title: Android CheckBox with indeterminated Status?
body: <p>in an android-project I need to have a checkbox which may have an indeterminate status, depending on the case if it is optional (true/false/null) or necessary (true/false) to set a value with this checkbox.</p>
  
  <p>While this is possible on MS.Net/WinForms I have no idea if there's a comparable possibility on Java/Android, as I found no documentation about this in the android-docs.</p>
  
  <p>Any ideas about this?
  Additional info: the layout is XML-based.</p>
  
  <p>Christoph</p>