AudioPauser.java

package ee.ioc.phon.android.speak;

import android.content.Context;
import android.media.AudioManager;
import android.media.AudioManager.OnAudioFocusChangeListener;

public class AudioPauser {

    private final AudioManager mAudioManager;
    private final OnAudioFocusChangeListener mAfChangeListener;
    private int mCurrentVolume;
    private boolean isPausing = false;

    public AudioPauser(Context context) {
        mAudioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);

        mAfChangeListener = new OnAudioFocusChangeListener() {
            public void onAudioFocusChange(int focusChange) {
                Log.i("onAudioFocusChange" + focusChange);
            }
        };
    }


    /**
     * Requests audio focus with the goal of pausing any existing audio player.
     * Additionally mutes the music stream, since some audio players might
     * ignore the focus request.
     * In other words, during the pause no sound will be heard,
     * but whether the audio resumes from the same position after the pause
     * depends on the audio player.
     * <p/>
     * TODO: we do this only if the music is active (not sure it always works)
     */
    public void pause() {
        if (!isPausing && mAudioManager.isMusicActive()) {
            mCurrentVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
            int result = mAudioManager.requestAudioFocus(mAfChangeListener, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
            if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
                Log.i("AUDIOFOCUS_REQUEST_GRANTED");
            }
            // TODO: improve this: cuts off the beep
            //mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, 0, 0);
            isPausing = true;
            Log.i("AudioPauser: pause: " + mCurrentVolume);
        }
    }


    /**
     * Abandons audio focus and restores the audio volume.
     */
    public void resume() {
        if (isPausing) {
            mAudioManager.abandonAudioFocus(mAfChangeListener);
            mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, mCurrentVolume, 0);
            isPausing = false;
            Log.i("AudioPauser: resume: " + mCurrentVolume);
        }
    }

}