相关链接

• Android属性动画爬坑

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1.视图动画

AlphaAnimation、RotateAnimation、TranslateAnimation、ScaleAnimation继承自
Animation。AnimationSet表示动画集合。

动画的监听

animation.setAnimationListener(new Animation.AnimationListener(){
    void onAnimationStart(Animation animation);
    void onAnimationEnd(Animation animation);
    void onAnimationRepeat(Animation animation);
})

加载xml动画

Animation animation = AnimationUtils.loadAnimation(this,R.anim.abc_fade_in);

代码动画

//public TranslateAnimation(float fromXDelta, float toXDelta, float fromYDelta, float toYDelta)
TranslateAnimation ta = new TranslateAnimation(0, 100, 0, 200);
ta.setDuration(1000);
as.addAnimation(ta);

缺点

视图动画问题：只是对View的影像做动画，并不是真正改变View的状态。有时候动画完成后View无法隐藏的现象，即 setVisibility(View.GONE)失效了，只要调用view.clearAnimation()清除view动画就可解决这个问题。

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2.帧动画(AnimationDrawable)

在xml中的定义

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:oneshot="true">
    <item android:drawable="@drawable/rocket_thrust1" android:duration="200" />
    <item android:drawable="@drawable/rocket_thrust2" android:duration="200" />
    <item android:drawable="@drawable/rocket_thrust3" android:duration="200" />
</animation-list>

注意： xml需要定义在draw目录下，否则打包时有如下错误提示:

Element animation-list must be declared <animation-list> XML file should be in "drawable", not "anim".

使用

ImageView rocketImage = (ImageView) findViewById(R.id.rocket_image);
rocketImage.setBackgroundResource(R.anim.rocket_thrust);
rocketAnimation = (AnimationDrawable) rocketImage.getBackground();
rocketAnimation.start();

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3.属性动画(Animator 框架 AnimatorSet ObjectAnimator)

API11 android3.0 之后才有， nineoldandroids

PropertyValuesHolder 针对作用同一个对象的多个属性

PropertyValuesHolder pvh1 = PropertyValuesHolder.ofFloat("translationX",300f);
PropertyValuesHolder pvh2 = PropertyValuesHolder.ofFloat("scaleX",1f,0.1f);     //缩放属性
PropertyValuesHolder pvh3 = PropertyValuesHolder.ofFloat("scaleY",1f,0.1f);
ObjectAnimator.ofPropertyHolder(view,pvh1,pvh2,pvh3).setDuration(1000).start();

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ValueAnimator

示例1：View的显示与隐藏

@Override
public void onWindowFocusChanged(boolean hasFocus) {
    if (hasFocus){
        //获取要隐藏view的高度
        mHiddenViewMeasuredHeight = mHiddenView.getMeasuredHeight();
    }
    super.onWindowFocusChanged(hasFocus);
}

public void llClick(View view) {
    if (mHiddenView.getVisibility() == View.GONE) {
        // 打开动画
        animateOpen(mHiddenView);
    } else {
        // 关闭动画
        animateClose(mHiddenView);
    }
}

private void animateOpen(final View view) {
    view.setVisibility(View.VISIBLE);
    ValueAnimator animator = createDropAnimator(
            view,
            0,
            mHiddenViewMeasuredHeight);
    animator.start();
}

private void animateClose(final View view) {
    int origHeight = view.getHeight();
    ValueAnimator animator = createDropAnimator(view, origHeight, 0);
    animator.addListener(new AnimatorListenerAdapter() {
        public void onAnimationEnd(Animator animation) {
            view.setVisibility(View.GONE);
        }
    });
    animator.start();
}

private ValueAnimator createDropAnimator(
        final View view, int start, int end) {
    ValueAnimator animator = ValueAnimator.ofInt(start, end);
    animator.addUpdateListener(
            new ValueAnimator.AnimatorUpdateListener() {

        @Override
        public void onAnimationUpdate(ValueAnimator valueAnimator) {
            int value = (Integer) valueAnimator.getAnimatedValue();
            ViewGroup.LayoutParams layoutParams =
                    view.getLayoutParams();
            layoutParams.height = value;
            view.setLayoutParams(layoutParams);
        }
    });
    return animator;
}

动画的监听

ObjectAnimator anim = ObjectAnimator.ofFloat(view,"alpha",0.5f);
anim.addListener(new AnimatorListener(){
    void onAnimationStart(Animator animation);
    void onAnimationEnd(Animator animation);
    void onAnimationCancel(Animator animation);
    void onAnimationRepeat(Animator animation);
});

