import android.app.Activity;

import android.os.Bundle;

import android.os.Environment;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import java.io.IOException;

public class MainActivity extends Activity {

    private static final String SAMPLE = Environment.getExternalStorageDirectory() + "/test.aac";

    protected static AudioDecoderThread mAudioDecoder;

    private Button btn;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        btn = (Button) findViewById(R.id.play);

        mAudioDecoder = new AudioDecoderThread();

        btn.setOnClickListener(new OnClickListener() {

            @Override

            public void onClick(View view) {

                try {

                    mAudioDecoder.startPlay(SAMPLE);

                } catch (IOException e) {

                    e.printStackTrace();

                }

            }

        });

    }

    @Override

    protected void onStop() {

        super.onStop();

        mAudioDecoder.stop();

    }

}

import android.media.AudioFormat;

import android.media.AudioManager;

import android.media.AudioTrack;

import android.media.MediaCodec;

import android.media.MediaCodec.BufferInfo;

import android.media.MediaExtractor;

import android.media.MediaFormat;

import android.util.Log;

import java.io.IOException;

import java.nio.ByteBuffer;

public class AudioDecoderThread {

    private static final int TIMEOUT_US = 1000;

    private MediaExtractor mExtractor;

    private MediaCodec mDecoder;

    private boolean eosReceived;

    private int mSampleRate = 0;

    int channel = 0;

    private final String TAG = "AACPlay";

    public void startPlay(String path) throws IOException {

        eosReceived = false;

        //创建MediaExtractor对象用来解AAC封装

        mExtractor = new MediaExtractor();

        try {

            //设置需要MediaExtractor解析的文件的路径

            mExtractor.setDataSource(path);

        } catch (IOException e) {

            e.printStackTrace();

        }

            MediaFormat format = mExtractor.getTrackFormat(0);

            if (format == null)

            {

                Log.e(TAG,"format is null");

                return;

            }

            //判断当前帧的文件类型是否为audio

            String mime = format.getString(MediaFormat.KEY_MIME);

            if (mime.startsWith("audio/")) {

                Log.d(TAG, "format : " + format);

                //获取当前帧的采样率

                mExtractor.selectTrack(0);

                mSampleRate = format.getInteger(MediaFormat.KEY_SAMPLE_RATE);

                //获取当前帧的通道数

                channel = format.getInteger(MediaFormat.KEY_CHANNEL_COUNT);

                //音频文件长度

                long duration = format.getLong(MediaFormat.KEY_DURATION);

                Log.d(TAG,"length:"+duration/1000000);

            }

        //创建MediaCodec对象

        mDecoder = MediaCodec.createDecoderByType(mime);

        //配置MediaCodec

        mDecoder.configure(format, null, null, 0);

        if (mDecoder == null) {

            Log.e(TAG, "Can't find video info!");

            return;

        }

        //启动MediaCodec

        mDecoder.start();

        new Thread(AACDecoderAndPlayRunnable).start();

    }

    Runnable AACDecoderAndPlayRunnable = new Runnable() {

        @Override

        public void run() {

            AACDecoderAndPlay();

        }

    };

    public void AACDecoderAndPlay() {

        ByteBuffer[] inputBuffers = mDecoder.getInputBuffers();

        ByteBuffer[] outputBuffers = mDecoder.getOutputBuffers();

        BufferInfo info = new BufferInfo();

        int buffsize = AudioTrack.getMinBufferSize(mSampleRate, AudioFormat.CHANNEL_OUT_STEREO, AudioFormat.ENCODING_PCM_16BIT);

        // 创建AudioTrack对象

        AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, mSampleRate,

                AudioFormat.CHANNEL_OUT_STEREO,

                AudioFormat.ENCODING_PCM_16BIT,

                buffsize,

                AudioTrack.MODE_STREAM);

        //启动AudioTrack

        audioTrack.play();

        while (!eosReceived) {

            int inIndex = mDecoder.dequeueInputBuffer(TIMEOUT_US);

            if (inIndex >= 0) {

                ByteBuffer buffer = inputBuffers[inIndex];

                //从MediaExtractor中读取一帧待解数据

                int sampleSize = mExtractor.readSampleData(buffer, 0);

                if (sampleSize < 0) {

                    // We shouldn't stop the playback at this point, just pass the EOS

                    // flag to mDecoder, we will get it again from the

                    // dequeueOutputBuffer

                    Log.d(TAG, "InputBuffer BUFFER_FLAG_END_OF_STREAM");

                    mDecoder.queueInputBuffer(inIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);

                } else {

                    //向MediaDecoder输入一帧待解码数据

                    mDecoder.queueInputBuffer(inIndex, 0, sampleSize, mExtractor.getSampleTime(), 0);

                    mExtractor.advance();

                }

                //从MediaDecoder队列取出一帧解码后的数据

                int outIndex = mDecoder.dequeueOutputBuffer(info, TIMEOUT_US);

                switch (outIndex) {

                    case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED:

                        Log.d(TAG, "INFO_OUTPUT_BUFFERS_CHANGED");

                        outputBuffers = mDecoder.getOutputBuffers();

                        break;

                    case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED:

                        MediaFormat format = mDecoder.getOutputFormat();

                        Log.d(TAG, "New format " + format);

                        audioTrack.setPlaybackRate(format.getInteger(MediaFormat.KEY_SAMPLE_RATE));

                        break;

                    case MediaCodec.INFO_TRY_AGAIN_LATER:

                        Log.d(TAG, "dequeueOutputBuffer timed out!");

                        break;

                    default:

                        ByteBuffer outBuffer = outputBuffers[outIndex];

                        //Log.v(TAG, "outBuffer: " + outBuffer);

                        final byte[] chunk = new byte[info.size];

                        // Read the buffer all at once

                        outBuffer.get(chunk);

                        //清空buffer,否则下一次得到的还会得到同样的buffer

                        outBuffer.clear();

                        // AudioTrack write data

                        audioTrack.write(chunk, info.offset, info.offset + info.size);

                        mDecoder.releaseOutputBuffer(outIndex, false);

                        break;

                }

                // 所有帧都解码、播放完之后退出循环

                if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {

                    Log.d(TAG, "OutputBuffer BUFFER_FLAG_END_OF_STREAM");

                    break;

                }

            }

        }

        //释放MediaDecoder资源

        mDecoder.stop();

        mDecoder.release();

        mDecoder = null;

        //释放MediaExtractor资源

        mExtractor.release();

        mExtractor = null;

        //释放AudioTrack资源

        audioTrack.stop();

        audioTrack.release();

        audioTrack = null;

    }

    public void stop() {

        eosReceived = true;

    }

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical">

    <Button

        android:id="@+id/play"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="Play" />

</LinearLayout>