ValueAnimator.java revision 96e942dabeeaaa9ab6df3a870668c6fe53d930da
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 */ 43public class ValueAnimator extends Animator { 44 45 /** 46 * Internal constants 47 */ 48 49 /** 50 * Messages sent to timing handler: START is sent when an animation first begins. 51 */ 52 static final int ANIMATION_START = 0; 53 54 /** 55 * Values used with internal variable mPlayingState to indicate the current state of an 56 * animation. 57 */ 58 static final int STOPPED = 0; // Not yet playing 59 static final int RUNNING = 1; // Playing normally 60 static final int SEEKED = 2; // Seeked to some time value 61 62 /** 63 * Internal variables 64 * NOTE: This object implements the clone() method, making a deep copy of any referenced 65 * objects. As other non-trivial fields are added to this class, make sure to add logic 66 * to clone() to make deep copies of them. 67 */ 68 69 // The first time that the animation's animateFrame() method is called. This time is used to 70 // determine elapsed time (and therefore the elapsed fraction) in subsequent calls 71 // to animateFrame() 72 long mStartTime; 73 74 /** 75 * Set when setCurrentPlayTime() is called. If negative, animation is not currently seeked 76 * to a value. 77 */ 78 long mSeekTime = -1; 79 80 // The static sAnimationHandler processes the internal timing loop on which all animations 81 // are based 82 private static ThreadLocal<AnimationHandler> sAnimationHandler = 83 new ThreadLocal<AnimationHandler>(); 84 85 // The time interpolator to be used if none is set on the animation 86 private static final TimeInterpolator sDefaultInterpolator = 87 new AccelerateDecelerateInterpolator(); 88 89 /** 90 * Used to indicate whether the animation is currently playing in reverse. This causes the 91 * elapsed fraction to be inverted to calculate the appropriate values. 92 */ 93 private boolean mPlayingBackwards = false; 94 95 /** 96 * This variable tracks the current iteration that is playing. When mCurrentIteration exceeds the 97 * repeatCount (if repeatCount!=INFINITE), the animation ends 98 */ 99 private int mCurrentIteration = 0; 100 101 /** 102 * Tracks current elapsed/eased fraction, for querying in getAnimatedFraction(). 103 */ 104 private float mCurrentFraction = 0f; 105 106 /** 107 * Tracks whether a startDelay'd animation has begun playing through the startDelay. 108 */ 109 private boolean mStartedDelay = false; 110 111 /** 112 * Tracks the time at which the animation began playing through its startDelay. This is 113 * different from the mStartTime variable, which is used to track when the animation became 114 * active (which is when the startDelay expired and the animation was added to the active 115 * animations list). 116 */ 117 private long mDelayStartTime; 118 119 /** 120 * Flag that represents the current state of the animation. Used to figure out when to start 121 * an animation (if state == STOPPED). Also used to end an animation that 122 * has been cancel()'d or end()'d since the last animation frame. Possible values are 123 * STOPPED, RUNNING, SEEKED. 124 */ 125 int mPlayingState = STOPPED; 126 127 /** 128 * Additional playing state to indicate whether an animator has been start()'d. There is 129 * some lag between a call to start() and the first animation frame. We should still note 130 * that the animation has been started, even if it's first animation frame has not yet 131 * happened, and reflect that state in isRunning(). 132 * Note that delayed animations are different: they are not started until their first 133 * animation frame, which occurs after their delay elapses. 134 */ 135 private boolean mRunning = false; 136 137 /** 138 * Additional playing state to indicate whether an animator has been start()'d, whether or 139 * not there is a nonzero startDelay. 140 */ 141 private boolean mStarted = false; 142 143 /** 144 * Flag that denotes whether the animation is set up and ready to go. Used to 145 * set up animation that has not yet been started. 146 */ 147 boolean mInitialized = false; 148 149 // 150 // Backing variables 151 // 152 153 // How long the animation should last in ms 154 private long mDuration = 300; 155 156 // The amount of time in ms to delay starting the animation after start() is called 157 private long mStartDelay = 0; 158 159 // The number of times the animation will repeat. The default is 0, which means the animation 160 // will play only once 161 private int mRepeatCount = 0; 162 163 /** 164 * The type of repetition that will occur when repeatMode is nonzero. RESTART means the 165 * animation will start from the beginning on every new cycle. REVERSE means the animation 166 * will reverse directions on each iteration. 167 */ 168 private int mRepeatMode = RESTART; 169 170 /** 171 * The time interpolator to be used. The elapsed fraction of the animation will be passed 172 * through this interpolator to calculate the interpolated fraction, which is then used to 173 * calculate the animated values. 174 */ 175 private TimeInterpolator mInterpolator = sDefaultInterpolator; 176 177 /** 178 * The set of listeners to be sent events through the life of an animation. 179 */ 180 private ArrayList<AnimatorUpdateListener> mUpdateListeners = null; 181 182 /** 183 * The property/value sets being animated. 184 */ 185 PropertyValuesHolder[] mValues; 186 187 /** 188 * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values 189 * by property name during calls to getAnimatedValue(String). 190 */ 191 HashMap<String, PropertyValuesHolder> mValuesMap; 192 193 /** 194 * Public constants 195 */ 196 197 /** 198 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 199 * or a positive value, the animation restarts from the beginning. 