ValueAnimator.java revision c38fa1f63674971f9ac6ced1a449fb81026b62f7
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.os.SystemProperties; 23import android.util.AndroidRuntimeException; 24import android.view.Choreographer; 25import android.view.animation.AccelerateDecelerateInterpolator; 26import android.view.animation.AnimationUtils; 27import android.view.animation.LinearInterpolator; 28 29import java.util.ArrayList; 30import java.util.HashMap; 31 32/** 33 * This class provides a simple timing engine for running animations 34 * which calculate animated values and set them on target objects. 35 * 36 * <p>There is a single timing pulse that all animations use. It runs in a 37 * custom handler to ensure that property changes happen on the UI thread.</p> 38 * 39 * <p>By default, ValueAnimator uses non-linear time interpolation, via the 40 * {@link AccelerateDecelerateInterpolator} class, which accelerates into and decelerates 41 * out of an animation. This behavior can be changed by calling 42 * {@link ValueAnimator#setInterpolator(TimeInterpolator)}.</p> 43 * 44 * <div class="special reference"> 45 * <h3>Developer Guides</h3> 46 * <p>For more information about animating with {@code ValueAnimator}, read the 47 * <a href="{@docRoot}guide/topics/graphics/prop-animation.html#value-animator">Property 48 * Animation</a> developer guide.</p> 49 * </div> 50 */ 51public class ValueAnimator extends Animator { 52 53 /** 54 * Internal constants 55 */ 56 private static float sDurationScale = 1.0f; 57 58 /** 59 * Messages sent to timing handler: START is sent when an animation first begins. 60 */ 61 static final int ANIMATION_START = 0; 62 63 /** 64 * Values used with internal variable mPlayingState to indicate the current state of an 65 * animation. 66 */ 67 static final int STOPPED = 0; // Not yet playing 68 static final int RUNNING = 1; // Playing normally 69 static final int SEEKED = 2; // Seeked to some time value 70 71 /** 72 * Internal variables 73 * NOTE: This object implements the clone() method, making a deep copy of any referenced 74 * objects. As other non-trivial fields are added to this class, make sure to add logic 75 * to clone() to make deep copies of them. 76 */ 77 78 // The first time that the animation's animateFrame() method is called. This time is used to 79 // determine elapsed time (and therefore the elapsed fraction) in subsequent calls 80 // to animateFrame() 81 long mStartTime; 82 83 /** 84 * Set when setCurrentPlayTime() is called. If negative, animation is not currently seeked 85 * to a value. 86 */ 87 long mSeekTime = -1; 88 89 // The static sAnimationHandler processes the internal timing loop on which all animations 90 // are based 91 private static ThreadLocal<AnimationHandler> sAnimationHandler = 92 new ThreadLocal<AnimationHandler>(); 93 94 // The time interpolator to be used if none is set on the animation 95 private static final TimeInterpolator sDefaultInterpolator = 96 new AccelerateDecelerateInterpolator(); 97 98 /** 99 * Used to indicate whether the animation is currently playing in reverse. This causes the 100 * elapsed fraction to be inverted to calculate the appropriate values. 101 */ 102 private boolean mPlayingBackwards = false; 103 104 /** 105 * This variable tracks the current iteration that is playing. When mCurrentIteration exceeds the 106 * repeatCount (if repeatCount!=INFINITE), the animation ends 107 */ 108 private int mCurrentIteration = 0; 109 110 /** 111 * Tracks current elapsed/eased fraction, for querying in getAnimatedFraction(). 112 */ 113 private float mCurrentFraction = 0f; 114 115 /** 116 * Tracks whether a startDelay'd animation has begun playing through the startDelay. 117 */ 118 private boolean mStartedDelay = false; 119 120 /** 121 * Tracks the time at which the animation began playing through its startDelay. This is 122 * different from the mStartTime variable, which is used to track when the animation became 123 * active (which is when the startDelay expired and the animation was added to the active 124 * animations list). 125 */ 126 private long mDelayStartTime; 127 128 /** 129 * Flag that represents the current state of the animation. Used to figure out when to start 130 * an animation (if state == STOPPED). Also used to end an animation that 131 * has been cancel()'d or end()'d since the last animation frame. Possible values are 132 * STOPPED, RUNNING, SEEKED. 133 */ 134 int mPlayingState = STOPPED; 135 136 /** 137 * Additional playing state to indicate whether an animator has been start()'d. There is 138 * some lag between a call to start() and the first animation frame. We should still note 139 * that the animation has been started, even if it's first animation frame has not yet 140 * happened, and reflect that state in isRunning(). 141 * Note that delayed animations are different: they are not started until their first 142 * animation frame, which occurs after their delay elapses. 143 */ 144 private boolean mRunning = false; 145 146 /** 147 * Additional playing state to indicate whether an animator has been start()'d, whether or 148 * not there is a nonzero startDelay. 149 */ 150 private boolean mStarted = false; 151 152 /** 153 * Flag that denotes whether the animation is set up and ready to go. Used to 154 * set up animation that has not yet been started. 155 */ 156 boolean mInitialized = false; 157 158 // 159 // Backing variables 160 // 161 162 // How long the animation should last in ms 163 private long mDuration = (long)(300 * sDurationScale); 164 private long mUnscaledDuration = 300; 165 166 // The amount of time in ms to delay starting the animation after start() is called 167 private long mStartDelay = 0; 168 private long mUnscaledStartDelay = 0; 169 170 // The number of times the animation will repeat. The default is 0, which means the animation 171 // will play only once 172 private int mRepeatCount = 0; 173 174 /** 175 * The type of repetition that will occur when repeatMode is nonzero. RESTART means the 176 * animation will start from the beginning on every new cycle. REVERSE means the animation 177 * will reverse directions on each iteration. 