How to get the id in case no id in the layout - android-studio

Question

I have faced the problem of my application always show keep stopping. It show me the problem is not been initialized. I have try insert findViewbyId for mListener but it say i cannot insert id in constraint layout so mean this way cannot be used. Can somebody help me? Thank for your help
Below are my original code which problem out :
package com.example.assignment_mad
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.google.android.material.imageview.ShapeableImageView
class NotificationAdapter(private val companysList:ArrayList<Company>):RecyclerView.Adapter<NotificationAdapter.MyViewHolder>() {
private lateinit var mListener:onItemClickListener
interface onItemClickListener{
fun onItemClick(position: Int)
}
fun setOnItemClickListener(listener: onItemClickListener){
mListener=listener
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val itemView=LayoutInflater.from(parent.context).inflate(R.layout.list_item,parent,false)
return MyViewHolder(itemView,mListener)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val currentItem=companysList[position]
holder.titleImage.setImageResource(currentItem.titleImage)
holder.tvHeading.text=currentItem.heading
}
override fun getItemCount(): Int {
return companysList.size
}
//to insert the post detail
class MyViewHolder(itemView: View,listener: onItemClickListener):RecyclerView.ViewHolder(itemView){
val titleImage:ShapeableImageView=itemView.findViewById(R.id.title_image)
val tvHeading: TextView =itemView.findViewById(R.id.tvHeading)
init {
itemView.setOnClickListener{
listener.onItemClick(adapterPosition)
}
}
}
}
The list_item xml :
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_margin="8dp">
<com.google.android.material.imageview.ShapeableImageView
android:layout_width="80dp"
android:layout_height="80dp"
android:id="#+id/title_image"
android:scaleType="centerCrop"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:shapeAppearanceOverlay="#style/RoundCorner"
android:src="#drawable/company_logo_1"/>
<TextView
android:id="#+id/tvHeading"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:textColor="#color/black"
android:text="Candidate Biden Called Saudi Arable a Pareft eaft."
android:textSize="16dp"
android:textStyle="bold"
android:layout_marginStart="16dp"
android:layout_marginEnd="32dp"
android:layout_marginTop="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/title_image"
app:layout_constraintTop_toTopOf="parent"/>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_margin="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/title_image"
android:background="#color/underline"/>
</androidx.constraintlayout.widget.ConstraintLayout>
The problem showing :
kotlin.UninitializedPropertyAccessException: lateinit property mListener has not been initialized
at com.example.assignment_mad.NotificationAdapter.onCreateViewHolder(Notificatiion_Adapter.kt:25)
at com.example.assignment_mad.NotificationAdapter.onCreateViewHolder(Notificatiion_Adapter.kt:10)

Answer 1

Add the Nullable check for onItemClickListener type of variable will solve your problem.
package com.example.assignment_mad
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.google.android.material.imageview.ShapeableImageView
class NotificationAdapter(private val companysList:ArrayList<Company>):RecyclerView.Adapter<NotificationAdapter.MyViewHolder>() {
private var mListener:onItemClickListener?=null
interface onItemClickListener{
fun onItemClick(position: Int)
}
fun setOnItemClickListener(listener: onItemClickListener){
mListener=listener
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val itemView=LayoutInflater.from(parent.context).inflate(R.layout.list_item,parent,false)
return MyViewHolder(itemView,mListener)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val currentItem=companysList[position]
holder.titleImage.setImageResource(currentItem.titleImage)
holder.tvHeading.text=currentItem.heading
}
override fun getItemCount(): Int {
return companysList.size
}
//to insert the post detail
class MyViewHolder(itemView: View,listener: onItemClickListener?):RecyclerView.ViewHolder(itemView){
val titleImage:ShapeableImageView=itemView.findViewById(R.id.title_image)
val tvHeading: TextView =itemView.findViewById(R.id.tvHeading)
init {
itemView.setOnClickListener{
listener?.onItemClick(adapterPosition)
}
}
}
}

Answer 2

Your problem is you are not initilizing the mListener properly
kotlin.UninitializedPropertyAccessException: lateinit property mListener has not been initialized at com.example.assignment_mad.NotificationAdapter.onCreateViewHolder(Notificatiion_Adapter.kt:25) at com.example.assignment_mad.NotificationAdapter.onCreateViewHolder(Notificatiion_Adapter.kt:10)
My solution is to pass the listener in the adapter constructor
class NotificationAdapter(
private val companysList:ArrayList<Company>,
private val listener:onItemClickListener
){
// delete
private var mListener:onItemClickListener?=null
// and
fun setOnItemClickListener(listener: onItemClickListener){
mListener=listener
}
}
use it in activity/fragment
adapter = NotificationAdapter(list, object: NotificationAdapter.onItemClickListener{
override fun onItemClick(position:Int){
}
})