200 */ 201 public static final int RESTART = 1; 202 /** 203 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 204 * or a positive value, the animation reverses direction on every iteration. 205 */ 206 public static final int REVERSE = 2; 207 /** 208 * This value used used with the {@link #setRepeatCount(int)} property to repeat 209 * the animation indefinitely. 210 */ 211 public static final int INFINITE = -1; 212 213 /** 214 * Creates a new ValueAnimator object. This default constructor is primarily for 215 * use internally; the factory methods which take parameters are more generally 216 * useful. 217 */ 218 public ValueAnimator() { 219 } 220 221 /** 222 * Constructs and returns a ValueAnimator that animates between int values. A single 223 * value implies that that value is the one being animated to. However, this is not typically 224 * useful in a ValueAnimator object because there is no way for the object to determine the 225 * starting value for the animation (unlike ObjectAnimator, which can derive that value 226 * from the target object and property being animated). Therefore, there should typically 227 * be two or more values. 228 * 229 * @param values A set of values that the animation will animate between over time. 230 * @return A ValueAnimator object that is set up to animate between the given values. 231 */ 232 public static ValueAnimator ofInt(int... values) { 233 ValueAnimator anim = new ValueAnimator(); 234 anim.setIntValues(values); 235 return anim; 236 } 237 238 /** 239 * Constructs and returns a ValueAnimator that animates between float values. A single 240 * value implies that that value is the one being animated to. However, this is not typically 241 * useful in a ValueAnimator object because there is no way for the object to determine the 242 * starting value for the animation (unlike ObjectAnimator, which can derive that value 243 * from the target object and property being animated). Therefore, there should typically 244 * be two or more values. 245 * 246 * @param values A set of values that the animation will animate between over time. 247 * @return A ValueAnimator object that is set up to animate between the given values. 248 */ 249 public static ValueAnimator ofFloat(float... values) { 250 ValueAnimator anim = new ValueAnimator(); 251 anim.setFloatValues(values); 252 return anim; 253 } 254 255 /** 256 * Constructs and returns a ValueAnimator that animates between the values 257 * specified in the PropertyValuesHolder objects. 258 * 259 * @param values A set of PropertyValuesHolder objects whose values will be animated 260 * between over time. 261 * @return A ValueAnimator object that is set up to animate between the given values. 262 */ 263 public static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values) { 264 ValueAnimator anim = new ValueAnimator(); 265 anim.setValues(values); 266 return anim; 267 } 268 /** 269 * Constructs and returns a ValueAnimator that animates between Object values. A single 270 * value implies that that value is the one being animated to. However, this is not typically 271 * useful in a ValueAnimator object because there is no way for the object to determine the 272 * starting value for the animation (unlike ObjectAnimator, which can derive that value 273 * from the target object and property being animated). Therefore, there should typically 274 * be two or more values. 275 * 276 * <p>Since ValueAnimator does not know how to animate between arbitrary Objects, this 277 * factory method also takes a TypeEvaluator object that the ValueAnimator will use 278 * to perform that interpolation. 279 * 280 * @param evaluator A TypeEvaluator that will be called on each animation frame to 281 * provide the ncessry interpolation between the Object values to derive the animated 282 * value. 283 * @param values A set of values that the animation will animate between over time. 284 * @return A ValueAnimator object that is set up to animate between the given values. 285 */ 286 public static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values) { 287 ValueAnimator anim = new ValueAnimator(); 288 anim.setObjectValues(values); 289 anim.setEvaluator(evaluator); 290 return anim; 291 } 292 293 /** 294 * Sets int values that will be animated between. A single 295 * value implies that that value is the one being animated to. However, this is not typically 296 * useful in a ValueAnimator object because there is no way for the object to determine the 297 * starting value for the animation (unlike ObjectAnimator, which can derive that value 298 * from the target object and property being animated). Therefore, there should typically 299 * be two or more values. 300 * 301 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 302 * than one PropertyValuesHolder object, this method will set the values for the first 303 * of those objects.</p> 304 * 305 * @param values A set of values that the animation will animate between over time. 306 */ 307 public void setIntValues(int... values) { 308 if (values == null || values.length == 0) { 309 return; 310 } 311 if (mValues == null || mValues.length == 0) { 312 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofInt("", values)}); 313 } else { 314 PropertyValuesHolder valuesHolder = mValues[0]; 315 valuesHolder.setIntValues(values); 316 } 317 // New property/values/target should cause re-initialization prior to starting 318 mInitialized = false; 319 } 320 321 /** 322 * Sets float values that will be animated between. A single 323 * value implies that that value is the one being animated to. However, this is not typically 324 * useful in a ValueAnimator object because there is no way for the object to determine the 325 * starting value for the animation (unlike ObjectAnimator, which can derive that value 326 * from the target object and property being animated). Therefore, there should typically 327 * be two or more values. 