title: The method getWindow().setBackgroundDrawableResource(int resid) doesn't work outside of onCreate()
body: <p>Here is a short sketch of my application</p>
  
  <pre><code>...
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.start);
  
      ... //at this place, getWindow().setBackgroundDrawableResource(int resid)
          //would work perfectly
  
      mainView();
  
  }
  
  void mainView() {
     setContentView(R.layout.main);
  
     ...
  
     if (...) {
       getWindow().setBackgroundDrawableResource(R.drawable.anyDrawable);
     }
  
     ...
  
  }
  </code></pre>
  
  <p>But in mainView() that method doesn't effect anything. And no Exception is thrown out.</p>
  
  <p>main.xml already defines a background image, but start.xml doesn't do it. Could this cause my problem?</p>
  
  <p>Or can I change the background image in another way?</p>