AudioSoundPlayer object for the Piano Tutorial on the SSaurel's Channel

AudioSoundPlayer.java

package com.ssaurel.piano;

import android.content.Context;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
import android.util.SparseArray;

import java.io.InputStream;

/**
 * Created by ssaurel on 15/03/2018.
 */
public class AudioSoundPlayer {

  private SparseArray<PlayThread> threadMap = null;
  private Context context;
  private static final SparseArray<String> SOUND_MAP = new SparseArray<>();
  public static final int MAX_VOLUME = 100, CURRENT_VOLUME = 90;

  static {
    // white keys sounds
    SOUND_MAP.put(1, "note_do");
    SOUND_MAP.put(2, "note_re");
    SOUND_MAP.put(3, "note_mi");
    SOUND_MAP.put(4, "note_fa");
    SOUND_MAP.put(5, "note_sol");
    SOUND_MAP.put(6, "note_la");
    SOUND_MAP.put(7, "note_si");
    SOUND_MAP.put(8, "second_do");
    SOUND_MAP.put(9, "second_re");
    SOUND_MAP.put(10, "second_mi");
    SOUND_MAP.put(11, "second_fa");
    SOUND_MAP.put(12, "second_sol");
    SOUND_MAP.put(13, "second_la");
    SOUND_MAP.put(14, "second_si");
    // black keys sounds
    SOUND_MAP.put(15, "do_dies");
    SOUND_MAP.put(16, "re_dies");
    SOUND_MAP.put(17, "fa_dies");
    SOUND_MAP.put(18, "sol_dies");
    SOUND_MAP.put(19, "la_dies");
    SOUND_MAP.put(20, "second_dies_do");
    SOUND_MAP.put(21, "second_dies_re");
    SOUND_MAP.put(22, "second_dies_fa");
    SOUND_MAP.put(23, "second_dies_sol");
    SOUND_MAP.put(24, "second_dies_la");
  }

  public AudioSoundPlayer(Context context) {
    this.context = context;
    threadMap = new SparseArray<>();
  }

  public void playNote(int note) {
    if (!isNotePlaying(note)) {
      PlayThread thread = new PlayThread(note);
      thread.start();
      threadMap.put(note, thread);
    }
  }

  public void stopNote(int note) {
    PlayThread thread = threadMap.get(note);

    if (thread != null) {
      threadMap.remove(note);
    }
  }

  public boolean isNotePlaying(int note) {
    return threadMap.get(note) != null;
  }

  private class PlayThread extends Thread {
    int note;
    AudioTrack audioTrack;

    public PlayThread(int note) {
      this.note = note;
    }

    @Override
    public void run() {
      try {
        String path = SOUND_MAP.get(note) + ".wav";
        AssetManager assetManager = context.getAssets();
        AssetFileDescriptor ad = assetManager.openFd(path);
        long fileSize = ad.getLength();
        int bufferSize = 4096;
        byte[] buffer = new byte[bufferSize];

        audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, 44100, AudioFormat.CHANNEL_CONFIGURATION_MONO,
               AudioFormat.ENCODING_PCM_16BIT, bufferSize, AudioTrack.MODE_STREAM);

        float logVolume = (float) (1 - (Math.log(MAX_VOLUME - CURRENT_VOLUME) / Math.log(MAX_VOLUME)));
        audioTrack.setStereoVolume(logVolume, logVolume);

        audioTrack.play();
        InputStream audioStream = null;
        int headerOffset = 0x2C; long bytesWritten = 0; int bytesRead = 0;

        audioStream = assetManager.open(path);
        audioStream.read(buffer, 0, headerOffset);

        while (bytesWritten < fileSize - headerOffset) {
          bytesRead = audioStream.read(buffer, 0, bufferSize);
          bytesWritten += audioTrack.write(buffer, 0, bytesRead);
        }

        audioTrack.stop();
        audioTrack.release();

      } catch (Exception e) {
      } finally {
        if (audioTrack != null) {
          audioTrack.release();
        }
      }
    }
  }

}