Android : Open mutiple intents separately in android

My application generates multiple separate notifications, for eg, Notification A, Notification B, Notification C. etc...

If i tap on Notification A, the details of A will be visible, after that if i open Notification C or B, the activity still shows Notification A contents only. How to make it to update to show corresponding notification data. I'm assigning unique key for each notification.

Here is my code to generate notification

CharSequence title = title1;
    CharSequence description = notes;

    Uri soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

    Intent intent = new Intent(this.getApplicationContext(), Google_task_notification_preview.class);
    intent.putExtra("CODE", key);        

    PendingIntent pendingNotificationIntent = PendingIntent.getActivity(
            this.getApplicationContext(), key, intent,
            PendingIntent.FLAG_UPDATE_CURRENT);

    try
    {

        Drawable d = getResources().getDrawable(ic_launcher);
        Bitmap bitmap = ((BitmapDrawable)d).getBitmap();    

    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(
            getApplicationContext()).setLargeIcon(bitmap)
            .setContentTitle(title)
            .setContentText(description)
            .setContentIntent(pendingNotificationIntent)
            .setSound(soundUri);

    if(priority == 0)
    mBuilder.setSmallIcon(R.drawable.ic_low);
    else
    mBuilder.setSmallIcon(R.drawable.ic_high);  

    mBuilder.setWhen(timestamp);


    Notification notification = mBuilder.build();

    notification.defaults |= Notification.DEFAULT_VIBRATE;
    notification.defaults |= Notification.DEFAULT_SOUND;

        // cancel notification after click
    notification.flags |= Notification.FLAG_AUTO_CANCEL;
        // show scrolling text on status bar when notification arrives
    notification.tickerText = title + "\n" + description;

    NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    manager.notify(key, notification);

    }
    catch(SecurityException se)
    {
        se.printStackTrace();
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }