ValueAnimator.java revision 2b072677538de979961b5bf527109fdab1713731
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.Choreographer; 24import android.view.animation.AccelerateDecelerateInterpolator; 25import android.view.animation.AnimationUtils; 26import android.view.animation.LinearInterpolator; 27 28import java.util.ArrayList; 29import java.util.HashMap; 30 31/** 32 * This class provides a simple timing engine for running animations 33 * which calculate animated values and set them on target objects. 34 * 35 * <p>There is a single timing pulse that all animations use. It runs in a 36 * custom handler to ensure that property changes happen on the UI thread.</p> 37 * 38 * <p>By default, ValueAnimator uses non-linear time interpolation, via the 39 * {@link AccelerateDecelerateInterpolator} class, which accelerates into and decelerates 40 * out of an animation. This behavior can be changed by calling 41 * {@link ValueAnimator#setInterpolator(TimeInterpolator)}.</p> 42 * 43 * <div class="special reference"> 44 * <h3>Developer Guides</h3> 45 * <p>For more information about animating with {@code ValueAnimator}, read the 46 * <a href="{@docRoot}guide/topics/graphics/prop-animation.html#value-animator">Property 47 * Animation</a> developer guide.</p> 48 * </div> 49 */ 50public class ValueAnimator extends Animator { 51 52 /** 53 * Internal constants 54 */ 55 56 /** 57 * Messages sent to timing handler: START is sent when an animation first begins. 58 */ 59 static final int ANIMATION_START = 0; 60 61 /** 62 * Values used with internal variable mPlayingState to indicate the current state of an 63 * animation. 64 */ 65 static final int STOPPED = 0; // Not yet playing 66 static final int RUNNING = 1; // Playing normally 67 static final int SEEKED = 2; // Seeked to some time value 68 69 /** 70 * Internal variables 71 * NOTE: This object implements the clone() method, making a deep copy of any referenced 72 * objects. As other non-trivial fields are added to this class, make sure to add logic 73 * to clone() to make deep copies of them. 74 */ 75 76 // The first time that the animation's animateFrame() method is called. This time is used to 77 // determine elapsed time (and therefore the elapsed fraction) in subsequent calls 78 // to animateFrame() 79 long mStartTime; 80 81 /** 82 * Set when setCurrentPlayTime() is called. If negative, animation is not currently seeked 83 * to a value. 84 */ 85 long mSeekTime = -1; 86 87 // The static sAnimationHandler processes the internal timing loop on which all animations 88 // are based 89 private static ThreadLocal<AnimationHandler> sAnimationHandler = 90 new ThreadLocal<AnimationHandler>(); 91 92 // The time interpolator to be used if none is set on the animation 93 private static final TimeInterpolator sDefaultInterpolator = 94 new AccelerateDecelerateInterpolator(); 95 96 /** 97 * Used to indicate whether the animation is currently playing in reverse. This causes the 98 * elapsed fraction to be inverted to calculate the appropriate values. 99 */ 100 private boolean mPlayingBackwards = false; 101 102 /** 103 * This variable tracks the current iteration that is playing. When mCurrentIteration exceeds the 104 * repeatCount (if repeatCount!=INFINITE), the animation ends 105 */ 106 private int mCurrentIteration = 0; 107 108 /** 109 * Tracks current elapsed/eased fraction, for querying in getAnimatedFraction(). 110 */ 111 private float mCurrentFraction = 0f; 112 113 /** 114 * Tracks whether a startDelay'd animation has begun playing through the startDelay. 115 */ 116 private boolean mStartedDelay = false; 117 118 /** 119 * Tracks the time at which the animation began playing through its startDelay. This is 120 * different from the mStartTime variable, which is used to track when the animation became 121 * active (which is when the startDelay expired and the animation was added to the active 122 * animations list). 123 */ 124 private long mDelayStartTime; 125 126 /** 127 * Flag that represents the current state of the animation. Used to figure out when to start 128 * an animation (if state == STOPPED). Also used to end an animation that 129 * has been cancel()'d or end()'d since the last animation frame. Possible values are 130 * STOPPED, RUNNING, SEEKED. 131 */ 132 int mPlayingState = STOPPED; 133 134 /** 135 * Additional playing state to indicate whether an animator has been start()'d. There is 136 * some lag between a call to start() and the first animation frame. We should still note 137 * that the animation has been started, even if it's first animation frame has not yet 138 * happened, and reflect that state in isRunning(). 139 * Note that delayed animations are different: they are not started until their first 140 * animation frame, which occurs after their delay elapses. 141 */ 142 private boolean mRunning = false; 143 144 /** 145 * Additional playing state to indicate whether an animator has been start()'d, whether or 146 * not there is a nonzero startDelay. 147 */ 148 private boolean mStarted = false; 149 150 /** 151 * Flag that denotes whether the animation is set up and ready to go. Used to 152 * set up animation that has not yet been started. 