ValueAnimator.java revision 17cf42cb85c22b50ecfa8d21efc992f99d20fc45
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 * Tracks whether we've notified listeners of the onAnimationSTart() event. This can be 154 * complex to keep track of since we notify listeners at different times depending on 155 * startDelay and whether start() was called before end(). 156 */ 157 private boolean mStartListenersCalled = false; 158 159 /** 160 * Flag that denotes whether the animation is set up and ready to go. Used to 161 * set up animation that has not yet been started. 162 */ 163 boolean mInitialized = false; 164 165 // 166 // Backing variables 167 // 168 169 // How long the animation should last in ms 170 private long mDuration = (long)(300 * sDurationScale); 171 private long mUnscaledDuration = 300; 172 173 // The amount of time in ms to delay starting the animation after start() is called 174 private long mStartDelay = 0; 175 private long mUnscaledStartDelay = 0; 176 177 // The number of times the animation will repeat. The default is 0, which means the animation 178 // will play only once 179 private int mRepeatCount = 0; 180 181 /** 182 * The type of repetition that will occur when repeatMode is nonzero. RESTART means the 183 * animation will start from the beginning on every new cycle. REVERSE means the animation 184 * will reverse directions on each iteration. 185 */ 186 private int mRepeatMode = RESTART; 187 188 /** 189 * The time interpolator to be used. The elapsed fraction of the animation will be passed 190 * through this interpolator to calculate the interpolated fraction, which is then used to 191 * calculate the animated values. 192 */ 193 private TimeInterpolator mInterpolator = sDefaultInterpolator; 194 195 /** 196 * The set of listeners to be sent events through the life of an animation. 197 */ 198 private ArrayList<AnimatorUpdateListener> mUpdateListeners = null; 199 200 /** 201 * The property/value sets being animated. 202 */ 203 PropertyValuesHolder[] mValues; 204 205 /** 206 * A hashmap of the PropertyValuesHolder objects. This map is used to lookup animated values 207 * by property name during calls to getAnimatedValue(String). 208 */ 209 HashMap<String, PropertyValuesHolder> mValuesMap; 210 211 /** 212 * Public constants 213 */ 214 215 /** 216 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 217 * or a positive value, the animation restarts from the beginning. 218 */ 219 public static final int RESTART = 1; 220 /** 221 * When the animation reaches the end and <code>repeatCount</code> is INFINITE 222 * or a positive value, the animation reverses direction on every iteration. 223 */ 224 public static final int REVERSE = 2; 225 /** 226 * This value used used with the {@link #setRepeatCount(int)} property to repeat 227 * the animation indefinitely. 228 */ 229 public static final int INFINITE = -1; 230 231 232 /** 233 * @hide 234 */ 235 public static void setDurationScale(float durationScale) { 236 sDurationScale = durationScale; 237 } 238 239 /** 240 * Creates a new ValueAnimator object. This default constructor is primarily for 241 * use internally; the factory methods which take parameters are more generally 242 * useful. 243 */ 244 public ValueAnimator() { 245 } 246 247 /** 248 * Constructs and returns a ValueAnimator that animates between int values. A single 249 * value implies that that value is the one being animated to. However, this is not typically 250 * useful in a ValueAnimator object because there is no way for the object to determine the 251 * starting value for the animation (unlike ObjectAnimator, which can derive that value 252 * from the target object and property being animated). Therefore, there should typically 253 * be two or more values. 254 * 255 * @param values A set of values that the animation will animate between over time. 256 * @return A ValueAnimator object that is set up to animate between the given values. 257 */ 258 public static ValueAnimator ofInt(int... values) { 259 ValueAnimator anim = new ValueAnimator(); 260 anim.setIntValues(values); 261 return anim; 262 } 263 264 /** 265 * Constructs and returns a ValueAnimator that animates between float values. A single 266 * value implies that that value is the one being animated to. However, this is not typically 267 * useful in a ValueAnimator object because there is no way for the object to determine the 268 * starting value for the animation (unlike ObjectAnimator, which can derive that value 269 * from the target object and property being animated). Therefore, there should typically 270 * be two or more values. 271 * 272 * @param values A set of values that the animation will animate between over time. 273 * @return A ValueAnimator object that is set up to animate between the given values. 274 */ 275 public static ValueAnimator ofFloat(float... values) { 276 ValueAnimator anim = new ValueAnimator(); 277 anim.setFloatValues(values); 278 return anim; 279 } 280 281 /** 282 * Constructs and returns a ValueAnimator that animates between the values 283 * specified in the PropertyValuesHolder objects. 284 * 285 * @param values A set of PropertyValuesHolder objects whose values will be animated 286 * between over time. 287 * @return A ValueAnimator object that is set up to animate between the given values. 