328 * 329 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 330 * than one PropertyValuesHolder object, this method will set the values for the first 331 * of those objects.</p> 332 * 333 * @param values A set of values that the animation will animate between over time. 334 */ 335 public void setFloatValues(float... values) { 336 if (values == null || values.length == 0) { 337 return; 338 } 339 if (mValues == null || mValues.length == 0) { 340 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofFloat("", values)}); 341 } else { 342 PropertyValuesHolder valuesHolder = mValues[0]; 343 valuesHolder.setFloatValues(values); 344 } 345 // New property/values/target should cause re-initialization prior to starting 346 mInitialized = false; 347 } 348 349 /** 350 * Sets the values to animate between for this animation. A single 351 * value implies that that value is the one being animated to. However, this is not typically 352 * useful in a ValueAnimator object because there is no way for the object to determine the 353 * starting value for the animation (unlike ObjectAnimator, which can derive that value 354 * from the target object and property being animated). Therefore, there should typically 355 * be two or more values. 356 * 357 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 358 * than one PropertyValuesHolder object, this method will set the values for the first 359 * of those objects.</p> 360 * 361 * <p>There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate 362 * between these value objects. ValueAnimator only knows how to interpolate between the 363 * primitive types specified in the other setValues() methods.</p> 364 * 365 * @param values The set of values to animate between. 366 */ 367 public void setObjectValues(Object... values) { 368 if (values == null || values.length == 0) { 369 return; 370 } 371 if (mValues == null || mValues.length == 0) { 372 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofObject("", 373 (TypeEvaluator)null, values)}); 374 } else { 375 PropertyValuesHolder valuesHolder = mValues[0]; 376 valuesHolder.setObjectValues(values); 377 } 378 // New property/values/target should cause re-initialization prior to starting 379 mInitialized = false; 380 } 381 382 /** 383 * Sets the values, per property, being animated between. This function is called internally 384 * by the constructors of ValueAnimator that take a list of values. But an ValueAnimator can 385 * be constructed without values and this method can be called to set the values manually 386 * instead. 387 * 388 * @param values The set of values, per property, being animated between. 389 */ 390 public void setValues(PropertyValuesHolder... values) { 391 int numValues = values.length; 392 mValues = values; 393 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 394 for (int i = 0; i < numValues; ++i) { 395 PropertyValuesHolder valuesHolder = (PropertyValuesHolder) values[i]; 396 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 397 } 398 // New property/values/target should cause re-initialization prior to starting 399 mInitialized = false; 400 } 401 402 /** 403 * Returns the values that this ValueAnimator animates between. These values are stored in 404 * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list 405 * of value objects instead. 406 * 407 * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the 408 * values, per property, that define the animation. 409 */ 410 public PropertyValuesHolder[] getValues() { 411 return mValues; 412 } 413 414 /** 415 * This function is called immediately before processing the first animation 416 * frame of an animation. If there is a nonzero <code>startDelay</code>, the 417 * function is called after that delay ends. 418 * It takes care of the final initialization steps for the 419 * animation. 420 * 421 * <p>Overrides of this method should call the superclass method to ensure 422 * that internal mechanisms for the animation are set up correctly.</p> 423 */ 424 void initAnimation() { 425 if (!mInitialized) { 426 int numValues = mValues.length; 427 for (int i = 0; i < numValues; ++i) { 428 mValues[i].init(); 429 } 430 mInitialized = true; 431 } 432 } 433 434 435 /** 436 * Sets the length of the animation. The default duration is 300 milliseconds. 437 * 438 * @param duration The length of the animation, in milliseconds. This value cannot 439 * be negative. 440 * @return ValueAnimator The object called with setDuration(). This return 441 * value makes it easier to compose statements together that construct and then set the 442 * duration, as in <code>ValueAnimator.ofInt(0, 10).setDuration(500).start()</code>. 443 */ 444 public ValueAnimator setDuration(long duration) { 445 if (duration < 0) { 446 throw new IllegalArgumentException("Animators cannot have negative duration: " + 447 duration); 448 } 449 mDuration = duration; 450 return this; 451 } 452 453 /** 454 * Gets the length of the animation. The default duration is 300 milliseconds. 455 * 456 * @return The length of the animation, in milliseconds. 457 */ 458 public long getDuration() { 459 return mDuration; 460 } 461 462 /** 463 * Sets the position of the animation to the specified point in time. This time should 464 * be between 0 and the total duration of the animation, including any repetition. If 465 * the animation has not yet been started, then it will not advance forward after it is 466 * set to this time; it will simply set the time to this value and perform any appropriate 467 * actions based on that time. If the animation is already running, then setCurrentPlayTime() 468 * will set the current playing time to this value and continue playing from that point. 