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:

1 Bitmap  b = ThumbnailUtils.createVideoThumbnail(path,Video.Thumbnails.MICRO_KIND);  
2 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)

 1  // 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。
 2  private Bitmap createVideoThumbnail(String filePath) {
 3  Bitmap bitmap = null;
 4  MediaMetadataRetriever retriever = new MediaMetadataRetriever();
 5  try {
 6     retriever.setMode(MediaMetadataRetriever.MODE_CAPTURE_FRAME_ONLY);
 7     retriever.setDataSource(filePath);
 8     bitmap = retriever.captureFrame();
 9  } catch(IllegalArgumentException ex) {
10     // Assume this is a corrupt video file
11  } catch (RuntimeException ex) {
12     // Assume this is a corrupt video file.
13  } finally {
14     try {
15        retriever.release();
16     } catch (RuntimeException ex) {
17        // Ignore failures while cleaning up.
18     }
19   }
20   return bitmap;
21 }

（2）关于音乐缩略图：

 1  // 对于音乐，取得AlbumImage作为缩略图，还是用MediaMetadataRetriever
 2  private Bitmap createAlbumThumbnail(String filePath) {
 3  Bitmap bitmap = null;
 4  MediaMetadataRetriever retriever = new MediaMetadataRetriever();
 5  try {
 6      retriever.setMode(MediaMetadataRetriever.MODE_GET_METADATA_ONLY);
 7      retriever.setDataSource(filePath);
 8      byte[] art = retriever.extractAlbumArt();
 9      bitmap = BitmapFactory.decodeByteArray(art, 0, art.length);
10  } catch(IllegalArgumentException ex) {
11  } catch (RuntimeException ex) {
12  } finally {
13      try {
14         retriever.release();
15      } catch (RuntimeException ex) {
16         // Ignore failures while cleaning up.
17      }
18   }
19   return bitmap;
20 }

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。

 1 private boolean isMessyCode(String strName) {
 2         try {
 3             Pattern p = Pattern.compile("\s*|	*|
*|
*");
 4             Matcher m = p.matcher(strName);
 5             String after = m.replaceAll("");
 6             String temp = after.replaceAll("\p{P}", "");
 7             char[] ch = temp.trim().toCharArray();
 8 
 9             int length = (ch != null) ? ch.length : 0;
10             for (int i = 0; i < length; i++) {
11                 char c = ch[i];
12                 if (!Character.isLetterOrDigit(c)) {
13                     String str = "" + ch[i];
14                     if (!str.matches("[u4e00-u9fa5]+")) {
15                         return true;
16                     }
17                 }
18             }
19         } catch (Exception e) {
20             e.printStackTrace();
21         }
22 
23         return false;
24     }

检查字符串是否乱码，乱码情况下要做相应的处理

2、二种方式：读取媒体文件数据库（避免乱码）

创建java bean：

 1 public class MediaInfo {  
 2         private int playDuration = 0;  
 3         private String mediaName = "";  
 4         private String mediaAlbum = "";  
 5         private String mediaArtist = "";  
 6         private String mediaYear = "";  
 7         private String mFileName = "";  
 8         private String mFileType = "";  
 9         private String mFileSize = "";  
10         private String mFilePath = "";  
11          
12         public Bitmap getmBitmap() {  
13                 return mBitmap;  
14         }  
15   
16         public void setmBitmap(Bitmap mBitmap) {  
17                 this.mBitmap = mBitmap;  
18         }  
19   
20         private Bitmap mBitmap = null;  
21 
22         public String getMediaName() {  
23                 return mediaName;  
24         }  
25 
26         public void setMediaName(String mediaName) {  
27                 try {  
28                         mediaName =new String (mediaName.getBytes("ISO-8859-1"),"GBK");  
29                 } catch (UnsupportedEncodingException e) {  
30                         // TODO Auto-generated catch block  
31                         e.printStackTrace();  
32                 }  
33                 this.mediaName = mediaName;  
34         }  
35   
36         public String getMediaAlbum() {  
37                 return mediaAlbum;  
38         }  
39   
40         public void setMediaAlbum(String mediaAlbum) {  
41                 try {  
42                         mediaAlbum =new String (mediaAlbum.getBytes("ISO-8859-1"),"GBK");  
43                 } catch (UnsupportedEncodingException e) {  
44                         // TODO Auto-generated catch block  
45                         e.printStackTrace();  
46                 }  
47                 this.mediaAlbum = mediaAlbum;  
48         }  
49 
50         public String getMediaArtist() {  
51                 return mediaArtist;  
52         }  
53 
54         public void setMediaArtist(String mediaArtist) {  
55                 try {  
56                         mediaArtist =new String (mediaArtist.getBytes("ISO-8859-1"),"GBK");  
57                 } catch (UnsupportedEncodingException e) {  
58                         // TODO Auto-generated catch block  
59                         e.printStackTrace();  
60                 }  
61                 this.mediaArtist = mediaArtist;  
62         }  
63 }

