Initializing And Calling Our Adapter Class

MainActivity.kt

package com.carnot.recyclerviewlistadapter

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {
    lateinit var adapter: PostAdapter
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        //We initialise the postList just and abstract source 
        //which can be anything(Network, DB call, File etc)
        val postList = getListOfPost(5)
        adapter = PostAdapter()
        rvTask.adapter = adapter

        updatePostAdapter(postList)

         fbRefresh.setOnClickListener {
             // Just and example of data refresh which gets a new list and passes it to adapter.
            val updatedPostList = getListOfPost(10)
            updatePostAdapter(updatedPostList)
        }
    }

    fun updatePostAdapter(postList: List<Post>) {
        //important method which does the work of updating the items in Adapter
        adapter.submitList(postList)
    }

}