469 * 470 * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. 471 */ 472 public void setCurrentPlayTime(long playTime) { 473 initAnimation(); 474 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 475 if (mPlayingState != RUNNING) { 476 mSeekTime = playTime; 477 mPlayingState = SEEKED; 478 } 479 mStartTime = currentTime - playTime; 480 animationFrame(currentTime); 481 } 482 483 /** 484 * Gets the current position of the animation in time, which is equal to the current 485 * time minus the time that the animation started. An animation that is not yet started will 486 * return a value of zero. 487 * 488 * @return The current position in time of the animation. 489 */ 490 public long getCurrentPlayTime() { 491 if (!mInitialized || mPlayingState == STOPPED) { 492 return 0; 493 } 494 return AnimationUtils.currentAnimationTimeMillis() - mStartTime; 495 } 496 497 /** 498 * This custom, static handler handles the timing pulse that is shared by 499 * all active animations. This approach ensures that the setting of animation 500 * values will happen on the UI thread and that all animations will share 501 * the same times for calculating their values, which makes synchronizing 502 * animations possible. 503 * 504 */ 505 private static class AnimationHandler extends Handler 506 implements Choreographer.OnAnimateListener { 507 // The per-thread list of all active animations 508 private final ArrayList<ValueAnimator> mAnimations = new ArrayList<ValueAnimator>(); 509 510 // The per-thread set of animations to be started on the next animation frame 511 private final ArrayList<ValueAnimator> mPendingAnimations = new ArrayList<ValueAnimator>(); 512 513 /** 514 * Internal per-thread collections used to avoid set collisions as animations start and end 515 * while being processed. 516 */ 517 private final ArrayList<ValueAnimator> mDelayedAnims = new ArrayList<ValueAnimator>(); 518 private final ArrayList<ValueAnimator> mEndingAnims = new ArrayList<ValueAnimator>(); 519 private final ArrayList<ValueAnimator> mReadyAnims = new ArrayList<ValueAnimator>(); 520 521 private final Choreographer mChoreographer; 522 private boolean mIsChoreographed; 523 524 private AnimationHandler() { 525 mChoreographer = Choreographer.getInstance(); 526 } 527 528 /** 529 * The START message is sent when an animation's start() method is called. 530 * It cannot start synchronously when start() is called 531 * because the call may be on the wrong thread, and it would also not be 532 * synchronized with other animations because it would not start on a common 533 * timing pulse. So each animation sends a START message to the handler, which 534 * causes the handler to place the animation on the active animations queue and 535 * start processing frames for that animation. 536 */ 537 @Override 538 public void handleMessage(Message msg) { 539 switch (msg.what) { 540 case ANIMATION_START: 541 doAnimationStart(); 542 break; 543 } 544 } 545 546 private void doAnimationStart() { 547 // mPendingAnimations holds any animations that have requested to be started 548 // We're going to clear mPendingAnimations, but starting animation may 549 // cause more to be added to the pending list (for example, if one animation 550 // starting triggers another starting). So we loop until mPendingAnimations 551 // is empty. 552 while (mPendingAnimations.size() > 0) { 553 ArrayList<ValueAnimator> pendingCopy = 554 (ArrayList<ValueAnimator>) mPendingAnimations.clone(); 555 mPendingAnimations.clear(); 556 int count = pendingCopy.size(); 557 for (int i = 0; i < count; ++i) { 558 ValueAnimator anim = pendingCopy.get(i); 559 // If the animation has a startDelay, place it on the delayed list 560 if (anim.mStartDelay == 0) { 561 anim.startAnimation(this); 562 } else { 563 mDelayedAnims.add(anim); 564 } 565 } 566 } 567 doAnimationFrame(); 568 } 569 570 private void doAnimationFrame() { 571 // currentTime holds the common time for all animations processed 572 // during this frame 573 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 574 575 // First, process animations currently sitting on the delayed queue, adding 576 // them to the active animations if they are ready 577 int numDelayedAnims = mDelayedAnims.size(); 578 for (int i = 0; i < numDelayedAnims; ++i) { 579 ValueAnimator anim = mDelayedAnims.get(i); 580 if (anim.delayedAnimationFrame(currentTime)) { 581 mReadyAnims.add(anim); 582 } 583 } 584 int numReadyAnims = mReadyAnims.size(); 585 if (numReadyAnims > 0) { 586 for (int i = 0; i < numReadyAnims; ++i) { 587 ValueAnimator anim = mReadyAnims.get(i); 588 anim.startAnimation(this); 589 anim.mRunning = true; 590 mDelayedAnims.remove(anim); 591 } 592 mReadyAnims.clear(); 593 } 594 595 // Now process all active animations. The return value from animationFrame() 596 // tells the handler whether it should now be ended 597 int numAnims = mAnimations.size(); 598 int i = 0; 599 while (i < numAnims) { 600 ValueAnimator anim = mAnimations.get(i); 601 if (anim.animationFrame(currentTime)) { 602 mEndingAnims.add(anim); 603 } 604 if (mAnimations.size() == numAnims) { 605 ++i; 606 } else { 607 // An animation might be canceled or ended by client code 608 // during the animation frame. Check to see if this happened by 609 // seeing whether the current index is the same as it was before 610 // calling animationFrame(). Another approach would be to copy 611 // animations to a temporary list and process that list instead, 612 // but that entails garbage and processing overhead that would 613 // be nice to avoid. 