// Add this code in a method

AudioManager am = null;

// Request focus for music stream and pass AudioManager.OnAudioFocusChangeListener
// implementation reference
int result = am.requestAudioFocus(this, AudioManager.STREAM_MUSIC,
                AudioManager.AUDIOFOCUS_GAIN);

if(result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED)
{
    // Play
}

// Implements AudioManager.OnAudioFocusChangeListener

@Override
public void onAudioFocusChange(int focusChange)
{
    if(focusChange == AudioManager.AUDIOFOCUS_LOSS_TRANSIENT)
    {
        // Pause
    }
    else if(focusChange == AudioManager.AUDIOFOCUS_GAIN)
    {
        // Resume
    }
    else if(focusChange == AudioManager.AUDIOFOCUS_LOSS)
    {
        // Stop or pause depending on your need
    }
}