title: How to hide system overlay window when a fullscreen app is launched?
body: <p>I want my app to display a permanently visible view (like the status bar) no matter which app the user is in, except full-screen apps such as games.</p>
  
  <p>So far my app starts a service, which inflates a view and adds it to the WindowManager as a TYPE_SYSTEM_OVERLAY, as described <a href="https://stackoverflow.com/questions/7457730/preventing-status-bar-expansion">here</a>.</p>
  
  <p>The issue I am having is that when I launch a full-screen app (the gallery, Angry Birds, etc), my overlay is still there. How can I detect when a full screen app is launched or when the status bar has been hidden so I can remove it?</p>