614 --numAnims; 615 mEndingAnims.remove(anim); 616 } 617 } 618 if (mEndingAnims.size() > 0) { 619 for (i = 0; i < mEndingAnims.size(); ++i) { 620 mEndingAnims.get(i).endAnimation(this); 621 } 622 mEndingAnims.clear(); 623 } 624 625 // If there are still active or delayed animations, schedule a future call to 626 // onAnimate to process the next frame of the animations. 627 if (!mAnimations.isEmpty() || !mDelayedAnims.isEmpty()) { 628 if (!mIsChoreographed) { 629 mIsChoreographed = true; 630 mChoreographer.addOnAnimateListener(this); 631 } 632 mChoreographer.scheduleAnimation(); 633 } else { 634 if (mIsChoreographed) { 635 mIsChoreographed = false; 636 mChoreographer.removeOnAnimateListener(this); 637 } 638 } 639 } 640 641 @Override 642 public void onAnimate() { 643 doAnimationFrame(); 644 } 645 } 646 647 /** 648 * The amount of time, in milliseconds, to delay starting the animation after 649 * {@link #start()} is called. 650 * 651 * @return the number of milliseconds to delay running the animation 652 */ 653 public long getStartDelay() { 654 return mStartDelay; 655 } 656 657 /** 658 * The amount of time, in milliseconds, to delay starting the animation after 659 * {@link #start()} is called. 660 661 * @param startDelay The amount of the delay, in milliseconds 662 */ 663 public void setStartDelay(long startDelay) { 664 this.mStartDelay = startDelay; 665 } 666 667 /** 668 * The amount of time, in milliseconds, between each frame of the animation. This is a 669 * requested time that the animation will attempt to honor, but the actual delay between 670 * frames may be different, depending on system load and capabilities. This is a static 671 * function because the same delay will be applied to all animations, since they are all 672 * run off of a single timing loop. 673 * 674 * The frame delay may be ignored when the animation system uses an external timing 675 * source, such as the display refresh rate (vsync), to govern animations. 676 * 677 * @return the requested time between frames, in milliseconds 678 */ 679 public static long getFrameDelay() { 680 return Choreographer.getFrameDelay(); 681 } 682 683 /** 684 * The amount of time, in milliseconds, between each frame of the animation. This is a 685 * requested time that the animation will attempt to honor, but the actual delay between 686 * frames may be different, depending on system load and capabilities. This is a static 687 * function because the same delay will be applied to all animations, since they are all 688 * run off of a single timing loop. 689 * 690 * The frame delay may be ignored when the animation system uses an external timing 691 * source, such as the display refresh rate (vsync), to govern animations. 692 * 693 * @param frameDelay the requested time between frames, in milliseconds 694 */ 695 public static void setFrameDelay(long frameDelay) { 696 Choreographer.setFrameDelay(frameDelay); 697 } 698 699 /** 700 * The most recent value calculated by this <code>ValueAnimator</code> when there is just one 701 * property being animated. This value is only sensible while the animation is running. The main 702 * purpose for this read-only property is to retrieve the value from the <code>ValueAnimator</code> 703 * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 704 * is called during each animation frame, immediately after the value is calculated. 705 * 706 * @return animatedValue The value most recently calculated by this <code>ValueAnimator</code> for 707 * the single property being animated. If there are several properties being animated 708 * (specified by several PropertyValuesHolder objects in the constructor), this function 709 * returns the animated value for the first of those objects. 710 */ 711 public Object getAnimatedValue() { 712 if (mValues != null && mValues.length > 0) { 713 return mValues[0].getAnimatedValue(); 714 } 715 // Shouldn't get here; should always have values unless ValueAnimator was set up wrong 716 return null; 717 } 718 719 /** 720 * The most recent value calculated by this <code>ValueAnimator</code> for <code>propertyName</code>. 721 * The main purpose for this read-only property is to retrieve the value from the 722 * <code>ValueAnimator</code> during a call to 723 * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 724 * is called during each animation frame, immediately after the value is calculated. 725 * 726 * @return animatedValue The value most recently calculated for the named property 727 * by this <code>ValueAnimator</code>. 728 */ 729 public Object getAnimatedValue(String propertyName) { 730 PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); 731 if (valuesHolder != null) { 732 return valuesHolder.getAnimatedValue(); 733 } else { 734 // At least avoid crashing if called with bogus propertyName 735 return null; 736 } 737 } 738 739 /** 740 * Sets how many times the animation should be repeated. If the repeat 741 * count is 0, the animation is never repeated. If the repeat count is 742 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken 743 * into account. The repeat count is 0 by default. 744 * 745 * @param value the number of times the animation should be repeated 746 */ 747 public void setRepeatCount(int value) { 748 mRepeatCount = value; 749 } 750 /** 751 * Defines how many times the animation should repeat. The default value 752 * is 0. 