StorageProvider.java 文件源码

protected AssetFileDescriptor openVideoThumbnailCleared(long id, CancellationSignal signal)
        throws FileNotFoundException {
    final ContentResolver resolver = getContext().getContentResolver();
    Cursor cursor = null;
    try {
        cursor = resolver.query(Video.Thumbnails.EXTERNAL_CONTENT_URI,
                VideoThumbnailQuery.PROJECTION, Video.Thumbnails.VIDEO_ID + "=" + id, null,
                null);
        if (cursor.moveToFirst()) {
            final String data = cursor.getString(VideoThumbnailQuery._DATA);
            return new AssetFileDescriptor(ParcelFileDescriptor.open(
                    new File(data), ParcelFileDescriptor.MODE_READ_ONLY), 0,
                    AssetFileDescriptor.UNKNOWN_LENGTH);
        }
    } finally {
        IoUtils.closeQuietly(cursor);
    }
    return null;
}