpty() || !delayedAnims.isEmpty())) { 659 sendEmptyMessageDelayed(ANIMATION_FRAME, Math.max(0, sFrameDelay - 660 (AnimationUtils.currentAnimationTimeMillis() - currentTime))); 661 } 662 break; 663 } 664 } 665 } 666 667 /** 668 * The amount of time, in milliseconds, to delay starting the animation after 669 * {@link #start()} is called. 670 * 671 * @return the number of milliseconds to delay running the animation 672 */ 673 public long getStartDelay() { 674 return mStartDelay; 675 } 676 677 /** 678 * The amount of time, in milliseconds, to delay starting the animation after 679 * {@link #start()} is called. 680 681 * @param startDelay The amount of the delay, in milliseconds 682 */ 683 public void setStartDelay(long startDelay) { 684 this.mStartDelay = startDelay; 685 } 686 687 /** 688 * The amount of time, in milliseconds, between each frame of the animation. This is a 689 * requested time that the animation will attempt to honor, but the actual delay between 690 * frames may be different, depending on system load and capabilities. This is a static 691 * function because the same delay will be applied to all animations, since they are all 692 * run off of a single timing loop. 693 * 694 * @return the requested time between frames, in milliseconds 695 */ 696 public static long getFrameDelay() { 697 return sFrameDelay; 698 } 699 700 /** 701 * The amount of time, in milliseconds, between each frame of the animation. This is a 702 * requested time that the animation will attempt to honor, but the actual delay between 703 * frames may be different, depending on system load and capabilities. This is a static 704 * function because the same delay will be applied to all animations, since they are all 705 * run off of a single timing loop. 706 * 707 * @param frameDelay the requested time between frames, in milliseconds 708 */ 709 public static void setFrameDelay(long frameDelay) { 710 sFrameDelay = frameDelay; 711 } 712 713 /** 714 * The most recent value calculated by this <code>ValueAnimator</code> when there is just one 715 * property being animated. This value is only sensible while the animation is running. The main 716 * purpose for this read-only property is to retrieve the value from the <code>ValueAnimator</code> 717 * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 718 * is called during each animation frame, immediately after the value is calculated. 719 * 720 * @return animatedValue The value most recently calculated by this <code>ValueAnimator</code> for 721 * the single property being animated. If there are several properties being animated 722 * (specified by several PropertyValuesHolder objects in the constructor), this function 723 * returns the animated value for the first of those objects. 724 */ 725 public Object getAnimatedValue() { 726 if (mValues != null && mValues.length > 0) { 727 return mValues[0].getAnimatedValue(); 728 } 729 // Shouldn't get here; should always have values unless ValueAnimator was set up wrong 730 return null; 731 } 732 733 /** 734 * The most recent value calculated by this <code>ValueAnimator</code> for <code>propertyName</code>. 735 * The main purpose for this read-only property is to retrieve the value from the 736 * <code>ValueAnimator</code> during a call to 737 * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 738 * is called during each animation frame, immediately after the value is calculated. 739 * 740 * @return animatedValue The value most recently calculated for the named property 741 * by this <code>ValueAnimator</code>. 742 */ 743 public Object getAnimatedValue(String propertyName) { 744 PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); 745 if (valuesHolder != null) { 746 return valuesHolder.getAnimatedValue(); 747 } else { 748 // At least avoid crashing if called with bogus propertyName 749 return null; 750 } 751 } 752 753 /** 754 * Sets how many times the animation should be repeated. If the repeat 755 * count is 0, the animation is never repeated. If the repeat count is 756 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken 757 * into account. The repeat count is 0 by default. 