Android属性动画设置中心点

public static void rotateIn(RelativeLayout layout, long delay) {    ObjectAnimator rotate = ObjectAnimator.ofFloat(layout, "rotation", -180f, 0f);    layout.setPivotX(layout.getWidth()/2);    layout.setPivotY(layout.getHeight());    //显示的调用invalidate    layout.invalidate();    rotate.setDuration(500);    rotate.setStartDelay(delay);    rotate.addListener(new MyAnimationListener2());    rotate.start();}