288 */ 289 public static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values) { 290 ValueAnimator anim = new ValueAnimator(); 291 anim.setValues(values); 292 return anim; 293 } 294 /** 295 * Constructs and returns a ValueAnimator that animates between Object values. A single 296 * value implies that that value is the one being animated to. However, this is not typically 297 * useful in a ValueAnimator object because there is no way for the object to determine the 298 * starting value for the animation (unlike ObjectAnimator, which can derive that value 299 * from the target object and property being animated). Therefore, there should typically 300 * be two or more values. 301 * 302 * <p>Since ValueAnimator does not know how to animate between arbitrary Objects, this 303 * factory method also takes a TypeEvaluator object that the ValueAnimator will use 304 * to perform that interpolation. 305 * 306 * @param evaluator A TypeEvaluator that will be called on each animation frame to 307 * provide the ncessry interpolation between the Object values to derive the animated 308 * value. 309 * @param values A set of values that the animation will animate between over time. 310 * @return A ValueAnimator object that is set up to animate between the given values. 311 */ 312 public static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values) { 313 ValueAnimator anim = new ValueAnimator(); 314 anim.setObjectValues(values); 315 anim.setEvaluator(evaluator); 316 return anim; 317 } 318 319 /** 320 * Sets int values that will be animated between. A single 321 * value implies that that value is the one being animated to. However, this is not typically 322 * useful in a ValueAnimator object because there is no way for the object to determine the 323 * starting value for the animation (unlike ObjectAnimator, which can derive that value 324 * from the target object and property being animated). Therefore, there should typically 325 * be two or more values. 326 * 327 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 328 * than one PropertyValuesHolder object, this method will set the values for the first 329 * of those objects.</p> 330 * 331 * @param values A set of values that the animation will animate between over time. 332 */ 333 public void setIntValues(int... values) { 334 if (values == null || values.length == 0) { 335 return; 336 } 337 if (mValues == null || mValues.length == 0) { 338 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofInt("", values)}); 339 } else { 340 PropertyValuesHolder valuesHolder = mValues[0]; 341 valuesHolder.setIntValues(values); 342 } 343 // New property/values/target should cause re-initialization prior to starting 344 mInitialized = false; 345 } 346 347 /** 348 * Sets float values that will be animated between. A single 349 * value implies that that value is the one being animated to. However, this is not typically 350 * useful in a ValueAnimator object because there is no way for the object to determine the 351 * starting value for the animation (unlike ObjectAnimator, which can derive that value 352 * from the target object and property being animated). Therefore, there should typically 353 * be two or more values. 354 * 355 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 356 * than one PropertyValuesHolder object, this method will set the values for the first 357 * of those objects.</p> 358 * 359 * @param values A set of values that the animation will animate between over time. 360 */ 361 public void setFloatValues(float... values) { 362 if (values == null || values.length == 0) { 363 return; 364 } 365 if (mValues == null || mValues.length == 0) { 366 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofFloat("", values)}); 367 } else { 368 PropertyValuesHolder valuesHolder = mValues[0]; 369 valuesHolder.setFloatValues(values); 370 } 371 // New property/values/target should cause re-initialization prior to starting 372 mInitialized = false; 373 } 374 375 /** 376 * Sets the values to animate between for this animation. A single 377 * value implies that that value is the one being animated to. However, this is not typically 378 * useful in a ValueAnimator object because there is no way for the object to determine the 379 * starting value for the animation (unlike ObjectAnimator, which can derive that value 380 * from the target object and property being animated). Therefore, there should typically 381 * be two or more values. 382 * 383 * <p>If there are already multiple sets of values defined for this ValueAnimator via more 384 * than one PropertyValuesHolder object, this method will set the values for the first 385 * of those objects.</p> 386 * 387 * <p>There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate 388 * between these value objects. ValueAnimator only knows how to interpolate between the 389 * primitive types specified in the other setValues() methods.</p> 390 * 391 * @param values The set of values to animate between. 392 */ 393 public void setObjectValues(Object... values) { 394 if (values == null || values.length == 0) { 395 return; 396 } 397 if (mValues == null || mValues.length == 0) { 398 setValues(new PropertyValuesHolder[]{PropertyValuesHolder.ofObject("", 399 (TypeEvaluator)null, values)}); 400 } else { 401 PropertyValuesHolder valuesHolder = mValues[0]; 402 valuesHolder.setObjectValues(values); 403 } 404 // New property/values/target should cause re-initialization prior to starting 405 mInitialized = false; 406 } 407 408 /** 409 * Sets the values, per property, being animated between. This function is called internally 410 * by the constructors of ValueAnimator that take a list of values. But a ValueAnimator can 411 * be constructed without values and this method can be called to set the values manually 412 * instead. 