關於音樂列表的讀取，不同的音樂播放器都會有不同的方案，有的是有多重方案並用。例如說，全盤掃描音樂格式檔案等，但是Android本身有媒體庫，可以讀取本地媒體庫的資料，來快速獲知裝置上的音樂。

首先我封裝了一個Audio類來儲存讀取的音訊資訊。

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;
	}
	
}
 

以上類來封裝音樂媒體資訊，一些變數看名字也能看出來是什麼，例如說title,duration此類，無非就是歌曲名稱，時長之類的資訊，有些變數名字單詞認識，但是並不知道幹什麼用，其實我也不知道是什麼資訊，雖然打印出來過，但是並不懂到底哪裡能用到，反正一股腦都讀出來了先，以後再列印輸出看看都是些什麼。

其次，一個讀取媒體音訊的方法：

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;
    }
}
 

如此返回一個Audio的List，現在我們可以用這個List做一個列表展示。