753 * 754 * @return the number of times the animation should repeat, or {@link #INFINITE} 755 */ 756 public int getRepeatCount() { 757 return mRepeatCount; 758 } 759 760 /** 761 * Defines what this animation should do when it reaches the end. This 762 * setting is applied only when the repeat count is either greater than 763 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 764 * 765 * @param value {@link #RESTART} or {@link #REVERSE} 766 */ 767 public void setRepeatMode(int value) { 768 mRepeatMode = value; 769 } 770 771 /** 772 * Defines what this animation should do when it reaches the end. 773 * 774 * @return either one of {@link #REVERSE} or {@link #RESTART} 775 */ 776 public int getRepeatMode() { 777 return mRepeatMode; 778 } 779 780 /** 781 * Adds a listener to the set of listeners that are sent update events through the life of 782 * an animation. This method is called on all listeners for every frame of the animation, 783 * after the values for the animation have been calculated. 784 * 785 * @param listener the listener to be added to the current set of listeners for this animation. 786 */ 787 public void addUpdateListener(AnimatorUpdateListener listener) { 788 if (mUpdateListeners == null) { 789 mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 790 } 791 mUpdateListeners.add(listener); 792 } 793 794 /** 795 * Removes all listeners from the set listening to frame updates for this animation. 796 */ 797 public void removeAllUpdateListeners() { 798 if (mUpdateListeners == null) { 799 return; 800 } 801 mUpdateListeners.clear(); 802 mUpdateListeners = null; 803 } 804 805 /** 806 * Removes a listener from the set listening to frame updates for this animation. 807 * 808 * @param listener the listener to be removed from the current set of update listeners 809 * for this animation. 810 */ 811 public void removeUpdateListener(AnimatorUpdateListener listener) { 812 if (mUpdateListeners == null) { 813 return; 814 } 815 mUpdateListeners.remove(listener); 816 if (mUpdateListeners.size() == 0) { 817 mUpdateListeners = null; 818 } 819 } 820 821 822 /** 823 * The time interpolator used in calculating the elapsed fraction of this animation. The 824 * interpolator determines whether the animation runs with linear or non-linear motion, 825 * such as acceleration and deceleration. The default value is 826 * {@link android.view.animation.AccelerateDecelerateInterpolator} 827 * 828 * @param value the interpolator to be used by this animation. A value of <code>null</code> 829 * will result in linear interpolation. 830 */ 831 @Override 832 public void setInterpolator(TimeInterpolator value) { 833 if (value != null) { 834 mInterpolator = value; 835 } else { 836 mInterpolator = new LinearInterpolator(); 837 } 838 } 839 840 /** 841 * Returns the timing interpolator that this ValueAnimator uses. 842 * 843 * @return The timing interpolator for this ValueAnimator. 844 */ 845 public TimeInterpolator getInterpolator() { 846 return mInterpolator; 847 } 848 849 /** 850 * The type evaluator to be used when calculating the animated values of this animation. 851 * The system will automatically assign a float or int evaluator based on the type 852 * of <code>startValue</code> and <code>endValue</code> in the constructor. But if these values 853 * are not one of these primitive types, or if different evaluation is desired (such as is 854 * necessary with int values that represent colors), a custom evaluator needs to be assigned. 855 * For example, when running an animation on color values, the {@link ArgbEvaluator} 856 * should be used to get correct RGB color interpolation. 857 * 858 * <p>If this ValueAnimator has only one set of values being animated between, this evaluator 859 * will be used for that set. If there are several sets of values being animated, which is 860 * the case if PropertyValuesHOlder objects were set on the ValueAnimator, then the evaluator 861 * is assigned just to the first PropertyValuesHolder object.</p> 862 * 863 * @param value the evaluator to be used this animation 864 */ 865 public void setEvaluator(TypeEvaluator value) { 866 if (value != null && mValues != null && mValues.length > 0) { 867 mValues[0].setEvaluator(value); 868 } 869 } 870 871 /** 872 * Start the animation playing. This version of start() takes a boolean flag that indicates 873 * whether the animation should play in reverse. The flag is usually false, but may be set 874 * to true if called from the reverse() method. 875 * 876 * <p>The animation started by calling this method will be run on the thread that called 877 * this method. This thread should have a Looper on it (a runtime exception will be thrown if 878 * this is not the case). Also, if the animation will animate 879 * properties of objects in the view hierarchy, then the calling thread should be the UI 880 * thread for that view hierarchy.</p> 881 * 882 * @param playBackwards Whether the ValueAnimator should start playing in reverse. 883 */ 884 private void start(boolean playBackwards) { 885 if (Looper.myLooper() == null) { 886 throw new AndroidRuntimeException("Animators may only be run on Looper threads"); 887 } 888 mPlayingBackwards = playBackwards; 889 mCurrentIteration = 0; 890 mPlayingState = STOPPED; 891 mStarted = true; 892 mStartedDelay = false; 893 AnimationHandler animationHandler = getOrCreateAnimationHandler(); 894 animationHandler.mPendingAnimations.add(this); 895 if (mStartDelay == 0) { 896 // This sets the initial value of the animation, prior to actually starting it running 897 setCurrentPlayTime(getCurrentPlayTime()); 898 mPlayingState = STOPPED; 899 mRunning = true; 900 901 if (mListeners != null) { 902 ArrayList<AnimatorListener> tmpListeners = 903 (ArrayList<AnimatorListener>) mListeners.clone(); 904 int numListeners = tmpListeners.size(); 905 for (int i = 0; i < numListeners; ++i) { 906 tmpListeners.get(i).onAnimationStart(this); 