title: ProgressDialog is not shown in the AsyncTask
body: <pre><code>Document doc = new Obtainer(context, uri).execute().get();
  </code></pre>
  
  <p>This code in the activity class renders the Obtainer(which extends AsyncTask) which gets the xml document from the url. This is the onPreExecute method:</p>
  
  <pre><code>protected void onPreExecute() {
          super.onPreExecute();
          System.out.println("Pre execute began");
          exception = null;
          dialog = new ProgressDialog(context);
          dialog.setMessage("Loading started");
          dialog.setIndeterminate(true);
          dialog.setCancelable(false);
          System.out.println("Preexecute end");
          dialog.show();
      }
  </code></pre>
  
  <p>context is set in the Constructor:</p>
  
  <pre><code>public Obtainer(Context c, String addr) {
      context = c;
      address = addr;
  }
  </code></pre>
  
  <p>During the runtime I can see in the console output both "Pre execute began" and "Preexecute end" but the progress dialog is not shown. What is the probleM?</p>