Hi Manju,
Kindly download the attached sample XSN (save the form > right click to open in design). In the sample, I have created three views with one mandatory field for each view. Notice the currentView field which is set to the default view but changes whenever a view is changed (see rules on view buttons). Using that field, you can set the mandatory field's validation rules based on that field.
Your conition should be similar to this:
CurrentView = View 1
and
View1Field is blank
Hope this helps.