758 * 759 * @param value the number of times the animation should be repeated 760 */ 761 public void setRepeatCount(int value) { 762 mRepeatCount = value; 763 } 764 /** 765 * Defines how many times the animation should repeat. The default value 766 * is 0. 767 * 768 * @return the number of times the animation should repeat, or {@link #INFINITE} 769 */ 770 public int getRepeatCount() { 771 return mRepeatCount; 772 } 773 774 /** 775 * Defines what this animation should do when it reaches the end. This 776 * setting is applied only when the repeat count is either greater than 777 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 778 * 779 * @param value {@link #RESTART} or {@link #REVERSE} 780 */ 781 public void setRepeatMode(int value) { 782 mRepeatMode = value; 783 } 784 785 /** 786 * Defines what this animation should do when it reaches the end. 787 * 788 * @return either one of {@link #REVERSE} or {@link #RESTART} 789 */ 790 public int getRepeatMode() { 791 return mRepeatMode; 792 } 793 794 /** 795 * Adds a listener to the set of listeners that are sent update events through the life of 796 * an animation. This method is called on all listeners for every frame of the animation, 797 * after the values for the animation have been calculated. 798 * 799 * @param listener the listener to be added to the current set of listeners for this animation. 800 */ 801 public void addUpdateListener(AnimatorUpdateListener listener) { 802 if (mUpdateListeners == null) { 803 mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 804 } 805 mUpdateListeners.add(listener); 806 } 807 808 /** 809 * Removes all listeners from the set listening to frame updates for this animation. 810 */ 811 public void removeAllUpdateListeners() { 812 if (mUpdateListeners == null) { 813 return; 814 } 815 mUpdateListeners.clear(); 816 mUpdateListeners = null; 817 } 818 819 /** 820 * Removes a listener from the set listening to frame updates for this animation. 821 * 822 * @param listener the listener to be removed from the current set of update listeners 823 * for this animation. 824 */ 825 public void removeUpdateListener(AnimatorUpdateListener listener) { 826 if (mUpdateListeners == null) { 827 return; 828 } 829 mUpdateListeners.remove(listener); 830 if (mUpdateListeners.size() == 0) { 831 mUpdateListeners = null; 832 } 833 } 834 835 836 /** 837 * The time interpolator used in calculating the elapsed fraction of this animation. The 838 * interpolator determines whether the animation runs with linear or non-linear motion, 839 * such as acceleration and deceleration. The default value is 840 * {@link android.view.animation.AccelerateDecelerateInterpolator} 841 * 842 * @param value the interpolator to be used by this animation. A value of <code>null</code> 843 * will result in linear interpolation. 844 */ 845 @Override 846 public void setInterpolator(TimeInterpolator value) { 847 if (value != null) { 848 mInterpolator = value; 849 } else { 850 mInterpolator = new LinearInterpolator(); 851 } 852 } 853 854 /** 855 * Returns the timing interpolator that this ValueAnimator uses. 856 * 857 * @return The timing interpolator for this ValueAnimator. 858 */ 859 public TimeInterpolator getInterpolator() { 860 return mInterpolator; 861 } 862 863 /** 864 * The type evaluator to be used when calculating the animated values of this animation. 865 * The system will automatically assign a float or int evaluator based on the type 866 * of <code>startValue</code> and <code>endValue</code> in the constructor. But if these values 867 * are not one of these primitive types, or if different evaluation is desired (such as is 868 * necessary with int values that represent colors), a custom evaluator needs to be assigned. 869 * For example, when running an animation on color values, the {@link ArgbEvaluator} 870 * should be used to get correct RGB color interpolation. 871 * 872 * <p>If this ValueAnimator has only one set of values being animated between, this evaluator 873 * will be used for that set. If there are several sets of values being animated, which is 874 * the case if PropertyValuesHOlder objects were set on the ValueAnimator, then the evaluator 875 * is assigned just to the first PropertyValuesHolder object.