Мне нужно записать аудио, когда я нажимаю кнопку, а затем сохранить эту запись во внешнем хранилище

Question

Я работаю над этим приложением и хочу записывать звук при нажатии кнопки и сохранять этот звук в хранилище устройства. Мое приложение аварийно завершает работу, когда я пытаюсь записать звук, хотя каталог во внутреннем хранилище записывается для того места, где сохраняется звук. Это мой код:

public class Recording extends AppCompatActivity { //<--- line 20

private Button mRecord;
private MediaRecorder mRecorder;
private static final int REQUEST_RECORD_AUDIO_PERMISSION = 200;

private String mFileName = null;
private static final String LOG_TAG = "Recorder";
private TextView mrecord_text;


private File file;

@SuppressLint("ClickableViewAccessibility")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recording);


mRecord = (Button)findViewById(R.id.record);
mrecord_text = (TextView)findViewById(R.id.record_text);


String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/RecorderfX");
myDir.mkdirs();
Random generator = new Random();
int n = 10000;
n = generator.nextInt(n);
mFileName = "/VM"+ n +"rscx.3gpp";
 file = new File (myDir, mFileName);
if (file.exists ())
    file.delete ();
try {
    FileOutputStream out = new FileOutputStream(file);
    out.flush();
    out.close();

} catch (Exception e) {
    e.printStackTrace();
}


mRecord.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View view, MotionEvent motionEvent)
    {
        if (motionEvent.getAction() == motionEvent.ACTION_DOWN)
        {

            startRecording();  //<-- line 79
            mrecord_text.setText("Recording started...");

        }
        else if(motionEvent.getAction() == MotionEvent.ACTION_UP)
        {

            stopRecording();
            mrecord_text.setText("Recording stopped...");
        }

        return false;
    }
  });
 }

 private void startRecording() {
  mRecorder = new MediaRecorder();

  mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
  mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
  mRecorder.setOutputFile(mFileName);
  mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

  try {
      mRecorder.prepare();
  } catch (IOException e) {
      Log.e(LOG_TAG, "prepare() failed");
  }
  mRecorder.start();  //<-- line 111
 }

 private void stopRecording() {
   mRecorder.stop();
   mRecorder.release();
   mRecorder = null;
 }
}

Это моя трассировка стека, и когда я смотрю на строки, предположительно ошибочные, все выглядит просто отлично. Что я могу делать не так?

05-12 11:39:41.937 4240-4240/com.recorderfx.recorderfx E/
AndroidRuntime: 
FATAL EXCEPTION: main                                                                      
 Process: com.recorderfx.recorderfx, PID: 4240

 java.lang.IllegalStateException
                                                                      at 
 android.media.MediaRecorder.start(Native Method)
                                                                      at 
 com.recorderfx.recorderfx.Recording.startRecording(Recording.java:111)
                                                                      at 
 com.recorderfx.recorderfx.Recording.access$000(Recording.java:20)
                                                                      at 
  com.recorderfx.recorderfx.Recording$1.onTouch(Recording.java:79)
                                                                      at 
  android.view.View.dispatchTouchEvent(View.java:8802)
                                                                      at 
   android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
                                                                      at 
    android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
                                                                      at 
  android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
                                                                      at 
   android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
                                                                      at 
   android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
                                                                      at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
                                                                      at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
                                                                      at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
                                                                      at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
                                                                      at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
                                                                      at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2581)
                                                                      at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2196)
                                                                      at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2607)
                                                                      at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1779)
                                                                      at android.app.Activity.dispatchTouchEvent(Activity.java:2846)
                                                                      at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:68)
                                                                      at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:68)
                                                                      at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2568)
                                                                      at android.view.View.dispatchPointerEvent(View.java:9003)
                                                                      at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4209)
                                                                      at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4072)
                                                                      at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3627)
                                                                      at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3680)
                                                                      at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3646)
                                                                      at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3763)
                                                                      at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3654)
                                                                      at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3820)
                                                                      at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3627)
                                                                      at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3680)
                                                                      at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3646)
                                                                      at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3654)
                                                                      at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3627)
                                                                      at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5910)
                                                                      at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5884)
                                                                      at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5855)
                                                                      at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6000)
                                                                      at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
                                                                      at android.os.MessageQueue.nativePollOnce(Native Method)
                                                                      at android.os.MessageQueue.next(MessageQueue.java:143)
                                                                      at android.os.Looper.loop(Looper.java:122)
                                                                      at android.app.ActivityThread.main(ActivityThread.java:5910)
                                                                      at java.lang.reflect.Method.invoke(Native Method)
                                                                      at java.lang.reflect.Method.invoke(Method.java:372)
                                                                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
                                                                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)