Question

I’m using AudioRecorder to record short audio clips but I’m getting IllegalStateException when calling AudioRecord.start() I’ve been looking for hours but can’t find the cause of this…

I’ve set Audio Rec + Write External Storage permissions.

Here’s a piece of my code:

// main activity...

// Audio inits
    final MediaRecorder recorder = new MediaRecorder();

    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
recorder.setOutputFile(getTempPath());

…

// called the sound rec async

new SoundComponent(tvmic, pb, tb).execute(recorder);

// SoundComponent.java
// Getting IllegalStateException when calling recorder[0].start();

[..]
protected Long doInBackground(MediaRecorder... recorder) {


     try {
         recorder[0].prepare();
        } catch (IOException e) {
            Log.e("100", "prepare() failed");
        }




    while (tb.isChecked())
    {
        //publishProgress();
        //recorder[0].prepare();

         recorder[0].start(); // here it were it throws
         try {
             Thread.sleep(250);
         } catch (InterruptedException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
        // int amplitude = recorder[0].getMaxAmplitude();

         recorder[0].stop();

    }


    // TODO Auto-generated method stub
    return null;
}

[..]

public String getTempPath() // audio temp path
{
    String path =  Environment.getExternalStorageDirectory().getAbsolutePath();
    path+="/temp/audiorectemp.3gp";
    return path;
}

Answer 1

Starting and stopping the MediaRecorder multiple times in a loop probably isn’t a good idea. Look closely at what you’re doing, I’ve trimmed your code to make it easier to see…

while (tb.isChecked())
{
     recorder[0].start(); // here it were it throws
     // Sleep here
     recorder[0].stop();
}

It probably isn’t throwing an exception the first time you call start() but it will on the second loop. See the state machine diagram…MediaRecorder

Also, to detect when the doInBackground(...) thread should be exited, ther is a method on AsyncTask which can be called from the UI thread to cancel it.

The loop should ideally be while (!isCancelled()) and you should call the AsyncTask.cancel(...) method from the onCheckedChanged listener of tb in the main Activity code (assuming tb is a CheckBox or some other CompoundButton).