Даниил

public class MainActivity extends AppCompatActivity {

    URL url;
    List<String> titles;
    ArrayList<String> links;
    ArrayList<String> description;
    ArrayList<String> pubDate;
    ArrayList<String> author;
    ArrayList<String> category;
    String HHMurl= "https://stalkerweb.ru/feed";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        RecyclerView mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);

        mRecyclerView.setHasFixedSize(false);

        RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(mLayoutManager);
   
        RecyclerView.Adapter mAdapter = new RecyclerAdapter(titles);
        mRecyclerView.setAdapter(mAdapter);
        try{
        titles = new ArrayList<>();
        links = new ArrayList<>();
        description = new ArrayList<>();
        pubDate = new ArrayList<>();
        author = new ArrayList<>();
        category = new ArrayList<>();

        RecycleClick.addTo(mRecyclerView).setOnItemClickListener(new RecycleClick.OnItemClickListener() {
            @Override
            public void onItemClicked(RecyclerView recyclerView, int position, View v) {

                 //to do something

            }

        });
            new ProcessInBackground().execute();

        } catch(Exception e){
            //to do something
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }


    public InputStream getInputStream (URL url)
    {
        try {
            return url.openConnection().getInputStream();
        } catch (IOException e) {
            return null;
        }
    }

    private class ProcessInBackground extends AsyncTask<Integer, Void, Exception> {

        ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);

        Exception exception = null;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progressDialog.setMessage("Загрузка...");
            progressDialog.show();
        }

        @Override
        protected Exception doInBackground(Integer... params) {

            try {
                url = new URL(HHMurl);
                XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
                factory.setNamespaceAware(false);
                XmlPullParser xpp = factory.newPullParser();
                xpp.setInput(getInputStream(url), "UTF_8");
                boolean insideItem = false;
                int eventType = xpp.getEventType();

                while (eventType != XmlPullParser.END_DOCUMENT) {
                    if (eventType == XmlPullParser.START_TAG) {
                        if (xpp.getName().equalsIgnoreCase("item")) {
                            insideItem = true;
                        } else if (xpp.getName().equalsIgnoreCase("title")) {
                            if (insideItem) {
                                titles.add(xpp.nextText());
                            }
                        } else if (xpp.getName().equalsIgnoreCase("link")) {
                            if (insideItem) {
                                links.add(xpp.nextText());
                            }
                        } else if (xpp.getName().equalsIgnoreCase("content:encoded")) {
                            if (insideItem) {
                                description.add(xpp.nextText());
                            }
                        } else if (xpp.getName().equalsIgnoreCase("pubDate")) {
                            if (insideItem) {
                                pubDate.add(xpp.nextText());
                            }
                        } else if (xpp.getName().equalsIgnoreCase("dc:creator")) {
                            if (insideItem) {
                                author.add(xpp.nextText());
                            }
                        } else if (xpp.getName().equalsIgnoreCase("category")) {
                            if (insideItem) {
                                category.add(xpp.nextText());
                            }
                        }

                    } else if (eventType == XmlPullParser.END_TAG && xpp.getName().equalsIgnoreCase("item")) {
                        insideItem = false;
                    }

                    eventType = xpp.next();
                }


            } catch (XmlPullParserException | IOException e) {
                exception = e;
            }

            return exception;
        }

    }}