Main issue is with the 'addParentStack' call, Your trying to add the Notification class as parent. It should be your OfferNotification Activity
which is the parent.
sb.addParentStack(OfferNotification.class);
Other issue is the Intent action should be an Activity.
Intent resultIntent = new Intent(this , YourActivity.class);
Next issue is with the setSmallIcon
, you should pass a valid resource id.
.setSmallIcon(R.drawable.your_icon)
Make all these three changes, Your are out of cracks.