媒体信息bean

操作类：

  1 public class MediaInfoProvider {  
  2   
  3         /** 
  4          * context 
  5          */  
  6         private Context mContext = null;  
  7   
  8         /** 
  9          * data path 
 10          */  
 11         private static final String dataPath = "/mnt";  
 12          
 13         /** 
 14          * query column 
 15          */  
 16         private static final String[] mCursorCols = new String[] {  
 17                         MediaStore.Audio.Media._ID, MediaStore.Audio.Media.DISPLAY_NAME,  
 18                         MediaStore.Audio.Media.TITLE, MediaStore.Audio.Media.DURATION,  
 19                         MediaStore.Audio.Media.ARTIST, MediaStore.Audio.Media.ALBUM,  
 20                         MediaStore.Audio.Media.YEAR, MediaStore.Audio.Media.MIME_TYPE,  
 21                         MediaStore.Audio.Media.SIZE, MediaStore.Audio.Media.DATA };  
 22   
 23         /** 
 24          * MediaInfoProvider 
 25          * @param context 
 26          */  
 27         public MediaInfoProvider(Context context) {  
 28                 this.mContext = context;  
 29         }  
 30   
 31         /** 
 32          * get the media file info by path 
 33          * @param filePath 
 34          * @return 
 35          */  
 36         public MediaInfo getMediaInfo(String filePath) {  
 37   
 38                 /* check a exit file */  
 39                 File file = new File(filePath);  
 40                 if (file.exists()) {  
 41                         Toast.makeText(mContext, "sorry, the file is not exit!",  
 42                                         Toast.LENGTH_SHORT);  
 43                 }  
 44                  
 45                 /* create the query URI, where, selectionArgs */  
 46                 Uri Media_URI = null;  
 47                 String where = null;  
 48                 String selectionArgs[] = null;  
 49                  
 50                 if (filePath.startsWith("content://media/")) {  
 51                         /* content type path */  
 52                         Media_URI = Uri.parse(filePath);  
 53                         where = null;  
 54                         selectionArgs = null;  
 55                 } else {  
 56                         /* external file path */  
 57                         if(filePath.indexOf(dataPath) < 0) {  
 58                                 filePath = dataPath + filePath;  
 59                         }  
 60                         Media_URI = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;  
 61                         where = MediaColumns.DATA + "=?";  
 62                         selectionArgs = new String[] { filePath };  
 63                 }  
 64                  
 65                 /* 查询 */  
 66                 Cursor cursor = mContext.getContentResolver().query(Media_URI,  
 67                                 mCursorCols, where, selectionArgs, null);  
 68                 if (cursor == null || cursor.getCount() == 0) {  
 69                         return null;  
 70                 } else {  
 71                         cursor.moveToFirst();  
 72                         MediaInfo info = getInfoFromCursor(cursor);  
 73                         printInfo(info);  
 74                         return info;  
 75                 }  
 76         }  
 77   
 78         /** 
 79          * 获取媒体信息
 80          * @param cursor 
 81          * @return 
 82          */  
 83         private MediaInfo getInfoFromCursor(Cursor cursor) {  
 84                 MediaInfo info = new MediaInfo();  
 85                  
 86                 /* file name */  
 87                 if(cursor.getString(1) != null) {  
 88                         info.setmFileName(cursor.getString(1));  
 89                 }  
 90                 /* media name */  
 91                 if(cursor.getString(2) != null) {  
 92                         info.setMediaName(cursor.getString(2));  
 93                 }  
 94                 /* play duration */  
 95                 if(cursor.getString(3) != null) {  
 96                         info.setPlayDuration(cursor.getInt(3));  
 97                 }  
 98                 /* artist */  
 99                 if(cursor.getString(4) != null) {  
100                         info.setMediaArtist(cursor.getString(4));  
101                 }  
102                 /* album */  
103                 if(cursor.getString(5) != null) {  
104                         info.setMediaAlbum(cursor.getString(5));  
105                 }  
106                 /* media year */  
107                 if (cursor.getString(6) != null) {  
108                         info.setMediaYear(cursor.getString(6));  
109                 } else {  
110                         info.setMediaYear("undefine");  
111                 }  
112                 /* media type */  
113                 if(cursor.getString(7) != null) {  
114                         info.setmFileType(cursor.getString(7).trim());  
115                 }  
116                 /* media size */  
117                 if (cursor.getString(8) != null) {  
118                         float temp = cursor.getInt(8) / 1024f / 1024f;  
119                         String sizeStr = (temp + "").substring(0, 4);  
120                         info.setmFileSize(sizeStr + "M");  
121                 } else {  
122                         info.setmFileSize("undefine");  
123                 }  
124                 /* media file path */  
125                 if (cursor.getString(9) != null) {  
126                         info.setmFilePath(cursor.getString(9));  
127                 }  
128   
129                 return info;  
130         }  
131 }