属性动画

0.使用例子

        // 1. 改变位置
        ObjectAnimator.ofFloat(imageView, "translationX", 0f, 300f).start();

        // 2. 改变背景颜色
        ValueAnimator valueAnimator = ObjectAnimator.ofInt(viewTwo,
                "backgroundColor", 0xFFFF0808, 0xFF08FF08);
        valueAnimator.setDuration(3000);
        valueAnimator.setEvaluator(new ArgbEvaluator());
        valueAnimator.setRepeatCount(ValueAnimator.INFINITE);
        valueAnimator.setRepeatMode(ValueAnimator.REVERSE);
        valueAnimator.start();

        // 3. AnimatorSet的使用
        AnimatorSet animatorSet = new AnimatorSet();
        animatorSet.playTogether(
                ObjectAnimator.ofFloat(viewThree, "rotationX", 0, 360),
                ObjectAnimator.ofFloat(viewThree, "rotationY", 0, 180),
                ObjectAnimator.ofFloat(viewThree, "rotation", 0, 90),
                ObjectAnimator.ofFloat(viewThree, "translationX", 0, 100),
                ObjectAnimator.ofFloat(viewThree, "translationY", 0, 100),
                ObjectAnimator.ofFloat(viewThree, "scaleX", 0, 1.5f),
                ObjectAnimator.ofFloat(viewThree, "scaleY", 0, 1.0f),
                ObjectAnimator.ofFloat(viewThree, "alpha", 1f, 0.75f, 1f)

        );
        animatorSet.setDuration(5000).start();


//4.两秒内先旋转一圈，再旋转一圈
ObjectAnimator animator = ObjectAnimator.ofFloat(imageView, "rotation", 0f, 360f, 0f);
animator.setDuration(2000);
animator.start();

//5.先X轴放大两倍再变回原样
ObjectAnimator animator = ObjectAnimator.ofFloat(imageView, "scaleX", 1f, 2f, 1f);
animator.setDuration(2000);
animator.start();

1. 补间动画的不足

1.补间动画只能对view进行操作
2.补间动画只能进行平移，缩放，旋转，淡入淡出四种操作
3.补间动画只是改变view的显示效果，而没有改变view的属性(例如一个按钮，通过补间动画移动之后，它其实只是将这个按钮绘制到了新的地方，而点击这个按钮是没有任何反应的，但是点击按钮的原来位置会有点击事件)

2.属性动画的引入

1.属性动画的操作对象不限于view
2.属性动画可以执行多种动画效果，不限于那四种，例如可以改变背景
3.属性动画其实是一种值机制，通过改变对象的属性来实现的动画效果，所以不存在移动之后的问题（按钮是真正的移动了，不仅仅是绘制）

3.常用的类

3.1 ValueAnimator 操作值

ValueAnimator的ofInt和ofFloat方法可以通过int和float类型的属性来同时结合IntEvaluator和FloatEvaluator执行动画，ValueAnimator还有一个ofObject方法，这时就需要自定义TypeEvaluator了。

如：

public class Point {

    private float x;

    private float y;

    public Point(float x, float y) {
        this.x = x;
        this.y = y;
    }

    public float getX() {
        return x;
    }

    public float getY() {
        return y;
    }

}

public class PointEvaluator implements TypeEvaluator{

    @Override
    public Object evaluate(float fraction, Object startValue, Object endValue) {
        Point startPoint = (Point) startValue;
        Point endPoint = (Point) endValue;
        float x = startPoint.getX() + fraction * (endPoint.getX() - startPoint.getX());
        float y = startPoint.getY() + fraction * (endPoint.getY() - startPoint.getY());
        Point point = new Point(x, y);
        return point;
    }

}

Point point1 = new Point(0, 0);  
Point point2 = new Point(300, 300);  
ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), point1, point2);  
anim.setDuration(5000);  
anim.start();

3.2 ObjectAnimator 操作属性

ObjectAnimator内部的工作机制是通过寻找特定属性的get和set方法，然后通过方法不断地对值进行改变，从而实现动画效果的

3.3 AnimatorSet 动画集合

ObjectAnimator moveIn = ObjectAnimator.ofFloat(textview, "translationX", -500f, 0f);
ObjectAnimator rotate = ObjectAnimator.ofFloat(textview, "rotation", 0f, 360f);
ObjectAnimator fadeInOut = ObjectAnimator.ofFloat(textview, "alpha", 1f, 0f, 1f);
AnimatorSet animSet = new AnimatorSet();
animSet.play(rotate).with(fadeInOut).after(moveIn);//设置动画集合的播放顺序
animSet.setDuration(5000);
animSet.start();

