RotateAnimation旋转坐标系为以旋转点为坐标系(0,0)点.x轴为0度,顺时针方向旋转一定的角度.1.RotateAnimation(fromDegrees, toDegrees) [默认以View左上角顶点为旋转点].X轴顺时针转动到fromDegrees为旋转的起始点,X轴顺时针转动到toDegrees为旋转的起始点.如fromDegrees=0,toDegrees=90:为左上角顶点为旋转点.0度为起始点,90度为终点.进行旋转,旋转了90度如fromDegrees=60,to