153 */ 154 boolean mInitialized = false; 155 156 // 157 // Backing variables 158 // 159 160 // How long the animation should last in ms 161 private long mDuration = 300; 162 163 // The amount of time in ms to delay starting the animation after start() is called 164 private long mStartDelay = 0; 165 166 // The number of times the animation will repeat. The default is 0, which means the animation 167 // will play only once 168 private int mRepeatCount = 0; 169 170 /** 171 * The type of repetition that will occur when repeatMode is nonzero. RESTART means the 172 * animation will start from the beginning on every new cycle. REVERSE means the animation 173 * will reverse directions on each iteration. 174 */ 175 private int mRepeatMode = RESTART; 176 177 /** 178 * The time interpolator to be used. The elapsed fraction of the animation will be passed 179 * through this interpolator to calculate the interpolated fraction, which is then used to 180 * calculate the animated values. 181 */ 182 private TimeInterpolator mInterpolator = sDefaultInterpolator; 183 184 /** 185 * The set of listeners to be sent events through the life of an animation. 186 */ 187 private ArrayList<AnimatorUpdateListener> mUpdateListeners = null; 188 189 /** 190 * The property/value sets being animated. 191 */ 192 PropertyValuesHolder[] mValues; 193 194 /** 195 * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values 196 * by property name during calls to getAnimatedValue(String). 197 */ 198 HashMap<String, PropertyValuesHolder> mValuesMap; 199 200 /** 201 * Public constants 202 */ 203 204 /** 205 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 206 * or a positive value, the animation restarts from the beginning. 207 */ 208 public static final int RESTART = 1; 209 /** 210 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 211 * or a positive value, the animation reverses direction on every iteration. 212 */ 213 public static final int REVERSE = 2; 214 /** 215 * This value used used with the {@link #setRepeatCount(int)} property to repeat 216 * the animation indefinitely. 217 */ 218 public static final int INFINITE = -1; 219 220 /** 221 * Creates a new ValueAnimator object. This default constructor is primarily for 222 * use internally; the factory methods which take parameters are more generally 223 * useful. 224 */ 225 public ValueAnimator() { 226 } 227 228 /** 229 * Constructs and returns a ValueAnimator that animates between int values. A single 230 * value implies that that value is the one being animated to. However, this is not typically 231 * useful in a ValueAnimator object because there is no way for the object to determine the 232 * starting value for the animation (unlike ObjectAnimator, which can derive that value 233 * from the target object and property being animated). Therefore, there should typically 234 * be two or more values. 235 * 236 * @param values A set of values that the animation will animate between over time. 237 * @return A ValueAnimator object that is set up to animate between the given values. 238 */ 239 public static ValueAnimator ofInt(int... values) { 240 ValueAnimator anim = new ValueAnimator(); 241 anim.setIntValues(values); 242 return anim; 243 } 244 245 /** 246 * Constructs and returns a ValueAnimator that animates between float values. A single 247 * value implies that that value is the one being animated to. However, this is not typically 248 * useful in a ValueAnimator object because there is no way for the object to determine the 249 * starting value for the animation (unlike ObjectAnimator, which can derive that value 250 * from the target object and property being animated). Therefore, there should typically 251 * be two or more values. 252 * 253 * @param values A set of values that the animation will animate between over time. 254 * @return A ValueAnimator object that is set up to animate between the given values. 255 */ 256 public static ValueAnimator ofFloat(float... values) { 257 ValueAnimator anim = new ValueAnimator(); 258 anim.setFloatValues(values); 259 return anim; 260 } 261 262 /** 263 * Constructs and returns a ValueAnimator that animates between the values 264 * specified in the PropertyValuesHolder objects. 265 * 266 * @param values A set of PropertyValuesHolder objects whose values will be animated 267 * between over time. 268 * @return A ValueAnimator object that is set up to animate between the given values. 269 */ 270 public static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values) { 271 ValueAnimator anim = new ValueAnimator(); 272 anim.setValues(values); 273 return anim; 274 } 275 /** 276 * Constructs and returns a ValueAnimator that animates between Object values. A single 277 * value implies that that value is the one being animated to. However, this is not typically 278 * useful in a ValueAnimator object because there is no way for the object to determine the 279 * starting value for the animation (unlike ObjectAnimator, which can derive that value 280 * from the target object and property being animated). Therefore, there should typically 281 * be two or more values. 282 * 283 * <p>Since ValueAnimator does not know how to animate between arbitrary Objects, this 284 * factory method also takes a TypeEvaluator object that the ValueAnimator will use 285 * to perform that interpolation. 286 * 287 * @param evaluator A TypeEvaluator that will be called on each animation frame to 288 * provide the ncessry interpolation between the Object values to derive the animated 289 * value. 290 * @param values A set of values that the animation will animate between over time. 291 * @return A ValueAnimator object that is set up to animate between the given values. 