Null Pointer Exception when Audio Record Stopping

Question

I need to record audio from an Android device. Start of recording is working fine, but i cannot stop audio recording. I am getting a null pointer exception error. I am accessing start() and stop() method from other classes. When I use the stop method the record is null.

Here is my audio class

private String getFilename(){
        String filepath = Environment.getExternalStorageDirectory().getPath();
        File file = new File(filepath,AUDIO_RECORDER_FOLDER);

        if(!file.exists()){
                file.mkdirs();
        }

        return (file.getAbsolutePath() + "/Questionnair_" + System.currentTimeMillis() + file_exts[currentFormat]);
}
         public String startRecording(){

                recorder = new MediaRecorder();
                recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
                recorder.setOutputFormat(MediaRecorder.OutputFormat.RAW_AMR);
                recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);


                recorder.setOutputFile(getFilename());
                recorder.setOnErrorListener(errorListener);
                recorder.setOnInfoListener(infoListener); 



        try {
                recorder.prepare();
                recorder.start();
                //dbstore(getFilename());






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



}
    private MediaRecorder.OnErrorListener errorListener = new        MediaRecorder.OnErrorListener() {
           @Override
            public void onError(MediaRecorder mr, int what, int extra) {
                AppLog.logString("Error: " + what + ", " + extra);
        }
};


public static Context getAppContext()
{
return Audio.context;
}
private MediaRecorder.OnInfoListener infoListener = new MediaRecorder.OnInfoListener() {
        @Override
        public void onInfo(MediaRecorder mr, int what, int extra) {
                AppLog.logString("Warning: " + what + ", " + extra);
        }
};




        public void stopRecording(View v) {
            // TODO Auto-generated method stub
            System.out.println("stoping");


              try {

                  if (null != recorder) {
                        System.out.println("recrder is null");

                  recorder.stop();
                  recorder.release();
                  recorder  = null;

                  }

               } catch (IllegalStateException e) {
                    //  it is called before start()


                    e.printStackTrace();
               } catch (RuntimeException e) {
                    // no valid audio/video data has been received
                    e.printStackTrace();
               }
        }

Here is the code how i am accessing methods

new Audio().startRecording();
new Audio().stopRecording();    

How to fix this issue for stop audio recording

Answer 1

You should do something like:

private Audio mAudio;

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

    mAudio = new Audio();
    mAudio.startRecording();               

}

public void stopRecording(){

    if(mAudio != null){

        mAudio.stopRecording();

    }

}