178 */ 179 private int mRepeatMode = RESTART; 180 181 /** 182 * The time interpolator to be used. The elapsed fraction of the animation will be passed 183 * through this interpolator to calculate the interpolated fraction, which is then used to 184 * calculate the animated values. 185 */ 186 private TimeInterpolator mInterpolator = sDefaultInterpolator; 187 188 /** 189 * The set of listeners to be sent events through the life of an animation. 190 */ 191 private ArrayList<AnimatorUpdateListener> mUpdateListeners = null; 192 193 /** 194 * The property/value sets being animated. 195 */ 196 PropertyValuesHolder[] mValues; 197 198 /** 199 * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values 200 * by property name during calls to getAnimatedValue(String). 201 */ 202 HashMap<String, PropertyValuesHolder> mValuesMap; 203 204 /** 205 * Public constants 206 */ 207 208 /** 209 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 210 * or a positive value, the animation restarts from the beginning. 211 */ 212 public static final int RESTART = 1; 213 /** 214 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 215 * or a positive value, the animation reverses direction on every iteration. 216 */ 217 public static final int REVERSE = 2; 218 /** 219 * This value used used with the {@link #setRepeatCount(int)} property to repeat 220 * the animation indefinitely. 221 */ 222 public static final int INFINITE = -1; 223 224 225 /** 226 * @hide 227 */ 228 public static void setDurationScale(float durationScale) { 229 sDurationScale = durationScale; 230 } 231 232 /** 233 * Creates a new ValueAnimator object. This default constructor is primarily for 234 * use internally; the factory methods which take parameters are more generally 235 * useful. 236 */ 237 public ValueAnimator() { 238 } 239 240 /** 241 * Constructs and returns a ValueAnimator that animates between int values. A single 242 * value implies that that value is the one being animated to. However, this is not typically 243 * useful in a ValueAnimator object because there is no way for the object to determine the 244 * starting value for the animation (unlike ObjectAnimator, which can derive that value 245 * from the target object and property being animated). Therefore, there should typically 246 * be two or more values. 247 * 248 * @param values A set of values that the animation will animate between over time. 249 * @return A ValueAnimator object that is set up to animate between the given values. 250 */ 251 public static ValueAnimator ofInt(int... values) { 252 ValueAnimator anim = new ValueAnimator(); 253 anim.setIntValues(values); 254 return anim; 255 } 256 257 /** 258 * Constructs and returns a ValueAnimator that animates between float values. A single 259 * value implies that that value is the one being animated to. However, this is not typically 260 * useful in a ValueAnimator object because there is no way for the object to determine the 261 * starting value for the animation (unlike ObjectAnimator, which can derive that value 262 * from the target object and property being animated). Therefore, there should typically 263 * be two or more values. 264 * 265 * @param values A set of values that the animation will animate between over time. 266 * @return A ValueAnimator object that is set up to animate between the given values. 267 */ 268 public static ValueAnimator ofFloat(float... values) { 269 ValueAnimator anim = new ValueAnimator(); 270 anim.setFloatValues(values); 271 return anim; 272 } 273 274 /** 275 * Constructs and returns a ValueAnimator that animates between the values 276 * specified in the PropertyValuesHolder objects. 277 * 278 * @param values A set of PropertyValuesHolder objects whose values will be animated 279 * between over time. 280 * @return A ValueAnimator object that is set up to animate between the given values. 281 */ 282 public static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values) { 283 ValueAnimator anim = new ValueAnimator(); 284 anim.setValues(values); 285 return anim; 286 } 287 /** 288 * Constructs and returns a ValueAnimator that animates between Object values. A single 289 * value implies that that value is the one being animated to. However, this is not typically 290 * useful in a ValueAnimator object because there is no way for the object to determine the 291 * starting value for the animation (unlike ObjectAnimator, which can derive that value 292 * from the target object and property being animated). Therefore, there should typically 293 * be two or more values. 294 * 295 * <p>Since ValueAnimator does not know how to animate between arbitrary Objects, this 296 * factory method also takes a TypeEvaluator object that the ValueAnimator will use 297 * to perform that interpolation. 298 * 299 * @param evaluator A TypeEvaluator that will be called on each animation frame to 300 * provide the ncessry interpolation between the Object values to derive the animated 301 * value. 302 * @param values A set of values that the animation will animate between over time. 303 * @return A ValueAnimator object that is set up to animate between the given values. 304 */ 305 public static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values) { 306 ValueAnimator anim = new ValueAnimator(); 307 anim.setObjectValues(values); 308 anim.setEvaluator(evaluator); 309 return anim; 310 } 311 312 /** 313 * Sets int values that will be animated between. A single 314 * value implies that that value is the one being animated to. However, this is not typically 315 * useful in a ValueAnimator object because there is no way for the object to determine the 316 * starting value for the animation (unlike ObjectAnimator, which can derive that value 317 * from the target object and property being animated). Therefore, there should typically 318 * be two or more values. 