title: Android: how to pop up a modal activity from an background activity, which remains in background
body: <p>when a notification comes in, the main activity is at the background(not showing)</p>
  
  <p>I want it to pop up a modal/dialog activity, but the main activity always shows as the background of the modal ...</p>
  
  <p>basically what I did is using </p>
  
  <pre><code>onReceiveNotificatioin(){
            Intent mIntent = new Intent(context, PopupActivity.class);
            mIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            mIntent.putExtra("msg", alert);
            startActivity(mIntent);
  }
  </code></pre>
  
  <p>how to prevent the main activity from showing itself as well?</p>