292 */ 293 public static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values) { 294 ValueAnimator anim = new ValueAnimator(); 295 anim.setObjectValues(values); 296 anim.setEvaluator(evaluator); 297 return anim; 298 } 299 300 /** 301 * Sets int values that will be animated between. A single 302 * value implies that that value is the one being animated to. However, this is not typically 303 * useful in a ValueAnimator object because there is no way for the object to determine the 304 * starting value for the animation (unlike ObjectAnimator, which can derive that value 305 * from the target object and property being animated). Therefore, there should typically 306 * be two or more values. 307 * 308 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 309 * than one PropertyValuesHolder object, this method will set the values for the first 310 * of those objects.</p> 311 * 312 * @param values A set of values that the animation will animate between over time. 313 */ 314 public void setIntValues(int... values) { 315 if (values == null || values.length == 0) { 316 return; 317 } 318 if (mValues == null || mValues.length == 0) { 319 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofInt("", values)}); 320 } else { 321 PropertyValuesHolder valuesHolder = mValues[0]; 322 valuesHolder.setIntValues(values); 323 } 324 // New property/values/target should cause re-initialization prior to starting 325 mInitialized = false; 326 } 327 328 /** 329 * Sets float values that will be animated between. A single 330 * value implies that that value is the one being animated to. However, this is not typically 331 * useful in a ValueAnimator object because there is no way for the object to determine the 332 * starting value for the animation (unlike ObjectAnimator, which can derive that value 333 * from the target object and property being animated). Therefore, there should typically 334 * be two or more values. 335 * 336 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 337 * than one PropertyValuesHolder object, this method will set the values for the first 338 * of those objects.</p> 339 * 340 * @param values A set of values that the animation will animate between over time. 341 */ 342 public void setFloatValues(float... values) { 343 if (values == null || values.length == 0) { 344 return; 345 } 346 if (mValues == null || mValues.length == 0) { 347 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofFloat("", values)}); 348 } else { 349 PropertyValuesHolder valuesHolder = mValues[0]; 350 valuesHolder.setFloatValues(values); 351 } 352 // New property/values/target should cause re-initialization prior to starting 353 mInitialized = false; 354 } 355 356 /** 357 * Sets the values to animate between for this animation. A single 358 * value implies that that value is the one being animated to. However, this is not typically 359 * useful in a ValueAnimator object because there is no way for the object to determine the 360 * starting value for the animation (unlike ObjectAnimator, which can derive that value 361 * from the target object and property being animated). Therefore, there should typically 362 * be two or more values. 363 * 364 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 365 * than one PropertyValuesHolder object, this method will set the values for the first 366 * of those objects.</p> 367 * 368 * <p>There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate 369 * between these value objects. ValueAnimator only knows how to interpolate between the 370 * primitive types specified in the other setValues() methods.</p> 371 * 372 * @param values The set of values to animate between. 373 */ 374 public void setObjectValues(Object... values) { 375 if (values == null || values.length == 0) { 376 return; 377 } 378 if (mValues == null || mValues.length == 0) { 379 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofObject("", 380 (TypeEvaluator)null, values)}); 381 } else { 382 PropertyValuesHolder valuesHolder = mValues[0]; 383 valuesHolder.setObjectValues(values); 384 } 385 // New property/values/target should cause re-initialization prior to starting 386 mInitialized = false; 387 } 388 389 /** 390 * Sets the values, per property, being animated between. This function is called internally 391 * by the constructors of ValueAnimator that take a list of values. But an ValueAnimator can 392 * be constructed without values and this method can be called to set the values manually 393 * instead. 394 * 395 * @param values The set of values, per property, being animated between. 396 */ 397 public void setValues(PropertyValuesHolder... values) { 398 int numValues = values.length; 399 mValues = values; 400 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 401 for (int i = 0; i < numValues; ++i) { 402 PropertyValuesHolder valuesHolder = (PropertyValuesHolder) values[i]; 403 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 404 } 405 // New property/values/target should cause re-initialization prior to starting 406 mInitialized = false; 407 } 408 409 /** 410 * Returns the values that this ValueAnimator animates between. These values are stored in 411 * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list 412 * of value objects instead. 413 * 414 * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the 415 * values, per property, that define the animation. 416 */ 417 public PropertyValuesHolder[] getValues() { 418 return mValues; 419 } 420 421 /** 422 * This function is called immediately before processing the first animation 423 * frame of an animation. If there is a nonzero <code>startDelay</code>, the 424 * function is called after that delay ends. 425 * It takes care of the final initialization steps for the 426 * animation. 