public class DownloadRecycleviewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    class DownloadFileFromURL extends AsyncTask<String, String, String> {

    protected void onProgressUpdate(String... progress) {

            progressBar.setProgress(Integer.parseInt(progress[0]));
            notifyItemChanged(Integer.parseInt(index[1]));
        }
}
}