</p> 876 * 877 * @param value the evaluator to be used this animation 878 */ 879 public void setEvaluator(TypeEvaluator value) { 880 if (value != null && mValues != null && mValues.length > 0) { 881 mValues[0].setEvaluator(value); 882 } 883 } 884 885 /** 886 * Start the animation playing. This version of start() takes a boolean flag that indicates 887 * whether the animation should play in reverse. The flag is usually false, but may be set 888 * to true if called from the reverse() method. 889 * 890 * <p>The animation started by calling this method will be run on the thread that called 891 * this method. This thread should have a Looper on it (a runtime exception will be thrown if 892 * this is not the case). Also, if the animation will animate 893 * properties of objects in the view hierarchy, then the calling thread should be the UI 894 * thread for that view hierarchy.</p> 895 * 896 * @param playBackwards Whether the ValueAnimator should start playing in reverse. 897 */ 898 private void start(boolean playBackwards) { 899 if (Looper.myLooper() == null) { 900 throw new AndroidRuntimeException("Animators may only be run on Looper threads"); 901 } 902 mPlayingBackwards = playBackwards; 903 mCurrentIteration = 0; 904 mPlayingState = STOPPED; 905 mStartedDelay = false; 906 sPendingAnimations.get().add(this); 907 if (mStartDelay == 0) { 908 // This sets the initial value of the animation, prior to actually starting it running 909 setCurrentPlayTime(getCurrentPlayTime()); 910 mPlayingState = STOPPED; 911 912 if (mListeners != null) { 913 ArrayList<AnimatorListener> tmpListeners = 914 (ArrayList<AnimatorListener>) mListeners.clone(); 915 int numListeners = tmpListeners.size(); 916 for (int i = 0; i < numListeners; ++i) { 917 tmpListeners.get(i).onAnimationStart(this); 918 } 919 } 920 } 921 AnimationHandler animationHandler = sAnimationHandler.get(); 922 if (animationHandler == null) { 923 animationHandler = new AnimationHandler(); 924 sAnimationHandler.set(animationHandler); 925 } 926 animationHandler.sendEmptyMessage(ANIMATION_START); 927 } 928 929 @Override 930 public void start() { 931 start(false); 932 } 933 934 @Override 935 public void cancel() { 936 if (mListeners != null) { 937 ArrayList<AnimatorListener> tmpListeners = 938 (ArrayList<AnimatorListener>) mListeners.clone(); 939 for (AnimatorListener listener : tmpListeners) { 940 listener.onAnimationCancel(this); 941 } 942 } 943 // Only cancel if the animation is actually running or has been started and is about 944 // to run 945 if (mPlayingState != STOPPED || sPendingAnimations.get().contains(this) || 946 sDelayedAnims.get().contains(this)) { 947 endAnimation(); 948 } 949 } 950 951 @Override 952 public void end() { 953 if (!sAnimations.get().contains(this) && !sPendingAnimations.get().contains(this)) { 954 // Special case if the animation has not yet started; get it ready for ending 955 mStartedDelay = false; 956 startAnimation(); 957 } else if (!mInitialized) { 958 initAnimation(); 959 } 960 // The final value set on the target varies, depending on whether the animation 961 // was supposed to repeat an odd number of times 962 if (mRepeatCount > 0 && (mRepeatCount & 0x01) == 1) { 963 animateValue(0f); 964 } else { 965 animateValue(1f); 966 } 967 endAnimation(); 968 } 969 970 @Override 971 public boolean isRunning() { 972 return (mPlayingState == RUNNING); 973 } 974 975 /** 976 * Plays the ValueAnimator in reverse. If the animation is already running, 977 * it will stop itself and play backwards from the point reached when reverse was called. 978 * If the animation is not currently running, then it will start from the end and 979 * play backwards. This behavior is only set for the current animation; future playing 980 * of the animation will use the default behavior of playing forward. 981 */ 982 public void reverse() { 983 mPlayingBackwards = !mPlayingBackwards; 984 if (mPlayingState == RUNNING) { 985 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 986 long currentPlayTime = currentTime - mStartTime; 987 long timeLeft = mDuration - currentPlayTime; 988 mStartTime = currentTime - timeLeft; 989 } else { 990 start(true); 991 } 992 } 993 994 /** 995 * Called internally to end an animation by removing it from the animations list. Must be 996 * called on the UI thread. 