413 * 414 * @param values The set of values, per property, being animated between. 415 */ 416 public void setValues(PropertyValuesHolder... values) { 417 int numValues = values.length; 418 mValues = values; 419 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 420 for (int i = 0; i < numValues; ++i) { 421 PropertyValuesHolder valuesHolder = (PropertyValuesHolder) values[i]; 422 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder); 423 } 424 // New property/values/target should cause re-initialization prior to starting 425 mInitialized = false; 426 } 427 428 /** 429 * Returns the values that this ValueAnimator animates between. These values are stored in 430 * PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list 431 * of value objects instead. 432 * 433 * @return PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the 434 * values, per property, that define the animation. 435 */ 436 public PropertyValuesHolder[] getValues() { 437 return mValues; 438 } 439 440 /** 441 * This function is called immediately before processing the first animation 442 * frame of an animation. If there is a nonzero <code>startDelay</code>, the 443 * function is called after that delay ends. 444 * It takes care of the final initialization steps for the 445 * animation. 446 * 447 * <p>Overrides of this method should call the superclass method to ensure 448 * that internal mechanisms for the animation are set up correctly.</p> 449 */ 450 void initAnimation() { 451 if (!mInitialized) { 452 int numValues = mValues.length; 453 for (int i = 0; i < numValues; ++i) { 454 mValues[i].init(); 455 } 456 mInitialized = true; 457 } 458 } 459 460 461 /** 462 * Sets the length of the animation. The default duration is 300 milliseconds. 463 * 464 * @param duration The length of the animation, in milliseconds. This value cannot 465 * be negative. 466 * @return ValueAnimator The object called with setDuration(). This return 467 * value makes it easier to compose statements together that construct and then set the 468 * duration, as in <code>ValueAnimator.ofInt(0, 10).setDuration(500).start()</code>. 469 */ 470 public ValueAnimator setDuration(long duration) { 471 if (duration < 0) { 472 throw new IllegalArgumentException("Animators cannot have negative duration: " + 473 duration); 474 } 475 mUnscaledDuration = duration; 476 mDuration = (long)(duration * sDurationScale); 477 return this; 478 } 479 480 /** 481 * Gets the length of the animation. The default duration is 300 milliseconds. 482 * 483 * @return The length of the animation, in milliseconds. 484 */ 485 public long getDuration() { 486 return mUnscaledDuration; 487 } 488 489 /** 490 * Sets the position of the animation to the specified point in time. This time should 491 * be between 0 and the total duration of the animation, including any repetition. If 492 * the animation has not yet been started, then it will not advance forward after it is 493 * set to this time; it will simply set the time to this value and perform any appropriate 494 * actions based on that time. If the animation is already running, then setCurrentPlayTime() 495 * will set the current playing time to this value and continue playing from that point. 496 * 497 * @param playTime The time, in milliseconds, to which the animation is advanced or rewound. 498 */ 499 public void setCurrentPlayTime(long playTime) { 500 initAnimation(); 501 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 502 if (mPlayingState != RUNNING) { 503 mSeekTime = playTime; 504 mPlayingState = SEEKED; 505 } 506 mStartTime = currentTime - playTime; 507 animationFrame(currentTime); 508 } 509 510 /** 511 * Gets the current position of the animation in time, which is equal to the current 512 * time minus the time that the animation started. An animation that is not yet started will 513 * return a value of zero. 514 * 515 * @return The current position in time of the animation. 516 */ 517 public long getCurrentPlayTime() { 518 if (!mInitialized || mPlayingState == STOPPED) { 519 return 0; 520 } 521 return AnimationUtils.currentAnimationTimeMillis() - mStartTime; 522 } 523 524 /** 525 * This custom, static handler handles the timing pulse that is shared by 526 * all active animations. This approach ensures that the setting of animation 527 * values will happen on the UI thread and that all animations will share 528 * the same times for calculating their values, which makes synchronizing 529 * animations possible. 530 * 531 */ 532 private static class AnimationHandler extends Handler implements Runnable { 533 // The per-thread list of all active animations 534 private final ArrayList<ValueAnimator> mAnimations = new ArrayList<ValueAnimator>(); 535 536 // The per-thread set of animations to be started on the next animation frame 537 private final ArrayList<ValueAnimator> mPendingAnimations = new ArrayList<ValueAnimator>(); 538 539 /** 540 * Internal per-thread collections used to avoid set collisions as animations start and end 541 * while being processed. 