Android Tone Generator

gistfile1.java

// Usage:
//    AudioTrack tone = generateTone(440, 250);
//    tone.play();
//
private AudioTrack generateTone(double freqHz, int durationMs)
{
	int count = (int)(44100.0 * 2.0 * (durationMs / 1000.0)) & ~1;
	short[] samples = new short[count];
	for(int i = 0; i < count; i += 2){
		short sample = (short)(Math.sin(2 * Math.PI * i / (44100.0 / freqHz)) * 0x7FFF);
		samples[i + 0] = sample;
		samples[i + 1] = sample;
	}
	AudioTrack track = new AudioTrack(AudioManager.STREAM_MUSIC, 44100,
		AudioFormat.CHANNEL_OUT_STEREO, AudioFormat.ENCODING_PCM_16BIT,
		count * (Short.SIZE / 8), AudioTrack.MODE_STATIC);
	track.write(samples, 0, count);
	return track;
}