val mItems = arrayOf("瀑布流", "宫格式")
        val adapter = ArrayAdapter(mContext, R.layout.spinner_item, mItems)    //选中项
        adapter.setDropDownViewResource(R.layout.simple_spinner_dropdown_item) //可选项



        holder.itemView.spinner.adapter=adapter
        holder.itemView.spinner.setOnItemSelectedListener(object : AdapterView.OnItemSelectedListener {
            override fun onItemSelected(parent: AdapterView<*>?, view: View, position: Int, id: Long) {
                mItems.get(position)
            }

            override fun onNothingSelected(parent: AdapterView<*>?) {}
        })


        holder.itemView.spinner.setSelection(0, true);

Android控件与布局——基础控件CheckedTextView
https://blog.csdn.net/hfut_why/article/details/90206071
 

修改Android中Spinner的显示及下拉样式的四种方法
https://blog.csdn.net/badboy007/article/details/19034609

如果需要实现的接口只有一个方法 可以这样写

  view.findViewById<TextView>(R.id.tvCancel).setOnClickListener {
                        bottomSheetDialog.dismiss()
                    }