There's no need to copy the demo code, instead, I recommend you to read the instructions below to get a better grasp.

1. Include jlayer library into your project.

jlayer directory in this demo: /app/libs/jl1.0.1.jar

2. Create a jlayer Decoder instance.

    Decoder decoder = new Decoder();
   

3. Create a jlayer BitStream instance of a given mp3 source.

    InputStream mp3Source = new URL("your network mp3 source")
            .openConnection()
            .getInputStream();
    Bitstream bitStream = new Bitstream(mp3Source);
   

4. Create an AudioTrack instance.

    final int sampleRate = 44100;
    final int minBufferSize = AudioTrack.getMinBufferSize(sampleRate,
            AudioFormat.CHANNEL_OUT_STEREO,
            AudioFormat.ENCODING_PCM_16BIT);
   
    AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
            sampleRate,
            AudioFormat.CHANNEL_OUT_STEREO,
            AudioFormat.ENCODING_PCM_16BIT,
            minBufferSize,
            AudioTrack.MODE_STREAM);
   

5. Decode the mp3 BitStream data by Decoder and feed the outcoming PCM chunks to AudioTrack.

    final int READ_THRESHOLD = 2147483647;
    
    Header frame;
    int framesReaded = 0;
    while (framesReaded++ <= READ_THRESHOLD && (frame = bitStream.readFrame()) != null) {
        SampleBuffer sampleBuffer = (SampleBuffer) decoder.decodeFrame(frame, bitStream);
        short[] pcmChunk = sampleBuffer.getBuffer();
        audioTrack.write(pcmChunk, 0, pcmChunk.length);
        bitstream.closeFrame();
    }