title: Updating parent entity when child entity is added (Greendao)
body: <p>I am using greendao in my android app and an Activity that needs to refresh some item in a listview.</p>
  
  <p>I have an entity "activity" that has an one-to-many relation to "exports"</p>
  
  <p>In order to update the "activity" when a new "exports" is added I do as described in <a href="http://greenrobot.org/greendao/documentation/relations/#Resolving_and_Updating_To-Many_Relations" rel="nofollow">http://greenrobot.org/greendao/documentation/relations/#Resolving_and_Updating_To-Many_Relations</a></p>
  
  <pre><code>Exports ex = new Exports();
  ex.setActivityId(activityEntry.getId());
  //DOING something...
  exportsDao.insert(ex);
  List&lt;Exports&gt; exportList = activityEntry.getExportsList();
  exportList.add(ex);
  </code></pre>
  
  <p>This however gives me an java.lang.UnsupportedOperationException at java.util.AbstractList.add(AbstractList.java:404)</p>
  
  <p>What am I doing wrong?</p>