Kotlin Android - RecyclerView Example

Hello Friends,
          Today I am sharing the demo of RecyclerView in Kotlin.
A RecyclerView is essentially a ViewGroup of containers called ViewHolders which
populate a particular item.

So lets first familiar with RecyclerView and What RecyclerView requires:
1. It requires a set of data objects to work with
2. An xml file of the individual view item
3. An adapter to bind that data to the views shown in the ViewHolders
4. ViewHolder to populate the UI from the xml item file


Getting Started

	<?xml version="1.0" encoding="utf-8"?>
	<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
	xmlns:app="http://schemas.android.com/apk/res-auto"
	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/recyclerView"
	android:layout_width="0dp"
	android:layout_height="0dp"
	android:layout_marginStart="8dp"
	android:layout_marginTop="8dp"
	android:layout_marginEnd="8dp"
	android:layout_marginBottom="8dp"
	app:layout_constraintBottom_toBottomOf="parent"
	app:layout_constraintEnd_toEndOf="parent"
	app:layout_constraintStart_toStartOf="parent"
	app:layout_constraintTop_toTopOf="parent" />
	</androidx.constraintlayout.widget.ConstraintLayout>

view raw activity_main.xml hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
	xmlns:app="http://schemas.android.com/apk/res-auto"
	android:layout_width="match_parent"
	android:layout_height="wrap_content">
	<androidx.constraintlayout.widget.ConstraintLayout
	android:layout_width="match_parent"
	android:layout_height="wrap_content">
	<TextView
	android:id="@+id/tvName"
	android:layout_width="match_parent"
	android:layout_height="wrap_content"
	android:layout_marginStart="8dp"
	android:layout_marginTop="8dp"
	android:layout_marginEnd="8dp"
	android:padding="5dp"
	android:text="Mukesh Yadav"
	android:textStyle="bold"
	android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"
	app:layout_constraintEnd_toEndOf="parent"
	app:layout_constraintStart_toStartOf="parent"
	app:layout_constraintTop_toTopOf="parent" />
	<TextView
	android:id="@+id/tvEmail"
	android:layout_width="match_parent"
	android:layout_height="wrap_content"
	android:layout_marginStart="5dp"
	android:layout_marginTop="4dp"
	android:layout_marginEnd="8dp"
	android:padding="5dp"
	android:text="himky02@gmail.com"
	android:textStyle="bold"
	app:layout_constraintTop_toBottomOf="@+id/tvName"
	android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium"
	app:layout_constraintEnd_toEndOf="parent"
	app:layout_constraintStart_toStartOf="parent" />
	<TextView
	android:id="@+id/tvMobile"
	android:layout_width="match_parent"
	android:layout_height="wrap_content"
	android:layout_marginStart="5dp"
	android:layout_marginTop="4dp"
	android:layout_marginEnd="8dp"
	android:padding="5dp"
	android:text="9555xxxx59"
	app:layout_constraintTop_toBottomOf="@+id/tvEmail"
	android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium"
	app:layout_constraintEnd_toEndOf="parent"
	app:layout_constraintStart_toStartOf="parent" />
	</androidx.constraintlayout.widget.ConstraintLayout>
	</androidx.cardview.widget.CardView>

view raw item_user.xml hosted with ❤ by GitHub

	package com.android.developer.soulutions.recyclerview
	import androidx.appcompat.app.AppCompatActivity
	import android.os.Bundle
	import android.widget.LinearLayout
	import androidx.recyclerview.widget.DividerItemDecoration
	import androidx.recyclerview.widget.LinearLayoutManager
	import androidx.recyclerview.widget.RecyclerView
	import kotlinx.android.synthetic.main.activity_main.*
	class MainActivity : AppCompatActivity() {
	override fun onCreate(savedInstanceState: Bundle?) {
	super.onCreate(savedInstanceState)
	setContentView(R.layout.activity_main)
	recyclerView.layoutManager = LinearLayoutManager(this,RecyclerView.VERTICAL,false)
	recyclerView.addItemDecoration(DividerItemDecoration(recyclerView.getContext(), DividerItemDecoration.VERTICAL))
	val users = ArrayList<User>()
	users.add(User("Mukesh Yadav",30,"himky02@gmail.com","955xxxxx59"))
	users.add(User("ABC Limited",30,"abc@gmail.com","880xxxxx53"))
	users.add(User("XYZ LTD",30,"xyz@gmail.com","966xxxxx59"))
	users.add(User("Muesh",30,"mukesh@gmail.com","955xxxxx99"))
	users.add(User("Android",30,"android@gmail.com","955xxxxx89"))
	users.add(User("Developer",30,"developer@gmail.com","955xxxxx49"))
	val adapter = UserAdapter(users)
	recyclerView.adapter = adapter
	}
	}

view raw MainActivity.kt hosted with ❤ by GitHub

	package com.android.developer.soulutions.recyclerview
	import android.os.Parcel
	import android.os.Parcelable
	/**
	* Created by Mukesh on 10/7/2019.
	* https://www.androiddevelopersolutions.com/
	*/
	data class User(val name: String, val age : Int,
	val email: String, val phone: String) : Parcelable {
	constructor(parcel: Parcel) : this(
	parcel.readString(),
	parcel.readInt(),
	parcel.readString(),
	parcel.readString()
	)
	override fun writeToParcel(parcel: Parcel, flags: Int) {
	parcel.writeString(name)
	parcel.writeInt(age)
	parcel.writeString(email)
	parcel.writeString(phone)
	}
	override fun describeContents(): Int {
	return 0
	}
	companion object CREATOR : Parcelable.Creator<User> {
	override fun createFromParcel(parcel: Parcel): User {
	return User(parcel)
	}
	override fun newArray(size: Int): Array<User?> {
	return arrayOfNulls(size)
	}
	}
	}

view raw User.kt hosted with ❤ by GitHub

	package com.android.developer.soulutions.recyclerview
	import android.view.LayoutInflater
	import android.view.View
	import android.view.ViewGroup
	import android.widget.TextView
	import androidx.recyclerview.widget.RecyclerView
	/**
	* Created by Mukesh on 10/7/2019.
	* https://www.androiddevelopersolutions.com/
	*/
	class UserAdapter(val userList : ArrayList<User>) : RecyclerView.Adapter<UserAdapter.ViewHolder>(){
	override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): UserAdapter.ViewHolder {
	val v = LayoutInflater.from(parent.context).inflate(R.layout.item_user, parent, false)
	return ViewHolder(v)
	}
	override fun getItemCount(): Int {
	return userList.size
	}
	override fun onBindViewHolder(holder: UserAdapter.ViewHolder, position: Int) {
	holder.bindItems(userList[position])
	}
	//the class is hodling the list view
	class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
	fun bindItems(user: User) {
	val tvName = itemView.findViewById(R.id.tvName) as TextView
	val tvEmail = itemView.findViewById(R.id.tvEmail) as TextView
	val tvPhone = itemView.findViewById(R.id.tvMobile) as TextView
	tvName.text = user.name
	tvEmail.text = user.email
	tvPhone.text = user.phone
	}
	}
	}

view raw UserAdapter.kt hosted with ❤ by GitHub

Download code from here
Hope this will helps someone.
Enjoy coding.... :)