动画

定义

优化

Android 2D动画

补间动画(AnimationDrawable)

DrawableAnimation源码分析

 private AnimationDrawable(AnimationState state, Resources res) {
 final AnimationState as = new AnimationState(state, this, res);
 setConstantState(as);
 if (state != null) {
 setFrame(0, true, false);
 }
 }

 public abstract static class DrawableContainerState extends ConstantState {
 final DrawableContainer mOwner;
 

 public void addFrame(@NonNull Drawable frame, int duration) {
 mAnimationState.addFrame(frame, duration);
 if (!mRunning) {
 setFrame(0, true, false);
 }
 }

 public void addFrame(Drawable dr, int dur) {
 int pos = super.addChild(dr);
 mDurations[pos] = dur;
 }

 private void setFrame(int frame, boolean unschedule, boolean animate) {
 if (frame >= mAnimationState.getChildCount()) {
 return;
 }
 mAnimating = animate;
 mCurFrame = frame;
 selectDrawable(frame);
 if (unschedule || animate) {
 unscheduleSelf(this);
 }
 if (animate) {
 // Unscheduling may have clobbered these values; restore them
 mCurFrame = frame;
 mRunning = true;
 scheduleSelf(this, SystemClock.uptimeMillis() + mAnimationState.mDurations[frame]);
 }
 }

 public void start() {
 mAnimating = true;
 if (!isRunning()) {
 // Start from 0th frame.
 setFrame(0, false, mAnimationState.getChildCount() > 1
 || !mAnimationState.mOneShot);
 }
 }

 private void nextFrame(boolean unschedule) {
 int nextFrame = mCurFrame + 1;
 final int numFrames = mAnimationState.getChildCount();
 final boolean isLastFrame = mAnimationState.mOneShot && nextFrame >= (numFrames - 1);
 // Loop if necessary. One-shot animations should never hit this case.
 if (!mAnimationState.mOneShot && nextFrame >= numFrames) {
 nextFrame = 0;
 }
 setFrame(nextFrame, unschedule, !isLastFrame);
 }

视图动画(ViewAnimation)

 <alpha>, <scale>, <translate>, <rotate>,<set>
 <layoutAnimation xmlns:android="http://schemas.android.com/apk/res/android" 
 android:animation="@anim/list_item_alpha" 
 android:animationOrder="normal" 
 android:delay="0.8" />

Animation源码分析

 public AlphaAnimation(float fromAlpha, float toAlpha) {
 mFromAlpha = fromAlpha;
 mToAlpha = toAlpha;
 }
 

 /**
 * When this animation should start. When the start time is set to
 * {@link #START_ON_FIRST_FRAME}, the animation will start the first time
 * {@link #getTransformation(long, Transformation)} is invoked. The time passed
 * to this method should be obtained by calling
 * {@link AnimationUtils#currentAnimationTimeMillis()} instead of
 * {@link System#currentTimeMillis()}.
 *
 * @param startTimeMillis the start time in milliseconds
 */
 public void setStartTime(long startTimeMillis) {
 mStartTime = startTimeMillis;
 mStarted = mEnded = false;
 mCycleFlip = false;
 mRepeated = 0;
 mMore = true;
 }

draw()绘制的元素
 * 1. Draw the background
 * 2. If necessary, save the canvas' layers to prepare for fading
 * 3. Draw view's content
 * 4. Draw children
 * 5. If necessary, draw the fading edges and restore layers
 * 6. Draw decorations (scrollbars for instance)
applyLegacyAnimation方法
 private boolean applyLegacyAnimation(ViewGroup parent, long drawingTime,
 Animation a, boolean scalingRequired) {
 Transformation invalidationTransform;
 final int flags = parent.mGroupFlags;
 final boolean initialized = a.isInitialized();
 if (!initialized) {
 a.initialize(mRight - mLeft, mBottom - mTop, parent.getWidth(), parent.getHeight());
 a.initializeInvalidateRegion(0, 0, mRight - mLeft, mBottom - mTop);
 if (mAttachInfo != null) a.setListenerHandler(mAttachInfo.mHandler);
 onAnimationStart();
 }
 final Transformation t = parent.getChildTransformation();
 boolean more = a.getTransformation(drawingTime, t, 1f);
 if (scalingRequired && mAttachInfo.mApplicationScale != 1f) {
 if (parent.mInvalidationTransformation == null) {
 parent.mInvalidationTransformation = new Transformation();
 }
 invalidationTransform = parent.mInvalidationTransformation;
 a.getTransformation(drawingTime, invalidationTransform, 1f);
 } else {
 invalidationTransform = t;
 }

 /**
 * Changes the alpha property of the supplied {@link Transformation}
 */
 @Override
 protected void applyTransformation(float interpolatedTime, Transformation t) {
 final float alpha = mFromAlpha;
 t.setAlpha(alpha + ((mToAlpha - alpha) * interpolatedTime));
 }

 protected Matrix mMatrix;
 protected float mAlpha;

 public void cancel() {
 if (mStarted && !mEnded) {
 fireAnimationEnd();
 mEnded = true;
 guard.close();
 }
 // Make sure we move the animation to the end
 mStartTime = Long.MIN_VALUE;
 mMore = mOneMoreTime = false;
 }