427 * 428 * <p>Overrides of this method should call the superclass method to ensure 429 * that internal mechanisms for the animation are set up correctly.</p> 430 */ 431 void initAnimation() { 432 if (!mInitialized) { 433 int numValues = mValues.length; 434 for (int i = 0; i < numValues; ++i) { 435 mValues[i].init(); 436 } 437 mInitialized = true; 438 } 439 } 440 441 442 /** 443 * Sets the length of the animation. The default duration is 300 milliseconds. 444 * 445 * @param duration The length of the animation, in milliseconds. This value cannot 446 * be negative. 447 * @return ValueAnimator The object called with setDuration(). This return 448 * value makes it easier to compose statements together that construct and then set the 449 * duration, as in <code>ValueAnimator.ofInt(0, 10).setDuration(500).start()</code>. 450 */ 451 public ValueAnimator setDuration(long duration) { 452 if (duration < 0) { 453 throw new IllegalArgumentException("Animators cannot have negative duration: " + 454 duration); 455 } 456 mDuration = duration; 457 return this; 458 } 459 460 /** 461 * Gets the length of the animation. The default duration is 300 milliseconds. 462 * 463 * @return The length of the animation, in milliseconds. 464 */ 465 public long getDuration() { 466 return mDuration; 467 } 468 469 /** 470 * Sets the position of the animation to the specified point in time. This time should 471 * be between 0 and the total duration of the animation, including any repetition. If 472 * the animation has not yet been started, then it will not advance forward after it is 473 * set to this time; it will simply set the time to this value and perform any appropriate 474 * actions based on that time. If the animation is already running, then setCurrentPlayTime() 475 * will set the current playing time to this value and continue playing from that point. 476 * 477 * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. 478 */ 479 public void setCurrentPlayTime(long playTime) { 480 initAnimation(); 481 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 482 if (mPlayingState != RUNNING) { 483 mSeekTime = playTime; 484 mPlayingState = SEEKED; 485 } 486 mStartTime = currentTime - playTime; 487 animationFrame(currentTime); 488 } 489 490 /** 491 * Gets the current position of the animation in time, which is equal to the current 492 * time minus the time that the animation started. An animation that is not yet started will 493 * return a value of zero. 494 * 495 * @return The current position in time of the animation. 496 */ 497 public long getCurrentPlayTime() { 498 if (!mInitialized || mPlayingState == STOPPED) { 499 return 0; 500 } 501 return AnimationUtils.currentAnimationTimeMillis() - mStartTime; 502 } 503 504 /** 505 * This custom, static handler handles the timing pulse that is shared by 506 * all active animations. This approach ensures that the setting of animation 507 * values will happen on the UI thread and that all animations will share 508 * the same times for calculating their values, which makes synchronizing 509 * animations possible. 510 * 511 */ 512 private static class AnimationHandler extends Handler 513 implements Choreographer.OnAnimateListener { 514 // The per-thread list of all active animations 515 private final ArrayList<ValueAnimator> mAnimations = new ArrayList<ValueAnimator>(); 516 517 // The per-thread set of animations to be started on the next animation frame 518 private final ArrayList<ValueAnimator> mPendingAnimations = new ArrayList<ValueAnimator>(); 519 520 /** 521 * Internal per-thread collections used to avoid set collisions as animations start and end 522 * while being processed. 523 */ 524 private final ArrayList<ValueAnimator> mDelayedAnims = new ArrayList<ValueAnimator>(); 525 private final ArrayList<ValueAnimator> mEndingAnims = new ArrayList<ValueAnimator>(); 526 private final ArrayList<ValueAnimator> mReadyAnims = new ArrayList<ValueAnimator>(); 527 528 private final Choreographer mChoreographer; 529 private boolean mIsChoreographed; 530 531 private AnimationHandler() { 532 mChoreographer = Choreographer.getInstance(); 533 } 534 535 /** 536 * The START message is sent when an animation's start() method is called. 537 * It cannot start synchronously when start() is called 538 * because the call may be on the wrong thread, and it would also not be 539 * synchronized with other animations because it would not start on a common 540 * timing pulse. So each animation sends a START message to the handler, which 541 * causes the handler to place the animation on the active animations queue and 542 * start processing frames for that animation. 543 */ 544 @Override 545 public void handleMessage(Message msg) { 546 switch (msg.what) { 547 case ANIMATION_START: 548 doAnimationStart(); 549 break; 550 } 551 } 552 553 private void doAnimationStart() { 554 // mPendingAnimations holds any animations that have requested to be started 555 // We're going to clear mPendingAnimations, 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 mPendingAnimations 558 // is empty. 559 while (mPendingAnimations.size() > 0) { 560 ArrayList<ValueAnimator> pendingCopy = 561 (ArrayList<ValueAnimator>) mPendingAnimations.clone(); 562 mPendingAnimations.