也可以用 AnimatorListenerAdapter

abstract class AnimatorListenerAdapter implements Animator.AnimatorListener,
Animator.AnimatorPauseListener {}

anim.addListener(new AnimatorListenerAdapter(){
    void onAnimationEnd(Animator animation){};
});

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AnimatorSet 将动画以组合的形式展现出来

示例：menu 打开关闭动画

private void startAnim() {
    ObjectAnimator animator0 = ObjectAnimator.ofFloat(mImageViews.get(0),"alpha",1F,0.5F);
    ObjectAnimator animator1 = ObjectAnimator.ofFloat(mImageViews.get(1),"translationY",200F);
    ObjectAnimator animator2 = ObjectAnimator.ofFloat(mImageViews.get(2),"translationX",200F);
    ObjectAnimator animator3 = ObjectAnimator.ofFloat(mImageViews.get(3),"translationY",-200F);
    ObjectAnimator animator4 = ObjectAnimator.ofFloat(mImageViews.get(4),"translationX",-200F);
    AnimatorSet set = new AnimatorSet();
    set.setDuration(200);
    set.setInterpolator(new LinearInterpolator());
    set.playTogether(animator0,animator1,animator2,animator3,animator4);
    set.start();
}
private void closeAnim() {
    ObjectAnimator animator0 = ObjectAnimator.ofFloat(mImageViews.get(0),"alpha", 0.5F, 1F);
    ObjectAnimator animator1 = ObjectAnimator.ofFloat(mImageViews.get(1),"translationY", 200F, 0);
    ObjectAnimator animator2 = ObjectAnimator.ofFloat(mImageViews.get(2),"translationX", 200F, 0);
    ObjectAnimator animator3 = ObjectAnimator.ofFloat(mImageViews.get(3),"translationY", -200F, 0);
    ObjectAnimator animator4 = ObjectAnimator.ofFloat(mImageViews.get(4),"translationX", -200F, 0);
    AnimatorSet set = new AnimatorSet();
    set.setDuration(500);
    set.setInterpolator(new BounceInterpolator());
    set.playTogether(animator0, animator1, animator2, animator3, animator4);
    set.start();
    mFlag = true;
}

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Interpolators 插值器

TimeInterpolation： 用于定义动画变化率的接口
系统预设的有：

AccelerateDecelerateInterpolator(两头慢，中间快)
LinearInterpolator(匀速)
AccelerateInterpolator(减速)
CycleInterpolator (正弦周期变化插值器)
BounceInterpolator
AccelerateDecelerateInterpolator, AccelerateInterpolator, AnticipateInterpolator, AnticipateOvershootInterpolator, BaseInterpolator, 
CycleInterpolator, DecelerateInterpolator, FastOutLinearInInterpolator, FastOutSlowInInterpolator, LinearInterpolator, LinearOutSlowInInterpolator, OvershootInterpolator, PathInterpolator

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TypeEvaluator 估值器(插值器的好基友)

TypeEvaluator： 用于定义属性值计算方式的接口，系统自带int,float,color类型。
系统预设: IntEvaluator FloatEvaluator ArgbEvaluator

//fraction:估值小数
public class IntEvaluator implements TypeEvaluator<Integer> {
    public Integer evaluate(float fraction, Integer startValue, Integer endValue) {
        int startInt = startValue;
        return (int)(startInt + fraction * (endValue - startInt));
    }
}

自定义一个贝塞尔曲线的估值器：

class BezierEvaluator implements TypeEvaluator<PointF> {

    @Override
    public PointF evaluate(float fraction, PointF startValue, PointF endValue) {
        float oneMinusT = 1.0f - fraction;

        //startValue;    //开始出现的点
        //endValue;      //结束终点

        PointF controlPoint = new PointF();    //贝塞尔曲线控制点
        controlPoint.set(mWidthPixels / 2 + 600, mHeightPixels / 2 - 300);

        PointF point = new PointF();    //返回计算好的点
        point.x = oneMinusT * oneMinusT * (startValue.x) + 2 * oneMinusT * fraction * (controlPoint.x) + fraction * fraction * (endValue.x);
        point.y = oneMinusT * oneMinusT * (startValue.y) + 2 * oneMinusT * fraction * (controlPoint.y) + fraction * fraction * (endValue.y);
        return point;
    }
}

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View 的 animate 方法

Android5.0后，view增加了 animate方法，供直接驱动view的属性动画。

view.animate()
    .translationZ(15F).setDuration(300)
    .setListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationEnd(Animator animation) {
            super.onAnimationEnd(animation);
            view.animate()
                    .translationZ(1f)           //require api 21
                    .setDuration(500).start();
        }
    })
    .withEndAction(new Runnable() {
        @Override
        public void run() {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    
                }
            });
        }
    })
    .start();

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