所以我想做的是，每当用户在recyclerview中向下滚动时，顶部应调整为0的高度，每当用户滚动到recyclerview的顶部时，都应重新调整大小。到正常大小。

这是用户界面

这是我的处理方式，但无法正常工作。

//sellerItems = the recyclerview
        sellerItems.addOnScrollListener(object : RecyclerView.OnScrollListener() {
            override fun onScrolled(recyclerView: RecyclerView,dx: Int,dy: Int) {
                val manager = recyclerView.layoutManager as LinearLayoutManager
                if (recyclerView.scrollState == 2 && dy < 0) {
                    val pram = LinearLayout.LayoutParams(
                            LinearLayout.LayoutParams.MATCH_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT
                    )
                    userStuff.layoutParams = pram
                }else if (dy > 0) {
                    val pram = LinearLayout.LayoutParams(
                            LinearLayout.LayoutParams.MATCH_PARENT,0
                    )
                    userStuff.layoutParams = pram
                }
            }
        })