Hi there,
What do you mean when one view is selected? If you have any fields in the form marked as Cannot be blank and they are blank when you submit the form regardless of what view they are in, InfoPath will not let you submit.
Do you want the user to fill out either all required fields in View1 OR View2? Just wanted to clarify whether this is the scenario you are trying to accomplish to make sure I'm answering your question correctly :)