997 */ 998 private void endAnimation() { 999 sAnimations.get().remove(this); 1000 sPendingAnimations.get().remove(this); 1001 sDelayedAnims.get().remove(this); 1002 mPlayingState = STOPPED; 1003 if (mListeners != null) { 1004 ArrayList<AnimatorListener> tmpListeners = 1005 (ArrayList<AnimatorListener>) mListeners.clone(); 1006 int numListeners = tmpListeners.size(); 1007 for (int i = 0; i < numListeners; ++i) { 1008 tmpListeners.get(i).onAnimationEnd(this); 1009 } 1010 } 1011 } 1012 1013 /** 1014 * Called internally to start an animation by adding it to the active animations list. Must be 1015 * called on the UI thread. 1016 */ 1017 private void startAnimation() { 1018 initAnimation(); 1019 sAnimations.get().add(this); 1020 if (mStartDelay > 0 && mListeners != null) { 1021 // Listeners were already notified in start() if startDelay is 0; this is 1022 // just for delayed animations 1023 ArrayList<AnimatorListener> tmpListeners = 1024 (ArrayList<AnimatorListener>) mListeners.clone(); 1025 int numListeners = tmpListeners.size(); 1026 for (int i = 0; i < numListeners; ++i) { 1027 tmpListeners.get(i).onAnimationStart(this); 1028 } 1029 } 1030 } 1031 1032 /** 1033 * Internal function called to process an animation frame on an animation that is currently 1034 * sleeping through its <code>startDelay</code> phase. The return value indicates whether it 1035 * should be woken up and put on the active animations queue. 1036 * 1037 * @param currentTime The current animation time, used to calculate whether the animation 1038 * has exceeded its <code>startDelay</code> and should be started. 1039 * @return True if the animation's <code>startDelay</code> has been exceeded and the animation 1040 * should be added to the set of active animations. 1041 */ 1042 private boolean delayedAnimationFrame(long currentTime) { 1043 if (!mStartedDelay) { 1044 mStartedDelay = true; 1045 mDelayStartTime = currentTime; 1046 } else { 1047 long deltaTime = currentTime - mDelayStartTime; 1048 if (deltaTime > mStartDelay) { 1049 // startDelay ended - start the anim and record the 1050 // mStartTime appropriately 1051 mStartTime = currentTime - (deltaTime - mStartDelay); 1052 mPlayingState = RUNNING; 1053 return true; 1054 } 1055 } 1056 return false; 1057 } 1058 1059 /** 1060 * This internal function processes a single animation frame for a given animation. The 1061 * currentTime parameter is the timing pulse sent by the handler, used to calculate the 1062 * elapsed duration, and therefore 1063 * the elapsed fraction, of the animation. The return value indicates whether the animation 1064 * should be ended (which happens when the elapsed time of the animation exceeds the 1065 * animation's duration, including the repeatCount). 1066 * 1067 * @param currentTime The current time, as tracked by the static timing handler 1068 * @return true if the animation's duration, including any repetitions due to 1069 * <code>repeatCount</code> has been exceeded and the animation should be ended. 1070 */ 1071 boolean animationFrame(long currentTime) { 1072 boolean done = false; 1073 1074 if (mPlayingState == STOPPED) { 1075 mPlayingState = RUNNING; 1076 if (mSeekTime < 0) { 1077 mStartTime = currentTime; 1078 } else { 1079 mStartTime = currentTime - mSeekTime; 1080 // Now that we're playing, reset the seek time 1081 mSeekTime = -1; 1082 } 1083 } 1084 switch (mPlayingState) { 1085 case RUNNING: 1086 case SEEKED: 1087 float fraction = mDuration > 0 ? (float)(currentTime - mStartTime) / mDuration : 1f; 1088 if (fraction >= 1f) { 1089 if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { 1090 // Time to repeat 1091 if (mListeners != null) { 1092 int numListeners = mListeners.size(); 1093 for (int i = 0; i < numListeners; ++i) { 1094 mListeners.get(i).onAnimationRepeat(this); 1095 } 1096 } 1097 if (mRepeatMode == REVERSE) { 1098 mPlayingBackwards = mPlayingBackwards ? false : true; 1099 } 1100 mCurrentIteration += (int)fraction; 1101 fraction = fraction % 1f; 1102 mStartTime += mDuration; 1103 } else { 1104 done = true; 1105 fraction = Math.min(fraction, 1.0f); 1106 } 1107 } 1108 if (mPlayingBackwards) { 1109 fraction = 1f - fraction; 1110 } 1111 animateValue(fraction); 1112 break; 1113 } 1114 1115 return done; 1116 } 1117 1118 /** 1119 * Returns the current animation fraction, which is the elapsed/interpolated fraction used in 1120 * the most recent frame update on the animation. 