319 * 320 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 321 * than one PropertyValuesHolder object, this method will set the values for the first 322 * of those objects.</p> 323 * 324 * @param values A set of values that the animation will animate between over time. 325 */ 326 public void setIntValues(int... values) { 327 if (values == null || values.length == 0) { 328 return; 329 } 330 if (mValues == null || mValues.length == 0) { 331 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofInt("", values)}); 332 } else { 333 PropertyValuesHolder valuesHolder = mValues[0]; 334 valuesHolder.setIntValues(values); 335 } 336 // New property/values/target should cause re-initialization prior to starting 337 mInitialized = false; 338 } 339 340 /** 341 * Sets float values that will be animated between. A single 342 * value implies that that value is the one being animated to. However, this is not typically 343 * useful in a ValueAnimator object because there is no way for the object to determine the 344 * starting value for the animation (unlike ObjectAnimator, which can derive that value 345 * from the target object and property being animated). Therefore, there should typically 346 * be two or more values. 347 * 348 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 349 * than one PropertyValuesHolder object, this method will set the values for the first 350 * of those objects.</p> 351 * 352 * @param values A set of values that the animation will animate between over time. 353 */ 354 public void setFloatValues(float... values) { 355 if (values == null || values.length == 0) { 356 return; 357 } 358 if (mValues == null || mValues.length == 0) { 359 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofFloat("", values)}); 360 } else { 361 PropertyValuesHolder valuesHolder = mValues[0]; 362 valuesHolder.setFloatValues(values); 363 } 364 // New property/values/target should cause re-initialization prior to starting 365 mInitialized = false; 366 } 367 368 /** 369 * Sets the values to animate between for this animation. A single 370 * value implies that that value is the one being animated to. However, this is not typically 371 * useful in a ValueAnimator object because there is no way for the object to determine the 372 * starting value for the animation (unlike ObjectAnimator, which can derive that value 373 * from the target object and property being animated). Therefore, there should typically 374 * be two or more values. 375 * 376 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 377 * than one PropertyValuesHolder object, this method will set the values for the first 378 * of those objects.</p> 379 * 380 * <p>There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate 381 * between these value objects. ValueAnimator only knows how to interpolate between the 382 * primitive types specified in the other setValues() methods.</p> 383 * 384 * @param values The set of values to animate between. 385 */ 386 public void setObjectValues(Object... values) { 387 if (values == null || values.length == 0) { 388 return; 389 } 390 if (mValues == null || mValues.length == 0) { 391 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofObject("", 392 (TypeEvaluator)null, values)}); 393 } else { 394 PropertyValuesHolder valuesHolder = mValues[0]; 395 valuesHolder.setObjectValues(values); 396 } 397 // New property/values/target should cause re-initialization prior to starting 398 mInitialized = false; 399 } 400 401 /** 402 * Sets the values, per property, being animated between. This function is called internally 403 * by the constructors of ValueAnimator that take a list of values. But an ValueAnimator can 404 * be constructed without values and this method can be called to set the values manually 405 * instead. 406 * 407 * @param values The set of values, per property, being animated between. 408 */ 409 public void setValues(PropertyValuesHolder... values) { 410 int numValues = values.length; 411 mValues = values; 412 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 413 for (int i = 0; i < numValues; ++i) { 414 PropertyValuesHolder valuesHolder = (PropertyValuesHolder) values[i]; 415 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 416 } 417 // New property/values/target should cause re-initialization prior to starting 418 mInitialized = false; 419 } 420 421 /** 422 * Returns the values that this ValueAnimator animates between. These values are stored in 423 * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list 424 * of value objects instead. 425 * 426 * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the 427 * values, per property, that define the animation. 428 */ 429 public PropertyValuesHolder[] getValues() { 430 return mValues; 431 } 432 433 /** 434 * This function is called immediately before processing the first animation 435 * frame of an animation. If there is a nonzero <code>startDelay</code>, the 436 * function is called after that delay ends. 437 * It takes care of the final initialization steps for the 438 * animation. 439 * 440 * <p>Overrides of this method should call the superclass method to ensure 441 * that internal mechanisms for the animation are set up correctly.</p> 442 */ 443 void initAnimation() { 444 if (!mInitialized) { 445 int numValues = mValues.length; 446 for (int i = 0; i < numValues; ++i) { 447 mValues[i].init(); 448 } 449 mInitialized = true; 450 } 451 } 452 453 454 /** 455 * Sets the length of the animation. The default duration is 300 milliseconds. 456 * 457 * @param duration The length of the animation, in milliseconds. This value cannot 458 * be negative. 