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 mDelayedAnims.add(anim); 571 } 572 } 573 } 574 doAnimationFrame(); 575 } 576 577 private void doAnimationFrame() { 578 // currentTime holds the common time for all animations processed 579 // during this frame 580 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 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 = mDelayedAnims.size(); 585 for (int i = 0; i < numDelayedAnims; ++i) { 586 ValueAnimator anim = mDelayedAnims.get(i); 587 if (anim.delayedAnimationFrame(currentTime)) { 588 mReadyAnims.add(anim); 589 } 590 } 591 int numReadyAnims = mReadyAnims.size(); 592 if (numReadyAnims > 0) { 593 for (int i = 0; i < numReadyAnims; ++i) { 594 ValueAnimator anim = mReadyAnims.get(i); 595 anim.startAnimation(this); 596 anim.mRunning = true; 597 mDelayedAnims.remove(anim); 598 } 599 mReadyAnims.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 = mAnimations.size(); 605 int i = 0; 606 while (i < numAnims) { 607 ValueAnimator anim = mAnimations.get(i); 608 if (anim.animationFrame(currentTime)) { 609 mEndingAnims.add(anim); 610 } 611 if (mAnimations.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 mEndingAnims.remove(anim); 623 } 624 } 625 if (mEndingAnims.size() > 0) { 626 for (i = 0; i < mEndingAnims.size(); ++i) { 627 mEndingAnims.get(i).endAnimation(this); 628 } 629 mEndingAnims.clear(); 630 } 631 632 // If there are still active or delayed animations, schedule a future call to 633 // onAnimate to process the next frame of the animations. 634 if (!mAnimations.isEmpty() || !mDelayedAnims.isEmpty()) { 635 if (!mIsChoreographed) { 636 mIsChoreographed = true; 637 mChoreographer.addOnAnimateListener(this); 638 } 639 mChoreographer.scheduleAnimation(); 640 } else { 641 if (mIsChoreographed) { 642 mIsChoreographed = false; 643 mChoreographer.removeOnAnimateListener(this); 644 } 645 } 646 } 647 648 @Override 649 public void onAnimate() { 650 doAnimationFrame(); 651 } 652 } 653 654 /** 655 * The amount of time, in milliseconds, to delay starting the animation after 656 * {@link #start()} is called. 657 * 658 * @return the number of milliseconds to delay running the animation 659 */ 660 public long getStartDelay() { 661 return mStartDelay; 662 } 663 664 /** 665 * The amount of time, in milliseconds, to delay starting the animation after 666 * {@link #start()} is called. 667 668 * @param startDelay The amount of the delay, in milliseconds 669 */ 670 public void setStartDelay(long startDelay) { 671 this.mStartDelay = startDelay; 672 } 673 674 /** 675 * The amount of time, in milliseconds, between each frame of the animation. This is a 676 * requested time that the animation will attempt to honor, but the actual delay between 677 * frames may be different, depending on system load and capabilities. This is a static 678 * function because the same delay will be applied to all animations, since they are all 679 * run off of a single timing loop. 680 * 681 * The frame delay may be ignored when the animation system uses an external timing 682 * source, such as the display refresh rate (vsync), to govern animations. 683 * 684 * @return the requested time between frames, in milliseconds 685 */ 686 public static long getFrameDelay() { 687 return Choreographer.getFrameDelay(); 688 } 689 690 /** 691 * The amount of time, in milliseconds, between each frame of the animation. This is a 692 * requested time that the animation will attempt to honor, but the actual delay between 693 * frames may be different, depending on system load and capabilities. This is a static 694 * function because the same delay will be applied to all animations, since they are all 695 * run off of a single timing loop. 696 * 697 * The frame delay may be ignored when the animation system uses an external timing 698 * source, such as the display refresh rate (vsync), to govern animations. 699 * 700 * @param frameDelay the requested time between frames, in milliseconds 701 */ 702 public static void setFrameDelay(long frameDelay) { 703 Choreographer.setFrameDelay(frameDelay); 704 } 705 706 /** 707 * The most recent value calculated by this <code>ValueAnimator</code> when there is just one 708 * property being animated. This value is only sensible while the animation is running. The main 709 * purpose for this read-only property is to retrieve the value from the <code>ValueAnimator</code> 710 * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 711 * is called during each animation frame, immediately after the value is calculated. 712 * 713 * @return animatedValue The value most recently calculated by this <code>ValueAnimator</code> for 714 * the single property being animated. If there are several properties being animated 715 * (specified by several PropertyValuesHolder objects in the constructor), this function 716 * returns the animated value for the first of those objects. 717 */ 718 public Object getAnimatedValue() { 719 if (mValues != null && mValues.length > 0) { 720 return mValues[0].getAnimatedValue(); 721 } 722 // Shouldn't get here; should always have values unless ValueAnimator was set up wrong 723 return null; 724 } 725 726 /** 727 * The most recent value calculated by this <code>ValueAnimator</code> for <code>propertyName</code>. 728 * The main purpose for this read-only property is to retrieve the value from the 729 * <code>ValueAnimator</code> during a call to 730 * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 731 * is called during each animation frame, immediately after the value is calculated. 732 * 733 * @return animatedValue The value most recently calculated for the named property 734 * by this <code>ValueAnimator</code>. 