Error while using recycler view in fragments - android-studio

Question

I am trying to use the recycler view in fragments.
But the app is crashing and showing this error.
The error shown is:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.mridul.expressions, PID: 7690
java.lang.RuntimeException: Cannot create an instance of class com.mridul.expressions.DiaryViewModel
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.java:275)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:187)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150)
at com.mridul.expressions.DiaryFragment.onViewCreated(DiaryFragment.kt:31)
at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:2987)
at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:546)
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189)
at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2106)
at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002)
at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:524)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7523)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941)
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.ViewModelProvider.get(ViewModelProvider.java:187) 
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150) 
at com.mridul.expressions.DiaryFragment.onViewCreated(DiaryFragment.kt:31) 
at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:2987) 
at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:546) 
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282) 
at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189) 
at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2106) 
at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002) 
at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:524) 
at android.os.Handler.handleCallback(Handler.java:938) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:223) 
at android.app.ActivityThread.main(ActivityThread.java:7523) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941) 
Caused by: java.lang.RuntimeException: cannot find implementation for com.mridul.expressions.DiaryDatabase. DiaryDatabase_Impl does not exist
at androidx.room.Room.getGeneratedImplementation(Room.java:97)
at androidx.room.RoomDatabase$Builder.build(RoomDatabase.java:1358)
at com.mridul.expressions.DiaryDatabase$Companion.getDatabase(DiaryDatabase.kt:25)
at com.mridul.expressions.DiaryViewModel.<init>(DiaryViewModel.kt:14)
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.ViewModelProvider.get(ViewModelProvider.java:187) 
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150) 
at com.mridul.expressions.DiaryFragment.onViewCreated(DiaryFragment.kt:31) 
at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:2987) 
at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:546) 
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282) 
at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189) 
at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2106) 
at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002) 
at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:524) 
at android.os.Handler.handleCallback(Handler.java:938) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:223) 
at android.app.ActivityThread.main(ActivityThread.java:7523) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941)
 
My Fragment.kt file:
package com.mridul.expressions
import android.app.Application
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.recyclerview.widget.LinearLayoutManager
import kotlinx.android.synthetic.main.fragment_diary.*
import kotlinx.android.synthetic.main.fragment_diary.view.*
import java.util.Calendar.getInstance
class DiaryFragment : Fragment(), IDiaryRVAdapter {
lateinit var viewModel: DiaryViewModel
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val adapter= this.context?.let { DiaryRVAdapter(it,this) }
diaryRecyclerView.adapter=adapter
diaryRecyclerView.layoutManager=LinearLayoutManager(
this.context)
val application: Application =requireActivity().application
viewModel=ViewModelProvider(this,
ViewModelProvider.AndroidViewModelFactory.getInstance(application)).get(DiaryViewModel::class.java)
viewModel.allDiary.observe(viewLifecycleOwner, Observer {list->
list?.let {
adapter?.updateList(it)
}
})
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view= inflater.inflate(R.layout.fragment_diary, container, false)
view.saveDiaryButton.setOnClickListener {
val diaryText=dateInDiary.text.toString()
if (diaryText.isNotEmpty()){
viewModel.insertNode(Diary(diaryText))
}
dateInDiary.text = null
}
return view
}
override fun onItemClicked(diary: Diary) {
viewModel.deleteNode(diary)
}
}
My Adapter is:
class DiaryRVAdapter(private val context: Context,
private val listner:IDiaryRVAdapter) : RecyclerView.Adapter<DiaryRVAdapter.DiaryViewHolder>()
{
val allNotes=ArrayList<Diary>()
inner class DiaryViewHolder(itemView:View) : RecyclerView.ViewHolder(itemView){
val textView=itemView.findViewById<TextView>(R.id.item)
val deletButton=itemView.findViewById<ImageView>(R.id.deleteButton)
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DiaryViewHolder {
valviewHolder=DiaryViewHolder(LayoutInflater.from(context).inflate
(R.layout.item_diary,parent,false))
viewHolder.deletButton.setOnClickListener{
listner.onItemClicked(allNotes[viewHolder.adapterPosition])}
return viewHolder
}
override fun onBindViewHolder(holder: DiaryViewHolder, position: Int) {
val currentNotes=allNotes[position]
holder.textView.text = currentNotes.text
}
override fun getItemCount(): Int {
return allNotes.size
}
fun updateList(newList: List<Diary>){
allNotes.clear()
allNotes.addAll(newList)
notifyDataSetChanged()
}
}
interface IDiaryRVAdapter{
fun onItemClicked(diary: Diary)
}
And layout file of fragment is:
<TextView
android:id="#+id/dearDiaryTxt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:text="#string/dear_diary"
android:textSize="20sp"
android:textColor="#d500f9"
android:layout_margin="12dp"
/>
<EditText
android:id="#+id/dateInDiary"
android:layout_width="match_parent"
android:layout_height="300dp"
app:layout_constraintTop_toBottomOf="#id/dearDiaryTxt"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:hint="Date-\nHow was your day🤗🤗🤗"
android:gravity="top"
android:background="#drawable/edit_text_round_box"
android:layout_marginTop="20dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
/>
<Button
android:id="#+id/saveDiaryButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/dateInDiary"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:text="Save"
android:textColor="#color/white"
android:layout_margin="5dp"
/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/diaryRecyclerView"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintTop_toBottomOf="#id/saveDiaryButton"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginTop="5dp"
tools:listitem="#layout/item_diary"
/>
And item is:
<TextView
android:id="#+id/item"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toLeftOf="#+id/deleteButton"
tools:text="Mridul"
android:textSize="16sp"
android:padding="12dp"
android:textColor="#3e2723"
/>
<ImageView
android:id="#+id/deleteButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="16dp"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintBottom_toBottomOf="#id/item"
app:layout_constraintTop_toTopOf="#id/item"
android:src="#drawable/ic_baseline_delete_outline_24"
/>
Please Help anyone.