【Android开发经验】如何获取媒体库中所有音频文件信息，并在文件增删后及时更新媒体库（转）

/**
 * 
 * @ClassName: com.example.mediastore.Song
 * @Description: 歌曲实体类
 * @author zhaokaiqiang
 * @date 2014-12-4 上午11:49:59
 * 
 */
public class Song {

  private String fileName;
  private String title;
  private int duration;
  private String singer;
  private String album;
  private String year;
  private String type;
  private String size;
  private String fileUrl;

  public String getFileName() {
    return fileName;
  }

  public void setFileName(String fileName) {
    this.fileName = fileName;
  }

  public String getTitle() {
    return title;
  }

  public void setTitle(String title) {
    this.title = title;
  }

  public int getDuration() {
    return duration;
  }

  public void setDuration(int duration) {
    this.duration = duration;
  }

  public String getSinger() {
    return singer;
  }

  public void setSinger(String singer) {
    this.singer = singer;
  }

  public String getAlbum() {
    return album;
  }

  public void setAlbum(String album) {
    this.album = album;
  }

  public String getYear() {
    return year;
  }

  public void setYear(String year) {
    this.year = year;
  }

  public String getType() {
    return type;
  }

  public void setType(String type) {
    this.type = type;
  }

  public String getSize() {
    return size;
  }

  public void setSize(String size) {
    this.size = size;
  }

  public String getFileUrl() {
    return fileUrl;
  }

  public void setFileUrl(String fileUrl) {
    this.fileUrl = fileUrl;
  }

  public Song() {
    super();
  }

  public Song(String fileName, String title, int duration, String singer,
      String album, String year, String type, String size, String fileUrl) {
    super();
    this.fileName = fileName;
    this.title = title;
    this.duration = duration;
    this.singer = singer;
    this.album = album;
    this.year = year;
    this.type = type;
    this.size = size;
    this.fileUrl = fileUrl;
  }

  @Override
  public String toString() {
    return "Song [fileName=" + fileName + ", title=" + title
        + ", duration=" + duration + ", singer=" + singer + ", album="
        + album + ", year=" + year + ", type=" + type + ", size="
        + size + ", fileUrl=" + fileUrl + "]";
  }

}

/**
 * 
 * @ClassName: com.example.mediastore.AudioUtils
 * @Description: 音频文件帮助类
 * @author zhaokaiqiang
 * @date 2014-12-4 上午11:39:45
 * 
 */
public class AudioUtils {

  /**
   * 获取sd卡所有的音乐文件
   * 
   * @return
   * @throws Exception
   */
  public static ArrayList<Song> getAllSongs(Context context) {

    ArrayList<Song> songs = null;

    Cursor cursor = context.getContentResolver().query(
        MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
        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 },
        MediaStore.Audio.Media.MIME_TYPE + "=? or "
            + MediaStore.Audio.Media.MIME_TYPE + "=?",
        new String[] { "audio/mpeg", "audio/x-ms-wma" }, null);

    songs = new ArrayList<Song>();

    if (cursor.moveToFirst()) {

      Song song = null;

      do {
        song = new Song();
        // 文件名
        song.setFileName(cursor.getString(1));
        // 歌曲名
        song.setTitle(cursor.getString(2));
        // 时长
        song.setDuration(cursor.getInt(3));
        // 歌手名
        song.setSinger(cursor.getString(4));
        // 专辑名
        song.setAlbum(cursor.getString(5));
        // 年代
        if (cursor.getString(6) != null) {
          song.setYear(cursor.getString(6));
        } else {
          song.setYear("未知");
        }
        // 歌曲格式
        if ("audio/mpeg".equals(cursor.getString(7).trim())) {
          song.setType("mp3");
        } else if ("audio/x-ms-wma".equals(cursor.getString(7).trim())) {
          song.setType("wma");
        }
        // 文件大小
        if (cursor.getString(8) != null) {
          float size = cursor.getInt(8) / 1024f / 1024f;
          song.setSize((size + "").substring(0, 4) + "M");
        } else {
          song.setSize("未知");
        }
        // 文件路径
        if (cursor.getString(9) != null) {
          song.setFileUrl(cursor.getString(9));
        }
        songs.add(song);
      } while (cursor.moveToNext());

      cursor.close();

    }
    return songs;
  }

}

IntentFilter intentFilter = new IntentFilter(
        Intent.ACTION_MEDIA_SCANNER_STARTED);
    intentFilter.addAction(Intent.ACTION_MEDIA_SCANNER_FINISHED);
    intentFilter.addDataScheme("file");
    sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED,
        Uri.parse("file://"
            + Environment.getExternalStorageDirectory()
                .getAbsolutePath())));

private class ScanReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
      String action = intent.getAction();
      // 当系统开始扫描sd卡时，为了用户体验，可以加上一个等待框
      if (Intent.ACTION_MEDIA_SCANNER_STARTED.equals(action)) {
      }
      // 当系统扫描完毕时，停止显示等待框，并重新查询ContentProvider
      if (Intent.ACTION_MEDIA_SCANNER_FINISHED.equals(action)) {
      }
    }
  }

Caused by: java.lang.SecurityException: Permission Denial: not allowed to send broadcast android.intent.action.MEDIA_MOUNTED from pid=22360, uid=10163

MediaScannerConnection.scanFile(this, new String[] { Environment
        .getExternalStorageDirectory().getAbsolutePath() }, null, null);

使用MediaScannerConnection的scanFile方法，就可以强制扫描我们需要更新的文件路径，之后媒体数据库也会同步更新，这样，就不会出现文件删除，在媒体库中却能搜索到的情况了，也能解决这位朋友提出的新增加歌曲的信息获取问题了。