AnimationUtils将xml动画文件转换为Animation

 public static Animation loadAnimation(Context context, @AnimRes int id)
 throws NotFoundException {
 XmlResourceParser parser = null;
 try {
 parser = context.getResources().getAnimation(id);
 return createAnimationFromXml(context, parser);

 private static Animation createAnimationFromXml(Context c, XmlPullParser parser,
 AnimationSet parent, AttributeSet attrs) throws XmlPullParserException, IOException {
 Animation anim = null;
 // Make sure we are on a start tag.
 int type;
 int depth = parser.getDepth();
 while (((type=parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth)
 && type != XmlPullParser.END_DOCUMENT) {
 if (type != XmlPullParser.START_TAG) {
 continue;
 }
 String name = parser.getName();
 if (name.equals("set")) {
 anim = new AnimationSet(c, attrs);
 createAnimationFromXml(c, parser, (AnimationSet)anim, attrs);
 } else if (name.equals("alpha")) {
 anim = new AlphaAnimation(c, attrs);
 } else if (name.equals("scale")) {
 anim = new ScaleAnimation(c, attrs);
 } else if (name.equals("rotate")) {
 anim = new RotateAnimation(c, attrs);
 } else if (name.equals("translate")) {
 anim = new TranslateAnimation(c, attrs);
 } else {
 throw new RuntimeException("Unknown animation name: " + parser.getName());
 }
 if (parent != null) {
 parent.addAnimation(anim);
 }
 }
 return anim;
 }

属性动画(PropertyAnimation Android 3.0,API level 11)

java:
android.animation.ObjectAnimator
android.animation.Animator
android.animation.AnimatorSet
android.animation.ValueAnimator
TimeInterpolator
android.view.ViewPropertyAnimator 封装了ValueAnimator
Duration:一个动画的时长,默认300ms
Time interpolation: 一段代码块计算当前的属性的值
Frame refresh delay:刷新的时间,默认10ms

ValueAnimator

ObjectAnimator

ObjectAnimator源码分析

创建ObjectAnimator

 public static ObjectAnimator ofInt(Object target, String propertyName, int... values) {
 ObjectAnimator anim = new ObjectAnimator(target, propertyName);
 anim.setIntValues(values);
 return anim;
 }

 private ObjectAnimator(Object target, String propertyName) {
 setTarget(target);
 setPropertyName(propertyName);
 }

 @Override
 public void setIntValues(int... values) {
 if (mValues == null || mValues.length == 0) {
 // No values yet - this animator is being constructed piecemeal. Init the values with
 // whatever the current propertyName is
 if (mProperty != null) {
 setValues(PropertyValuesHolder.ofInt(mProperty, values));
 } else {
 setValues(PropertyValuesHolder.ofInt(mPropertyName, values));
 }
 } else {
 super.setIntValues(values);
 }
 }

 public void setValues(PropertyValuesHolder... values) {
 int numValues = values.length;
 mValues = values;
 mValuesMap = new HashMap<String, PropertyValuesHolder>(numValues);
 for (int i = 0; i < numValues; ++i) {
 PropertyValuesHolder valuesHolder = values[i];
 mValuesMap.put(valuesHolder.getPropertyName(), valuesHolder);
 }
 // New property/values/target should cause re-initialization prior to starting
 mInitialized = false;
 }

启动ObjectAnimator动画

 AnimationHandler animationHandler = getOrCreateAnimationHandler();
 animationHandler.mPendingAnimations.add(this);
 if (mStartDelay == 0) {
 // This sets the initial value of the animation, prior to actually starting it running
 if (prevPlayingState != SEEKED) {
 setCurrentPlayTime(0);
 }
 mPlayingState = STOPPED;
 mRunning = true;
 notifyStartListeners();
 }
 animationHandler.start();

 void animateValue(float fraction) {
 final Object target = getTarget();
 if (mTarget != null && target == null) {
 // We lost the target reference, cancel and clean up.
 cancel();
 return;
 }
 super.animateValue(fraction);
 int numValues = mValues.length;
 for (int i = 0; i < numValues; ++i) {
 mValues[i].setAnimatedValue(target);
 }
 }

 //android.animation.ValueAnimator#animateValue
 void animateValue(float fraction) {
 fraction = mInterpolator.getInterpolation(fraction);
 mCurrentFraction = fraction;
 int numValues = mValues.length;
 for (int i = 0; i < numValues; ++i) {
 mValues[i].calculateValue(fraction);
 }
 if (mUpdateListeners != null) {
 int numListeners = mUpdateListeners.size();
 for (int i = 0; i < numListeners; ++i) {
 mUpdateListeners.get(i).onAnimationUpdate(this);
 }
 }
 }

