RSSActivity.java

Parser parser = new Parser();
parser.execute(urlString);
parser.onFinish(new Parser.OnTaskCompleted() {
    //what to do when the parsing is done
    @Override
    public void onTaskCompleted(ArrayList<Article> list) {
        //list is an Array List with all article's information
        //set the adapter to recycler view
        mAdapter = new ArticleAdapter(list, R.layout.row, MainActivity.this);
        mRecyclerView.setAdapter(mAdapter);
        progressBar.setVisibility(View.GONE);
        mSwipeRefreshLayout.setRefreshing(false);
    }

    //what to do in case of error
    @Override
    public void onError() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                progressBar.setVisibility(View.GONE);
                mSwipeRefreshLayout.setRefreshing(false);
                Toast.makeText(MainActivity.this, "Unable to load data.",
                        Toast.LENGTH_LONG).show();
                Log.i("Unable to load ", "articles");
            }
        });
    }
});