밑에 소스 이용하면 저장은 되는 것 같은데 stop버튼을 누르면 멈추지가 않네요... 왜그러죠..ㅠㅠㅠ

고수님들 도와주세요..
//////////////////////////////////////////////////////////////////////////////////////////////
public class aaa extends Activity {
    /** Called when the activity is first created. */
 private Button mStart_btn;
 private Button mStop_btn;
 private boolean isRecording = false;
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mStart_btn = (Button)findViewById(R.id.start_btn);
        mStop_btn  = (Button)findViewById(R.id.stop_btn);
       
       
        mStart_btn.setOnClickListener(new Button.OnClickListener()
        {
         public void onClick(View v)
         {
          isRecording = true;
          bbb();
         }
        });
        mStop_btn.setOnClickListener(new Button.OnClickListener()
        {
         public void onClick(View v)
         {
          isRecording = false;
         }
        });
    }
    public void bbb() {
        int sampleRateInHz = 8000;// 44100, 22050 and 11025
        int channelConfig = AudioFormat.CHANNEL_CONFIGURATION_MONO;
        int audioFormat = AudioFormat.ENCODING_PCM_16BIT;
        File file = new
        File(Environment.getExternalStorageDirectory(), "xyz.pcm");
       
        if (file.exists())
                file.delete();

        try {
                file.createNewFile();
        } catch (IOException e) {
                Log.e("crate file:", e.toString());
        }

        try {

                OutputStream os = new FileOutputStream(file);
                BufferedOutputStream bos = new BufferedOutputStream(os);
                DataOutputStream dos = new DataOutputStream(bos);

                //int bufferSize =11025 +
                AudioRecord.getMinBufferSize(sampleRateInHz,channelConfig,
                  audioFormat);

                int bufferSize = 440000;

                short[] buffer = new short[bufferSize];

                AudioRecord audioRecord = new
                AudioRecord(MediaRecorder.AudioSource.MIC, sampleRateInHz,
                                channelConfig, audioFormat, bufferSize);

                audioRecord.startRecording();
                Log.e("recording", "before");

                while (isRecording) {
                        int bufferReadResult = audioRecord.read(buffer, 0, bufferSize);
                        for (int i = 0; i < bufferReadResult; i++) {
                                dos.writeShort(buffer[i]);
                                Log.e("recording", "recording....");

                        }
                }
           
                audioRecord.stop();
                dos.close();
                Log.e("recording", "stopeed");

        } catch (Throwable e) {
                Log.e("record:", e.toString());
        }

    }
}