542 */ 543 private final ArrayList<ValueAnimator> mDelayedAnims = new ArrayList<ValueAnimator>(); 544 private final ArrayList<ValueAnimator> mEndingAnims = new ArrayList<ValueAnimator>(); 545 private final ArrayList<ValueAnimator> mReadyAnims = new ArrayList<ValueAnimator>(); 546 547 private final Choreographer mChoreographer; 548 private boolean mAnimationScheduled; 549 550 private AnimationHandler() { 551 mChoreographer = Choreographer.getInstance(); 552 } 553 554 /** 555 * The START message is sent when an animation's start() method is called. 556 * It cannot start synchronously when start() is called 557 * because the call may be on the wrong thread, and it would also not be 558 * synchronized with other animations because it would not start on a common 559 * timing pulse. So each animation sends a START message to the handler, which 560 * causes the handler to place the animation on the active animations queue and 561 * start processing frames for that animation. 562 */ 563 @Override 564 public void handleMessage(Message msg) { 565 switch (msg.what) { 566 case ANIMATION_START: 567 // If there are already active animations, or if another ANIMATION_START 568 // message was processed during this frame, then the pending list may already 569 // have been cleared. If that's the case, we've already processed the 570 // active animations for this frame - don't do it again. 571 if (mPendingAnimations.size() > 0) { 572 doAnimationFrame(); 573 } 574 break; 575 } 576 } 577 578 private void doAnimationFrame() { 579 // currentTime holds the common time for all animations processed 580 // during this frame 581 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 582 583 // mPendingAnimations holds any animations that have requested to be started 584 // We're going to clear mPendingAnimations, but starting animation may 585 // cause more to be added to the pending list (for example, if one animation 586 // starting triggers another starting). So we loop until mPendingAnimations 587 // is empty. 588 while (mPendingAnimations.size() > 0) { 589 ArrayList<ValueAnimator> pendingCopy = 590 (ArrayList<ValueAnimator>) mPendingAnimations.clone(); 591 mPendingAnimations.clear(); 592 int count = pendingCopy.size(); 593 for (int i = 0; i < count; ++i) { 594 ValueAnimator anim = pendingCopy.get(i); 595 // If the animation has a startDelay, place it on the delayed list 596 if (anim.mStartDelay == 0) { 597 anim.startAnimation(this); 598 } else { 599 mDelayedAnims.add(anim); 600 } 601 } 602 } 603 // Next, process animations currently sitting on the delayed queue, adding 604 // them to the active animations if they are ready 605 int numDelayedAnims = mDelayedAnims.size(); 606 for (int i = 0; i < numDelayedAnims; ++i) { 607 ValueAnimator anim = mDelayedAnims.get(i); 608 if (anim.delayedAnimationFrame(currentTime)) { 609 mReadyAnims.add(anim); 610 } 611 } 612 int numReadyAnims = mReadyAnims.size(); 613 if (numReadyAnims > 0) { 614 for (int i = 0; i < numReadyAnims; ++i) { 615 ValueAnimator anim = mReadyAnims.get(i); 616 anim.startAnimation(this); 617 anim.mRunning = true; 618 mDelayedAnims.remove(anim); 619 } 620 mReadyAnims.clear(); 621 } 622 623 // Now process all active animations. The return value from animationFrame() 624 // tells the handler whether it should now be ended 625 int numAnims = mAnimations.size(); 626 int i = 0; 627 while (i < numAnims) { 628 ValueAnimator anim = mAnimations.get(i); 629 if (anim.animationFrame(currentTime)) { 630 mEndingAnims.add(anim); 631 } 632 if (mAnimations.size() == numAnims) { 633 ++i; 634 } else { 635 // An animation might be canceled or ended by client code 636 // during the animation frame. Check to see if this happened by 637 // seeing whether the current index is the same as it was before 638 // calling animationFrame(). Another approach would be to copy 639 // animations to a temporary list and process that list instead, 640 // but that entails garbage and processing overhead that would 641 // be nice to avoid. 642 --numAnims; 643 mEndingAnims.remove(anim); 644 } 645 } 646 if (mEndingAnims.size() > 0) { 647 for (i = 0; i < mEndingAnims.size(); ++i) { 648 mEndingAnims.get(i).endAnimation(this); 649 } 650 mEndingAnims.clear(); 651 } 652 653 // If there are still active or delayed animations, schedule a future call to 654 // onAnimate to process the next frame of the animations. 655 if (!mAnimationScheduled 656 && (!mAnimations.isEmpty() || !mDelayedAnims.isEmpty())) { 657 mChoreographer.postCallback(Choreographer.CALLBACK_ANIMATION, this, null); 658 mAnimationScheduled = true; 659 } 660 } 661 662 // Called by the Choreographer. 663 @Override 664 public void run() { 665 mAnimationScheduled = false; 666 doAnimationFrame(); 667 } 668 } 669 670 /** 671 * The amount of time, in milliseconds, to delay starting the animation after 672 * {@link #start()} is called. 673 * 674 * @return the number of milliseconds to delay running the animation 675 */ 676 public long getStartDelay() { 677 return mUnscaledStartDelay; 678 } 679 680 /** 681 * The amount of time, in milliseconds, to delay starting the animation after 682 * {@link #start()} is called. 