使用AudioRecord实例获取错误代码20

Question

我正在开发一个通过MIC记录并改变其频率的Android应用程序。类似于iphone的Helium booth应用程序。目前我已编写代码来记录文件并将其保存在SD卡中。我收到的错误是：

Could not get audio input for record source 1
Error creating AudioRecord instance: initialization check failed.
[ android.media.AudioRecord ] Error code -20 when initializing native
FATAL EXCEPTION: Thread-10
java.lang.IllegalStateException: startRecording() called on an uninitialized 

以下是我的代码：

public class MainActivity extends Activity {

Integer[] freqset = {8000};
 private ArrayAdapter<Integer> adapter;

 Spinner spFrequency;
 Button startRec, stopRec, playBack;

 Boolean recording;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        startRec = (Button)findViewById(R.id.startrec);
        stopRec = (Button)findViewById(R.id.stoprec);
        playBack = (Button)findViewById(R.id.playback);

        startRec.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                   Thread recordThread = new Thread(new Runnable(){

                        @Override
                        public void run() {
                         recording = true;
                         startRecord();
                        }

                       });

                       recordThread.start();

            }
        });
        stopRec.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                recording = false;

            }
        });
        playBack.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                 playRecord();

            }
        });

        spFrequency = (Spinner)findViewById(R.id.frequency);
        adapter = new ArrayAdapter<Integer>(this, android.R.layout.simple_spinner_item, freqset);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spFrequency.setAdapter(adapter);

    }

 private void startRecord(){

  File file = new File(Environment.getExternalStorageDirectory(), "test.pcm"); 
  int BytesPerElement = 2;
  int sampleFreq = (Integer)spFrequency.getSelectedItem();
    Log.e("Test","Start Recording"+sampleFreq);
  try {
   file.createNewFile();

   OutputStream outputStream = new FileOutputStream(file);
   BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(outputStream);
   DataOutputStream dataOutputStream = new DataOutputStream(bufferedOutputStream);

   int minBufferSize = AudioRecord.getMinBufferSize(sampleFreq, 
     AudioFormat.CHANNEL_IN_MONO, 
     AudioFormat.ENCODING_PCM_16BIT);
   Log.i("Test","Buffer Size is"+minBufferSize);

   short[] audioData = new short[minBufferSize];
   Log.i("Test","audioData initialized"+audioData);
   AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,
     sampleFreq,
     AudioFormat.CHANNEL_IN_MONO,
     AudioFormat.ENCODING_PCM_16BIT,
     minBufferSize*BytesPerElement);
   Log.i("Test","audioRecord initialized"+audioRecord);

   audioRecord.startRecording();

   while(recording){
    int numberOfShort = audioRecord.read(audioData, 0, minBufferSize);
    for(int i = 0; i < numberOfShort; i++){
     dataOutputStream.writeShort(audioData[i]);
       Log.i("Test","Recording buzzz");

    }
   }

   audioRecord.stop();
   dataOutputStream.close();

  } catch (IOException e) {
   e.printStackTrace();
   Log.e("Testing", "Esception Found");
  }

 }

 void playRecord(){

  File file = new File(Environment.getExternalStorageDirectory(), "test.pcm");

        int shortSizeInBytes = Short.SIZE/Byte.SIZE;

  int bufferSizeInBytes = (int)(file.length()/shortSizeInBytes);
  short[] audioData = new short[bufferSizeInBytes];

  try {
   InputStream inputStream = new FileInputStream(file);
   BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);
   DataInputStream dataInputStream = new DataInputStream(bufferedInputStream);

   int i = 0;
   while(dataInputStream.available() > 0){
    audioData[i] = dataInputStream.readShort();
    i++;
   }

   dataInputStream.close();

   int sampleFreq = (Integer)spFrequency.getSelectedItem();

   AudioTrack audioTrack = new AudioTrack(
     AudioManager.STREAM_MUSIC,
     sampleFreq,
     AudioFormat.CHANNEL_CONFIGURATION_MONO,
     AudioFormat.ENCODING_PCM_16BIT,
     bufferSizeInBytes,
     AudioTrack.MODE_STREAM);

   audioTrack.play();
   audioTrack.write(audioData, 0, bufferSizeInBytes);


  } catch (FileNotFoundException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.printStackTrace();
  }
 }}

P.S我之前问了类似的问题，但我使用的是MediaRecorder。我现在正在使用AudioRecord课程。