title: Activity struck while pressing back key
body: <p>There is no action performed on the activity when i press back key till some time. No code return to handle back key in my activity. I am starting a activity when user clicks on list item. Like</p>
  
  <pre><code>Intent intent = new Intent(cxt, MyActivity.class);
  intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
  startActivity(intent);
  </code></pre>
  
  <p>Actual thing hapening is,when user clicks instantly thrice,My activity is launched multiple times.How can i avoid launch activity more than once.
  I can not use single instance/singleton because my <code>OnCreate</code> should be called every time the  activity is launched.</p>