title: Why is getCallingActivity always returning null?
body: <p>I have a welcome screen that can be started as the first activity in my app, or it can be started by the main activity that the user spends their time in. I want it to act slightly differently when it's started from the home screen (or any other app) or the main activity.</p>
  
  <p>Calling <code>getCallingActivity()</code> in onCreate seems to always return null, regardless of what called the activity. This is strange, because it did work earlier, which is how I found what format the string returns in (which should be in the documentation anyway). I can't see what could have affected it, because the only thing that happens before calling <code>getCallingActivity()</code> is calling <code>super.onCreate(savedInstanceState)</code>. I am calling the activity with <code>startActivityForResult(welcomeIntent, RESULT_WELCOME)</code>.</p>
  
  <p>What am I doing wrong? Is there an alternative way to get this info?</p>