title: Change TextView inside Fragment
body: <p>I followed this guy's <a href="http://arvid-g.de/12/android-4-actionbar-with-tabs-example" rel="noreferrer">tutorial</a> on how to make an ActionBar. Let's say I want to change the TextView inside one of the fragments. So I added this on my StartActivity.java, under onCreate:</p>
  
  <pre><code>TextView textview = (TextView) findViewById(R.id.textView1);
  textview.setText("HI!");
  </code></pre>
  
  <p>When I start my app, it crashes. Can somebody point me to the right direction?</p>
  
  <p>I hope somebody takes the time to look at the guy's tutorial because his layout is basically the same as mine. Thank you.</p>