ViewModel作成時に「java.lang.RuntimeException: Cannot create an instance of class 」のエラーになる

Question

ViewModelのことで質問させてください。該当箇所のソースを念のため載せさせて頂きます。長文で申し訳ありません
RequestDocumentsForm1Activity画面で次へボタンを押下すると、「Cannot create an instance of class」のエラーが出て画面が落ちてしまいます。

エラー全文は以下になります。

java.lang.RuntimeException: Cannot create an instance of class com.example.rworksample00025.RequestDocumentsViewModel
        at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.java:275)
        at androidx.lifecycle.SavedStateViewModelFactory.create(SavedStateViewModelFactory.java:112)
        at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:185)
        at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150)
        at androidx.lifecycle.ViewModelLazy.getValue(ViewModelProvider.kt:54)
        at androidx.lifecycle.ViewModelLazy.getValue(ViewModelProvider.kt:41)
        at com.example.rworksample00025.RequestDocumentsForm1Activity$onCreate$1.onClick(RequestDocumentsForm1Activity.kt:34)
        at android.view.View.performClick(View.java:7448)
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1119)
        at android.view.View.performClickInternal(View.java:7425)
        at android.view.View.access$3600(View.java:810)
        at android.view.View$PerformClick.run(View.java:28305)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7660)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Constructor.newInstance0(Native Method)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
        at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.java:267)
        at androidx.lifecycle.SavedStateViewModelFactory.create(SavedStateViewModelFactory.java:112) 
        at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:185) 
        at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150) 
        at androidx.lifecycle.ViewModelLazy.getValue(ViewModelProvider.kt:54) 
        at androidx.lifecycle.ViewModelLazy.getValue(ViewModelProvider.kt:41) 
        at com.example.rworksample00025.RequestDocumentsForm1Activity$onCreate$1.onClick(RequestDocumentsForm1Activity.kt:34) 
        at android.view.View.performClick(View.java:7448) 
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1119) 
        at android.view.View.performClickInternal(View.java:7425) 
        at android.view.View.access$3600(View.java:810) 
        at android.view.View$PerformClick.run(View.java:28305) 
        at android.os.Handler.handleCallback(Handler.java:938) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:223) 
        at android.app.ActivityThread.main(ActivityThread.java:7660) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) 
     Caused by: java.lang.IllegalStateException: Cannot access database on the main thread since it may potentially lock the UI for a long period of time.
        at androidx.room.RoomDatabase.assertNotMainThread(RoomDatabase.java:267)
        at androidx.room.RoomDatabase.query(RoomDatabase.java:323)
        at androidx.room.util.DBUtil.query(DBUtil.java:83)
        at com.example.rworksample00025.RequestDocumentsPersonInfoDao_Impl.loadAllRequestDocumentsPersonInfo(RequestDocumentsPersonInfoDao_Impl.java:229)
        at com.example.rworksample00025.RequestDocumentsViewModel.<init>(RequestDocumentsViewModel.kt:19)
        at java.lang.reflect.Constructor.newInstance0(Native Method) 
        at java.lang.reflect.Constructor.newInstance(Constructor.java:343) 
        at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.java:267) 
        at androidx.lifecycle.SavedStateViewModelFactory.create(SavedStateViewModelFactory.java:112) 
        at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:185) 
        at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150) 
        at androidx.lifecycle.ViewModelLazy.getValue(ViewModelProvider.kt:54) 
        at androidx.lifecycle.ViewModelLazy.getValue(ViewModelProvider.kt:41) 
        at com.example.rworksample00025.RequestDocumentsForm1Activity$onCreate$1.onClick(RequestDocumentsForm1Activity.kt:34) 
        at android.view.View.performClick(View.java:7448) 
        at (略)