 //android.animation.KeyframeSet#getValue
 public Object getValue(float fraction) {
 // Special-case optimization for the common case of only two keyframes
 if (mNumKeyframes == 2) {
 if (mInterpolator != null) {
 fraction = mInterpolator.getInterpolation(fraction);
 }
 return mEvaluator.evaluate(fraction, mFirstKeyframe.getValue(),
 mLastKeyframe.getValue());
 }
 ···
 ···
 ···
 }

 void doAnimationFrame(long frameTime) {
 mLastFrameTime = frameTime;
 // mPendingAnimations holds any animations that have requested to be started
 // We're going to clear mPendingAnimations, but starting animation may
 // cause more to be added to the pending list (for example, if one animation
 // starting triggers another starting). So we loop until mPendingAnimations
 // is empty.
 while (mPendingAnimations.size() > 0) {
 ArrayList<ValueAnimator> pendingCopy =
 (ArrayList<ValueAnimator>) mPendingAnimations.clone();
 mPendingAnimations.clear();
 int count = pendingCopy.size();
 for (int i = 0; i < count; ++i) {
 ValueAnimator anim = pendingCopy.get(i);
 // If the animation has a startDelay, place it on the delayed list
 if (anim.mStartDelay == 0) {
 anim.startAnimation(this);
 } else {
 mDelayedAnims.add(anim);
 }
 }
 }

 // Next, process animations currently sitting on the delayed queue, adding
 // them to the active animations if they are ready
 int numDelayedAnims = mDelayedAnims.size();
 for (int i = 0; i < numDelayedAnims; ++i) {
 ValueAnimator anim = mDelayedAnims.get(i);
 if (anim.delayedAnimationFrame(frameTime)) {
 mReadyAnims.add(anim);
 }
 }
 int numReadyAnims = mReadyAnims.size();
 if (numReadyAnims > 0) {
 for (int i = 0; i < numReadyAnims; ++i) {
 ValueAnimator anim = mReadyAnims.get(i);
 anim.startAnimation(this);
 anim.mRunning = true;
 mDelayedAnims.remove(anim);
 }
 mReadyAnims.clear();
 }

 // Now process all active animations. The return value from animationFrame()
 // tells the handler whether it should now be ended
 int numAnims = mAnimations.size();
 for (int i = 0; i < numAnims; ++i) {
 mTmpAnimations.add(mAnimations.get(i));
 }
 for (int i = 0; i < numAnims; ++i) {
 ValueAnimator anim = mTmpAnimations.get(i);
 if (mAnimations.contains(anim) && anim.doAnimationFrame(frameTime)) {
 mEndingAnims.add(anim);
 }
 }
 mTmpAnimations.clear();
 if (mEndingAnims.size() > 0) {
 for (int i = 0; i < mEndingAnims.size(); ++i) {
 mEndingAnims.get(i).endAnimation(this);
 }
 mEndingAnims.clear();
 }

 // Schedule final commit for the frame.
 mChoreographer.postCallback(Choreographer.CALLBACK_COMMIT, mCommit, null);

 // If there are still active or delayed animations, schedule a future call to
 // onAnimate to process the next frame of the animations.
 if (!mAnimations.isEmpty() || !mDelayedAnims.isEmpty()) {
 scheduleAnimation();
 }

ViewPager切换动画

Path动画

canvas.drawBitmapMesh(mBitmap,
 mInhaleMesh.getWidth(),
 mInhaleMesh.getHeight(),
 mInhaleMesh.getVertices(),
 0, null, 0, mPaint);

Android 3D动画

android.graphics.Camera

案例结构

Animation
|____src
| |____main
| | |____AndroidManifest.xml
| | |____java
| | | |____edu
| | | | |____ptu
| | | | | |____androidanimation
| | | | | | |____AnimationActivity.java
| | | | | | |____animation
| | | | | | | |____AnimationFactory.java #抽象工厂实现,可以返回ViewAnimation,AnimationDrawable,Animator动画类
| | | | | | | |____CustomAnimation.java
| | | | | | |____graphics
| | | | | | | |____PathUtils.java
| | | | | | |____viewpager
| | | | | | | |____ColorFragment.java
| | | | | | | |____impl
| | | | | | | | |____CustomTransformer.java
| | | | | | | |____ViewPagerFactory.java
CustomView
|____src
| |____main
| | |____AndroidManifest.xml
| | |____java
| | | |____edu
| | | | |____ptu
| | | | | |____customview
| | | | | | |____CustomAbstractView.java
| | | | | | |____CustomCompositeView.java
| | | | | | |____MainActivity.java
| | | | | | |____CustomDrawView.java
| | | | | | |____element
| | | | | | | |____impl 
| | | | | | | | |____LineChart.java
| | | | | | | | |____PathInfo.java #绘图元素实现类,路径绘制( element implement)
| | | | | | | |____IDrawElement.java #绘图元素接口(drawable element interface)