Android Open Source - android-a2dpnostandby A2dp Player Service

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Back to project page android-a2dpnostandby.

License

The source code is released under:

GNU General Public License

Java Source Code

package co.telnet.a2dpnostandby;
// w  ww  .j  av  a 2  s  .  c  o  m
import co.telnet.a2dpnostandby.R;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

public class A2dpPlayerService extends Service {
  private static final String TAG = "A2DP No Standby";

  private final IBinder mBinder = new LocalBinder();
  private final int NOTIFICATION = 1;
  private NotificationManager nm;
  private volatile Thread playerThread;

  private final int duration = 1; // seconds
  private final int sampleRate = 44100;
  private final int numSamples = duration * sampleRate;
  private final double sample[] = new double[numSamples];
  private final double freqOfTone = 440; // hz
  private final byte generatedSnd[] = new byte[2 * numSamples];
  private AudioTrack audioTrack = null;

  public class LocalBinder extends Binder {
    A2dpPlayerService getService() {
      return A2dpPlayerService.this;
    }
  }

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

  @Override
  public void onCreate() {
    showNotification();
    startSoundThread();
  }

  @Override
  public void onDestroy() {
    stopSoundThread();
    stopNotification();
  }

  private void showNotification() {
    nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    PendingIntent pendingIntent = PendingIntent.getActivity(this, 0,
        new Intent(), 0);
    Notification notification = new Notification.Builder(this)
        .setContentTitle("A2DP Player").setContentText("Running")
        .setContentIntent(pendingIntent)
        .setSmallIcon(R.drawable.ic_launcher).build();
    notification.flags = Notification.FLAG_ONGOING_EVENT;
    nm.notify(NOTIFICATION, notification);
  }

  private void stopNotification() {
    nm.cancel(NOTIFICATION);
  }

  /* Tone generation example from http://stackoverflow.com/questions/2413426/playing-an-arbitrary-tone-with-android
   * Not really necessary in practice since the volume is turned down, but a tone is nice for testing. */
  void genTone() {
    // fill out the array
    for (int i = 0; i < numSamples; ++i) {
      sample[i] = Math.sin(2 * Math.PI * i / (sampleRate / freqOfTone));
    }

    // convert to 16 bit pcm sound array
    // assumes the sample buffer is normalized.
    int idx = 0;
    for (final double dVal : sample) {
      // scale to maximum amplitude
      final short val = (short) ((dVal * 32767));
      // in 16 bit wav PCM, first byte is the low order byte
      generatedSnd[idx++] = (byte) (val & 0x00ff);
      generatedSnd[idx++] = (byte) ((val & 0xff00) >>> 8);

    }
  }

  private synchronized void startSoundThread(){
    if(playerThread == null){
      playerThread = new Thread(new Runnable() {
        public void run() {
          Log.v(TAG, "Player thread started.");
          initSound();
          while(Thread.currentThread() == playerThread) {
            playSound();
          }
          cleanupSound();
          Log.v(TAG, "Player thread stopped.");
        }
      });
      playerThread.start();
    }
  }

  private synchronized void stopSoundThread(){
    if(playerThread != null){
      Thread moribund = playerThread;
      playerThread = null;
      moribund.interrupt();
    }
  }

  private void initSound() {
    audioTrack = new AudioTrack(
        AudioManager.STREAM_MUSIC, sampleRate,
        AudioFormat.CHANNEL_OUT_MONO,
        AudioFormat.ENCODING_PCM_16BIT, numSamples, AudioTrack.MODE_STREAM);
    audioTrack.setStereoVolume(0, 0);
    genTone();
  }

  private void playSound() {
    audioTrack.write(generatedSnd, 0, generatedSnd.length);
    audioTrack.play();
  }

  private void cleanupSound() {
    audioTrack.stop();
    audioTrack.release();
    audioTrack = null;
  }
}

Java Source Code List

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