Call class inside another in PendingIntent

I have this class that plays a song through MediaPlayer . This is working well. Now I want to implement playback controls in the notification area, but I'm having trouble calling the class I have in NotificationReturnSlot where I grab the corresponding action of each button.

I tried to put the inner class in another file but then I could not call the methods of the class AudioInterface . How can I do this? o How could I make it work?

I clarify that this is a Interface call from a WebView , which creates the Play controls and pauses in the notification bar.

public class AudioInterface {
        private NotificationManager nManager;
        private NotificationCompat.Builder nBuilder;
        private RemoteViews remoteView;

    MediaPlayer mPlayer;
    Context mContext;

    AudioInterface(Context c) {
        mContext = c;
    }

    //Play an audio file from the webpage
    @JavascriptInterface
    public void playAudio(String aud) { //String aud - file name passed
        mPlayer = new MediaPlayer();
        mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        //String url = aud;
        String url = "http://mysite.com/file.mp3";

        try {
            mPlayer.setDataSource(url);
        } catch (IllegalArgumentException e) {
            Toast.makeText(mContext, "Wrong URI", Toast.LENGTH_LONG).show();
        } catch (SecurityException e) {
            Toast.makeText(mContext, "Wrong URI", Toast.LENGTH_LONG).show();
        } catch (IllegalStateException e) {
            Toast.makeText(mContext, "Wrong URI", Toast.LENGTH_LONG).show();
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            mPlayer.prepare();
        } catch (IllegalStateException e) {
            Toast.makeText(mContext, "Wrong URI", Toast.LENGTH_LONG).show();
        } catch (IOException e) {
            Toast.makeText(mContext, "Wrong URI", Toast.LENGTH_LONG).show();
        }

        nBuilder = new NotificationCompat.Builder(mContext)
                .setContentTitle("Test")
                .setSmallIcon(R.drawable.splash_image)
                .setOngoing(true);

        remoteView = new RemoteViews(mContext.getPackageName(), R.layout.notificationview);

        //set the button listeners
        setListeners(remoteView);
        nBuilder.setContent(remoteView);

        nManager = (NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);
        nManager.notify(2, nBuilder.build());
    }

    public void play(){
        this.mPlayer.start();
    }

    public void pause(){
        this.mPlayer.pause();
    }

    public void setListeners(RemoteViews view){
        //listener 1
        Intent playMP = new Intent(mContext,NotificationReturnSlot.class);
        playMP.putExtra("DO", "play");
        PendingIntent btn1 = PendingIntent.getActivity(mContext, 0, playMP, 0);
        view.setOnClickPendingIntent(R.id.btn1, btn1);

        //listener 2
        Intent pauseMP = new Intent(mContext, NotificationReturnSlot.class);
        pauseMP.putExtra("DO", "pause");
        PendingIntent btn2 = PendingIntent.getActivity(mContext, 1, pauseMP, 0);
        view.setOnClickPendingIntent(R.id.btn2, btn2);
    }

    public void notificationCancel() {
        nManager.cancel(2);
    }

    public class NotificationReturnSlot extends Activity {
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);

            String action = (String) getIntent().getExtras().get("DO");

            if (action.equals("play")) {
                Log.i("NotificationReturnSlot", "play");

                Toast.makeText(this, "playing", Toast.LENGTH_SHORT).show();
                play();

            } else if (action.equals("pause")) {
                //Log.i("NotificationReturnSlot", "stopNotification");
                Log.i("NotificationReturnSlot", "pause");

                Toast.makeText(this, "paused", Toast.LENGTH_SHORT).show();
                pause();
            }
            //finish();
        }
    }
}