How to disable the collapsing of an ExpandableListView?

You can define a OnGroupClickListener which returns true, like so:

expandableList.setOnGroupClickListener(new OnGroupClickListener() {
  @Override
  public boolean onGroupClick(ExpandableListView parent, View v,
                              int groupPosition, long id) { 
    return true; // This way the expander cannot be collapsed
  }
});