459 * @return ValueAnimator The object called with setDuration(). This return 460 * value makes it easier to compose statements together that construct and then set the 461 * duration, as in <code>ValueAnimator.ofInt(0, 10).setDuration(500).start()</code>. 462 */ 463 public ValueAnimator setDuration(long duration) { 464 if (duration < 0) { 465 throw new IllegalArgumentException("Animators cannot have negative duration: " + 466 duration); 467 } 468 mUnscaledDuration = duration; 469 mDuration = (long)(duration * sDurationScale); 470 return this; 471 } 472 473 /** 474 * Gets the length of the animation. The default duration is 300 milliseconds. 475 * 476 * @return The length of the animation, in milliseconds. 477 */ 478 public long getDuration() { 479 return mUnscaledDuration; 480 } 481 482 /** 483 * Sets the position of the animation to the specified point in time. This time should 484 * be between 0 and the total duration of the animation, including any repetition. If 485 * the animation has not yet been started, then it will not advance forward after it is 486 * set to this time; it will simply set the time to this value and perform any appropriate 487 * actions based on that time. If the animation is already running, then setCurrentPlayTime() 488 * will set the current playing time to this value and continue playing from that point. 489 * 490 * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. 491 */ 492 public void setCurrentPlayTime(long playTime) { 493 initAnimation(); 494 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 495 if (mPlayingState != RUNNING) { 496 mSeekTime = playTime; 497 mPlayingState = SEEKED; 498 } 499 mStartTime = currentTime - playTime; 500 animationFrame(currentTime); 501 } 502 503 /** 504 * Gets the current position of the animation in time, which is equal to the current 505 * time minus the time that the animation started. An animation that is not yet started will 506 * return a value of zero. 507 * 508 * @return The current position in time of the animation. 509 */ 510 public long getCurrentPlayTime() { 511 if (!mInitialized || mPlayingState == STOPPED) { 512 return 0; 513 } 514 return AnimationUtils.currentAnimationTimeMillis() - mStartTime; 515 } 516 517 /** 518 * This custom, static handler handles the timing pulse that is shared by 519 * all active animations. This approach ensures that the setting of animation 520 * values will happen on the UI thread and that all animations will share 521 * the same times for calculating their values, which makes synchronizing 522 * animations possible. 523 * 524 */ 525 private static class AnimationHandler extends Handler 526 implements Choreographer.OnAnimateListener { 527 // The per-thread list of all active animations 528 private final ArrayList<ValueAnimator> mAnimations = new ArrayList<ValueAnimator>(); 529 530 // The per-thread set of animations to be started on the next animation frame 531 private final ArrayList<ValueAnimator> mPendingAnimations = new ArrayList<ValueAnimator>(); 532 533 /** 534 * Internal per-thread collections used to avoid set collisions as animations start and end 535 * while being processed. 536 */ 537 private final ArrayList<ValueAnimator> mDelayedAnims = new ArrayList<ValueAnimator>(); 538 private final ArrayList<ValueAnimator> mEndingAnims = new ArrayList<ValueAnimator>(); 539 private final ArrayList<ValueAnimator> mReadyAnims = new ArrayList<ValueAnimator>(); 540 541 private final Choreographer mChoreographer; 542 private boolean mIsChoreographed; 543 544 private AnimationHandler() { 545 mChoreographer = Choreographer.getInstance(); 546 } 547 548 /** 549 * The START message is sent when an animation's start() method is called. 550 * It cannot start synchronously when start() is called 551 * because the call may be on the wrong thread, and it would also not be 552 * synchronized with other animations because it would not start on a common 553 * timing pulse. So each animation sends a START message to the handler, which 554 * causes the handler to place the animation on the active animations queue and 555 * start processing frames for that animation. 556 */ 557 @Override 558 public void handleMessage(Message msg) { 559 switch (msg.what) { 560 case ANIMATION_START: 561 doAnimationStart(); 562 break; 563 } 564 } 565 566 private void doAnimationStart() { 567 // mPendingAnimations holds any animations that have requested to be started 568 // We're going to clear mPendingAnimations, but starting animation may 569 // cause more to be added to the pending list (for example, if one animation 570 // starting triggers another starting). So we loop until mPendingAnimations 571 // is empty. 572 while (mPendingAnimations.size() > 0) { 573 ArrayList<ValueAnimator> pendingCopy = 574 (ArrayList<ValueAnimator>) mPendingAnimations.clone(); 575 mPendingAnimations.clear(); 576 int count = pendingCopy.size(); 577 for (int i = 0; i < count; ++i) { 578 ValueAnimator anim = pendingCopy.get(i); 579 // If the animation has a startDelay, place it on the delayed list 580 if (anim.mStartDelay == 0) { 581 anim.startAnimation(this); 582 } else { 583 mDelayedAnims.add(anim); 584 } 585 } 586 } 587 doAnimationFrame(); 588 } 589 590 private void doAnimationFrame() { 591 // currentTime holds the common time for all animations processed 592 // during this frame 593 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 594 595 // First, process animations currently sitting on the delayed queue, adding 596 // them to the active animations if they are ready 597 int numDelayedAnims = mDelayedAnims.size(); 598 for (int i = 0; i < numDelayedAnims; ++i) { 599 ValueAnimator anim = mDelayedAnims.get(i); 600 if (anim.delayedAnimationFrame(currentTime)) { 601 mReadyAnims.add(anim); 602 } 603 } 604 int numReadyAnims = mReadyAnims.size(); 605 if (numReadyAnims > 0) { 606 for (int i = 0; i < numReadyAnims; ++i) { 607 ValueAnimator anim = mReadyAnims.get(i); 608 anim.startAnimation(this); 609 anim.mRunning = true; 610 mDelayedAnims.remove(anim); 611 } 612 mReadyAnims.clear(); 613 } 614 615 // Now process all active animations. The return value from animationFrame() 616 // tells the handler whether it should now be ended 617 int numAnims = mAnimations.size(); 618 int i = 0; 619 while (i < numAnims) { 620 ValueAnimator anim = mAnimations.get(i); 621 if (anim.animationFrame(currentTime)) { 622 mEndingAnims.add(anim); 623 } 624 if (mAnimations.size() == numAnims) { 625 ++i; 626 } else { 627 // An animation might be canceled or ended by client code 628 // during the animation frame. Check to see if this happened by 629 // seeing whether the current index is the same as it was before 630 // calling animationFrame(). Another approach would be to copy 631 // animations to a temporary list and process that list instead, 632 // but that entails garbage and processing overhead that would 633 // be nice to avoid. 634 --numAnims; 635 mEndingAnims.remove(anim); 636 } 637 } 638 if (mEndingAnims.size() > 0) { 639 for (i = 0; i < mEndingAnims.size(); ++i) { 640 mEndingAnims.get(i).endAnimation(this); 641 } 642 mEndingAnims.clear(); 643 } 644 645 // If there are still active or delayed animations, schedule a future call to 646 // onAnimate to process the next frame of the animations. 647 if (!mAnimations.isEmpty() || !mDelayedAnims.isEmpty()) { 648 if (!mIsChoreographed) { 649 mIsChoreographed = true; 650 mChoreographer.addOnAnimateListener(this); 651 } 652 mChoreographer.scheduleAnimation(); 653 } else { 654 if (mIsChoreographed) { 655 mIsChoreographed = false; 656 mChoreographer.removeOnAnimateListener(this); 657 } 658 } 659 } 660 661 @Override 662 public void onAnimate() { 663 doAnimationFrame(); 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 mUnscaledStartDelay; 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 = (long)(startDelay * sDurationScale); 685 mUnscaledStartDelay = startDelay; 686 } 687 688 /** 689 * The amount of time, in milliseconds, between each frame of the animation. This is a 690 * requested time that the animation will attempt to honor, but the actual delay between 691 * frames may be different, depending on system load and capabilities. This is a static 692 * function because the same delay will be applied to all animations, since they are all 693 * run off of a single timing loop. 694 * 695 * The frame delay may be ignored when the animation system uses an external timing 696 * source, such as the display refresh rate (vsync), to govern animations. 697 * 698 * @return the requested time between frames, in milliseconds 699 */ 700 public static long getFrameDelay() { 701 return Choreographer.getFrameDelay(); 702 } 703 704 /** 705 * The amount of time, in milliseconds, between each frame of the animation. This is a 706 * requested time that the animation will attempt to honor, but the actual delay between 707 * frames may be different, depending on system load and capabilities. This is a static 708 * function because the same delay will be applied to all animations, since they are all 709 * run off of a single timing loop. 710 * 711 * The frame delay may be ignored when the animation system uses an external timing 712 * source, such as the display refresh rate (vsync), to govern animations. 713 * 714 * @param frameDelay the requested time between frames, in milliseconds 715 */ 716 public static void setFrameDelay(long frameDelay) { 717 Choreographer.setFrameDelay(frameDelay); 718 } 719 720 /** 721 * The most recent value calculated by this <code>ValueAnimator</code> when there is just one 722 * property being animated. This value is only sensible while the animation is running. The main 723 * purpose for this read-only property is to retrieve the value from the <code>ValueAnimator</code> 724 * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 725 * is called during each animation frame, immediately after the value is calculated. 726 * 727 * @return animatedValue The value most recently calculated by this <code>ValueAnimator</code> for 728 * the single property being animated. If there are several properties being animated 729 * (specified by several PropertyValuesHolder objects in the constructor), this function 730 * returns the animated value for the first of those objects. 731 */ 732 public Object getAnimatedValue() { 733 if (mValues != null && mValues.length > 0) { 734 return mValues[0].getAnimatedValue(); 735 } 736 // Shouldn't get here; should always have values unless ValueAnimator was set up wrong 737 return null; 738 } 739 740 /** 741 * The most recent value calculated by this <code>ValueAnimator</code> for <code>propertyName</code>. 742 * The main purpose for this read-only property is to retrieve the value from the 743 * <code>ValueAnimator</code> during a call to 744 * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 745 * is called during each animation frame, immediately after the value is calculated. 746 * 747 * @return animatedValue The value most recently calculated for the named property 748 * by this <code>ValueAnimator</code>. 749 */ 750 public Object getAnimatedValue(String propertyName) { 751 PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); 752 if (valuesHolder != null) { 753 return valuesHolder.getAnimatedValue(); 754 } else { 755 // At least avoid crashing if called with bogus propertyName 756 return null; 757 } 758 } 759 760 /** 761 * Sets how many times the animation should be repeated. If the repeat 762 * count is 0, the animation is never repeated. If the repeat count is 763 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken 764 * into account. The repeat count is 0 by default. 