<?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:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginStart="16dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="16dp"
        android:text="Manage Audio Focus (Handling Audio interruptions in Android"
        android:textSize="18sp"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:gravity="center_horizontal"
        android:orientation="horizontal">

        <Button
            android:id="@+id/stopButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="32dp"
            android:backgroundTint="@color/colorPrimary"
            android:drawableStart="@drawable/ic_stop"
            android:text="STOP"
            android:textColor="@android:color/white" />

        <Button
            android:id="@+id/playButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="32dp"
            android:backgroundTint="@color/colorPrimary"
            android:drawableStart="@drawable/ic_play"
            android:text="PLAY"
            android:textColor="@android:color/white" />

        <Button
            android:id="@+id/pasueButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:backgroundTint="@color/colorPrimary"
            android:drawableStart="@drawable/ic_pause"
            android:text="PAUSE"
            android:textColor="@android:color/white" />

    </LinearLayout>

</RelativeLayout>

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.media.AudioAttributes;
import android.media.AudioFocusRequest;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import java.io.IOException;

@RequiresApi(api = Build.VERSION_CODES.O)
public class MainActivity extends AppCompatActivity {

    // media player instance to playback 
      // the media file from the raw folder
    MediaPlayer mediaPlayer;

    // Audio manager instance to manage or 
      // handle the audio interruptions
    AudioManager audioManager;

    // Audio attributes instance to set the playback 
      // attributes for the media player instance
    // these attributes specify what type of media is 
      // to be played and used to callback the audioFocusChangeListener
    AudioAttributes playbackAttributes;

    // media player is handled according to the 
      // change in the focus which Android system grants for
    AudioManager.OnAudioFocusChangeListener audioFocusChangeListener = new AudioManager.OnAudioFocusChangeListener() {
        @Override
        public void onAudioFocusChange(int focusChange) {
            if (focusChange == AudioManager.AUDIOFOCUS_GAIN) {
                mediaPlayer.start();
            } else if (focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT) {
                mediaPlayer.pause();
                mediaPlayer.seekTo(0);
            } else if (focusChange == AudioManager.AUDIOFOCUS_LOSS) {
                mediaPlayer.release();
            }
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // get the audio system service for 
          // the audioManger instance
        audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

        // initiate the audio playback attributes
        playbackAttributes = new AudioAttributes.Builder()
                .setUsage(AudioAttributes.USAGE_GAME)
                .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
                .build();

        // set the playback attributes for the focus requester
        AudioFocusRequest focusRequest = new AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN)
                .setAudioAttributes(playbackAttributes)
                .setAcceptsDelayedFocusGain(true)
                .setOnAudioFocusChangeListener(audioFocusChangeListener)
                .build();

        // request the audio focus and
          // store it in the int variable
        final int audioFocusRequest = audioManager.requestAudioFocus(focusRequest);

        // register all three buttons
        Button bPlay = findViewById(R.id.playButton);
        Button bPause = findViewById(R.id.pasueButton);
        Button bStop = findViewById(R.id.stopButton);

        // initiate the media player instance with
          // the media file from the raw folder
        mediaPlayer = MediaPlayer.create(getApplicationContext(), R.raw.music);

        // handle the PLAY button to play the audio
        bPlay.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // request the audio focus by the Android system
                  // if the system grants the permission
                // then start playing the audio file
                if (audioFocusRequest == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
                    mediaPlayer.start();
                }
            }
        });

        // handle the PAUSE button to pause the media player
        bPause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mediaPlayer.pause();
            }
        });

        // handle the STOP button to stop the media player
        bStop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mediaPlayer.stop();

                try {
                    // if the mediaplayer is stopped then
                      // it should be again prepared for
                    // next instance of play
                    mediaPlayer.prepare();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });

    }
}