实现的效果是页面向下滑动时topbar显示，往上滑动时topbar隐藏（也可以在监听中加透明度），代码如下：

scrollView.setScrollListener(new ObserveScrollView.ScrollListener() {

            @Override
            public void scrollOritention(int l, int t, int oldl, int oldt) {
                // TODO Auto-generated method stub
                //滑动数据已经接收，在这里实现你的功能
                int scrollY = scrollView.getScrollY();
                int height = scrollView.getHeight();
                int scrollViewMeasuredHeight = scrollView.getChildAt(0).getMeasuredHeight();
                if (t - oldt > 1 || (scrollY + height) == scrollViewMeasuredHeight) {//往下滑动或者滑动到底部
                    StatusBarUtil.setColor(UpdateShopDetailInfoActivity.this, Color.WHITE, 0);
                    topbar.setBackgroundColor(AppUtils.getColor(R.color.white));
                    tvTitle.setText(decodedData == null ? "店铺详情" : decodedData.getShop_name());
                } else if (scrollY == 0) {//滑动到顶部
                    StatusBarUtil.setColor(UpdateShopDetailInfoActivity.this, Color.TRANSPARENT, 0);
                    topbar.setBackgroundColor(AppUtils.getColor(R.color.transparent));
                    tvTitle.setText("");
                }
            }
        });

效果图：