파이어베이스 리얼타임 데이터베이스 불러오기 - 질문

1. 질문 : 파이어베이스 리얼타임 데이터베이스에 날짜와 메모가 입력이 잘되었는데 어플 창에는 날짜가 뜨지 않습니다.

   -adapter_list.notifyDataSetChanged()하기 전까지는 날짜가 잘 떳는데 그 다음부턴 날짜가 파이어베이스에만 입력되고 어플 창에는 뜨지 않습니다 ㅜㅜ

   왜이런걸까요?

    

   -파이어베이스 리얼타임 데이터베이스에 입력이 잘됨

   문제 화면: 어플 화면에 날짜가 안뜸

   

   -MainActivity.kt 코드입니다

    

   package com.ipari.diet_memo
   
   import android.app.DatePickerDialog
   import androidx.appcompat.app.AppCompatActivity
   import android.os.Bundle
   import android.util.Log
   import android.view.LayoutInflater
   import android.widget.*
   import androidx.appcompat.app.AlertDialog
   import com.google.firebase.auth.ktx.auth
   import com.google.firebase.database.DataSnapshot
   import com.google.firebase.database.DatabaseError
   import com.google.firebase.database.ValueEventListener
   import com.google.firebase.database.ktx.database
   import com.google.firebase.ktx.Firebase
   import java.util.*
   
   class MainActivity : AppCompatActivity() {
   
       val dataModelList = mutableListOf<DataModel>()
   
       override fun onCreate(savedInstanceState: Bundle?) {
   
           super.onCreate(savedInstanceState)
           setContentView(R.layout.activity_main)
   
           val database = Firebase.database
           val myRef = database.getReference("myMemo")
   
           val listView = findViewById<ListView>(R.id.mainLV)
           val adapter_list = ListViewAdapter(dataModelList)
   
           listView.adapter= adapter_list
   
           Log.d("DataModel------", dataModelList.toString())
   
           myRef.child(Firebase.auth.currentUser!!.uid).addValueEventListener(object : ValueEventListener{
               override fun onDataChange(snapshot: DataSnapshot) {
                   dataModelList.clear()
   
                   for (dataModel in snapshot.children) {
                       Log.d("Data", dataModel.toString())
                       dataModelList.add(dataModel.getValue(DataModel::class.java)!!)
                   }
                   adapter_list.notifyDataSetChanged()
                   Log.d("DataModel", dataModelList.toString())
               }
   
               override fun onCancelled(error: DatabaseError) {
   
               }
   
           })
   
           val writeButton = findViewById<ImageView>(R.id.writeBtn)
           writeButton.setOnClickListener {
   
               val mDialogView = LayoutInflater.from(this).inflate(R.layout.custom_dialog, null)
               val mBuilder = AlertDialog.Builder(this)
                   .setView(mDialogView)
                   .setTitle("운동 메모 다이얼로그")
   
               val mAlertDialog = mBuilder.show()
               val DateSelectBtn = mAlertDialog.findViewById<Button>(R.id.dataSelectBtn)
   
               var dateText=""
   
               DateSelectBtn?.setOnClickListener {
                   val today = GregorianCalendar()
                   val year : Int = today.get(Calendar.YEAR)
                   val month : Int = today.get(Calendar.MONTH)
                   val date : Int = today.get(Calendar.DATE)
   
                   val dlg = DatePickerDialog(this, object : DatePickerDialog.OnDateSetListener{
                       override fun onDateSet(view: DatePicker?, year: Int, month: Int, dayOfMonth: Int
                       ) {
                           Log.d("MAIN", "${year}, ${month +1}, ${dayOfMonth}")
                           DateSelectBtn.setText("${year}, ${month +1}, ${dayOfMonth}")
   
                           dateText = "${year}, ${month +1}, ${dayOfMonth}"
                       }
                   }, year, month, date)
                   dlg.show()
   
               }
   
               val saveBtn = mAlertDialog.findViewById<Button>(R.id.saveBtn)
               saveBtn?.setOnClickListener {
   
                   val healthMemo = mAlertDialog.findViewById<EditText>(R.id.healthMemo)?.text.toString()
                   val database = Firebase.database
                   val myRef = database.getReference("myMemo").child(Firebase.auth.currentUser!!.uid)
   
                   val model = DataModel(dateText, healthMemo)
   
                   myRef
                       .push()
                       .setValue(model)
                   mAlertDialog.dismiss()
               }
   
           }
       }
   }