[Android/Java] Media player(local storage)

MainActivity.java

package com.example.recyclerview;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.MediaController;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
import android.widget.VideoView;

import static com.example.recyclerview.Data.IMAGE_DRAWABLES;
import static com.example.recyclerview.Data.PROFILE_TEXT;

public class MainActivity extends AppCompatActivity {
    private MediaPlayer mediaPlayer;

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

        mediaPlayer = null;
    }

    public void music(View view) {
        switch (view.getId()) {
            case R.id.btn_play:
                if(mediaPlayer == null) {
                    mediaPlayer = MediaPlayer.create(this, R.raw.media_sample_01);
                }
                mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                    @Override
                    public void onCompletion(MediaPlayer mp) {
                        stopMusic();
                    }
                });
                mediaPlayer.start();
                break;
            case R.id.btn_pause:
                if(mediaPlayer != null)
                    mediaPlayer.pause();
                break;
            case R.id.btn_stop:
                if(mediaPlayer != null) {
                    mediaPlayer.stop();
                    stopMusic();
                }
                break;
        }
    }

    private void stopMusic() {
        mediaPlayer.release();
        mediaPlayer = null;
    }

    @Override
    protected void onStop() {
        super.onStop();
        stopMusic();
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:layout_gravity="center"
    android:padding="16dp">


    <TextView
        android:id="@+id/text_view_01"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="MediaPlayer Demo"
        android:textSize="32dp"
        android:layout_centerHorizontal="true"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_centerVertical="true">

        <Button
            android:id="@+id/btn_play"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="music"
            android:text="play" />

        <Button
            android:id="@+id/btn_pause"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="music"
            android:text="pause" />

        <Button
            android:id="@+id/btn_stop"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="music"
            android:text="stop" />
    </LinearLayout>


</RelativeLayout>