helper for playing sounds

SoundPoolHelper.java

package com.grasshopper.dialer.util;

import android.content.Context;
import android.media.AudioManager;
import android.media.SoundPool;
import android.support.annotation.RawRes;

import java.util.HashMap;
import java.util.Map;

import rx.functions.Action1;

public class SoundPoolHelper extends SoundPool {
    private float volume;
    private Map<Integer, Integer> loaded;
    private Map<Integer, Integer> tempLoaded;
    private Context mContext;

    public SoundPoolHelper(int maxStreams, Context context) {
        this(maxStreams, AudioManager.STREAM_MUSIC, 0, context);
        AudioManager audioManager = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);
        float actualVolume = (float) audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
        float maxVolume = (float) audioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
        volume = actualVolume / maxVolume;
    }

    private SoundPoolHelper(int maxStreams, int streamType, int srcQuality, Context context) {
        super(maxStreams, streamType, srcQuality);
        mContext = context;
        loaded = new HashMap<>();
        tempLoaded = new HashMap<>();
        setOnLoadCompleteListener((soundPool, sampleId, status) -> {
            int resId = tempLoaded.get(sampleId);
            tempLoaded.remove(sampleId);
            if (status == 0) {
                loaded.put(resId, sampleId);
            }
        });

    }

    @Override public int load(Context context, int resId, int priority) {
        int id = super.load(context, resId, priority);
        tempLoaded.put(id, resId);
        return id;
    }

    public void play(@RawRes int res) {
        if (loaded.containsKey(res)) {
            play(loaded.get(res), volume, volume, 0, 0, 1.0f);
        } else {
            throw new IllegalAccessError("Load this raw resource previously.");
        }
    }

    public Action1<Integer> asAction() {
        return this::play;
    }
}