735 */ 736 public Object getAnimatedValue(String propertyName) { 737 PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); 738 if (valuesHolder != null) { 739 return valuesHolder.getAnimatedValue(); 740 } else { 741 // At least avoid crashing if called with bogus propertyName 742 return null; 743 } 744 } 745 746 /** 747 * Sets how many times the animation should be repeated. If the repeat 748 * count is 0, the animation is never repeated. If the repeat count is 749 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken 750 * into account. The repeat count is 0 by default. 751 * 752 * @param value the number of times the animation should be repeated 753 */ 754 public void setRepeatCount(int value) { 755 mRepeatCount = value; 756 } 757 /** 758 * Defines how many times the animation should repeat. The default value 759 * is 0. 760 * 761 * @return the number of times the animation should repeat, or {@link #INFINITE} 762 */ 763 public int getRepeatCount() { 764 return mRepeatCount; 765 } 766 767 /** 768 * Defines what this animation should do when it reaches the end. This 769 * setting is applied only when the repeat count is either greater than 770 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 771 * 772 * @param value {@link #RESTART} or {@link #REVERSE} 773 */ 774 public void setRepeatMode(int value) { 775 mRepeatMode = value; 776 } 777 778 /** 779 * Defines what this animation should do when it reaches the end. 780 * 781 * @return either one of {@link #REVERSE} or {@link #RESTART} 782 */ 783 public int getRepeatMode() { 784 return mRepeatMode; 785 } 786 787 /** 788 * Adds a listener to the set of listeners that are sent update events through the life of 789 * an animation. This method is called on all listeners for every frame of the animation, 790 * after the values for the animation have been calculated. 791 * 792 * @param listener the listener to be added to the current set of listeners for this animation. 793 */ 794 public void addUpdateListener(AnimatorUpdateListener listener) { 795 if (mUpdateListeners == null) { 796 mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 797 } 798 mUpdateListeners.add(listener); 799 } 800 801 /** 802 * Removes all listeners from the set listening to frame updates for this animation. 803 */ 804 public void removeAllUpdateListeners() { 805 if (mUpdateListeners == null) { 806 return; 807 } 808 mUpdateListeners.clear(); 809 mUpdateListeners = null; 810 } 811 812 /** 813 * Removes a listener from the set listening to frame updates for this animation. 814 * 815 * @param listener the listener to be removed from the current set of update listeners 816 * for this animation. 817 */ 818 public void removeUpdateListener(AnimatorUpdateListener listener) { 819 if (mUpdateListeners == null) { 820 return; 821 } 822 mUpdateListeners.remove(listener); 823 if (mUpdateListeners.size() == 0) { 824 mUpdateListeners = null; 825 } 826 } 827 828 829 /** 830 * The time interpolator used in calculating the elapsed fraction of this animation. The 831 * interpolator determines whether the animation runs with linear or non-linear motion, 832 * such as acceleration and deceleration. The default value is 833 * {@link android.view.animation.AccelerateDecelerateInterpolator} 834 * 835 * @param value the interpolator to be used by this animation. A value of <code>null</code> 836 * will result in linear interpolation. 837 */ 838 @Override 839 public void setInterpolator(TimeInterpolator value) { 840 if (value != null) { 841 mInterpolator = value; 842 } else { 843 mInterpolator = new LinearInterpolator(); 844 } 845 } 846 847 /** 848 * Returns the timing interpolator that this ValueAnimator uses. 849 * 850 * @return The timing interpolator for this ValueAnimator. 851 */ 852 public TimeInterpolator getInterpolator() { 853 return mInterpolator; 854 } 855 856 /** 857 * The type evaluator to be used when calculating the animated values of this animation. 858 * The system will automatically assign a float or int evaluator based on the type 859 * of <code>startValue</code> and <code>endValue</code> in the constructor. But if these values 860 * are not one of these primitive types, or if different evaluation is desired (such as is 861 * necessary with int values that represent colors), a custom evaluator needs to be assigned. 862 * For example, when running an animation on color values, the {@link ArgbEvaluator} 863 * should be used to get correct RGB color interpolation. 864 * 865 * <p>If this ValueAnimator has only one set of values being animated between, this evaluator 866 * will be used for that set. If there are several sets of values being animated, which is 867 * the case if PropertyValuesHOlder objects were set on the ValueAnimator, then the evaluator 868 * is assigned just to the first PropertyValuesHolder object.</p> 869 * 870 * @param value the evaluator to be used this animation 871 */ 872 public void setEvaluator(TypeEvaluator value) { 873 if (value != null && mValues != null && mValues.length > 0) { 874 mValues[0].setEvaluator(value); 875 } 876 } 877 878 /** 879 * Start the animation playing. This version of start() takes a boolean flag that indicates 880 * whether the animation should play in reverse. The flag is usually false, but may be set 881 * to true if called from the reverse() method. 