Android 实现多个Audio文件的顺序播放

最近开发Android通讯录播报号码时需用到播放多个连续音频文件，用传统的MediaManager无法满足复杂性需求，而 SoundPool则满足，于是写了一个SoundPool的管理类SoundManager管理音频的播放。

代码如下：

package com.yous365.android.util;

import org.xml.sax.SAXException;

import android.content.Context;
import android.content.res.AssetFileDescriptor;
import android.media.AudioManager;
import android.media.SoundPool;
import android.os.Handler;
import android.util.Log;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Vector;

import javax.xml.parsers.ParserConfigurationException;

public class SoundManager {

private SoundPool mSoundPool;

private HashMap<String, Integer> mSoundPoolMap;

private AudioManager mAudioManager;

private Context mContext;

private Handler mHandler = new Handler();

private Vector<Integer> mKillSoundQueue = new Vector<Integer>();

private VoicePhoneNumberUtil util;

private long delay = 1000;

private long seperateTime = 700;

private float rate = 1.0f;

private String locale;

static private SoundManager _instance;

/**
     * Requests the instance of the Sound Manager and creates it if it does not
     * exist.
     *
     * @return Returns the single instance of the SoundManager
     */
    static synchronized public SoundManager getInstance() {
        if (_instance == null)
            _instance = new SoundManager();
        return _instance;
    }

/**
     *
     */
    private SoundManager() {
        util = VoicePhoneNumberUtil.getInstance();
    }

/**
     * Initialises the storage for the sounds
     *
     * @param theContext The Application context
     */

public void initSounds(Context theContext) {
        mContext = theContext;
        mSoundPool = new SoundPool(1,
                AudioManager.STREAM_MUSIC, 0);
        mSoundPoolMap = new HashMap<String, Integer>();
        mAudioManager = (AudioManager) mContext
                .getSystemService(Context.AUDIO_SERVICE);
    }

/**
     * Add a new Sound to the SoundPool
     *
     * @param key - The Sound Index for Retrieval
     * @param SoundID - The Android ID for the Sound asset.
     */

public void addSound(String key, int SoundID) {
        mSoundPoolMap.put(key,
                mSoundPool.load(mContext, SoundID, 1));
    }
    /**
     *
     * @param key the key we need to get the sound later
     * @param afd  the fie store in the asset
     */
    public void addSound(String key, AssetFileDescriptor afd) {
        mSoundPoolMap.put(key, mSoundPool.load(
                afd.getFileDescriptor(),
                afd.getStartOffset(), afd.getLength(), 1));
    }
   
    /**
     * play the sound loaded to the SoundPool by the key we set
     * @param key  the key in the map
     */
    public void playSound(String key) {

int streamVolume = mAudioManager
                .getStreamVolume(AudioManager.STREAM_MUSIC);
        streamVolume = streamVolume
                / mAudioManager
                        .getStreamMaxVolume(AudioManager.STREAM_MUSIC);