Android Open Source - Android_Simple_Game_Audio Frequency Thread

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License

The source code is released under:

Copyright (c) 2011, 2012, Hunter Davis All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are m...

Java Source Code

package com.hunterdavis.easyaudiomanager;
//from w  w  w  .  jav  a  2s.c  om
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
import android.os.AsyncTask;
import android.util.FloatMath;

public class FrequencyThread extends AsyncTask<Float, Integer, Integer> {
  // our audio device
  private AudioTrack track;

  public static boolean KeepPlayingTheTrack = true;

  protected Integer doInBackground(Float... freqParams) {
    int count = freqParams.length;
    if (count != 2) {
      return -1;
    }

    // what to play
    Float frequency = freqParams[0];

    // how long to play
    Float duration = freqParams[1];

    // our integer playback buffer
    short[] buffer = new short[1024];

    // our float sample buffer
    float samples[] = new float[1024];

    int minSize = AudioTrack.getMinBufferSize(44100,
        AudioFormat.CHANNEL_CONFIGURATION_MONO,
        AudioFormat.ENCODING_PCM_16BIT);
    track = new AudioTrack(AudioManager.STREAM_MUSIC, 44100,
        AudioFormat.CHANNEL_CONFIGURATION_MONO,
        AudioFormat.ENCODING_PCM_16BIT, minSize, AudioTrack.MODE_STREAM);
    try {
      track.play();
    } catch (IllegalStateException e) {
      return 1;
    }

    // we'll increment our wave angle by the frequency over the sample rate
    float increment = (float) (2 * Math.PI) * frequency / 44100;

    // our current angle for the sine wave
    float angle = 0;

    // loop over our duration (40 ~ samplerate/buffersize)
    for (int j = 0; j < (duration * 40); j++) {
      for (int i = 0; i < samples.length; i++) {
        buffer[i] = (short) (FloatMath.sin(angle) * Short.MAX_VALUE);
        angle += increment;
      }
      if (KeepPlayingTheTrack == false) {
        KeepPlayingTheTrack = true;
        track.stop();
        return 1;
      }
      track.write(buffer, 0, samples.length);
    }

    track.stop();
    return 1;
  }

  protected void onProgressUpdate(Integer... progress) {

  }

  protected void onPostExecute(Long result) {

  }
}

Java Source Code List

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