882 * 883 * <p>The animation started by calling this method will be run on the thread that called 884 * this method. This thread should have a Looper on it (a runtime exception will be thrown if 885 * this is not the case). Also, if the animation will animate 886 * properties of objects in the view hierarchy, then the calling thread should be the UI 887 * thread for that view hierarchy.</p> 888 * 889 * @param playBackwards Whether the ValueAnimator should start playing in reverse. 890 */ 891 private void start(boolean playBackwards) { 892 if (Looper.myLooper() == null) { 893 throw new AndroidRuntimeException("Animators may only be run on Looper threads"); 894 } 895 mPlayingBackwards = playBackwards; 896 mCurrentIteration = 0; 897 mPlayingState = STOPPED; 898 mStarted = true; 899 mStartedDelay = false; 900 AnimationHandler animationHandler = getOrCreateAnimationHandler(); 901 animationHandler.mPendingAnimations.add(this); 902 if (mStartDelay == 0) { 903 // This sets the initial value of the animation, prior to actually starting it running 904 setCurrentPlayTime(getCurrentPlayTime()); 905 mPlayingState = STOPPED; 906 mRunning = true; 907 908 if (mListeners != null) { 909 ArrayList<AnimatorListener> tmpListeners = 910 (ArrayList<AnimatorListener>) mListeners.clone(); 911 int numListeners = tmpListeners.size(); 912 for (int i = 0; i < numListeners; ++i) { 913 tmpListeners.get(i).onAnimationStart(this); 914 } 915 } 916 } 917 animationHandler.sendEmptyMessage(ANIMATION_START); 918 } 919 920 @Override 921 public void start() { 922 start(false); 923 } 924 925 @Override 926 public void cancel() { 927 // Only cancel if the animation is actually running or has been started and is about 928 // to run 929 AnimationHandler handler = getOrCreateAnimationHandler(); 930 if (mPlayingState != STOPPED 931 || handler.mPendingAnimations.contains(this) 932 || handler.mDelayedAnims.contains(this)) { 933 // Only notify listeners if the animator has actually started 934 if (mRunning && mListeners != null) { 935 ArrayList<AnimatorListener> tmpListeners = 936 (ArrayList<AnimatorListener>) mListeners.clone(); 937 for (AnimatorListener listener : tmpListeners) { 938 listener.onAnimationCancel(this); 939 } 940 } 941 endAnimation(handler); 942 } 943 } 944 945 @Override 946 public void end() { 947 AnimationHandler handler = getOrCreateAnimationHandler(); 948 if (!handler.mAnimations.contains(this) && !handler.mPendingAnimations.contains(this)) { 949 // Special case if the animation has not yet started; get it ready for ending 950 mStartedDelay = false; 951 startAnimation(handler); 952 } else if (!mInitialized) { 953 initAnimation(); 954 } 955 // The final value set on the target varies, depending on whether the animation 956 // was supposed to repeat an odd number of times 957 if (mRepeatCount > 0 && (mRepeatCount & 0x01) == 1) { 958 animateValue(0f); 959 } else { 960 animateValue(1f); 961 } 962 endAnimation(handler); 963 } 964 965 @Override 966 public boolean isRunning() { 967 return (mPlayingState == RUNNING || mRunning); 968 } 969 970 @Override 971 public boolean isStarted() { 972 return mStarted; 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(AnimationHandler handler) { 999 handler.mAnimations.remove(this); 1000 handler.mPendingAnimations.remove(this); 1001 handler.mDelayedAnims.remove(this); 1002 mPlayingState = STOPPED; 1003 if (mRunning && 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 mRunning = false; 1012 mStarted = false; 1013 } 1014 1015 /** 1016 * Called internally to start an animation by adding it to the active animations list. Must be 1017 * called on the UI thread. 1018 */ 1019 private void startAnimation(AnimationHandler handler) { 1020 initAnimation(); 1021 handler.mAnimations.add(this); 1022 if (mStartDelay > 0 && mListeners != null) { 1023 // Listeners were already notified in start() if startDelay is 0; this is 1024 // just for delayed animations 1025 ArrayList<AnimatorListener> tmpListeners = 1026 (ArrayList<AnimatorListener>) mListeners.clone(); 1027 int numListeners = tmpListeners.size(); 1028 for (int i = 0; i < numListeners; ++i) { 1029 tmpListeners.get(i).onAnimationStart(this); 1030 } 1031 } 1032 } 1033 1034 /** 1035 * Internal function called to process an animation frame on an animation that is currently 1036 * sleeping through its <code>startDelay</code> phase. The return value indicates whether it 1037 * should be woken up and put on the active animations queue. 1038 * 1039 * @param currentTime The current animation time, used to calculate whether the animation 1040 * has exceeded its <code>startDelay</code> and should be started. 1041 * @return True if the animation's <code>startDelay</code> has been exceeded and the animation 1042 * should be added to the set of active animations. 1043 */ 1044 private boolean delayedAnimationFrame(long currentTime) { 1045 if (!mStartedDelay) { 1046 mStartedDelay = true; 1047 mDelayStartTime = currentTime; 1048 } else { 1049 long deltaTime = currentTime - mDelayStartTime; 1050 if (deltaTime > mStartDelay) { 1051 // startDelay ended - start the anim and record the 1052 // mStartTime appropriately 1053 mStartTime = currentTime - (deltaTime - mStartDelay); 1054 mPlayingState = RUNNING; 1055 return true; 1056 } 1057 } 1058 return false; 1059 } 1060 1061 /** 1062 * This internal function processes a single animation frame for a given animation. The 1063 * currentTime parameter is the timing pulse sent by the handler, used to calculate the 1064 * elapsed duration, and therefore 1065 * the elapsed fraction, of the animation. The return value indicates whether the animation 1066 * should be ended (which happens when the elapsed time of the animation exceeds the 1067 * animation's duration, including the repeatCount). 