全体のソースコード

ViewModelが以下です。

package com.example.rworksample00025

import android.app.Application
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch

class RequestDocumentsViewModel(application: Application): AndroidViewModel(application) {

    private val requestDocumentsPersonInfoDao: RequestDocumentsPersonInfoDao

    init {
        val db = RequestDocumentsPersonInfoDatabase.buildDatabase(application)
        requestDocumentsPersonInfoDao = db.requestDocumentsPersonInfoDao()
    }

    val personData = requestDocumentsPersonInfoDao.loadAllRequestDocumentsPersonInfo()
    val personDataAll = requestDocumentsPersonInfoDao.loadAllRequestDocumentsPersonInfoLiveData()

    fun insert(name: String, phoneticGuides: String, birthday: String, mailAddress: String, phoneNumber: String) {
        viewModelScope.launch(Dispatchers.IO) {
            requestDocumentsPersonInfoDao.saveRequestDocumentsPersonInfo(
                RequestDocumentsPersonInfo(
                    id = 0,
                    name = name,
                    phoneticGuides = phoneticGuides,
                    birthday = birthday,
                    mailAddress = mailAddress,
                    phoneNumber = phoneNumber,
                    zipStr = "",
                    prefecture = "",
                    city = "",
                    address = "",
                    disableCertifidate = "",
                    sendingMaterials = "",
                    remarks = ""
                )
            )
        }
    }

    (略)
}

ViewModelを呼び出している該当の箇所のActivityです。

package com.example.rworksample00025

import android.app.DatePickerDialog
import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.util.Patterns
import android.view.View
import android.widget.DatePicker
import android.widget.EditText
import android.widget.Toast
import androidx.activity.viewModels
import com.example.rworksample00025.databinding.ActivityRequestDocumentsForm1Binding
import java.util.*

class RequestDocumentsForm1Activity : AppCompatActivity(), DatePickerDialog.OnDateSetListener {

    private lateinit var binding: ActivityRequestDocumentsForm1Binding


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityRequestDocumentsForm1Binding.inflate(layoutInflater)
        setContentView(binding.root)

        val viewModel: RequestDocumentsViewModel by viewModels()

        binding.nextPageBtn.setOnClickListener (object: View.OnClickListener {
            override fun onClick(v: View?) {
                val check = validationCheck(binding.name, binding.mailAddress, binding.phoneNumber)
                if (check) {
                    viewModel.insert(binding.name.text.toString(), binding.phoneticGuides.text.toString(), binding.birthday.text.toString(), binding.mailAddress.text.toString(), binding.phoneNumber.text.toString())
                    val intent = Intent(this@RequestDocumentsForm1Activity, RequestDocumentsForm2Activity::class.java)
                    startActivity(intent)
                }
            }
        })


    }

    fun validationCheck(name: EditText, mail: EditText, phone: EditText) : Boolean {
        
        if (binding.name.text.toString().length == 0) {
            
            binding.name.requestFocus()
            
            Toast.makeText(applicationContext, "名前が未入力です。", Toast.LENGTH_SHORT).show()
            return false
        }

        if (binding.mailAddress.text.toString().length == 0 && !Patterns.EMAIL_ADDRESS.matcher(mail.text.toString()).matches()){
            binding.mailAddress.requestFocus()
            Toast.makeText(applicationContext, "メールアドレスが未入力または不正です。", Toast.LENGTH_SHORT).show()
            return false
        }

        if (binding.phoneNumber.text.toString().length == 0) {
            binding.phoneNumber.requestFocus()
            Toast.makeText(applicationContext, "電話番号が未入力です。", Toast.LENGTH_SHORT).show()
            return false
        }
        return true
    }
    (略)

環境情報
OS: Windows10
Android Studio 4.1.2
Kotlin 1.4.30
使用したライブラリ:
SQLCipher

Comments

[hoshi-takanori]

Caused by を辿っていくと Cannot access database on the main thread と言われてるので、RequestDocumentsViewModel のコンストラクタで DB を触ってるのがまずそうですね。(Room 使ってないので、修正方法は分かりません。)

[pice]

ViewModel内でviewModeScope.launch(Dispatchers.IO)としていたため、非同期で触れているのではないかと漠然と思っていたのですが、そうではなかったみたいですね。https://qiita.com/toastkidjp/items/49ad3035a6df525ce040
ここが参考になりそうですので、それで進めてみたいと思います。ありがとうございました。

Answer 1

hoshi-takanoriさんのおっしゃる通り、Cannot access database on the main thread since it may potentially lock the UI for a long period of time.というのが下の方に出ており、Kotlin で Room を使う際に詰まったところをまとめる - Qiitaこちらの記事を参考に進めてみたいと思います。ありがとうございました。