683 684 * @param startDelay The amount of the delay, in milliseconds 685 */ 686 public void setStartDelay(long startDelay) { 687 this.mStartDelay = (long)(startDelay * sDurationScale); 688 mUnscaledStartDelay = startDelay; 689 } 690 691 /** 692 * The amount of time, in milliseconds, between each frame of the animation. This is a 693 * requested time that the animation will attempt to honor, but the actual delay between 694 * frames may be different, depending on system load and capabilities. This is a static 695 * function because the same delay will be applied to all animations, since they are all 696 * run off of a single timing loop. 697 * 698 * The frame delay may be ignored when the animation system uses an external timing 699 * source, such as the display refresh rate (vsync), to govern animations. 700 * 701 * @return the requested time between frames, in milliseconds 702 */ 703 public static long getFrameDelay() { 704 return Choreographer.getFrameDelay(); 705 } 706 707 /** 708 * The amount of time, in milliseconds, between each frame of the animation. This is a 709 * requested time that the animation will attempt to honor, but the actual delay between 710 * frames may be different, depending on system load and capabilities. This is a static 711 * function because the same delay will be applied to all animations, since they are all 712 * run off of a single timing loop. 713 * 714 * The frame delay may be ignored when the animation system uses an external timing 715 * source, such as the display refresh rate (vsync), to govern animations. 716 * 717 * @param frameDelay the requested time between frames, in milliseconds 718 */ 719 public static void setFrameDelay(long frameDelay) { 720 Choreographer.setFrameDelay(frameDelay); 721 } 722 723 /** 724 * The most recent value calculated by this <code>ValueAnimator</code> when there is just one 725 * property being animated. This value is only sensible while the animation is running. The main 726 * purpose for this read-only property is to retrieve the value from the <code>ValueAnimator</code> 727 * during a call to {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 728 * is called during each animation frame, immediately after the value is calculated. 729 * 730 * @return animatedValue The value most recently calculated by this <code>ValueAnimator</code> for 731 * the single property being animated. If there are several properties being animated 732 * (specified by several PropertyValuesHolder objects in the constructor), this function 733 * returns the animated value for the first of those objects. 734 */ 735 public Object getAnimatedValue() { 736 if (mValues != null && mValues.length > 0) { 737 return mValues[0].getAnimatedValue(); 738 } 739 // Shouldn't get here; should always have values unless ValueAnimator was set up wrong 740 return null; 741 } 742 743 /** 744 * The most recent value calculated by this <code>ValueAnimator</code> for <code>propertyName</code>. 745 * The main purpose for this read-only property is to retrieve the value from the 746 * <code>ValueAnimator</code> during a call to 747 * {@link AnimatorUpdateListener#onAnimationUpdate(ValueAnimator)}, which 748 * is called during each animation frame, immediately after the value is calculated. 749 * 750 * @return animatedValue The value most recently calculated for the named property 751 * by this <code>ValueAnimator</code>. 752 */ 753 public Object getAnimatedValue(String propertyName) { 754 PropertyValuesHolder valuesHolder = mValuesMap.get(propertyName); 755 if (valuesHolder != null) { 756 return valuesHolder.getAnimatedValue(); 757 } else { 758 // At least avoid crashing if called with bogus propertyName 759 return null; 760 } 761 } 762 763 /** 764 * Sets how many times the animation should be repeated. If the repeat 765 * count is 0, the animation is never repeated. If the repeat count is 766 * greater than 0 or {@link #INFINITE}, the repeat mode will be taken 767 * into account. The repeat count is 0 by default. 768 * 769 * @param value the number of times the animation should be repeated 770 */ 771 public void setRepeatCount(int value) { 772 mRepeatCount = value; 773 } 774 /** 775 * Defines how many times the animation should repeat. The default value 776 * is 0. 777 * 778 * @return the number of times the animation should repeat, or {@link #INFINITE} 779 */ 780 public int getRepeatCount() { 781 return mRepeatCount; 782 } 783 784 /** 785 * Defines what this animation should do when it reaches the end. This 786 * setting is applied only when the repeat count is either greater than 787 * 0 or {@link #INFINITE}. Defaults to {@link #RESTART}. 788 * 789 * @param value {@link #RESTART} or {@link #REVERSE} 790 */ 791 public void setRepeatMode(int value) { 792 mRepeatMode = value; 793 } 794 795 /** 796 * Defines what this animation should do when it reaches the end. 797 * 798 * @return either one of {@link #REVERSE} or {@link #RESTART} 799 */ 800 public int getRepeatMode() { 801 return mRepeatMode; 802 } 803 804 /** 805 * Adds a listener to the set of listeners that are sent update events through the life of 806 * an animation. This method is called on all listeners for every frame of the animation, 807 * after the values for the animation have been calculated. 808 * 809 * @param listener the listener to be added to the current set of listeners for this animation. 810 */ 811 public void addUpdateListener(AnimatorUpdateListener listener) { 812 if (mUpdateListeners == null) { 813 mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 814 } 815 mUpdateListeners.add(listener); 816 } 817 818 /** 819 * Removes all listeners from the set listening to frame updates for this animation. 