Part 2 – Adapter

RecyclerView & CardView dependencies:

developer.android.com/jetpack/androidx/releases/recyclerview

developer.android.com/jetpack/androidx/releases/cardview

package com.codinginflow.recyclerviewexample

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
import kotlinx.android.synthetic.main.example_item.view.*

class ExampleAdapter(private val exampleList: List<ExampleItem>) : 
    RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ExampleViewHolder {
        val itemView = LayoutInflater.from(parent.context).inflate(R.layout.example_item,
            parent, false)

        return ExampleViewHolder(itemView)
    }

    override fun onBindViewHolder(holder: ExampleViewHolder, position: Int) {
        val currentItem = exampleList[position]

        holder.imageView.setImageResource(currentItem.imageResource)
        holder.textView1.text = currentItem.text1
        holder.textView2.text = currentItem.text2
    }

    override fun getItemCount() = exampleList.size

    class ExampleViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val imageView: ImageView = itemView.image_view
        val textView1: TextView = itemView.text_view_1
        val textView2: TextView = itemView.text_view_2
    }
}

package com.codinginflow.recyclerviewexample

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

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val exampleList = generateDummyList(500)

        recycler_view.adapter = ExampleAdapter(exampleList)
        recycler_view.layoutManager = LinearLayoutManager(this)
        recycler_view.setHasFixedSize(true)
    }

    private fun generateDummyList(size: Int): List<ExampleItem> {

        val list = ArrayList<ExampleItem>()

        for (i in 0 until size) {
            val drawable = when (i % 3) {
                0 -> R.drawable.ic_android
                1 -> R.drawable.ic_audio
                else -> R.drawable.ic_sun
            }

            val item = ExampleItem(drawable, "Item $i", "Line 2")
            list += item
        }

        return list
    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clipToPadding="false"
        android:padding="4dp"
        tools:listitem="@layout/example_item" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="4dp">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="8dp">

        <ImageView
            android:id="@+id/image_view"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_marginEnd="8dp"
            android:src="@drawable/ic_android" />

        <TextView
            android:id="@+id/text_view_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toEndOf="@id/image_view"
            android:text="Line 1"
            android:textColor="@android:color/black"
            android:textSize="18sp"
            android:textStyle="bold" />

        <TextView
            android:id="@+id/text_view_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/text_view_1"
            android:layout_toEndOf="@id/image_view"
            android:text="Line 2" />

    </RelativeLayout>

</androidx.cardview.widget.CardView>

package com.codinginflow.recyclerviewexample

data class ExampleItem(val imageResource: Int, val text1: String, val text2: String)