Я пытаюсь разработать приложение для Android, которое извлекает звуковую частоту из инструмента. Я'используя метод быстрого преобразования Фурье с Jtransforms. Вот что у меня так далеко:}

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    new readFrequencies().execute();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

private class readFrequencies extends AsyncTask {

        @Override
        protected Integer doInBackground(Void... arg0) {
            AudioRecord recorder = null;
            int bufferSize = 0;
            boolean recording = true;

            int rate = 8000;
            short audioFormat = AudioFormat.ENCODING_PCM_16BIT;
            short channelConfig = AudioFormat.CHANNEL_IN_MONO;

            try {
                bufferSize = AudioRecord.getMinBufferSize(rate,channelConfig, audioFormat);

                recorder = new AudioRecord(AudioSource.DEFAULT, rate, 
                    channelConfig, audioFormat, bufferSize);

                if (recorder.getState() == AudioRecord.STATE_INITIALIZED) {
                    /*
                     *  Android 4.1.2
                     * 
                    int recorder_id = recorder.getAudioSessionId();
                    if (NoiseSuppressor.isAvailable()) NoiseSuppressor.create(recorder_id);
                    */
                }
                else {
                    Toast.makeText(getApplicationContext(), 
                            "Error en la inicialización", Toast.LENGTH_SHORT).show();
                }
            } catch (Exception e) {}

            short[] audioData = new short[bufferSize];

            if (recorder != null) {
                while (recording) {
                    if (recorder.getRecordingState() == AudioRecord.RECORDSTATE_STOPPED) {
                        recorder.startRecording();
                    }
                    else {
                        int numshorts = recorder.read(audioData,0,audioData.length);
                        if ((numshorts != AudioRecord.ERROR_INVALID_OPERATION) && 
                            (numshorts != AudioRecord.ERROR_BAD_VALUE)) {

                            //  Hann
                            double[] preRealData = new double[bufferSize];
                            double PI = 3.14159265359;
                            for (int i = 0; i < bufferSize; i++) {
                                double multiplier = 0.5 * (1 - Math.cos(2*PI*i/(bufferSize-1)));
                                preRealData[i] = multiplier * audioData[i];
                            }

                            DoubleFFT_1D fft = new DoubleFFT_1D(bufferSize);
                            double[] realData = new double[bufferSize * 2];

                            for (int i=0;i