Audio Track实现关机音乐

在关机流程中实现关机音乐自定义
/frameworks/base/services/core/java/com/android/server/power/ShutdownThread.java

    //For shutdown music
    private static final String mShutDownMusicPath = "/system/media/shutdownmusic.wav";

          //begin to start shutdown music
        if(DEBUG){
        Log.d(TAG,"EdwardSDT begin to start SDT MUSIC");
            }
        minBufferSize = AudioTrack.getMinBufferSize(44100, AudioFormat.CHANNEL_OUT_STEREO, AudioFormat.ENCODING_PCM_16BIT);
        if(DEBUG){
        Log.d(TAG,"EdwardSDT get the min buffer size " + minBufferSize);
            }
            mAudioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, 44100, AudioFormat.CHANNEL_OUT_STEREO, AudioFormat.ENCODING_PCM_16BIT, minBufferSize*2, AudioTrack.MODE_STREAM);
            if(DEBUG){
        Log.d(TAG,"EdwardSDT has started the track with 2 min buffer size");
            }

        try {
        if(DEBUG){
            Log.d(TAG,"EdwardSDT begin to read file");
        }
        mFile = new File(mShutDownMusicPath);
        mDataInputStream = new DataInputStream(new FileInputStream(mFile));
        } catch (IOException e) {
        e.printStackTrace();
        }

            if(DEBUG){
        Log.d(TAG,"EdwardSDT begin to start Thead");
            }
            playbackthread = new Thread(playTrackThread);
            playbackthread.start();