前一段时间一直在研究Android上面的媒体播放器MediaPlayer，不巧的是发现MediaPlayer的不同版本对于网络上的mp3流支持不是很好，于是就下载了网上的Java开源mp3解码播放源码，然后包装了一下之后发现不知道如何在Android系统上进行播放解码出来的音频数据，因此在网上找了大量的相关资料后，发现在Android系统中有一个AudioTrack类，该类可是实现将音频数据输出到音频设备中。
    该类的SDK文档是如下描述的：

android.media.AudioTrack.AudioTrack(int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode) throws IllegalArgumentException

 

public AudioTrack (int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode)

Since: API Level 3

Class constructor.

Parameters

streamType the type of the audio stream. See STREAM_VOICE_CALL, , , and

sampleRateInHz the sample rate expressed in Hertz. Examples of rates are (but not limited to) 44100, 22050 and 11025.

channelConfig describes the configuration of the audio channels. See CHANNEL_OUT_MONO and CHANNEL_OUT_STEREO

audioFormat the format in which the audio data is represented. See ENCODING_PCM_16BIT and ENCODING_PCM_8BIT

bufferSizeInBytes the total size (in bytes) of the buffer where audio data is read from for playback. If using the AudioTrack in streaming mode, you can write data into this buffer in smaller chunks than this size. If using the AudioTrack in static mode, this is the maximum size of the sound that will be played for this instance. See getMinBufferSize(int, int, int) to determine the minimum required buffer size for the successful creation of an AudioTrack instance in streaming mode. Using values smaller than getMinBufferSize() will result in an initialization failure.

mode streaming or static buffer. See and

Throws

IllegalArgumentException

    使用这个类可以很强轻松地将音频数据在Android系统上播放出来，下面贴出我自己写的源码：
    AudioTrack audio = new AudioTrack(
                           AudioManager.STREAM_MUSIC, // 指定在流的类型
                           32000, // 设置音频数据的采样率 32k，如果是44.1k就是44100
                           AudioFormat.CHANNEL_OUT_STEREO, // 设置输出声道为双声道立体声，而CHANNEL_OUT_MONO类型是单声道
                           AudioFormat.ENCODING_PCM_16BIT, // 设置音频数据块是8位还是16位，这里设置为16位。好像现在绝大多数的音频都是16位的了
                           AudioTrack.MODE_STREAM // 设置模式类型，在这里设置为流类型，另外一种MODE_STATIC貌似没有什么效果
                       );
    audio.play(); // 启动音频设备，下面就可以真正开始音频数据的播放了
    // 打开mp3文件，读取数据，解码等操作省略 ...
    byte[] buffer = new buffer[4096];
    int count;
    while(true)
    {
        // 最关键的是将解码后的数据，从缓冲区写入到AudioTrack对象中
        audio.write(buffer, 0, 4096);
        if(文件结束) break;
    }
    // 最后别忘了关闭并释放资源
    audio.stop();
    audio.release();