820 */ 821 public void removeAllUpdateListeners() { 822 if (mUpdateListeners == null) { 823 return; 824 } 825 mUpdateListeners.clear(); 826 mUpdateListeners = null; 827 } 828 829 /** 830 * Removes a listener from the set listening to frame updates for this animation. 831 * 832 * @param listener the listener to be removed from the current set of update listeners 833 * for this animation. 834 */ 835 public void removeUpdateListener(AnimatorUpdateListener listener) { 836 if (mUpdateListeners == null) { 837 return; 838 } 839 mUpdateListeners.remove(listener); 840 if (mUpdateListeners.size() == 0) { 841 mUpdateListeners = null; 842 } 843 } 844 845 846 /** 847 * The time interpolator used in calculating the elapsed fraction of this animation. The 848 * interpolator determines whether the animation runs with linear or non-linear motion, 849 * such as acceleration and deceleration. The default value is 850 * {@link android.view.animation.AccelerateDecelerateInterpolator} 851 * 852 * @param value the interpolator to be used by this animation. A value of <code>null</code> 853 * will result in linear interpolation. 854 */ 855 @Override 856 public void setInterpolator(TimeInterpolator value) { 857 if (value != null) { 858 mInterpolator = value; 859 } else { 860 mInterpolator = new LinearInterpolator(); 861 } 862 } 863 864 /** 865 * Returns the timing interpolator that this ValueAnimator uses. 866 * 867 * @return The timing interpolator for this ValueAnimator. 868 */ 869 public TimeInterpolator getInterpolator() { 870 return mInterpolator; 871 } 872 873 /** 874 * The type evaluator to be used when calculating the animated values of this animation. 875 * The system will automatically assign a float or int evaluator based on the type 876 * of <code>startValue</code> and <code>endValue</code> in the constructor. But if these values 877 * are not one of these primitive types, or if different evaluation is desired (such as is 878 * necessary with int values that represent colors), a custom evaluator needs to be assigned. 879 * For example, when running an animation on color values, the {@link ArgbEvaluator} 880 * should be used to get correct RGB color interpolation. 881 * 882 * <p>If this ValueAnimator has only one set of values being animated between, this evaluator 883 * will be used for that set. If there are several sets of values being animated, which is 884 * the case if PropertyValuesHOlder objects were set on the ValueAnimator, then the evaluator 885 * is assigned just to the first PropertyValuesHolder object.</p> 886 * 887 * @param value the evaluator to be used this animation 888 */ 889 public void setEvaluator(TypeEvaluator value) { 890 if (value != null && mValues != null && mValues.length > 0) { 891 mValues[0].setEvaluator(value); 892 } 893 } 894 895 private void notifyStartListeners() { 896 if (mListeners != null && !mStartListenersCalled) { 897 ArrayList<AnimatorListener> tmpListeners = 898 (ArrayList<AnimatorListener>) mListeners.clone(); 899 int numListeners = tmpListeners.size(); 900 for (int i = 0; i < numListeners; ++i) { 901 tmpListeners.get(i).onAnimationStart(this); 902 } 903 } 904 mStartListenersCalled = true; 905 } 906 907 /** 908 * Start the animation playing. This version of start() takes a boolean flag that indicates 909 * whether the animation should play in reverse. The flag is usually false, but may be set 910 * to true if called from the reverse() method. 911 * 912 * <p>The animation started by calling this method will be run on the thread that called 913 * this method. This thread should have a Looper on it (a runtime exception will be thrown if 914 * this is not the case). Also, if the animation will animate 915 * properties of objects in the view hierarchy, then the calling thread should be the UI 916 * thread for that view hierarchy.</p> 917 * 918 * @param playBackwards Whether the ValueAnimator should start playing in reverse. 919 */ 920 private void start(boolean playBackwards) { 921 if (Looper.myLooper() == null) { 922 throw new AndroidRuntimeException("Animators may only be run on Looper threads"); 923 } 924 mPlayingBackwards = playBackwards; 925 mCurrentIteration = 0; 926 mPlayingState = STOPPED; 927 mStarted = true; 928 mStartedDelay = false; 929 AnimationHandler animationHandler = getOrCreateAnimationHandler(); 930 animationHandler.mPendingAnimations.add(this); 931 if (mStartDelay == 0) { 932 // This sets the initial value of the animation, prior to actually starting it running 933 setCurrentPlayTime(getCurrentPlayTime()); 934 mPlayingState = STOPPED; 935 mRunning = true; 936 notifyStartListeners(); 937 } 938 animationHandler.sendEmptyMessage(ANIMATION_START); 939 } 940 941 @Override 942 public void start() { 943 start(false); 944 } 945 946 @Override 947 public void cancel() { 948 // Only cancel if the animation is actually running or has been started and is about 949 // to run 950 AnimationHandler handler = getOrCreateAnimationHandler(); 951 if (mPlayingState != STOPPED 952 || handler.mPendingAnimations.contains(this) 953 || handler.mDelayedAnims.contains(this)) { 954 // Only notify listeners if the animator has actually started 955 if ((mStarted || mRunning) && mListeners != null) { 956 if (!mRunning) { 957 // If it's not yet running, then start listeners weren't called. Call them now. 958 notifyStartListeners(); 959 } 960 ArrayList<AnimatorListener> tmpListeners = 961 (ArrayList<AnimatorListener>) mListeners.clone(); 962 for (AnimatorListener listener : tmpListeners) { 963 