765 * 766 * @param value the number of times the animation should be repeated 767 */ 768 public void setRepeatCount(int value) { 769 mRepeatCount = value; 770 } 771 /** 772 * Defines how many times the animation should repeat. The default value 773 * is 0. 774 * 775 * @return the number of times the animation should repeat, or {@link #INFINITE} 776 */ 777 public int getRepeatCount() { 778 return mRepeatCount; 779 } 780 781 /** 782 * Defines what this animation should do when it reaches the end. This 783 * setting is applied only when the repeat count is either greater than 784 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 785 * 786 * @param value {@link #RESTART} or {@link #REVERSE} 787 */ 788 public void setRepeatMode(int value) { 789 mRepeatMode = value; 790 } 791 792 /** 793 * Defines what this animation should do when it reaches the end. 794 * 795 * @return either one of {@link #REVERSE} or {@link #RESTART} 796 */ 797 public int getRepeatMode() { 798 return mRepeatMode; 799 } 800 801 /** 802 * Adds a listener to the set of listeners that are sent update events through the life of 803 * an animation. This method is called on all listeners for every frame of the animation, 804 * after the values for the animation have been calculated. 805 * 806 * @param listener the listener to be added to the current set of listeners for this animation. 807 */ 808 public void addUpdateListener(AnimatorUpdateListener listener) { 809 if (mUpdateListeners == null) { 810 mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 811 } 812 mUpdateListeners.add(listener); 813 } 814 815 /** 816 * Removes all listeners from the set listening to frame updates for this animation. 817 */ 818 public void removeAllUpdateListeners() { 819 if (mUpdateListeners == null) { 820 return; 821 } 822 mUpdateListeners.clear(); 823 mUpdateListeners = null; 824 } 825 826 /** 827 * Removes a listener from the set listening to frame updates for this animation. 828 * 829 * @param listener the listener to be removed from the current set of update listeners 830 * for this animation. 831 */ 832 public void removeUpdateListener(AnimatorUpdateListener listener) { 833 if (mUpdateListeners == null) { 834 return; 835 } 836 mUpdateListeners.remove(listener); 837 if (mUpdateListeners.size() == 0) { 838 mUpdateListeners = null; 839 } 840 } 841 842 843 /** 844 * The time interpolator used in calculating the elapsed fraction of this animation. The 845 * interpolator determines whether the animation runs with linear or non-linear motion, 846 * such as acceleration and deceleration. The default value is 847 * {@link android.view.animation.AccelerateDecelerateInterpolator} 848 * 849 * @param value the interpolator to be used by this animation. A value of <code>null</code> 850 * will result in linear interpolation. 851 */ 852 @Override 853 public void setInterpolator(TimeInterpolator value) { 854 if (value != null) { 855 mInterpolator = value; 856 } else { 857 mInterpolator = new LinearInterpolator(); 858 } 859 } 860 861 /** 862 * Returns the timing interpolator that this ValueAnimator uses. 863 * 864 * @return The timing interpolator for this ValueAnimator. 865 */ 866 public TimeInterpolator getInterpolator() { 867 return mInterpolator; 868 } 869 870 /** 871 * The type evaluator to be used when calculating the animated values of this animation. 872 * The system will automatically assign a float or int evaluator based on the type 873 * of <code>startValue</code> and <code>endValue</code> in the constructor. But if these values 874 * are not one of these primitive types, or if different evaluation is desired (such as is 875 * necessary with int values that represent colors), a custom evaluator needs to be assigned. 876 * For example, when running an animation on color values, the {@link ArgbEvaluator} 877 * should be used to get correct RGB color interpolation. 878 * 879 * <p>If this ValueAnimator has only one set of values being animated between, this evaluator 880 * will be used for that set. If there are several sets of values being animated, which is 881 * the case if PropertyValuesHOlder objects were set on the ValueAnimator, then the evaluator 882 * is assigned just to the first PropertyValuesHolder object.</p> 883 * 884 * @param value the evaluator to be used this animation 885 */ 886 public void setEvaluator(TypeEvaluator value) { 887 if (value != null && mValues != null && mValues.length > 0) { 888 mValues[0].setEvaluator(value); 889 } 890 } 891 892 /** 893 * Start the animation playing. This version of start() takes a boolean flag that indicates 894 * whether the animation should play in reverse. The flag is usually false, but may be set 895 * to true if called from the reverse() method. 896 * 897 * <p>The animation started by calling this method will be run on the thread that called 898 * this method. This thread should have a Looper on it (a runtime exception will be thrown if 899 * this is not the case). Also, if the animation will animate 900 * properties of objects in the view hierarchy, then the calling thread should be the UI 901 * thread for that view hierarchy.</p> 902 * 903 * @param playBackwards Whether the ValueAnimator should start playing in reverse. 