3.4 ViewPropertyAnimator

1.整个ViewPropertyAnimator的功能都是建立在View类新增的animate()方法之上的，这个方法会创建并返回一个ViewPropertyAnimator的实例，之后的调用的所有方法，设置的所有属性都是通过这个实例完成的
2.在使用ViewPropertyAnimator时，我们自始至终没有调用过start()方法，这是因为新的接口中使用了隐式启动动画的功能，只要我们将动画定义完成之后，动画就会自动启动。

//把textview变成透明状态
textview.animate().alpha(0f);

//移动到400,400动画执行3秒
view.animate().x(400).y(400).setDuration(3000);

view.animate().x(300).y(300).setDuration(2000)  
        .setInterpolator(new BounceInterpolator());

     imageView.animate()
     .alpha(0.5f)
     .y(300)
     .setDuration(2000)
     //api min is 16
     .withStartAction(new Runnable() {
         @Override
         public void run() {

         }
     })
     //api min is 16
     .withEndAction(new Runnable() {
         @Override
         public void run() {

         }
     })
     .start();

4.监听器的设置


        anim.addListener(new Animator.AnimatorListener() {

            @Override
            public void onAnimationStart(Animator animation) {

            } 
            @Override
            public void onAnimationEnd(Animator animation) {

            } 
            @Override
            public void onAnimationCancel(Animator animation) {

            } 
            @Override
            public void onAnimationRepeat(Animator animation) {

            }
        });

4.1 监听器简单版本

anim.addListener(new  AnimatorListenerAdapter() {
            //需要哪个实现哪个
            
       });

5.通过XML来实现

5.1 XML的编写

1.对应ValueAnimator
2.对应ObjectAnimator
3.对应AnimatorSet

5.2 加载XML:通过AnimatorInflater来加载

Animator animator = AnimatorInflater.loadAnimator(context, R.animator.anim_file);  
animator.setTarget(view);  
animator.start();

https://developer.android.com/guide/topics/graphics/prop-animation.html

6.TypeEvaluator估值器：从开始值到结束值如何过渡

系统内置的有
1.IntEvaluator
2.FloatEvaluator
3.ArgbEvaluator

    public class FloatEvaluator implements TypeEvaluator { 
       //按比例fraction返回一个值
        public Float evaluate(float fraction, Number startValue, Number endValue) {
            float startFloat = startValue.floatValue();
            return startFloat + fraction * (endValue.floatValue() - startFloat);
        }
    }

7.Interpolator插值器:控制动画的变化速率

系统预置的有
1.LinearInterpolator线性插值器
2.AccelerateDecelerateInterpolator加减速插值器，两头慢中间快
3.DecelerateIntepolator减速插值器，越来越慢
4.BounceIntepolator

    public class AccelerateDecelerateInterpolator extends BaseInterpolator
            implements NativeInterpolatorFactory {
        public AccelerateDecelerateInterpolator() {
        }

        @SuppressWarnings({ "UnusedDeclaration" })
        public AccelerateDecelerateInterpolator(Context context,
                AttributeSet attrs) {
        }

        public float getInterpolation(float input) {
            return (float) (Math.cos((input + 1) * Math.PI) / 2.0f) + 0.5f;
        } 
         
    }
    
    
    
    public class LinearInterpolator extends BaseInterpolator implements NativeInterpolatorFactory {

        public LinearInterpolator() {
        }

        public LinearInterpolator(Context context, AttributeSet attrs) {
        }

        public float getInterpolation(float input) {
            return input;
        } 
        
    }

8.PropertyValuesHolder:针对同一个对象多个属性，同时作用多种动画

    
    PropertyValuesHolder propertyValuesHolder1 = PropertyValuesHolder.ofFloat("translationX", 300f);
    PropertyValuesHolder propertyValuesHolder2 = PropertyValuesHolder.ofFloat("alpha", 1f, 0.5f);
    PropertyValuesHolder propertyValuesHolder3 = PropertyValuesHolder.ofFloat("scaleX", 1f, 0, 1f);
    PropertyValuesHolder propertyValuesHolder4 = PropertyValuesHolder.ofFloat("scaleY", 1f, 0, 1f);
    ObjectAnimator.ofPropertyValuesHolder(imageView, propertyValuesHolder1,
            propertyValuesHolder2, propertyValuesHolder3, propertyValuesHolder4)
            .setDuration(5000).start();

参考
http://blog.csdn.net/cxmscb/article/details/52655075
http://blog.csdn.net/cxmscb/article/details/52636918
http://blog.csdn.net/cxmscb/article/details/52685864
http://blog.csdn.net/ahence/article/details/46646559
https://github.com/ASPOOK/Android-AnimationBanner
http://www.jianshu.com/p/03fdcfd3ae9c