动画效果改变view的高度

private void startPropertyAnim() {        ViewGroup.LayoutParams layoutParams = ll_big.getLayoutParams();        ValueAnimator anim = ValueAnimator.ofInt(layoutParams.height, 100);        ll_big.setPivotX(0.0f);        ll_big.setPivotY(0.0f);        anim.setDuration(2000);        anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {            @Override            public void onAnimationUpdate(ValueAnimator valueAnimator) {                int h = (int) valueAnimator.getAnimatedValue();                ViewGroup.LayoutParams layoutParams = ll_big.getLayoutParams();                layoutParams.height = h;                ll_big.requestLayout();            }        });        // 正式开始启动执行动画        anim.start();    }