//用AnimationUtils这个工具类加载XML文件,该方法返回一个Animation对象
Animation animaDemo = AnimationUtils.loadAnimation(this, R.anim.rotate);
/*An interpolator defines the rate of change of an animation.
This allows the basic animation effects (alpha, scale, translate, rotate) to be accelerated, decelerated, repeated, etc.
Interpolator是一个接口,用来定义动画改变的速度,旗下有5个实现类,分别为AccelerateDecelerateInterpolator,
AccelerateInterpolator, CycleInterpolator, DecelerateInterpolator, LinearInterpolator
LinearInterpolator为匀速效果,AccelerateInterpolator为加速效果、DecelerateInterpolator为减速效果
这里是设置了一个匀速的效果