车载系统 降噪处理

private AudioManager.OnAudioFocusChangeListener mAudioFocusListener = new AudioManager.OnAudioFocusChangeListener() {    public void onAudioFocusChange(int focusChange) {        switch (focusChange) {            case AudioManager.AUDIOFOCUS_GAIN:     // 之前的音量    1                if (mAudioManager != null)                    mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC,                            (int) (mMaxVolum * 0.8), 0);                if (mIsLossAutioFocus) {                    weDriveResume();                    mIsLossAutioFocus = false;                }                break;

            case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:  // 降音处理  －3                if (mAudioManager != null)                    mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC,                            (int) (mMaxVolum * 0.3), 0);                break;

            case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT: // 失去音频焦点  暂停播放  -2                mIsLossAutioFocus = true;                weDrivePause();                break;

            case AudioManager.AUDIOFOCUS_LOSS:   // -1                // weDrivePause();                break;

            default:                break;        }    }};

//   请求焦点mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

if (mAudioManager != null)

    mAudioManager.requestAudioFocus(mAudioFocusListener,AudioManager.STREAM_MUSIC,AudioManager.AUDIOFOCUS_GAIN);

// 放弃焦点

if (mAudioManager != null)    mAudioManager.abandonAudioFocus(mAudioFocusListener);