904 */ 905 private void start(boolean playBackwards) { 906 if (Looper.myLooper() == null) { 907 throw new AndroidRuntimeException("Animators may only be run on Looper threads"); 908 } 909 mPlayingBackwards = playBackwards; 910 mCurrentIteration = 0; 911 mPlayingState = STOPPED; 912 mStarted = true; 913 mStartedDelay = false; 914 AnimationHandler animationHandler = getOrCreateAnimationHandler(); 915 animationHandler.mPendingAnimations.add(this); 916 if (mStartDelay == 0) { 917 // This sets the initial value of the animation, prior to actually starting it running 918 setCurrentPlayTime(getCurrentPlayTime()); 919 mPlayingState = STOPPED; 920 mRunning = true; 921 922 if (mListeners != null) { 923 ArrayList<AnimatorListener> tmpListeners = 924 (ArrayList<AnimatorListener>) mListeners.clone(); 925 int numListeners = tmpListeners.size(); 926 for (int i = 0; i < numListeners; ++i) { 927 tmpListeners.get(i).onAnimationStart(this); 928 } 929 } 930 } 931 animationHandler.sendEmptyMessage(ANIMATION_START); 932 } 933 934 @Override 935 public void start() { 936 start(false); 937 } 938 939 @Override 940 public void cancel() { 941 // Only cancel if the animation is actually running or has been started and is about 942 // to run 943 AnimationHandler handler = getOrCreateAnimationHandler(); 944 if (mPlayingState != STOPPED 945 || handler.mPendingAnimations.contains(this) 946 || handler.mDelayedAnims.contains(this)) { 947 // Only notify listeners if the animator has actually started 948 if (mRunning && mListeners != null) { 949 ArrayList<AnimatorListener> tmpListeners = 950 (ArrayList<AnimatorListener>) mListeners.clone(); 951 for (AnimatorListener listener : tmpListeners) { 952 listener.onAnimationCancel(this); 953 } 954 } 955 endAnimation(handler); 956 } 957 } 958 959 @Override 960 public void end() { 961 AnimationHandler handler = getOrCreateAnimationHandler(); 962 if (!handler.mAnimations.contains(this) && !handler.mPendingAnimations.contains(this)) { 963 // Special case if the animation has not yet started; get it ready for ending 964 mStartedDelay = false; 965 startAnimation(handler); 966 } else if (!mInitialized) { 967 initAnimation(); 968 } 969 // The final value set on the target varies, depending on whether the animation 970 // was supposed to repeat an odd number of times 971 if (mRepeatCount > 0 && (mRepeatCount & 0x01) == 1) { 972 animateValue(0f); 973 } else { 974 animateValue(1f); 975 } 976 endAnimation(handler); 977 } 978 979 @Override 980 public boolean isRunning() { 981 return (mPlayingState == RUNNING || mRunning); 982 } 983 984 @Override 985 public boolean isStarted() { 986 return mStarted; 987 } 988 989 /** 990 * Plays the ValueAnimator in reverse. If the animation is already running, 991 * it will stop itself and play backwards from the point reached when reverse was called. 992 * If the animation is not currently running, then it will start from the end and 993 * play backwards. This behavior is only set for the current animation; future playing 994 * of the animation will use the default behavior of playing forward. 995 */ 996 public void reverse() { 997 mPlayingBackwards = !mPlayingBackwards; 998 if (mPlayingState == RUNNING) { 999 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 1000 long currentPlayTime = currentTime - mStartTime; 1001 long timeLeft = mDuration - currentPlayTime; 1002 mStartTime = currentTime - timeLeft; 1003 } else { 1004 start(true); 1005 } 1006 } 1007 1008 /** 1009 * Called internally to end an animation by removing it from the animations list. Must be 1010 * called on the UI thread. 1011 */ 1012 private void endAnimation(AnimationHandler handler) { 1013 handler.mAnimations.remove(this); 1014 handler.mPendingAnimations.remove(this); 1015 handler.mDelayedAnims.remove(this); 1016 mPlayingState = STOPPED; 1017 if (mRunning && mListeners != null) { 1018 ArrayList<AnimatorListener> tmpListeners = 1019 (ArrayList<AnimatorListener>) mListeners.clone(); 1020 int numListeners = tmpListeners.size(); 1021 for (int i = 0; i < numListeners; ++i) { 1022 tmpListeners.get(i).onAnimationEnd(this); 1023 } 1024 } 1025 mRunning = false; 1026 mStarted = false; 1027 } 1028 1029 /** 1030 * Called internally to start an animation by adding it to the active animations list. Must be 1031 * called on the UI thread. 1032 */ 1033 private void startAnimation(AnimationHandler handler) { 1034 initAnimation(); 1035 handler.mAnimations.add(this); 1036 if (mStartDelay > 0 && mListeners != null) { 1037 // Listeners were already notified in start() if startDelay is 0; this is 1038 // just for delayed animations 1039 ArrayList<AnimatorListener> tmpListeners = 1040 (ArrayList<AnimatorListener>) mListeners.clone(); 1041 int numListeners = tmpListeners.size(); 1042 for (int i = 0; i < numListeners; ++i) { 1043 tmpListeners.get(i).onAnimationStart(this); 1044 } 1045 } 1046 } 1047 1048 /** 1049 * Internal function called to process an animation frame on an animation that is currently 1050 * sleeping through its <code>startDelay</code> phase. The return value indicates whether it 1051 * should be woken up and put on the active animations queue. 1052 * 1053 * @param currentTime The current animation time, used to calculate whether the animation 1054 * has exceeded its <code>startDelay</code> and should be started. 1055 * @return True if the animation's <code>startDelay</code> has been exceeded and the animation 1056 * should be added to the set of active animations. 1057 */ 1058 private boolean delayedAnimationFrame(long currentTime) { 1059 if (!mStartedDelay) { 1060 mStartedDelay = true; 1061 mDelayStartTime = currentTime; 1062 } else { 1063 long deltaTime = currentTime - mDelayStartTime; 1064 if (deltaTime > mStartDelay) { 1065 // startDelay ended - start the anim and record the 1066 // mStartTime appropriately 1067 mStartTime = currentTime - (deltaTime - mStartDelay); 1068 mPlayingState = RUNNING; 1069 return true; 1070 } 1071 } 1072 return false; 1073 } 1074 1075 /** 1076 * This internal function processes a single animation frame for a given animation. The 1077 * currentTime parameter is the timing pulse sent by the handler, used to calculate the 1078 * elapsed duration, and therefore 1079 * the elapsed fraction, of the animation. The return value indicates whether the animation 1080 * should be ended (which happens when the elapsed time of the animation exceeds the 1081 * animation's duration, including the repeatCount). 1082 * 1083 * @param currentTime The current time, as tracked by the static timing handler 1084 * @return true if the animation's duration, including any repetitions due to 1085 * <code>repeatCount</code> has been exceeded and the animation should be ended. 