listener.onAnimationCancel(this); 964 } 965 } 966 endAnimation(handler); 967 } 968 } 969 970 @Override 971 public void end() { 972 AnimationHandler handler = getOrCreateAnimationHandler(); 973 if (!handler.mAnimations.contains(this) && !handler.mPendingAnimations.contains(this)) { 974 // Special case if the animation has not yet started; get it ready for ending 975 mStartedDelay = false; 976 startAnimation(handler); 977 mStarted = true; 978 } else if (!mInitialized) { 979 initAnimation(); 980 } 981 // The final value set on the target varies, depending on whether the animation 982 // was supposed to repeat an odd number of times 983 if (mRepeatCount > 0 && (mRepeatCount & 0x01) == 1) { 984 animateValue(0f); 985 } else { 986 animateValue(1f); 987 } 988 endAnimation(handler); 989 } 990 991 @Override 992 public boolean isRunning() { 993 return (mPlayingState == RUNNING || mRunning); 994 } 995 996 @Override 997 public boolean isStarted() { 998 return mStarted; 999 } 1000 1001 /** 1002 * Plays the ValueAnimator in reverse. If the animation is already running, 1003 * it will stop itself and play backwards from the point reached when reverse was called. 1004 * If the animation is not currently running, then it will start from the end and 1005 * play backwards. This behavior is only set for the current animation; future playing 1006 * of the animation will use the default behavior of playing forward. 1007 */ 1008 public void reverse() { 1009 mPlayingBackwards = !mPlayingBackwards; 1010 if (mPlayingState == RUNNING) { 1011 long currentTime = AnimationUtils.currentAnimationTimeMillis(); 1012 long currentPlayTime = currentTime - mStartTime; 1013 long timeLeft = mDuration - currentPlayTime; 1014 mStartTime = currentTime - timeLeft; 1015 } else { 1016 start(true); 1017 } 1018 } 1019 1020 /** 1021 * Called internally to end an animation by removing it from the animations list. Must be 1022 * called on the UI thread. 1023 */ 1024 private void endAnimation(AnimationHandler handler) { 1025 handler.mAnimations.remove(this); 1026 handler.mPendingAnimations.remove(this); 1027 handler.mDelayedAnims.remove(this); 1028 mPlayingState = STOPPED; 1029 if ((mStarted || mRunning) && mListeners != null) { 1030 if (!mRunning) { 1031 // If it's not yet running, then start listeners weren't called. Call them now. 1032 notifyStartListeners(); 1033 } 1034 ArrayList<AnimatorListener> tmpListeners = 1035 (ArrayList<AnimatorListener>) mListeners.clone(); 1036 int numListeners = tmpListeners.size(); 1037 for (int i = 0; i < numListeners; ++i) { 1038 tmpListeners.get(i).onAnimationEnd(this); 1039 } 1040 } 1041 mRunning = false; 1042 mStarted = false; 1043 mStartListenersCalled = false; 1044 } 1045 1046 /** 1047 * Called internally to start an animation by adding it to the active animations list. Must be 1048 * called on the UI thread. 1049 */ 1050 private void startAnimation(AnimationHandler handler) { 1051 initAnimation(); 1052 handler.mAnimations.add(this); 1053 if (mStartDelay > 0 && mListeners != null) { 1054 // Listeners were already notified in start() if startDelay is 0; this is 1055 // just for delayed animations 1056 notifyStartListeners(); 1057 } 1058 } 1059 1060 /** 1061 * Internal function called to process an animation frame on an animation that is currently 1062 * sleeping through its <code>startDelay</code> phase. The return value indicates whether it 1063 * should be woken up and put on the active animations queue. 1064 * 1065 * @param currentTime The current animation time, used to calculate whether the animation 1066 * has exceeded its <code>startDelay</code> and should be started. 1067 * @return True if the animation's <code>startDelay</code> has been exceeded and the animation 1068 * should be added to the set of active animations. 1069 */ 1070 private boolean delayedAnimationFrame(long currentTime) { 1071 if (!mStartedDelay) { 1072 mStartedDelay = true; 1073 mDelayStartTime = currentTime; 1074 } else { 1075 long deltaTime = currentTime - mDelayStartTime; 1076 if (deltaTime > mStartDelay) { 1077 // startDelay ended - start the anim and record the 1078 // mStartTime appropriately 1079 mStartTime = currentTime - (deltaTime - mStartDelay); 1080 mPlayingState = RUNNING; 1081 return true; 1082 } 1083 } 1084 return false; 1085 } 1086 1087 /** 1088 * This internal function processes a single animation frame for a given animation. The 1089 * currentTime parameter is the timing pulse sent by the handler, used to calculate the 1090 * elapsed duration, and therefore 1091 * the elapsed fraction, of the animation. The return value indicates whether the animation 1092 * should be ended (which happens when the elapsed time of the animation exceeds the 1093 * animation's duration, including the repeatCount). 1094 * 1095 * @param currentTime The current time, as tracked by the static timing handler 1096 * @return true if the animation's duration, including any repetitions due to 1097 * <code>repeatCount</code> has been exceeded and the animation should be ended. 