Media Player with Buffer progress and play position

public class SoundActivity extends Activity  {
 
    private MediaPlayer mediaPlayer;
    ProgressBar progress_bar;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tool_sound);
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        progress_bar = (ProgressBar) findViewById(R.id.progress_bar);
   
        btn_play_stop.setEnabled(false);
        btn_play_stop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(mediaPlayer.isPlaying()) {
                    mediaPlayer.pause();
                    btn_play_stop.setImageResource(R.drawable.ic_pause_black_24dp);
                } else {
                    mediaPlayer.start();
                    btn_play_stop.setImageResource(R.drawable.ic_play_arrow_black_24px);
                }
            }
        });

        mediaPlayer.setDataSource(proxyUrl);
        mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                observer.stop();
                progress_bar.setProgress(mp.getCurrentPosition());
                // TODO Auto-generated method stub
                mediaPlayer.stop();
                mediaPlayer.reset();
            }
        });
        mediaPlayer.setOnBufferingUpdateListener(new MediaPlayer.OnBufferingUpdateListener() {
            @Override
            public void onBufferingUpdate(MediaPlayer mp, int percent) {
                progress_bar.setSecondaryProgress(percent);
            }
        });
        mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            @Override
            public void onPrepared(MediaPlayer mediaPlayer) {
                btn_play_stop.setEnabled(true);

            }
        });
        observer = new MediaObserver();
        mediaPlayer.prepare();
        mediaPlayer.start();
        new Thread(observer).start();
    }

   
    private MediaObserver observer = null;

    private class MediaObserver implements Runnable {
        private AtomicBoolean stop = new AtomicBoolean(false);

        public void stop() {
            stop.set(true);
        }

        @Override
        public void run() {
            while (!stop.get()) {
                progress_bar.setProgress((int)((double)mediaPlayer.getCurrentPosition() / (double)mediaPlayer.getDuration()*100));
                try {
                    Thread.sleep(200);
                } catch (Exception ex) {
                    Logger.log(ToolSoundActivity.this, ex);
                }

            }
        }
    }
 
    @Override
    protected void onDestroy() {
        super.onDestroy();
        mediaPlayer.stop();
    }
}

xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<LinearLayout
    android:gravity="bottom"
    android:layout_gravity="bottom"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:weightSum="1">

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

    <ImageButton
        app:srcCompat="@drawable/ic_play_arrow_black_24px"
        android:layout_width="48dp"
        android:layout_height="48dp"
        android:id="@+id/btn_play_stop" />

    <ProgressBar
        android:padding="8dp"
        android:progress="0"
        android:id="@+id/progress_bar"
        style="@style/Widget.AppCompat.ProgressBar.Horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center" />

</LinearLayout>

</LinearLayout>