Android MediaMetadataRetriever 读取多媒体文件信息，元数据(MetaData)

音乐播放器通常需要获取歌曲的专辑、作者、标题、年代等信息，将这些信息显示到UI界面上。

1、一种方式：解析媒体文件  

命名空间：android.media.MediaMetadataRetriever 

android提供统一的接口MediaMetadataRetriever解析媒体文件、获取媒体文件中取得帧和元数据（视频/音频包含的标题、格式、艺术家等信息）。

1   MediaMetadataRetriever mmr = new MediaMetadataRetriever();  
2   String str = getExternalStorageDirectory() + "music/hetangyuese.mp3";

3   mmr.setDataSource(str);  
4   // api level 10, 即从GB2.3.3开始有此功能  
5   String title = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_TITLE); 
6   // 专辑名
7   String album = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ALBUM);  
8   // 媒体格式
9   String mime = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_MIMETYPE);  
10  // 艺术家
11  String artist = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ARTIST);  
12  // 播放时长单位为毫秒  
13  String duration = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
14  // 从api level 14才有，即从ICS4.0才有此功能  
15  String bitrate = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_BITRATE);
16  // 路径
17  String date = mmr.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DATE);  

（1）关于视频缩略图：

2.2 之后：因为用了ThumbnailUtils类:

Bitmap  b = ThumbnailUtils.createVideoThumbnail(path,Video.Thumbnails.MICRO_KIND);  
ImageView iv = new ImageView(this);  

2.2 之前：

使用MediaMetadataRetriever这个类；还可以通过getFrameAtTime方法取得指定time位置的Bitmap，即可以实现抓图（包括缩略图）功能

但是 里面有个问题 
1.0之后 这个类被隐藏了 貌似2.3之后这个类又出现了，但是还可以直接copy源码进去使用:http://blog.csdn.net/lostinai/article/details/7734699 (教程)

 // 对于视频，取第一帧作为缩略图，也就是怎样从filePath得到一个Bitmap对象。
 private Bitmap createVideoThumbnail(String filePath) {
 Bitmap bitmap = null;
 MediaMetadataRetriever retriever = new MediaMetadataRetriever();
 try {
    retriever.setMode(MediaMetadataRetriever.MODE_CAPTURE_FRAME_ONLY);
    retriever.setDataSource(filePath);
    bitmap = retriever.captureFrame();
 } catch(IllegalArgumentException ex) {
    // Assume this is a corrupt video file
 } catch (RuntimeException ex) {
    // Assume this is a corrupt video file.
 } finally {
    try {
       retriever.release();
    } catch (RuntimeException ex) {
       // Ignore failures while cleaning up.
    }
  }
  return bitmap;
}

（2）关于音乐缩略图：

 // 对于音乐，取得AlbumImage作为缩略图，还是用MediaMetadataRetriever
 private Bitmap createAlbumThumbnail(String filePath) {
 Bitmap bitmap = null;
 MediaMetadataRetriever retriever = new MediaMetadataRetriever();
 try {
     retriever.setMode(MediaMetadataRetriever.MODE_GET_METADATA_ONLY);
     retriever.setDataSource(filePath);
     byte[] art = retriever.extractAlbumArt();
     bitmap = BitmapFactory.decodeByteArray(art, 0, art.length);
 } catch(IllegalArgumentException ex) {
 } catch (RuntimeException ex) {
 } finally {
     try {
        retriever.release();
     } catch (RuntimeException ex) {
        // Ignore failures while cleaning up.
     }
  }
  return bitmap;
}

注意：直接得到Bitmap对象，把图片缩小到合适大小就OK。

这样获取出来的，信息有时候可能有乱码：

1、Java如何获取文件编码格式  （使用第三方库进行处理）

2、自己判断字符串是否有乱码，然后自行处理。

private boolean isMessyCode(String strName) {
        try {
            Pattern p = Pattern.compile("\s*|	*|
*|
*");
            Matcher m = p.matcher(strName);
            String after = m.replaceAll("");
            String temp = after.replaceAll("\p{P}", "");
            char[] ch = temp.trim().toCharArray();

            int length = (ch != null) ? ch.length : 0;
            for (int i = 0; i < length; i++) {
                char c = ch[i];
                if (!Character.isLetterOrDigit(c)) {
                    String str = "" + ch[i];
                    if (!str.matches("[u4e00-u9fa5]+")) {
                        return true;
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return false;
    }

2、二种方式：读取媒体文件数据库（避免乱码）

创建java bean： 

public class MediaInfo {  
        private int playDuration = 0;  
        private String mediaName = "";  
        private String mediaAlbum = "";  
        private String mediaArtist = "";  
        private String mediaYear = "";  
        private String mFileName = "";  
        private String mFileType = "";  
        private String mFileSize = "";  
        private String mFilePath = "";  
         
        public Bitmap getmBitmap() {  
                return mBitmap;  
        }  
  
        public void setmBitmap(Bitmap mBitmap) {  
                this.mBitmap = mBitmap;  
        }  
  
        private Bitmap mBitmap = null;  

