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基于Android掃描sd卡與系統(tǒng)文件的介紹

更新時(shí)間：2013年06月19日 09:40:53 作者：

本篇文章是對(duì)Android掃描sd卡與系統(tǒng)文件進(jìn)行了詳細(xì)的分析介紹，需要的朋友參考下

如果你做過(guò)多媒體應(yīng)用，一定會(huì)苦惱過(guò)，怎樣獲取sd卡中的多媒體文件。android還是很強(qiáng)大的，如果你知道怎么調(diào)用android的api，萬(wàn)事就ok了。
當(dāng)手機(jī)或模擬器開(kāi)機(jī)時(shí)，會(huì)調(diào)用android的MediaScanner，掃描sd卡和內(nèi)存里的文件。以下是log信息。

復(fù)制代碼代碼如下:

12-13 15:39:11.062: VERBOSE/MediaPlayerService(67): Create new media retriever from pid 349<BR> 
12-13 15:39:11.082: DEBUG/MediaScannerService(349): getDefaultLocale =zh_CN 
12-13 15:39:11.122: DEBUG/SurfaceFlinger(102): Layer::requestBuffer(this=0x7c8c68), index=1, pid=12866, w=309, h=192 success 
12-13 15:39:11.142: INFO/MediaScanner(349): mOriginalCount = 14, prune thumb flag = false<BR> 
12-13 15:39:11.142: DEBUG/MediaScanner(349):  prescan time: 44ms<BR> 
12-13 15:39:11.142: DEBUG/MediaScanner(349):     scan time: 13ms<BR> 
12-13 15:39:11.142: DEBUG/MediaScanner(349): postscan time: 2ms<BR> 
12-13 15:39:11.142: DEBUG/MediaScanner(349):    total time: 59ms<BR> 
12-13 15:39:11.152: DEBUG/MediaProvider(349): un-lock thumbnail worker<BR> 
12-13 15:39:11.152: DEBUG/MediaProvider(349): un-lock thumbnail worker<BR> 
12-13 15:39:11.182: DEBUG/MediaScannerService(349): done scanning volume external 

那么掃描后的記錄它保存到哪里了呢。哈。你覺(jué)得在哪里呢？data/data/com.android.media/providers/databases/external
它存了些什么信息呢，拉出來(lái)看看吧：

那么，我們直接使用ContentProvider就可以直接獲取到sd卡中多媒體的信息了，你還用去listfile么？還用去自己解析媒體文件中的信息么(時(shí)長(zhǎng)，文件名，專輯名。。應(yīng)有盡有哦)？

復(fù)制代碼代碼如下:

Cursor 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); 

好了，最后一個(gè)問(wèn)題<BR> 當(dāng)你往sd卡中添加一些多媒體文件的時(shí)候，android沒(méi)有自動(dòng)將它刷新到數(shù)據(jù)庫(kù)中。那么我們?cè)趺醋屗謩?dòng)刷新呢，如下：

復(fù)制代碼代碼如下:

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

  
private class ScanSdFilesReceiver extends BroadcastReceiver { 
        public void onReceive(Context context, Intent intent) { 
            String action = intent.getAction(); 
            if (Intent.ACTION_MEDIA_SCANNER_STARTED.equals(action)) { 
                scanHandler.sendEmptyMessage(STARTED); 
            } 
            if (Intent.ACTION_MEDIA_SCANNER_FINISHED.equals(action)) { 
                scanHandler.sendEmptyMessage(FINISHED); 
            } 
        } 
    } 

  
private Handler scanHandler = new Handler() { 
        public void handleMessage(Message msg) { 
            super.handleMessage(msg); 
            switch (msg.what) { 
            case STARTED: 
                MyDialog scanDialog = new MyDialog(LocalList.this); 
                scanAlertDialog = scanDialog.scanFile(); 
                scanAlertDialog.show(); 
                Log.i(TAG, "showing"); 
                break; 
            case FINISHED: 
                ArrayList<Song> tempSongs = ReadFileList.readDataFromSD(LocalList.this, LOCAL); 
                if (tempSongs != null && tempSongs.size()>0) { 
                    if (songs != null && songs.size()>0) { 
                        songs.clear(); 
                        songs.addAll(tempSongs); 
                        songAdapter.notifyDataSetChanged(); 
                    }else { 
                        songs = new ArrayList<Song>(); 
                        songs.addAll(tempSongs); 
                        initSong_lv(); 
                    } 
                }else { 
                    Toast.makeText(LocalList.this, "SD卡中沒(méi)有歌曲，請(qǐng)?zhí)砑雍笤賿呙?, Toast.LENGTH_SHORT).show(); 
                } 
                Log.i(TAG, "finish"); 
                if (scanAlertDialog!=null && scanAlertDialog.isShowing()) { 
                    scanAlertDialog.dismiss(); 
                } 
                unregisterReceiver(scanReceiver); 
                break; 
            case DISMISS: 
                Log.i(TAG, "dismiss"); 
                if (scanAlertDialog!=null && scanAlertDialog.isShowing()) { 
                    scanAlertDialog.dismiss(); 
                } 
            default: 
                break; 
            }