907 } 908 } 909 } 910 animationHandler.sendEmptyMessage(ANIMATION_START); 911 } 912 913 @Override 914 public void start() { 915 start(false); 916 } 917 918 @Override 919 public void cancel() { 920 // Only cancel if the animation is actually running or has been started and is about 921 // to run 922 AnimationHandler handler = getOrCreateAnimationHandler(); 923 if (mPlayingState != STOPPED 924 || handler.mPendingAnimations.contains(this) 925 || handler.mDelayedAnims.contains(this)) { 926 // Only notify listeners if the animator has actually started 927 if (mRunning && mListeners != null) { 928 ArrayList<AnimatorListener> tmpListeners = 929 (ArrayList<AnimatorListener>) mListeners.clone(); 930 for (AnimatorListener listener : tmpListeners) { 931 listener.onAnimationCancel(this); 932 } 933 } 934 endAnimation(handler); 935 } 936 } 937 938 @Override 939 public void end() { 940 AnimationHandler handler = getOrCreateAnimationHandler(); 941 if (!handler.mAnimations.contains(this) && !handler.mPendingAnimations.contains(this)) { 942 // Special case if the animation has not yet started; get it ready for ending 943 mStartedDelay = false; 944 startAnimation(handler); 945 } else if (!mInitialized) { 946 initAnimation(); 947 } 948 // The final value set on the target varies, depending on whether the animation 949 // was supposed to repeat an odd number of times 950 if (mRepeatCount > 0 && (mRepeatCount & 0x01) == 1) { 951 animateValue(0f); 952 } else { 953 animateValue(1f); 954 } 955 endAnimation(handler); 956 } 957 958 @Override 959 public boolean isRunning() { 960 return (mPlayingState == RUNNING || mRunning); 961 } 962 963 @Override 964 public boolean isStarted() { 965 return mStarted; 966 } 967 968 /** 969 * Plays the ValueAnimator in reverse. If the animation is already running, 970 * it will stop itself and play backwards from the point reached when reverse was called. 971 * If the animation is not currently running, then it will start from the end and 972 * play backwards. This behavior is only set for the current animation; future playing 973 * of the animation will use the default behavior of playing forward. 974 */ 975 public void reverse() { 976 mPlayingBackwards = !mPlayingBackwards; 977 if (mPlayingState == RUNNING) { 978 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 979 long currentPlayTime = currentTime - mStartTime; 980 long timeLeft = mDuration - currentPlayTime; 981 mStartTime = currentTime - timeLeft; 982 } else { 983 start(true); 984 } 985 } 986 987 /** 988 * Called internally to end an animation by removing it from the animations list. Must be 989 * called on the UI thread. 990 */ 991 private void endAnimation(AnimationHandler handler) { 992 handler.mAnimations.remove(this); 993 handler.mPendingAnimations.remove(this); 994 handler.mDelayedAnims.remove(this); 995 mPlayingState = STOPPED; 996 if (mRunning && mListeners != null) { 997 ArrayList<AnimatorListener> tmpListeners = 998 (ArrayList<AnimatorListener>) mListeners.clone(); 999 int numListeners = tmpListeners.size(); 1000 for (int i = 0; i < numListeners; ++i) { 1001 tmpListeners.get(i).onAnimationEnd(this); 1002 } 1003 } 1004 mRunning = false; 1005 mStarted = false; 1006 } 1007 1008 /** 1009 * Called internally to start an animation by adding it to the active animations list. Must be 1010 * called on the UI thread. 1011 */ 1012 private void startAnimation(AnimationHandler handler) { 1013 initAnimation(); 1014 handler.mAnimations.add(this); 1015 if (mStartDelay > 0 && mListeners != null) { 1016 // Listeners were already notified in start() if startDelay is 0; this is 1017 // just for delayed animations 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).onAnimationStart(this); 1023 } 1024 } 1025 } 1026 1027 /** 1028 * Internal function called to process an animation frame on an animation that is currently 1029 * sleeping through its <code>startDelay</code> phase. The return value indicates whether it 1030 * should be woken up and put on the active animations queue. 1031 * 1032 * @param currentTime The current animation time, used to calculate whether the animation 1033 * has exceeded its <code>startDelay</code> and should be started. 1034 * @return True if the animation's <code>startDelay</code> has been exceeded and the animation 1035 * should be added to the set of active animations. 1036 */ 1037 private boolean delayedAnimationFrame(long currentTime) { 1038 if (!mStartedDelay) { 1039 mStartedDelay = true; 1040 mDelayStartTime = currentTime; 1041 } else { 1042 long deltaTime = currentTime - mDelayStartTime; 1043 if (deltaTime > mStartDelay) { 1044 // startDelay ended - start the anim and record the 1045 // mStartTime appropriately 1046 mStartTime = currentTime - (deltaTime - mStartDelay); 1047 mPlayingState = RUNNING; 1048 return true; 1049 } 1050 } 1051 return false; 1052 } 1053 1054 /** 1055 * This internal function processes a single animation frame for a given animation. The 1056 * currentTime parameter is the timing pulse sent by the handler, used to calculate the 1057 * elapsed duration, and therefore 1058 * the elapsed fraction, of the animation. The return value indicates whether the animation 1059 * should be ended (which happens when the elapsed time of the animation exceeds the 1060 * animation's duration, including the repeatCount). 1061 * 1062 * @param currentTime The current time, as tracked by the static timing handler 1063 * @return true if the animation's duration, including any repetitions due to 1064 * <code>repeatCount</code> has been exceeded and the animation should be ended. 