Android Pull to Refresh with RecyclerView in Kotlin

package com.gtappdevelopers.kotlingfgproject

data class CourseRVModal(
    // on below line we are creating a two variable one 
    // for course name and other for course image.
    var courseName: String,
    var courseImg: Int
)

package com.gtappdevelopers.kotlingfgproject

import android.content.Context
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

// on below line we are creating a course rv adapter class.
class CourseRVAdapter(
    // on below line we are passing variables
    // as course list and context
    private val courseList: ArrayList<CourseRVModal>,
    private val context: Context
) : RecyclerView.Adapter<CourseRVAdapter.CourseViewHolder>() {
    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): CourseRVAdapter.CourseViewHolder {
        // this method is use to inflate the layout file 
        // which we have created for our recycler view.
        // on below line we are inflating our layout file.
        val itemView = LayoutInflater.from(parent.context).inflate(
            R.layout.course_rv_item,
            parent, false
        )
        // at last we are returning our view holder 
        // class with our item View File.
        return CourseViewHolder(itemView)
    }

    override fun onBindViewHolder(holder: CourseRVAdapter.CourseViewHolder, position: Int) {
        // on below line we are setting data to our text view and our image view.
        holder.courseNameTV.text = courseList.get(position).courseName
        holder.courseIV.setImageResource(courseList.get(position).courseImg)
    }

    override fun getItemCount(): Int {
        // on below line we are returning 
        // our size of our list
        return courseList.size
    }

    class CourseViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        // on below line we are initializing our course name text view and our image view.
        val courseNameTV: TextView = itemView.findViewById(R.id.idTVCourse)
        val courseIV: ImageView = itemView.findViewById(R.id.idIVCourse)
    }
}

package com.gtappdevelopers.kotlingfgproject

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.RecyclerView
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
import java.util.*
import kotlin.collections.ArrayList

class MainActivity : AppCompatActivity() {

    // on below line we are creating variables for our swipe 
    // to refresh layout, recycler view, adapter and list.
    lateinit var swipeRefreshLayout: SwipeRefreshLayout
    lateinit var courseRV: RecyclerView
    lateinit var courseRVAdapter: CourseRVAdapter
    lateinit var courseList: ArrayList<CourseRVModal>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        
        // on below line we are initializing our views with their ids.
        swipeRefreshLayout = findViewById(R.id.container)
        courseRV = findViewById(R.id.idRVCourses)

        // on below line we are initializing our list
        courseList = ArrayList()

        // on below line we are initializing our adapter
        courseRVAdapter = CourseRVAdapter(courseList, this)

        // on below line we are setting adapter to our recycler view.
        courseRV.adapter = courseRVAdapter

        // on below line we are adding data to our list
        courseList.add(CourseRVModal("Android Development", R.drawable.android))
        courseList.add(CourseRVModal("C++ Development", R.drawable.c))
        courseList.add(CourseRVModal("Java Development", R.drawable.java))
        courseList.add(CourseRVModal("Python Development", R.drawable.python))
        courseList.add(CourseRVModal("JavaScript Development", R.drawable.js))

        // on below line we are notifying adapter 
        // that data has been updated.
        courseRVAdapter.notifyDataSetChanged()

        // on below line we are adding refresh listener 
        // for our swipe to refresh method.
        swipeRefreshLayout.setOnRefreshListener {

            // on below line we are setting is refreshing to false.
            swipeRefreshLayout.isRefreshing = false

            // on below line we are shuffling our list using random
            Collections.shuffle(courseList, Random(System.currentTimeMillis()))

            // on below line we are notifying adapter 
            // that data has changed in recycler view.
            courseRVAdapter.notifyDataSetChanged()
        }
    }
}