Z轴阴影： Z = elevation + translationZ
elevation 是静态值,是View在Z轴上的初始值
translationZ是动态值，是Z上的偏移变化
参考 http://stackoverflow.com/questions/29367804/difference-between-elevation-and-translationz
That is because the actual Z value is the sum of the elevation and the translationZ
In the docs the say elevation is "base z depth of the view" and this is a static variable, while translationZ is dynamic.
So elevation is your start value and for animations you should use translationZ.
原文：http://www.cnblogs.com/krislight1105/p/5041587.html