1121 * 1122 * @return Elapsed/interpolated fraction of the animation. 1123 */ 1124 public float getAnimatedFraction() { 1125 return mCurrentFraction; 1126 } 1127 1128 /** 1129 * This method is called with the elapsed fraction of the animation during every 1130 * animation frame. This function turns the elapsed fraction into an interpolated fraction 1131 * and then into an animated value (from the evaluator. The function is called mostly during 1132 * animation updates, but it is also called when the <code>end()</code> 1133 * function is called, to set the final value on the property. 1134 * 1135 * <p>Overrides of this method must call the superclass to perform the calculation 1136 * of the animated value.</p> 1137 * 1138 * @param fraction The elapsed fraction of the animation. 1139 */ 1140 void animateValue(float fraction) { 1141 fraction = mInterpolator.getInterpolation(fraction); 1142 mCurrentFraction = fraction; 1143 int numValues = mValues.length; 1144 for (int i = 0; i < numValues; ++i) { 1145 mValues[i].calculateValue(fraction); 1146 } 1147 if (mUpdateListeners != null) { 1148 int numListeners = mUpdateListeners.size(); 1149 for (int i = 0; i < numListeners; ++i) { 1150 mUpdateListeners.get(i).onAnimationUpdate(this); 1151 } 1152 } 1153 } 1154 1155 @Override 1156 public ValueAnimator clone() { 1157 final ValueAnimator anim = (ValueAnimator) super.clone(); 1158 if (mUpdateListeners != null) { 1159 ArrayList<AnimatorUpdateListener> oldListeners = mUpdateListeners; 1160 anim.mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 1161 int numListeners = oldListeners.size(); 1162 for (int i = 0; i < numListeners; ++i) { 1163 anim.mUpdateListeners.add(oldListeners.get(i)); 1164 } 1165 } 1166 anim.mSeekTime = -1; 1167 anim.mPlayingBackwards = false; 1168 anim.mCurrentIteration = 0; 1169 anim.mInitialized = false; 1170 anim.mPlayingState = STOPPED; 1171 anim.mStartedDelay = false; 1172 PropertyValuesHolder[] oldValues = mValues; 1173 if (oldValues != null) { 1174 int numValues = oldValues.length; 1175 anim.mValues = new PropertyValuesHolder[numValues]; 1176 for (int i = 0; i < numValues; ++i) { 1177 anim.mValues[i] = oldValues[i].clone(); 1178 } 1179 anim.mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 1180 for (int i = 0; i < numValues; ++i) { 1181 PropertyValuesHolder valuesHolder = mValues[i]; 1182 anim.mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 1183 } 1184 } 1185 return anim; 1186 } 1187 1188 /** 1189 * Implementors of this interface can add themselves as update listeners 1190 * to an <code>ValueAnimator</code> instance to receive callbacks on every animation 1191 * frame, after the current frame's values have been calculated for that 1192 * <code>ValueAnimator</code>. 1193 */ 1194 public static interface AnimatorUpdateListener { 1195 /** 1196 * <p>Notifies the occurrence of another frame of the animation.</p> 1197 * 1198 * @param animation The animation which was repeated. 1199 */ 1200 void onAnimationUpdate(ValueAnimator animation); 1201 1202 } 1203 1204 /** 1205 * Return the number of animations currently running. 1206 * 1207 * Used by StrictMode internally to annotate violations. Only 1208 * called on the main thread. 1209 * 1210 * @hide 1211 */ 1212 public static int getCurrentAnimationsCount() { 1213 return sAnimations.get().size(); 1214 } 1215 1216 /** 1217 * Clear all animations on this thread, without canceling or ending them. 1218 * This should be used with caution. 1219 * 1220 * @hide 1221 */ 1222 public static void clearAllAnimations() { 1223 sAnimations.get().clear(); 1224 sPendingAnimations.get().clear(); 1225 sDelayedAnims.get().clear(); 1226 } 1227 1228 @Override 1229 public String toString() { 1230 String returnVal = "ValueAnimator@" + Integer.toHexString(hashCode()); 1231 if (mValues != null) { 1232 for (int i = 0; i < mValues.length; ++i) { 1233 returnVal += "\n " + mValues[i].toString(); 1234 } 1235 } 1236 return returnVal; 1237 } 1238} 1239