StorageProvider.java 文件源码

protected AssetFileDescriptor openOrCreateVideoThumbnailCleared(
        long id, CancellationSignal signal) throws FileNotFoundException {
    final ContentResolver resolver = getContext().getContentResolver();

    AssetFileDescriptor afd = openVideoThumbnailCleared(id, signal);
    if (afd == null) {
        // No thumbnail yet, so generate. This is messy, since we drop the
        // Bitmap on the floor, but its the least-complicated way.
        final BitmapFactory.Options opts = new BitmapFactory.Options();
        opts.inJustDecodeBounds = true;
        Video.Thumbnails.getThumbnail(resolver, id, Video.Thumbnails.MINI_KIND, opts);

        afd = openVideoThumbnailCleared(id, signal);
    }

    return afd;
}