Android Audio Recording in Background with Service

 

In android audio recording is simple task but when it comes to record in background it becomes little bit difficult so here we are gonna explore audio recording with service.
How to record a audio when the app is running in background ?

In Android any task which has to be done in background we have to use extend Service Class.

How does this Service Class works?
A Service is an application component that can perform long-running operations in the background and does not provide a user interface. Another application component can start a service and it will continue to run in the background even if the user switches to another application. Additionally, a component can bind to a service to interact with it and even perform interprocess communication (IPC). For example, a service might handle network transactions, play music, perform file I/O, or interact with a content provider, all from the background.
AudioService.class

public class AudioService extends Service 

             implements MediaRecorder.OnInfoListener {

private MediaRecorder mRecorder;
//setting maximum file size to be recorded
private long Audio_MAX_FILE_SIZE = 1000000;//1Mb

private int[] amplitudes = new int[100];
private int i = 0;

private File mOutputFile;

@Override
public void onCreate() {
    super.onCreate();
}

@Override
public int onStartCommand(Intent intent, int flags, 

                               int startId) {
    super.onStartCommand(intent, flags, startId);
    return Service.START_STICKY;
}

@Override
public void onStart(Intent intent, int startId) {
    super.onStart(intent, startId);
    startRecording();
}

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}

private void startRecording() {
    mRecorder = new MediaRecorder();
    mRecorder.setOnInfoListener(this);
    mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    mRecorder.setMaxFileSize(Audio_MAX_FILE_SIZE);
    mRecorder.setOutputFormat

                      (MediaRecorder.OutputFormat.MPEG_4);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)

    {
     mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.HE_AAC);
     mRecorder.setAudioEncodingBitRate(48000);
    } else {
      mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
      mRecorder.setAudioEncodingBitRate(64000);
    }
    mRecorder.setAudioSamplingRate(16000);
    mOutputFile = getOutputFile();
    mOutputFile.getParentFile().mkdirs();
    mRecorder.setOutputFile(mOutputFile.getAbsolutePath());

    try {
        mRecorder.prepare();
        mRecorder.start();
        mStartTime = SystemClock.elapsedRealtime();
    } catch (IOException e) {
    }
}

protected void stopRecording(boolean saveFile) {
    mRecorder.stop();
    mRecorder.release();
    mRecorder = null;
    mStartTime = 0;
    if (!saveFile && mOutputFile != null) {
        mOutputFile.delete();
    }

    // to stop the service by itself
    stopSelf();

}

private File getOutputFile() {
    SimpleDateFormat dateFormat = new SimpleDateFormat

                 ("yyyyMMdd_HHmmssSSS", Locale.US);
    return new File(Environment.getExternalStorageDirectory()

             .getAbsolutePath().toString()
            + "/Voice Recorder/RECORDING_"
            + dateFormat.format(new Date())
            + ".m4a");
}

@Override
public void onInfo(MediaRecorder mr, int what, int extra) {
  //check whether file size has reached to 1MB to stop recording
if (what == MediaRecorder.MEDIA_RECORDER_INFO_MAX_FILESIZE_REACHED) {
    stopRecording(true);
}
}

@Override
public void onDestroy() {
    super.onDestroy();
    stopRecording(true);
}

To stop or start the recording or service manually
In Fragment:
Start Service->

getActivity().startService(

new Intent(getActivity(), AudioService.class));

Stop Service->

getActivity().stopService(

new Intent(getActivity(), AudioService.class));

In Activity:
Start Service->

startService(new Intent(ClassName.this, AudioService.class));

Stop Service->

stopService(new Intent(getApplicationContext(),

 AudioService.class));
or
stopService(new Intent(ClassName.this,  

AudioService.class));

November 24, 2015

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