title: iPhone/Android SDK , detect when in sleep/standby
body: <p>How can I tell when my app is open and the user use the power button to shut the display, or the iPhone shuts the display on its own ?</p>
  
  <p>what I need to do, is wait for an event, then  figure out if the screen is off and wake the screen with an alert.</p>
  
  <p>actually, I need this to work on both the iPhone and Android versions of my app</p>
  
  <p>I'll appreciate any insight for both platforms</p>
  
  <p>thanks</p>