        public String getMediaName() {  
                return mediaName;  
        }  

        public void setMediaName(String mediaName) {  
                try {  
                        mediaName =new String (mediaName.getBytes("ISO-8859-1"),"GBK");  
                } catch (UnsupportedEncodingException e) {  
                        // TODO Auto-generated catch block  
                        e.printStackTrace();  
                }  
                this.mediaName = mediaName;  
        }  
  
        public String getMediaAlbum() {  
                return mediaAlbum;  
        }  
  
        public void setMediaAlbum(String mediaAlbum) {  
                try {  
                        mediaAlbum =new String (mediaAlbum.getBytes("ISO-8859-1"),"GBK");  
                } catch (UnsupportedEncodingException e) {  
                        // TODO Auto-generated catch block  
                        e.printStackTrace();  
                }  
                this.mediaAlbum = mediaAlbum;  
        }  

        public String getMediaArtist() {  
                return mediaArtist;  
        }  

        public void setMediaArtist(String mediaArtist) {  
                try {  
                        mediaArtist =new String (mediaArtist.getBytes("ISO-8859-1"),"GBK");  
                } catch (UnsupportedEncodingException e) {  
                        // TODO Auto-generated catch block  
                        e.printStackTrace();  
                }  
                this.mediaArtist = mediaArtist;  
        }  
}  

操作类：

public class MediaInfoProvider {  
  
        /** 
         * context 
         */  
        private Context mContext = null;  
  
        /** 
         * data path 
         */  
        private static final String dataPath = "/mnt";  
         
        /** 
         * query column 
         */  
        private static final String[] mCursorCols = new String[] {  
                        MediaStore.Audio.Media._ID, MediaStore.Audio.Media.DISPLAY_NAME,  
                        MediaStore.Audio.Media.TITLE, MediaStore.Audio.Media.DURATION,  
                        MediaStore.Audio.Media.ARTIST, MediaStore.Audio.Media.ALBUM,  
                        MediaStore.Audio.Media.YEAR, MediaStore.Audio.Media.MIME_TYPE,  
                        MediaStore.Audio.Media.SIZE, MediaStore.Audio.Media.DATA };  
  
        /** 
         * MediaInfoProvider 
         * @param context 
         */  
        public MediaInfoProvider(Context context) {  
                this.mContext = context;  
        }  
  
        /** 
         * get the media file info by path 
         * @param filePath 
         * @return 
         */  
        public MediaInfo getMediaInfo(String filePath) {  
  
                /* check a exit file */  
                File file = new File(filePath);  
                if (file.exists()) {  
                        Toast.makeText(mContext, "sorry, the file is not exit!",  
                                        Toast.LENGTH_SHORT);  
                }  
                 
                /* create the query URI, where, selectionArgs */  
                Uri Media_URI = null;  
                String where = null;  
                String selectionArgs[] = null;  
                 
                if (filePath.startsWith("content://media/")) {  
                        /* content type path */  
                        Media_URI = Uri.parse(filePath);  
                        where = null;  
                        selectionArgs = null;  
                } else {  
                        /* external file path */  
                        if(filePath.indexOf(dataPath) < 0) {  
                                filePath = dataPath + filePath;  
                        }  
                        Media_URI = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;  
                        where = MediaColumns.DATA + "=?";  
                        selectionArgs = new String[] { filePath };  
                }  
                 
                /* 查询 */  
                Cursor cursor = mContext.getContentResolver().query(Media_URI,  
                                mCursorCols, where, selectionArgs, null);  
                if (cursor == null || cursor.getCount() == 0) {  
                        return null;  
                } else {  
                        cursor.moveToFirst();  
                        MediaInfo info = getInfoFromCursor(cursor);  
                        printInfo(info);  
                        return info;  
                }  
        }  
  
        /** 
         * 获取媒体信息
         * @param cursor 
         * @return 
         */  
        private MediaInfo getInfoFromCursor(Cursor cursor) {  
                MediaInfo info = new MediaInfo();  
                 
                /* file name */  
                if(cursor.getString(1) != null) {  
                        info.setmFileName(cursor.getString(1));  
                }  
                /* media name */  
                if(cursor.getString(2) != null) {  
                        info.setMediaName(cursor.getString(2));  
                }  
                /* play duration */  
                if(cursor.getString(3) != null) {  
                        info.setPlayDuration(cursor.getInt(3));  
                }  
                /* artist */  
                if(cursor.getString(4) != null) {  
                        info.setMediaArtist(cursor.getString(4));  
                }  
                /* album */  
                if(cursor.getString(5) != null) {  
                        info.setMediaAlbum(cursor.getString(5));  
                }  
                /* media year */  
                if (cursor.getString(6) != null) {  
                        info.setMediaYear(cursor.getString(6));  
                } else {  
                        info.setMediaYear("undefine");  
                }  
                /* media type */  
                if(cursor.getString(7) != null) {  
                        info.setmFileType(cursor.getString(7).trim());  
                }  
                /* media size */  
                if (cursor.getString(8) != null) {  
                        float temp = cursor.getInt(8) / 1024f / 1024f;  
                        String sizeStr = (temp + "").substring(0, 4);  
                        info.setmFileSize(sizeStr + "M");  
                } else {  
                        info.setmFileSize("undefine");  
                }  
                /* media file path */  
                if (cursor.getString(9) != null) {  
                        info.setmFilePath(cursor.getString(9));  
                }  
  
                return info;  
        }  
}