How to pass a variable to another activity in Android?

Question

Android

Hello. I'm making an RSS feed parser from my site. You need to pass a link to the WebView post in another activity. Using examples from the Internet, I tried to do it, but when I try to transfer the link, the application crashes.

spoiler

Класс MainActivity

public class MainActivity extends AppCompatActivity {

    ListView lvRss;
    ArrayList<String> titles;
    ArrayList<String> links;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        lvRss = (ListView) findViewById(R.id.lvRss);
        titles = new ArrayList<String>();
        links = new ArrayList<String>();




        lvRss.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                Uri uri = Uri.parse(links.get(position));
                String stringURI = String.valueOf(uri);
                Intent intent = new Intent(getApplicationContext(), Main2Activity.class);
                intent.putExtra("getURL", stringURI);
                startActivity(intent);
            }
        });

        new ProcessInBackground().execute();
    }

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

    public 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 url = new URL("https://hhmind.ru/feed");

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

                    eventType = xpp.next();
                }


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

            return exception;
        }

        @Override
        protected void onPostExecute(Exception s) {
            super.onPostExecute(s);

            ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1, titles);

            lvRss.setAdapter(adapter);
            progressDialog.dismiss();
        }
    }
}

Класс Main2Activity

public class Main2Activity extends AppCompatActivity {
    String postURL = getIntent().getStringExtra("getURL");

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        WebView webView = (WebView) findViewById(R.id.wv);
        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webView.loadUrl(postURL);
    }
}

Answer 1

String postURL = getIntent().getStringExtra("getURL");

move this thing to onCreate()