我对Kotlin和编程都是新手。
RestaurantModel.kt

package com.example.foodtogo.model

import android.os.Parcel
import android.os.Parcelable
import java.io.Serializable

class RestaurantModel(val name:String?, val address:String?, val delivery_charge: Int, val image: String?, val open: String?,
                      var menus: List<Menus?>?): Serializable {}

 class Menus(val name:String?, val price: Float, val url:String?, var totalInCart: Int):Serializable {}

RestaurantMainActivity.kt

package com.example.foodtogo

import android.os.Bundle
import android.util.Log
import android.view.Menu
import android.view.MenuItem
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import com.example.foodtogo.databinding.ActivityRestaurantMainBinding
import com.example.foodtogo.model.RestaurantModel
import com.example.foodtogo.view.RestaurantListAdapter
import com.google.firebase.auth.FirebaseAuth
import com.google.firebase.database.*
import android.content.Intent as Intent


class RestaurantMainActivity : AppCompatActivity(){
    private lateinit var binding: ActivityRestaurantMainBinding
    private lateinit var firebaseAuth: FirebaseAuth
    private lateinit var database: FirebaseDatabase
    private lateinit var reference: DatabaseReference
    private lateinit var restaurantList: ArrayList<RestaurantModel>
    //var adapter: RestaurantListAdapter?=null
    //private lateinit var restaurantList: MutableList<RestaurantModel?>
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityRestaurantMainBinding.inflate(layoutInflater)
        setContentView(binding.root)
        firebaseAuth = FirebaseAuth.getInstance()
        database = FirebaseDatabase.getInstance()
        reference = database.reference
        Log.e("AKSA", "TEST1")
        binding.recyclerViewRestaurant.layoutManager = LinearLayoutManager(this)
        Log.e("AKSA", "TEST")
        restaurantList = arrayListOf<RestaurantModel>()
        getRestaurantData()
        Log.e("AKSA", "TEST3")
    }
    private fun getRestaurantData() {
        
        reference=FirebaseDatabase.getInstance().getReference("RestaurantModel")
        reference.addValueEventListener(object : ValueEventListener,RestaurantListAdapter.ValueEventListener{
            override fun onDataChange(snapshot: DataSnapshot) {
                Log.e("AKSA", "TEST6")
                Log.e("AKSA", "TEST $snapshot")
                if (snapshot.exists()) {
                    Log.e("AKSA", "TEST00")
                    for (userSnapshot in snapshot.children) {
                        Log.e("AKSA", "TEST01")
                        val user =
                            userSnapshot.child("RestaurantModel").getValue(RestaurantModel::class.java)
                        Log.e("AKSA", "TEST02")
                        if (user != null) {
                            Log.e("AKSA", "TEST03")
                            restaurantList.add(user)
                        }
                    }
                    val adapter = RestaurantListAdapter(restaurantList, this)
                    binding.recyclerViewRestaurant.adapter = adapter
                    adapter.notifyDataSetChanged()
                }
            }

            override fun onCancelled(error: DatabaseError) {
                Toast.makeText(applicationContext, error.getMessage(), Toast.LENGTH_LONG).show()
            }

            override fun onItemClick(restaurantModel: RestaurantModel) {
                val intent = Intent(applicationContext,RestaurantMenuActivity::class.java)
                intent.putExtra("RestaurantModel", restaurantModel)
                    startActivity(intent)
                    Log.d("AKSA", "MESSAGE")
            }
        })
    }
        override fun onCreateOptionsMenu(menu: Menu?): Boolean {
            menuInflater.inflate(R.menu.menubar, menu)
            return super.onCreateOptionsMenu(menu)
        }
        override fun onOptionsItemSelected(item: MenuItem): Boolean {
            when (item.itemId) {
                R.id.home_menu -> {
                    val intent = Intent(this, ViewOrderActivity::class.java)
                    startActivity(intent)
                }
                R.id.signout_menu -> {
                    firebaseAuth.signOut()
                    val intent = Intent(this, LOGIN::class.java)
                    intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
                    startActivity(intent)
                    finish()
                }
            }
            return super.onOptionsItemSelected(item)
        }
    }

RestaurantListAdapter.kt

package com.example.foodtogo.view

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.bumptech.glide.Glide
import com.example.foodtogo.R
import com.example.foodtogo.model.RestaurantModel
import com.google.firebase.database.ValueEventListener

class RestaurantListAdapter(val restaurantList: ArrayList<RestaurantModel>, val clickListener: ValueEventListener):
    RecyclerView.Adapter<RestaurantListAdapter.MyViewHolder>() {
    //private lateinit var database: FirebaseDatabase
    //private lateinit var reference:DatabaseReference

    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): RestaurantListAdapter.MyViewHolder {
        val view: View = LayoutInflater.from(parent.context).inflate(R.layout.recycler_restaurantlist,parent,false)
        return MyViewHolder(view)


    }
    override fun onBindViewHolder(holder: RestaurantListAdapter.MyViewHolder, position: Int) {
        holder.bind(restaurantList.get(position))
        holder.itemView.setOnClickListener{
            clickListener.onItemClick(restaurantList.get(position))
        }
    }
    override fun getItemCount(): Int {
        return restaurantList.size
    }
    inner class MyViewHolder(view: View):RecyclerView.ViewHolder(view){

        val thumbImage: ImageView =view.findViewById(R.id.thumbImage)
        val restaurantName: TextView =view.findViewById(R.id.restaurantName)
        val restaurantAddress:TextView=view.findViewById(R.id.restaurantAddress)
        val restaurantHours:TextView=view.findViewById(R.id.restaurantHours)
        fun bind(restaurantModel: RestaurantModel?){
            restaurantName.text=restaurantModel?.name
            restaurantAddress.text="Address: "+restaurantModel?.address
            restaurantHours.text="Open: "+restaurantModel?.open
            Glide.with(this.thumbImage).load(restaurantModel?.image).centerCrop().placeholder(R.drawable.ic_launcher_background).into(thumbImage)

        }
    }
    interface ValueEventListener {
        fun onItemClick(restaurantModel: RestaurantModel)
    }
}

“Log.e（“AKSA”，“TEST02”）"。直到这个打印出来。但是在这个之后，用户显示空值。首先我在RecoverantModel.kt中使用了parcelize，后来我修改并添加了serializable。我也检查了其他程序。但是我卡住了。我不明白哪里出错了。