Android APP与媒体存储服务的交互

private static void requestScanFile(Context context, File file) {
    Intent i = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
    i.setData(Uri.fromFile(file));
    context.sendBroadcast(i);
}

private static void requestScanFile(Context context, String file) {
    Intent i = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
    i.setData(Uri.parse("file://" + Uri.encode(file)));
    context.sendBroadcast(i);
}

private void requestScanFile(Context context, String file) {
    MediaScannerConnection.scanFile(context, new String[] {file},
        null, // mime types，可不指定
        mListener);
}

MediaScannerConnection.OnScanCompletedListener mListener =
        new MediaScannerConnection.OnScanCompletedListener() {
    public void onScanCompleted(String path, Uri uri) {
        // TODO: 获取到该文件在多媒体数据库中的 uri，进行下一步动作
    }
};

private static void requestScanDisk(Context context) {
    Intent i = new Intent(Intent.ACTION_MEDIA_MOUNTED);
    String path = Environment.getExternalStorageDirectory().getPath();
    i.setData(Uri.parse("file://" + Uri.encode(path)));
    context.sendBroadcast(i);
}

private void registerReceiver(Context context) {
    IntentFilter filter = new IntentFilter(Intent.ACTION_MEDIA_MOUNTED);
    filter.addAction(Intent.ACTION_MEDIA_SCANNER_FINISHED);
    filter.addAction(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
    filter.addDataScheme("file");
    context.registerReceiver(mReceiver, filter);
}

private BroadcastReceiver mReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        Uri uri = intent.getData();
        if (uri != null && uri.getScheme().equals("file")) {
            Log.v("Receiver", "BroadcastReceiver action = " + action + ", uri = " + uri);
            if (Intent.ACTION_MEDIA_SCANNER_SCAN_FILE.equals(action)) {
                String filePath = uri.getPath();
                // TODO: filePath 文件已改变，APP 刷新界面
            } else if (Intent.ACTION_MEDIA_SCANNER_FINISHED.equals(action)) {
                // TODO: 整个磁盘扫描完成，APP 刷新界面
            }
        }
    }
};

private static boolean isMediaScannerScanning(ContentResolver cr) {
    Cursor cursor = null;
    try {
        cursor = cr.query(MediaStore.getMediaScannerUri(), new String[] {
            MediaStore.MEDIA_SCANNER_VOLUME}, null, null, null);

        if (cursor != null && cursor.getCount() > 0) {
            cursor.moveToFirst();
            return "external".equals(cursor.getString(0));
        }
    } finally {
        if (cursor != null) {
            cursor.close();
        }
    }

    return false;
}

private ContentObserver mContentObserver = new ContentObserver(null) {
    @Override
    public void onChange(boolean selfChange) { // 往后兼容
        onChange(selfChange, null);
    }

    public void onChange(boolean selfChange, Uri uri) {
        // TODO: 数据已改变，APP 重新查询数据库并刷新界面
    }
};

private void setupCursor(Context context, Cursor c) {
    c.unregisterContentObserver(mContentObserver); // c 为需要显示的数据
}