STEP 1: Create an Empty Activity
STEP 2: Create a raw resource folder
Create a raw resource folder under the res folder and copy one of 
the .mp3 file extension.
Right Click on "raw" folder ----> select "new" ---> click on "Android 
Resource Directory" ----> Change resource type values to "raw" ----> 
then finally click "OK".
Download required audio MP3 file (Size <500kb approximately) from 
Internet , right click and Paste it in "raw" folder whatever newly created.
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activity_main.xml:
<?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"
 tools:ignore="HardcodedText">
 <TextView
 android:id="@+id/headingText"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_centerHorizontal="true"
 android:layout_marginTop="32dp"
 android:text="MEDIA PLAYER"
 android:textSize="18sp"
 android:textStyle="bold" />
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:layout_below="@id/headingText"
 android:layout_marginTop="16dp"
 android:gravity="center_horizontal">
 <Button
 android:id="@+id/stopButton"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_marginEnd="8dp"
 android:backgroundTint="@color/colorPrimary"
 android:text="STOP"
 android:textColor="@android:color/white"
 tools:ignore="ButtonStyle,TextContrastCheck" />
 <Button
 android:id="@+id/playButton"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_marginEnd="8dp"
 android:backgroundTint="@color/colorPrimary"
 android:text="PLAY"
 android:textColor="@android:color/white"
 tools:ignore="ButtonStyle,TextContrastCheck" />
 <Button
 android:id="@+id/pauseButton"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:backgroundTint="@color/colorPrimary"
 android:text="PAUSE"
 android:textColor="@android:color/white"
 tools:ignore="ButtonStyle,TextContrastCheck" />
 </LinearLayout>
</RelativeLayout>
MainActivity.kt
// As per your application (or) file name package name will displayed
package com.example.mediaplayer 
import android.media.MediaPlayer
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
class MainActivity : AppCompatActivity() {
 override fun onCreate(savedInstanceState: Bundle?) {
 super.onCreate(savedInstanceState)
 setContentView(R.layout.activity_main)
 // create an instance of mediplayer for audio playback
 val mediaPlayer: MediaPlayer = 
MediaPlayer.create(applicationContext, R.raw.music)
 // register all the buttons using their appropriate IDs
 val bPlay: Button = findViewById(R.id.playButton)
 val bPause: Button = findViewById(R.id.pauseButton)
 val bStop: Button = findViewById(R.id.stopButton)
 // handle the start button to
 // start the audio playback
 bPlay.setOnClickListener {
 // start method is used to start
 // playing the audio file
 mediaPlayer.start()
 }
 // handle the pause button to put the
 // MediaPlayer instance at the Pause state
 bPause.setOnClickListener {
 // pause() method can be used to
 // pause the mediaplyer instance
 mediaPlayer.pause()
 }
 // handle the stop button to stop playing
 // and prepare the mediaplayer instance
 // for the next instance of play
 bStop.setOnClickListener {
 // stop() method is used to completely
 // stop playing the mediaplayer instance
 mediaPlayer.stop()
 // after stopping the mediaplayer instance
 // it is again need to be prepared
 // for the next instance of playback
 mediaPlayer.prepare()
 }
 }
}