1065 */ 1066 boolean animationFrame(long currentTime) { 1067 boolean done = false; 1068 1069 if (mPlayingState == STOPPED) { 1070 mPlayingState = RUNNING; 1071 if (mSeekTime < 0) { 1072 mStartTime = currentTime; 1073 } else { 1074 mStartTime = currentTime - mSeekTime; 1075 // Now that we're playing, reset the seek time 1076 mSeekTime = -1; 1077 } 1078 } 1079 switch (mPlayingState) { 1080 case RUNNING: 1081 case SEEKED: 1082 float fraction = mDuration > 0 ? (float)(currentTime - mStartTime) / mDuration : 1f; 1083 if (fraction >= 1f) { 1084 if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { 1085 // Time to repeat 1086 if (mListeners != null) { 1087 int numListeners = mListeners.size(); 1088 for (int i = 0; i < numListeners; ++i) { 1089 mListeners.get(i).onAnimationRepeat(this); 1090 } 1091 } 1092 if (mRepeatMode == REVERSE) { 1093 mPlayingBackwards = mPlayingBackwards ? false : true; 1094 } 1095 mCurrentIteration += (int)fraction; 1096 fraction = fraction % 1f; 1097 mStartTime += mDuration; 1098 } else { 1099 done = true; 1100 fraction = Math.min(fraction, 1.0f); 1101 } 1102 } 1103 if (mPlayingBackwards) { 1104 fraction = 1f - fraction; 1105 } 1106 animateValue(fraction); 1107 break; 1108 } 1109 1110 return done; 1111 } 1112 1113 /** 1114 * Returns the current animation fraction, which is the elapsed/interpolated fraction used in 1115 * the most recent frame update on the animation. 1116 * 1117 * @return Elapsed/interpolated fraction of the animation. 1118 */ 1119 public float getAnimatedFraction() { 1120 return mCurrentFraction; 1121 } 1122 1123 /** 1124 * This method is called with the elapsed fraction of the animation during every 1125 * animation frame. This function turns the elapsed fraction into an interpolated fraction 1126 * and then into an animated value (from the evaluator. The function is called mostly during 1127 * animation updates, but it is also called when the <code>end()</code> 1128 * function is called, to set the final value on the property. 1129 * 1130 * <p>Overrides of this method must call the superclass to perform the calculation 1131 * of the animated value.</p> 1132 * 1133 * @param fraction The elapsed fraction of the animation. 1134 */ 1135 void animateValue(float fraction) { 1136 fraction = mInterpolator.getInterpolation(fraction); 1137 mCurrentFraction = fraction; 1138 int numValues = mValues.length; 1139 for (int i = 0; i < numValues; ++i) { 1140 mValues[i].calculateValue(fraction); 1141 } 1142 if (mUpdateListeners != null) { 1143 int numListeners = mUpdateListeners.size(); 1144 for (int i = 0; i < numListeners; ++i) { 1145 mUpdateListeners.get(i).onAnimationUpdate(this); 1146 } 1147 } 1148 } 1149 1150 @Override 1151 public ValueAnimator clone() { 1152 final ValueAnimator anim = (ValueAnimator) super.clone(); 1153 if (mUpdateListeners != null) { 1154 ArrayList<AnimatorUpdateListener> oldListeners = mUpdateListeners; 1155 anim.mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 1156 int numListeners = oldListeners.size(); 1157 for (int i = 0; i < numListeners; ++i) { 1158 anim.mUpdateListeners.add(oldListeners.get(i)); 1159 } 1160 } 1161 anim.mSeekTime = -1; 1162 anim.mPlayingBackwards = false; 1163 anim.mCurrentIteration = 0; 1164 anim.mInitialized = false; 1165 anim.mPlayingState = STOPPED; 1166 anim.mStartedDelay = false; 1167 PropertyValuesHolder[] oldValues = mValues; 1168 if (oldValues != null) { 1169 int numValues = oldValues.length; 1170 anim.mValues = new PropertyValuesHolder[numValues]; 1171 anim.mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 1172 for (int i = 0; i < numValues; ++i) { 1173 PropertyValuesHolder newValuesHolder = oldValues[i].clone(); 1174 anim.mValues[i] = newValuesHolder; 1175 anim.mValuesMap.put(newValuesHolder.getPropertyName(), newValuesHolder); 1176 } 1177 } 1178 return anim; 1179 } 1180 1181 /** 1182 * Implementors of this interface can add themselves as update listeners 1183 * to an <code>ValueAnimator</code> instance to receive callbacks on every animation 1184 * frame, after the current frame's values have been calculated for that 1185 * <code>ValueAnimator</code>. 1186 */ 1187 public static interface AnimatorUpdateListener { 1188 /** 1189 * <p>Notifies the occurrence of another frame of the animation.</p> 1190 * 1191 * @param animation The animation which was repeated. 1192 */ 1193 void onAnimationUpdate(ValueAnimator animation); 1194 1195 } 1196 1197 /** 1198 * Return the number of animations currently running. 1199 * 1200 * Used by StrictMode internally to annotate violations. 1201 * May be called on arbitrary threads! 1202 * 1203 * @hide 1204 */ 1205 public static int getCurrentAnimationsCount() { 1206 AnimationHandler handler = sAnimationHandler.get(); 1207 return handler != null ? handler.mAnimations.size() : 0; 1208 } 1209 1210 /** 1211 * Clear all animations on this thread, without canceling or ending them. 1212 * This should be used with caution. 1213 * 1214 * @hide 1215 */ 1216 public static void clearAllAnimations() { 1217 AnimationHandler handler = sAnimationHandler.get(); 1218 if (handler != null) { 1219 handler.mAnimations.clear(); 1220 handler.mPendingAnimations.clear(); 1221 handler.mDelayedAnims.clear(); 1222 } 1223 } 1224 1225 private AnimationHandler getOrCreateAnimationHandler() { 1226 AnimationHandler handler = sAnimationHandler.get(); 1227 if (handler == null) { 1228 handler = new AnimationHandler(); 1229 sAnimationHandler.set(handler); 1230 } 1231 return handler; 1232 } 1233 1234 @Override 1235 public String toString() { 1236 String returnVal = "ValueAnimator@" + Integer.toHexString(hashCode()); 1237 if (mValues != null) { 1238 for (int i = 0; i < mValues.length; ++i) { 1239 returnVal += "\n " + mValues[i].toString(); 1240 } 1241 } 1242 return returnVal; 1243 } 1244} 1245