1086 */ 1087 boolean animationFrame(long currentTime) { 1088 boolean done = false; 1089 1090 if (mPlayingState == STOPPED) { 1091 mPlayingState = RUNNING; 1092 if (mSeekTime < 0) { 1093 mStartTime = currentTime; 1094 } else { 1095 mStartTime = currentTime - mSeekTime; 1096 // Now that we're playing, reset the seek time 1097 mSeekTime = -1; 1098 } 1099 } 1100 switch (mPlayingState) { 1101 case RUNNING: 1102 case SEEKED: 1103 float fraction = mDuration > 0 ? (float)(currentTime - mStartTime) / mDuration : 1f; 1104 if (fraction >= 1f) { 1105 if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { 1106 // Time to repeat 1107 if (mListeners != null) { 1108 int numListeners = mListeners.size(); 1109 for (int i = 0; i < numListeners; ++i) { 1110 mListeners.get(i).onAnimationRepeat(this); 1111 } 1112 } 1113 if (mRepeatMode == REVERSE) { 1114 mPlayingBackwards = mPlayingBackwards ? false : true; 1115 } 1116 mCurrentIteration += (int)fraction; 1117 fraction = fraction % 1f; 1118 mStartTime += mDuration; 1119 } else { 1120 done = true; 1121 fraction = Math.min(fraction, 1.0f); 1122 } 1123 } 1124 if (mPlayingBackwards) { 1125 fraction = 1f - fraction; 1126 } 1127 animateValue(fraction); 1128 break; 1129 } 1130 1131 return done; 1132 } 1133 1134 /** 1135 * Returns the current animation fraction, which is the elapsed/interpolated fraction used in 1136 * the most recent frame update on the animation. 1137 * 1138 * @return Elapsed/interpolated fraction of the animation. 1139 */ 1140 public float getAnimatedFraction() { 1141 return mCurrentFraction; 1142 } 1143 1144 /** 1145 * This method is called with the elapsed fraction of the animation during every 1146 * animation frame. This function turns the elapsed fraction into an interpolated fraction 1147 * and then into an animated value (from the evaluator. The function is called mostly during 1148 * animation updates, but it is also called when the <code>end()</code> 1149 * function is called, to set the final value on the property. 1150 * 1151 * <p>Overrides of this method must call the superclass to perform the calculation 1152 * of the animated value.</p> 1153 * 1154 * @param fraction The elapsed fraction of the animation. 1155 */ 1156 void animateValue(float fraction) { 1157 fraction = mInterpolator.getInterpolation(fraction); 1158 mCurrentFraction = fraction; 1159 int numValues = mValues.length; 1160 for (int i = 0; i < numValues; ++i) { 1161 mValues[i].calculateValue(fraction); 1162 } 1163 if (mUpdateListeners != null) { 1164 int numListeners = mUpdateListeners.size(); 1165 for (int i = 0; i < numListeners; ++i) { 1166 mUpdateListeners.get(i).onAnimationUpdate(this); 1167 } 1168 } 1169 } 1170 1171 @Override 1172 public ValueAnimator clone() { 1173 final ValueAnimator anim = (ValueAnimator) super.clone(); 1174 if (mUpdateListeners != null) { 1175 ArrayList<AnimatorUpdateListener> oldListeners = mUpdateListeners; 1176 anim.mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 1177 int numListeners = oldListeners.size(); 1178 for (int i = 0; i < numListeners; ++i) { 1179 anim.mUpdateListeners.add(oldListeners.get(i)); 1180 } 1181 } 1182 anim.mSeekTime = -1; 1183 anim.mPlayingBackwards = false; 1184 anim.mCurrentIteration = 0; 1185 anim.mInitialized = false; 1186 anim.mPlayingState = STOPPED; 1187 anim.mStartedDelay = false; 1188 PropertyValuesHolder[] oldValues = mValues; 1189 if (oldValues != null) { 1190 int numValues = oldValues.length; 1191 anim.mValues = new PropertyValuesHolder[numValues]; 1192 anim.mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 1193 for (int i = 0; i < numValues; ++i) { 1194 PropertyValuesHolder newValuesHolder = oldValues[i].clone(); 1195 anim.mValues[i] = newValuesHolder; 1196 anim.mValuesMap.put(newValuesHolder.getPropertyName(), newValuesHolder); 1197 } 1198 } 1199 return anim; 1200 } 1201 1202 /** 1203 * Implementors of this interface can add themselves as update listeners 1204 * to an <code>ValueAnimator</code> instance to receive callbacks on every animation 1205 * frame, after the current frame's values have been calculated for that 1206 * <code>ValueAnimator</code>. 1207 */ 1208 public static interface AnimatorUpdateListener { 1209 /** 1210 * <p>Notifies the occurrence of another frame of the animation.</p> 1211 * 1212 * @param animation The animation which was repeated. 1213 */ 1214 void onAnimationUpdate(ValueAnimator animation); 1215 1216 } 1217 1218 /** 1219 * Return the number of animations currently running. 1220 * 1221 * Used by StrictMode internally to annotate violations. 1222 * May be called on arbitrary threads! 1223 * 1224 * @hide 1225 */ 1226 public static int getCurrentAnimationsCount() { 1227 AnimationHandler handler = sAnimationHandler.get(); 1228 return handler != null ? handler.mAnimations.size() : 0; 1229 } 1230 1231 /** 1232 * Clear all animations on this thread, without canceling or ending them. 1233 * This should be used with caution. 1234 * 1235 * @hide 1236 */ 1237 public static void clearAllAnimations() { 1238 AnimationHandler handler = sAnimationHandler.get(); 1239 if (handler != null) { 1240 handler.mAnimations.clear(); 1241 handler.mPendingAnimations.clear(); 1242 handler.mDelayedAnims.clear(); 1243 } 1244 } 1245 1246 private AnimationHandler getOrCreateAnimationHandler() { 1247 AnimationHandler handler = sAnimationHandler.get(); 1248 if (handler == null) { 1249 handler = new AnimationHandler(); 1250 sAnimationHandler.set(handler); 1251 } 1252 return handler; 1253 } 1254 1255 @Override 1256 public String toString() { 1257 String returnVal = "ValueAnimator@" + Integer.toHexString(hashCode()); 1258 if (mValues != null) { 1259 for (int i = 0; i < mValues.length; ++i) { 1260 returnVal += "\n " + mValues[i].toString(); 1261 } 1262 } 1263 return returnVal; 1264 } 1265} 1266