Настройка громкости звука Soundpool

Не знаю как сделать так чтобы пользователь менял звук в моем приложении с помощью боковых кнопок громкости на телефоне.Помогите пожалуйста)) вот код:

public class BlankFragment5 extends Fragment {
    private int sound, sound1, sound2, sound3, sound4;
    private SoundPool soundPool;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_blank_fragment5, container, false);

        if  (Build.VERSION.SDK_INT >  Build.VERSION_CODES.LOLLIPOP){
            AudioAttributes audioAttributes = new AudioAttributes.Builder()
                    .setUsage(AudioAttributes.USAGE_ASSISTANCE_SONIFICATION)
                    .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
                    .build();
            soundPool = new SoundPool.Builder()
                    .setMaxStreams(1)
                    .setAudioAttributes(audioAttributes)
                    .build();
        }else {
            soundPool = new SoundPool(1, AudioManager.STREAM_MUSIC, 0);
        }

        sound = soundPool.load(getActivity(), R.raw.belkaaa,1);
        sound1 = soundPool.load(getActivity(), R.raw.zauacc,1);
        sound2 = soundPool.load(getActivity(), R.raw.mausse,1);
        sound3 = soundPool.load(getActivity(), R.raw.nutriia,1);
        sound4 = soundPool.load(getActivity(), R.raw.dikobrazz,1);

        ImageButton imageButton = (ImageButton) view.findViewById(R.id.imageButton);

        imageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
            /*  if (sound1 != null) {
                    sound1.stop();
                }
                if (sound2 != null) {
                    sound2.stop();
                }
                if (sound3 != null) {
                    sound3.stop();
                }
                if (sound4 != null) {
                    sound4.stop();
                }*/
                soundPool.play(sound,1,1,0,0,1);
            }
        });
        ImageButton imageButton2 = (ImageButton) view.findViewById(R.id.imageButton2);
        imageButton2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                soundPool.play(sound1,1,1,0,0,1);

            }
        });
        ImageButton imageButton3 = (ImageButton) view.findViewById(R.id.imageButton3);

        imageButton3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                soundPool.play(sound2,1,1,0,0,1);

            }
        });
        ImageButton imageButton4 = (ImageButton) view.findViewById(R.id.imageButton4);

        imageButton4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                soundPool.play(sound3,1,1,0,0,1);
            }
        });
        ImageButton imageButton5 = (ImageButton) view.findViewById(R.id.imageButton5);

        imageButton5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                soundPool.play(sound4,1,1,0,0,1);

            }
        });

        return view;
    }
    public void onCreate (Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setRetainInstance(true);
    }


    @Override
    public   void onDestroy(){
        super.onDestroy();
        soundPool.release();
        soundPool = null;
    }

}