title: EditText with soft keyboard and "Back" button
body: <p>When I'm using "EditText" I have the virtual keyboard.</p>
  
  <p>Pressing first time "Back" button hides the keyboard. Second press invokes "onBackPressed" callback in my activity. OK, but...</p>
  
  <p>I have no idea how to hook the very first press. I need to process input data as soon as the virtual keyboard dismissed.</p>
  
  <p>Any ideas are welcome.</p>
  
  <p>Thanks.</p>