Introduction of SD card and system files based on Android scan _android

If you have done multimedia applications, will certainly be distressed, how to obtain the SD card multimedia files. Android is still very powerful, and if you know how to invoke the Android API, everything is OK.
When a cell phone or simulator is powered on, the Android Mediascanner is invoked to scan the SD card and the files in memory. Here is the log information.

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12-13 15:39:11.062:verbose/mediaplayerservice: 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 = 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

So where did the record of the scan go? Ha. Where do you think it is? Data/data/com.android.media/providers/databases/external
what information did it save, pull it out and see:

Then, we directly use ContentProvider can directly access to the SD card multimedia information, you still use to listfile it? Also use to resolve the information in the media file yourself (time length, filename, album name ...). Everything, huh?

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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);

Okay, last question <BR> when you add some multimedia files to your SD card, Android doesn't automatically flush it into the database. So how do we get it to be refreshed manually, as follows:

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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 (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, "No songs in SD card, please add after Scan", 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
}