android 扫描SD卡与系统文件

 当手机或模拟器开机时，会调用android的MediaScanner，扫描sd卡和内存里的文件。以下是log信息。

 

112-13 15:39:11.062: VERBOSE/MediaPlayerService(67): Create new media retriever from pid 349<BR>

 

112-13 15:39:11.082: DEBUG/MediaScannerService(349): getDefaultLocale =zh_CN

 

112-13 15:39:11.122: DEBUG/SurfaceFlinger(102): Layer::requestBuffer(this=0x7c8c68), index=1, pid=12866, w=309, h=192 success

 

112-13 15:39:11.142: INFO/MediaScanner(349): mOriginalCount = 14, prune thumb flag = false<BR>

 

112-13 15:39:11.142: DEBUG/MediaScanner(349):  prescan time: 44ms<BR>

 

112-13 15:39:11.142: DEBUG/MediaScanner(349):     scan time: 13ms<BR>

 

112-13 15:39:11.142: DEBUG/MediaScanner(349): postscan time: 2ms<BR>

 

112-13 15:39:11.142: DEBUG/MediaScanner(349):    total time: 59ms<BR>

 

112-13 15:39:11.152: DEBUG/MediaProvider(349): un-lock thumbnail worker<BR>

 

112-13 15:39:11.152: DEBUG/MediaProvider(349): un-lock thumbnail worker<BR>

 

112-13 15:39:11.182: DEBUG/MediaScannerService(349): done scanning volume external

 

1那么扫描后的记录它保存到哪里了呢。哈。你觉得在哪里呢？data/data/com.android.media/providers/databases/external

 

1它存了些什么信息呢，拉出来看看吧：

 

1 那么，我们直接使用ContentProvider就可以直接获取到sd卡中多媒体的信息了，你还用去listfile么？还用去自己解析媒体文件中的信息么(时长，文件名，专辑名。。应有尽有哦)？

 

1Cursor cursor = context.getContentResolver().query(<BR>    MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,<BR>    new String[] { MediaStore.Audio.Media._ID, MediaStore.Audio.Media.DISPLAY_NAME, MediaStore.Audio.Media.TITLE,<BR>      MediaStore.Audio.Media.DURATION, MediaStore.Audio.Media.ARTIST, MediaStore.Audio.Media.ALBUM,<BR>      MediaStore.Audio.Media.YEAR, MediaStore.Audio.Media.MIME_TYPE, MediaStore.Audio.Media.SIZE, MediaStore.Audio.Media.DATA}<BR>    , "_size>?", new String[]{1024*1024+""},null);

 

1好了，最后一个问题<BR> 当你往sd卡中添加一些多媒体文件的时候，android没有自动将它刷新到数据库中。那么我们怎么让它手动刷新呢，如下：

 

01IntentFilter intentFilter = new IntentFilter(Intent.ACTION_MEDIA_SCANNER_STARTED);

02        intentFilter.addAction(Intent.ACTION_MEDIA_SCANNER_FINISHED);

03        intentFilter.addDataScheme("file");

04        scanReceiver = new ScanSdFilesReceiver();

05        registerReceiver(scanReceiver, intentFilter);

06        sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://" + Environment.getExternalStorageDirectory())));

07  

08  

09private class ScanSdFilesReceiver extends BroadcastReceiver {

10        public void onReceive(Context context, Intent intent) {

11            String action = intent.getAction();

12            if (Intent.ACTION_MEDIA_SCANNER_STARTED.equals(action)) {

13                scanHandler.sendEmptyMessage(STARTED);

14            }

15            if (Intent.ACTION_MEDIA_SCANNER_FINISHED.equals(action)) {

16                scanHandler.sendEmptyMessage(FINISHED);

17            }

18        }

19    }

20  

21  

22private Handler scanHandler = new Handler() {

23        public void handleMessage(Message msg) {

24            super.handleMessage(msg);

25            switch (msg.what) {

26            case STARTED:

27                MyDialog scanDialog = new MyDialog(LocalList.this);

28                scanAlertDialog = scanDialog.scanFile();

29                scanAlertDialog.show();

30                Log.i(TAG, "showing");

31                break;

32            case FINISHED:

33                ArrayList<Song> tempSongs = ReadFileList.readDataFromSD(LocalList.this, LOCAL);

34                if (tempSongs != null && tempSongs.size()>0) {

35                    if (songs != null && songs.size()>0) {

36                        songs.clear();

37                        songs.addAll(tempSongs);

38                        songAdapter.notifyDataSetChanged();

39                    }else {

40                        songs = new ArrayList<Song>();

41                        songs.addAll(tempSongs);

42                        initSong_lv();

43                    }

44                }else {

45                    Toast.makeText(LocalList.this, "SD卡中没有歌曲，请添加后再扫描", Toast.LENGTH_SHORT).show();

46                }

47                Log.i(TAG, "finish");

48                if (scanAlertDialog!=null && scanAlertDialog.isShowing()) {

49                    scanAlertDialog.dismiss();

50                }

51                unregisterReceiver(scanReceiver);

52                break;

53            case DISMISS:

54                Log.i(TAG, "dismiss");

55                if (scanAlertDialog!=null && scanAlertDialog.isShowing()) {

56                    scanAlertDialog.dismiss();

57                }

58            default:

59                break;

60            }