title: Android: Why can't I see ListView items who fetch from the website?
body: <p>I wrote this Java code for <code>Android</code>:</p>
  
  <pre><code>public class MainActivity extends AppCompatActivity
  {
    private static final String WEBSITE_URL = "http://www.anywebsite.com/forum/";
  
    private ListView _lvForums;
    private ForumAdapter _forumAdapter;
    private List&lt;ForumContent&gt; _forumContents;
  
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
      super.onCreate(savedInstanceState);
      //setContentView(R.layout.activity_main);
  
      //_lvForums = findViewById(R.id.lvForums);
      _lvForums = new ListView(this);
      _lvForums.setLayoutParams(new ViewGroup.LayoutParams(
          ViewGroup.LayoutParams.MATCH_PARENT,
          ViewGroup.LayoutParams.MATCH_PARENT));
      _forumContents = new ArrayList&lt;&gt;();
      setContentView(_lvForums);
  
      new Thread(new Runnable() {
        @Override
        public void run() {
          try {
            Document doc = Jsoup.connect(WEBSITE_URL).get();
            //MainActivity.this.getActionBar().setTitle(doc.title());
  
            Elements forumContents = doc.select("div.forum_content.forum_forum");
            for (Element forum : forumContents) {
              String forumName = forum.select("span.name &gt; a").text();
              String link = forum.select("span.name &gt; a").attr("abs:href");
              String threadCount = forum.select("td.threadcount").text();
              String postCount = forum.select("td.postcount").text();
  
              Element lastPost = forum.select("td.lastpost").first();
              Element linkElement = lastPost.getElementsByTag("a").first();
  
              String lastPostText = lastPost.childNode(0).toString();
              String lastPostLink = linkElement.attr("abs:href");
  
              _forumContents.add(new ForumContent(
                  forumName, link, threadCount, postCount, lastPostText, lastPostLink));
            }
          } catch (IOException e) {
            e.printStackTrace();
          }
        }
      }).start();
  
      runOnUiThread(new Runnable() {
        @Override
        public void run() {
          _forumAdapter = new ForumAdapter(MainActivity.this, _forumContents);
          _lvForums.setAdapter(_forumAdapter);
        }
      });
    }
  }
  </code></pre>
  
  <p>When I run the app on <code>Android</code>, I see an empty white screen but I can't see <code>ListView</code> items. I'm pretty sure that <code>ForumAdapter</code> and <code>ForumContent</code> are working so good. Because if I try like this, I can see <code>ListView</code> items:</p>
  
  <pre><code>_forumContents.add(new ForumContent("Data1", "Data2", "Data3", "Data4", "Data5", "Data6"));
  </code></pre>
  
  <p>And I'm pretty sure that my <code>JSoup</code> codes, because I can get same datas with same code on Java console app.<br />
  What is the problem? How can I see <code>ListView</code> items who fetched data from the website?</p>