title: TextView.setText outside of onCreate doesn't work
body: <p>I'm writing an android app where I want to modify a text view. When I'm editing it in the <code>onCreate()</code> method it works fine, but I want to modify it when the user click on the screen.
  Now I know that the function for clicking on the screen is working, but the text doesn't get modified.</p>
  
  <p>In the <code>onCreate()</code> method (works fine):</p>
  
  <pre><code>    main = (TextView) findViewById(R.id.textView1_hidden_buttons);
      main.append(" " + newString);
  </code></pre>
  
  <p>Tap screen listener:</p>
  
  <pre><code>class MyGestureListener extends GestureDetector.SimpleOnGestureListener {
  
      // Clicking on the screen increases counter taps
      @Override
      public boolean onDown(MotionEvent event) {
          synchronized (this) {
              if (busy)
                  return true;
              busy = true;
          }
  
          main = (TextView) findViewById(R.id.textView1_hidden_buttons);
          main.setText("Waiting for other players");
  
          try {
              JSONObject json = new JSONObject();
              json.put("client", "ready");
  
              ConnectionHandler.send(json.toString());
  
              String serverResponse = ConnectionHandler.receive();
  
              Intent intent;
              intent = new Intent(MainActivity.this,
                      OrderedButtonsActivity.class);
  ...
  </code></pre>
  
  <p>The app is waiting on <code>ConnectionHandler.receive()</code>.
  After calling to modify the text, I call for a <code>wait()</code> method for the app, and after a while to another activity. For a short while (half a second or so) I could see the modified text.
  Why does it happen and how can I fix it so that the text get modifed after clicking the screen?</p>