关于音乐列表的读取，不同的音乐播放器都会有不同的方案，有的是有多重方案并用。例如说，全盘扫描音乐格式文件等，但是Android本身有媒体库，可以读取本地媒体库的数据，来快速获知设备上的音乐。

首先我封装了一个Audio类来存储读取的音频信息。

public class Audio {private String mTitle,mTitleKey,mArtist,mArtistKey,mComposer,mAlbum,mAlbumKey,mDisplayName,mMimeType,mPath;private int mId,mArtistId,mAlbumId,mYear,mTrack;private int mDuration = 0,mSize = 0;private boolean isRingtone = false,isPodcast = false,isAlarm = false,isMusic = false,isNotification = false;public Audio (Bundle bundle) {mId = bundle.getInt(MediaStore.Audio.Media._ID);mTitle = bundle.getString(MediaStore.Audio.Media.TITLE);mTitleKey = bundle.getString(MediaStore.Audio.Media.TITLE_KEY);mArtist = bundle.getString(MediaStore.Audio.Media.ARTIST);mArtistKey = bundle.getString(MediaStore.Audio.Media.ARTIST_KEY);mComposer = bundle.getString(MediaStore.Audio.Media.COMPOSER);mAlbum = bundle.getString(MediaStore.Audio.Media.ALBUM);mAlbumKey = bundle.getString(MediaStore.Audio.Media.ALBUM_KEY);mDisplayName = bundle.getString(MediaStore.Audio.Media.DISPLAY_NAME);mYear = bundle.getInt(MediaStore.Audio.Media.YEAR);mMimeType = bundle.getString(MediaStore.Audio.Media.MIME_TYPE);mPath = bundle.getString(MediaStore.Audio.Media.DATA);mArtistId = bundle.getInt(MediaStore.Audio.Media.ARTIST_ID);mAlbumId = bundle.getInt(MediaStore.Audio.Media.ALBUM_ID);mTrack = bundle.getInt(MediaStore.Audio.Media.TRACK);mDuration = bundle.getInt(MediaStore.Audio.Media.DURATION);mSize = bundle.getInt(MediaStore.Audio.Media.SIZE);isRingtone = bundle.getInt(MediaStore.Audio.Media.IS_RINGTONE) == 1;isPodcast = bundle.getInt(MediaStore.Audio.Media.IS_PODCAST) == 1;isAlarm = bundle.getInt(MediaStore.Audio.Media.IS_ALARM) == 1;isMusic = bundle.getInt(MediaStore.Audio.Media.IS_MUSIC) == 1;isNotification = bundle.getInt(MediaStore.Audio.Media.IS_NOTIFICATION) == 1;}public int getId() {return mId;}public String getMimeType () {return mMimeType;}public int getDuration () {return mDuration;}public int getSize () {return mSize;}public boolean isRingtone () {return isRingtone;}public boolean isPodcast () {return isPodcast;}public boolean isAlarm () {return isAlarm;}public boolean isMusic () {return isMusic;}public boolean isNotification () {return isNotification;}public String getTitle () {return mTitle;}public String getTitleKey () {return mTitleKey;}public String getArtist () {return mArtist;}public int getArtistId () {return mArtistId;}public String getArtistKey () {return mArtistKey;}public String getComposer () {return mComposer;}public String getAlbum () {return mAlbum;}public int getAlbumId () {return mAlbumId;}public String getAlbumKey () {return mAlbumKey;}public String getDisplayName () {return mDisplayName;}public int getYear () {return mYear;}public int getTrack () {return mTrack;}public String getPath () {return mPath;}}

以上类来封装音乐媒体信息，一些变量看名字也能看出来是什么，例如说title,duration此类，无非就是歌曲名称，时长之类的信息，有些变量名字单词认识，但是并不知道干什么用，其实我也不知道是什么信息，虽然打印出来过，但是并不懂到底哪里能用到，反正一股脑都读出来了先，以后再打印输出看看都是些什么。

其次，一个读取媒体音频的方法：

public class MediaUtils {public static final String[] AUDIO_KEYS = new String[]{MediaStore.Audio.Media._ID,MediaStore.Audio.Media.TITLE,MediaStore.Audio.Media.TITLE_KEY,MediaStore.Audio.Media.ARTIST,MediaStore.Audio.Media.ARTIST_ID,MediaStore.Audio.Media.ARTIST_KEY,MediaStore.Audio.Media.COMPOSER,MediaStore.Audio.Media.ALBUM,MediaStore.Audio.Media.ALBUM_ID,MediaStore.Audio.Media.ALBUM_KEY,MediaStore.Audio.Media.DISPLAY_NAME,MediaStore.Audio.Media.DURATION,MediaStore.Audio.Media.SIZE,MediaStore.Audio.Media.YEAR,MediaStore.Audio.Media.TRACK,MediaStore.Audio.Media.IS_RINGTONE,MediaStore.Audio.Media.IS_PODCAST,MediaStore.Audio.Media.IS_ALARM,MediaStore.Audio.Media.IS_MUSIC,MediaStore.Audio.Media.IS_NOTIFICATION,MediaStore.Audio.Media.MIME_TYPE,MediaStore.Audio.Media.DATA};public static List<Audio> getAudioList(Context context) {List<Audio> audioList = new ArrayList<Audio>();ContentResolver resolver = context.getContentResolver();Cursor cursor = resolver.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,AUDIO_KEYS,null,null,null);for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {Bundle bundle = new Bundle ();for (int i = 0; i < AUDIO_KEYS.length; i++) {final String key = AUDIO_KEYS[i];final int columnIndex = cursor.getColumnIndex(key);final int type = cursor.getType(columnIndex);switch (type) {case Cursor.FIELD_TYPE_BLOB:break;case Cursor.FIELD_TYPE_FLOAT:float floatValue = cursor.getFloat(columnIndex);bundle.putFloat(key, floatValue);break;case Cursor.FIELD_TYPE_INTEGER:int intValue = cursor.getInt(columnIndex);bundle.putInt(key, intValue);break;case Cursor.FIELD_TYPE_NULL:break;case Cursor.FIELD_TYPE_STRING:String strValue = cursor.getString(columnIndex);bundle.putString(key, strValue);break;}}Audio audio = new Audio (bundle);audioList.add(audio);}cursor.close();return audioList;}
}

如此返回一个Audio的List，现在我们可以用这个List做一个列表展示。