title: Notification cancel problem
body: <p>I want to delete all the notification that are present in the top bar. For that I use the following code.</p>
  
  <pre><code>notification = (NotificationManager) mContextNotification.getSystemService(NOTIFICATION_SERVICE);
  
  if(mNotificationManager != null)
    mNotificationManager.cancelAll();
  </code></pre>
  
  <p>But no notification is deleting from the bar. What is the problem in my code?</p>