title: How to determine which display an Android activity is using?
body: <p>As of Android O the following code can be used to launch an activity on a display other than default one:</p>
  
  <pre><code>ActivityOptions options = ActivityOptions.makeBasic();
  options.setLaunchDisplayId(d.getDisplayId());
  Intent i = new Intent(this, OtherActivity.class);
  i.addFlags(Intent.FLAG_ACTIVITY_MULTIPLE_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
  startActivity(i, options.toBundle());
  </code></pre>
  
  <p>In this case a new task is created which may start additional activities on the alternate display. From an activity how can I detect which display is currently being used? I was thinking the <code>Window</code> class would tell me but I can't find any function there.</p>