Audiorecord给出零值

Question

这个问题已被多次询问，但所提供的答案并没有解决我的问题。我正在使用此链接中提供的代码： How to record audio using AudioRecorder in Android

，代码是：

public class MainActivity extends Activity {

        private static final int RECORDER_SAMPLERATE = 8000;
        private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_MONO;
        private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;
        private AudioRecord recorder = null;
        private Thread recordingThread = null;
        private boolean isRecording = false;


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

            setButtonHandlers();
            enableButtons(false);             
    }

    int bufferSize = AudioRecord.getMinBufferSize(RECORDER_SAMPLERATE,
                    RECORDER_CHANNELS, RECORDER_AUDIO_ENCODING);

        private void setButtonHandlers() {
            ((Button) findViewById(R.id.btnStart)).setOnClickListener(btnClick);
            ((Button) findViewById(R.id.btnStop)).setOnClickListener(btnClick);
        }

        private void enableButton(int id, boolean isEnable) {
            ((Button) findViewById(id)).setEnabled(isEnable);
        }

        private void enableButtons(boolean isRecording) {
            enableButton(R.id.btnStart, !isRecording);
            enableButton(R.id.btnStop, isRecording);
        }

        int BufferElements2Rec = 1024; // want to play 2048 (2K) since 2 bytes we use only 1024
        int BytesPerElement = 2; // 2 bytes in 16bit format

        private void startRecording() {

            recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
                    RECORDER_SAMPLERATE, RECORDER_CHANNELS,
                    RECORDER_AUDIO_ENCODING, BufferElements2Rec * BytesPerElement);

            recorder.startRecording();
            isRecording = true;
            recordingThread = new Thread(new Runnable() {
                public void run() {
                   writeAudioDataToFile();
               }
           }, "AudioRecorder Thread");
           recordingThread.start();
        }

         //convert short to byte
        private byte[] short2byte(short[] sData) {
            int shortArrsize = sData.length;
            byte[] bytes = new byte[shortArrsize * 2];
            for (int i = 0; i < shortArrsize; i++) {
                bytes[i * 2] = (byte) (sData[i] & 0x00FF);
                bytes[(i * 2) + 1] = (byte) (sData[i] >> 8);
                sData[i] = 0;
            }
            return bytes;

        }

        private void writeAudioDataToFile() {
            // Write the output audio in byte

            String filePath = "/sdcard/voice8K16bitmono.pcm";
            short sData[] = new short[BufferElements2Rec];

            FileOutputStream os = null;
            try {
                os = new FileOutputStream(filePath);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }



            while (isRecording) {
                // gets the voice output from microphone to byte format

                recorder.read(sData, 0, BufferElements2Rec);
                System.out.println("Short wirting to file" + sData.toString());


                try {
                    // // writes the data to file from buffer
                    // // stores the voice buffer
                    byte bData[] = short2byte(sData);
                    os.write(bData, 0, BufferElements2Rec * BytesPerElement);



                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            try {
                os.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        private void stopRecording() {
            // stops the recording activity
            if (null != recorder) {
                isRecording = false;
                recorder.stop();
                recorder.release();
                recorder = null;
                recordingThread = null;
            }          
        }
        private View.OnClickListener btnClick = new View.OnClickListener() {
            public void onClick(View v) {
                switch (v.getId()) {
                case R.id.btnStart: {
                    enableButtons(true);
                    startRecording();
                    break;
                }
                case R.id.btnStop: {
                    enableButtons(false);
                    stopRecording();
                    break;
                }
                }
            }
        };

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
                finish();
            }
    return super.onKeyDown(keyCode, event); 
}     

我的问题是存储在sData数组中的数据都是零，我不确定是什么问题。我试图通过手机麦克风传递数据进行进一步分析。

感谢。