1068 * 1069 * @param currentTime The current time, as tracked by the static timing handler 1070 * @return true if the animation's duration, including any repetitions due to 1071 * <code>repeatCount</code> has been exceeded and the animation should be ended. 1072 */ 1073 boolean animationFrame(long currentTime) { 1074 boolean done = false; 1075 1076 if (mPlayingState == STOPPED) { 1077 mPlayingState = RUNNING; 1078 if (mSeekTime < 0) { 1079 mStartTime = currentTime; 1080 } else { 1081 mStartTime = currentTime - mSeekTime; 1082 // Now that we're playing, reset the seek time 1083 mSeekTime = -1; 1084 } 1085 } 1086 switch (mPlayingState) { 1087 case RUNNING: 1088 case SEEKED: 1089 float fraction = mDuration > 0 ? (float)(currentTime - mStartTime) / mDuration : 1f; 1090 if (fraction >= 1f) { 1091 if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { 1092 // Time to repeat 1093 if (mListeners != null) { 1094 int numListeners = mListeners.size(); 1095 for (int i = 0; i < numListeners; ++i) { 1096 mListeners.get(i).onAnimationRepeat(this); 1097 } 1098 } 1099 if (mRepeatMode == REVERSE) { 1100 mPlayingBackwards = mPlayingBackwards ? false : true; 1101 } 1102 mCurrentIteration += (int)fraction; 1103 fraction = fraction % 1f; 1104 mStartTime += mDuration; 1105 } else { 1106 done = true; 1107 fraction = Math.min(fraction, 1.0f); 1108 } 1109 } 1110 if (mPlayingBackwards) { 1111 fraction = 1f - fraction; 1112 } 1113 animateValue(fraction); 1114 break; 1115 } 1116 1117 return done; 1118 } 1119 1120 /** 1121 * Returns the current animation fraction, which is the elapsed/interpolated fraction used in 1122 * the most recent frame update on the animation. 1123 * 1124 * @return Elapsed/interpolated fraction of the animation. 1125 */ 1126 public float getAnimatedFraction() { 1127 return mCurrentFraction; 1128 } 1129 1130 /** 1131 * This method is called with the elapsed fraction of the animation during every 1132 * animation frame. This function turns the elapsed fraction into an interpolated fraction 1133 * and then into an animated value (from the evaluator. The function is called mostly during 1134 * animation updates, but it is also called when the <code>end()</code> 1135 * function is called, to set the final value on the property. 1136 * 1137 * <p>Overrides of this method must call the superclass to perform the calculation 1138 * of the animated value.</p> 1139 * 1140 * @param fraction The elapsed fraction of the animation. 1141 */ 1142 void animateValue(float fraction) { 1143 fraction = mInterpolator.getInterpolation(fraction); 1144 mCurrentFraction = fraction; 1145 int numValues = mValues.length; 1146 for (int i = 0; i < numValues; ++i) { 1147 mValues[i].calculateValue(fraction); 1148 } 1149 if (mUpdateListeners != null) { 1150 int numListeners = mUpdateListeners.size(); 1151 for (int i = 0; i < numListeners; ++i) { 1152 mUpdateListeners.get(i).onAnimationUpdate(this); 1153 } 1154 } 1155 } 1156 1157 @Override 1158 public ValueAnimator clone() { 1159 final ValueAnimator anim = (ValueAnimator) super.clone(); 1160 if (mUpdateListeners != null) { 1161 ArrayList<AnimatorUpdateListener> oldListeners = mUpdateListeners; 1162 anim.mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 1163 int numListeners = oldListeners.size(); 1164 for (int i = 0; i < numListeners; ++i) { 1165 anim.mUpdateListeners.add(oldListeners.get(i)); 1166 } 1167 } 1168 anim.mSeekTime = -1; 1169 anim.mPlayingBackwards = false; 1170 anim.mCurrentIteration = 0; 1171 anim.mInitialized = false; 1172 anim.mPlayingState = STOPPED; 1173 anim.mStartedDelay = false; 1174 PropertyValuesHolder[] oldValues = mValues; 1175 if (oldValues != null) { 1176 int numValues = oldValues.length; 1177 anim.mValues = new PropertyValuesHolder[numValues]; 1178 anim.mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 1179 for (int i = 0; i < numValues; ++i) { 1180 PropertyValuesHolder newValuesHolder = oldValues[i].clone(); 1181 anim.mValues[i] = newValuesHolder; 1182 anim.mValuesMap.put(newValuesHolder.getPropertyName(), newValuesHolder); 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. 1208 * May be called on arbitrary threads! 1209 * 1210 * @hide 1211 */ 1212 public static int getCurrentAnimationsCount() { 1213 AnimationHandler handler = sAnimationHandler.get(); 1214 return handler != null ? handler.mAnimations.size() : 0; 1215 } 1216 1217 /** 1218 * Clear all animations on this thread, without canceling or ending them. 1219 * This should be used with caution. 1220 * 1221 * @hide 1222 */ 1223 public static void clearAllAnimations() { 1224 AnimationHandler handler = sAnimationHandler.get(); 1225 if (handler != null) { 1226 handler.mAnimations.clear(); 1227 handler.mPendingAnimations.clear(); 1228 handler.mDelayedAnims.clear(); 1229 } 1230 } 1231 1232 private AnimationHandler getOrCreateAnimationHandler() { 1233 AnimationHandler handler = sAnimationHandler.get(); 1234 if (handler == null) { 1235 handler = new AnimationHandler(); 1236 sAnimationHandler.set(handler); 1237 } 1238 return handler; 1239 } 1240 1241 @Override 1242 public String toString() { 1243 String returnVal = "ValueAnimator@" + Integer.toHexString(hashCode()); 1244 if (mValues != null) { 1245 for (int i = 0; i < mValues.length; ++i) { 1246 returnVal += "\n " + mValues[i].toString(); 1247 } 1248 } 1249 return returnVal; 1250 } 1251} 1252