private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)
    }

// LottoNumber.kt
data class LottoNumber (val number: Int)

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.ListAdapter
import androidx.recyclerview.widget.RecyclerView
import com.jyh.numberpicker.databinding.ItemViewBinding

class NumberAdapter() : ListAdapter<LottoNumber,
        NumberAdapter.ViewHolder>(DiffCallback) {

    companion object DiffCallback : DiffUtil.ItemCallback<LottoNumber>() {
        override fun areItemsTheSame(oldItem: LottoNumber, newItem: LottoNumber): Boolean {
            return oldItem === newItem
        }

        override fun areContentsTheSame(oldItem: LottoNumber, newItem: LottoNumber): Boolean {
            return oldItem.number == newItem.number
        }
    }
    
    class ViewHolder(private val binding: ItemViewBinding):RecyclerView.ViewHolder(binding.root) {
        fun bind(lottoNumber: LottoNumber) {
            binding.lottoNumber = lottoNumber
            binding.executePendingBindings()
        }
    }


    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NumberAdapter.ViewHolder {
        return ViewHolder(ItemViewBinding.inflate(LayoutInflater.from(parent.context)))
    }

    override fun onBindViewHolder(holder: NumberAdapter.ViewHolder, position: Int) {
        val lottoNumber = getItem(position)
        holder.bind(lottoNumber)
    }
}

import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import kotlin.random.Random

class NumberViewModel: ViewModel(){

    // 선택된 번호
    private val _curNumber = MutableLiveData<Int>() // 외부에서 변경 가능
    val curNumber:LiveData<Int> // 외부에서 접근 가능
        get() = _curNumber

    // 현재 리스트
    private val _numberList = MutableLiveData<MutableList<LottoNumber>>()
    val numberSet:LiveData<MutableList<LottoNumber>>
        get() = _numberList

    // 초기화
    init{
        _numberList.value = mutableListOf()
        _curNumber.value = 1
    }

    // 리스트에 추가
    fun add(num: Int){
        if(_numberList.value!!.size>=6) return
        _numberList.value = mutableSetOf<LottoNumber>().apply {
            _numberList.value!!.forEach{this.add(it)}
            add(LottoNumber(num))
        }.toSortedSet { a, b -> a.number - b.number }.toMutableList()
    }

    // 랜덤 번호 추가
    fun random(){
        val tmp = _numberList.value!!.toMutableSet()
        while(tmp.size<6) { tmp.add( LottoNumber(Random.nextInt(1,45)))}
        _numberList.value = tmp.toSortedSet { a, b -> a.number - b.number }.toMutableList()
    }

    // 리스트 초기화
    fun reset(){
        _numberList.value = mutableListOf()
    }

    // 현재 번호 설정
    fun  setCurNum(num: Int){
        _curNumber.value = num
    }
}

// BindingAdapter.kt 생성
import android.widget.TextView
import androidx.databinding.BindingAdapter
import androidx.recyclerview.widget.RecyclerView

// 리사이클러뷰에서 사용됨
// 첫 번째 인자는 사용되는 뷰, 두 번째 인자는 view에 사용되는 객체
@BindingAdapter("listData")
fun bindRecyclerView(recyclerView: RecyclerView,
                     data: MutableList<LottoNumber>) {
    val adapter = recyclerView.adapter as NumberAdapter
    adapter.submitList(data)
}

// 아이탬 안 텍스트뷰에서 사용됨
@BindingAdapter("setNumber")
fun setNumber(textView: TextView,
                     lottoNumber: LottoNumber) {
    textView.text = lottoNumber.number.toString()
}

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

    // NumberPicker 초기화를 위해 선언
    val numberPicker: NumberPicker by lazy { binding.numberPicker }

    // ViewModel 초기화를 위해 선언
    private val viewModel: NumberViewModel by lazy {
        ViewModelProvider(this).get(NumberViewModel::class.java)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflat(layoutInflater)
        setContentView(binding.root)

        // NumberPicker 초기화를 위한 함수
        init()
    }


    // 라이프사이클, 데이터 바인딩을 위한 뷰모델, 넘버픽커 등 초기화
    private fun init() {
        binding.lifecycleOwner = this
        binding.viewModel = viewModel
        binding.recyclerView.layoutManager = LinearLayoutManager(this,LinearLayoutManager.HORIZONTAL, false)
        binding.recyclerView.adapter =NumberAdapter()
        numberPicker.minValue = 1
        numberPicker.maxValue = 45
    }
    
}

// 1번째 인자는 위 데이터 바인딩에 사용되는 리사이클러뷰
// 2번쨰 인자는 위에 사용된 listData의 인자가 전달된다.
@BindingAdapter("listData")
fun bindRecyclerView(recyclerView: RecyclerView,
                     data: MutableList<LottoNumber>) {
    val adapter = recyclerView.adapter as NumberAdapter
    adapter.submitList(data)
}