1098 */ 1099 boolean animationFrame(long currentTime) { 1100 boolean done = false; 1101 1102 if (mPlayingState == STOPPED) { 1103 mPlayingState = RUNNING; 1104 if (mSeekTime < 0) { 1105 mStartTime = currentTime; 1106 } else { 1107 mStartTime = currentTime - mSeekTime; 1108 // Now that we're playing, reset the seek time 1109 mSeekTime = -1; 1110 } 1111 } 1112 switch (mPlayingState) { 1113 case RUNNING: 1114 case SEEKED: 1115 float fraction = mDuration > 0 ? (float)(currentTime - mStartTime) / mDuration : 1f; 1116 if (fraction >= 1f) { 1117 if (mCurrentIteration < mRepeatCount || mRepeatCount == INFINITE) { 1118 // Time to repeat 1119 if (mListeners != null) { 1120 int numListeners = mListeners.size(); 1121 for (int i = 0; i < numListeners; ++i) { 1122 mListeners.get(i).onAnimationRepeat(this); 1123 } 1124 } 1125 if (mRepeatMode == REVERSE) { 1126 mPlayingBackwards = mPlayingBackwards ? false : true; 1127 } 1128 mCurrentIteration += (int)fraction; 1129 fraction = fraction % 1f; 1130 mStartTime += mDuration; 1131 } else { 1132 done = true; 1133 fraction = Math.min(fraction, 1.0f); 1134 } 1135 } 1136 if (mPlayingBackwards) { 1137 fraction = 1f - fraction; 1138 } 1139 animateValue(fraction); 1140 break; 1141 } 1142 1143 return done; 1144 } 1145 1146 /** 1147 * Returns the current animation fraction, which is the elapsed/interpolated fraction used in 1148 * the most recent frame update on the animation. 1149 * 1150 * @return Elapsed/interpolated fraction of the animation. 1151 */ 1152 public float getAnimatedFraction() { 1153 return mCurrentFraction; 1154 } 1155 1156 /** 1157 * This method is called with the elapsed fraction of the animation during every 1158 * animation frame. This function turns the elapsed fraction into an interpolated fraction 1159 * and then into an animated value (from the evaluator. The function is called mostly during 1160 * animation updates, but it is also called when the <code>end()</code> 1161 * function is called, to set the final value on the property. 1162 * 1163 * <p>Overrides of this method must call the superclass to perform the calculation 1164 * of the animated value.</p> 1165 * 1166 * @param fraction The elapsed fraction of the animation. 1167 */ 1168 void animateValue(float fraction) { 1169 fraction = mInterpolator.getInterpolation(fraction); 1170 mCurrentFraction = fraction; 1171 int numValues = mValues.length; 1172 for (int i = 0; i < numValues; ++i) { 1173 mValues[i].calculateValue(fraction); 1174 } 1175 if (mUpdateListeners != null) { 1176 int numListeners = mUpdateListeners.size(); 1177 for (int i = 0; i < numListeners; ++i) { 1178 mUpdateListeners.get(i).onAnimationUpdate(this); 1179 } 1180 } 1181 } 1182 1183 @Override 1184 public ValueAnimator clone() { 1185 final ValueAnimator anim = (ValueAnimator) super.clone(); 1186 if (mUpdateListeners != null) { 1187 ArrayList<AnimatorUpdateListener> oldListeners = mUpdateListeners; 1188 anim.mUpdateListeners = new ArrayList<AnimatorUpdateListener>(); 1189 int numListeners = oldListeners.size(); 1190 for (int i = 0; i < numListeners; ++i) { 1191 anim.mUpdateListeners.add(oldListeners.get(i)); 1192 } 1193 } 1194 anim.mSeekTime = -1; 1195 anim.mPlayingBackwards = false; 1196 anim.mCurrentIteration = 0; 1197 anim.mInitialized = false; 1198 anim.mPlayingState = STOPPED; 1199 anim.mStartedDelay = false; 1200 PropertyValuesHolder[] oldValues = mValues; 1201 if (oldValues != null) { 1202 int numValues = oldValues.length; 1203 anim.mValues = new PropertyValuesHolder[numValues]; 1204 anim.mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues); 1205 for (int i = 0; i < numValues; ++i) { 1206 PropertyValuesHolder newValuesHolder = oldValues[i].clone(); 1207 anim.mValues[i] = newValuesHolder; 1208 anim.mValuesMap.put(newValuesHolder.getPropertyName(), newValuesHolder); 1209 } 1210 } 1211 return anim; 1212 } 1213 1214 /** 1215 * Implementors of this interface can add themselves as update listeners 1216 * to an <code>ValueAnimator</code> instance to receive callbacks on every animation 1217 * frame, after the current frame's values have been calculated for that 1218 * <code>ValueAnimator</code>. 1219 */ 1220 public static interface AnimatorUpdateListener { 1221 /** 1222 * <p>Notifies the occurrence of another frame of the animation.</p> 1223 * 1224 * @param animation The animation which was repeated. 1225 */ 1226 void onAnimationUpdate(ValueAnimator animation); 1227 1228 } 1229 1230 /** 1231 * Return the number of animations currently running. 1232 * 1233 * Used by StrictMode internally to annotate violations. 1234 * May be called on arbitrary threads! 1235 * 1236 * @hide 1237 */ 1238 public static int getCurrentAnimationsCount() { 1239 AnimationHandler handler = sAnimationHandler.get(); 1240 return handler != null ? handler.mAnimations.size() : 0; 1241 } 1242 1243 /** 1244 * Clear all animations on this thread, without canceling or ending them. 1245 * This should be used with caution. 1246 * 1247 * @hide 1248 */ 1249 public static void clearAllAnimations() { 1250 AnimationHandler handler = sAnimationHandler.get(); 1251 if (handler != null) { 1252 handler.mAnimations.clear(); 1253 handler.mPendingAnimations.clear(); 1254 handler.mDelayedAnims.clear(); 1255 } 1256 } 1257 1258 private AnimationHandler getOrCreateAnimationHandler() { 1259 AnimationHandler handler = sAnimationHandler.get(); 1260 if (handler == null) { 1261 handler = new AnimationHandler(); 1262 sAnimationHandler.set(handler); 1263 } 1264 return handler; 1265 } 1266 1267 @Override 1268 public String toString() { 1269 String returnVal = "ValueAnimator@" + Integer.toHexString(hashCode()); 1270 if (mValues != null) { 1271 for (int i = 0; i < mValues.length; ++i) { 1272 returnVal += "\n " + mValues[i].toString(); 1273 } 1274 } 1275 return returnVal; 1276 } 1277} 1278