Make fragment mandatory to collect user inputs

Is it possible to make fragment as mandatory to close unless user enter some valid inputs in the fragment fields.

I am using a similar fragment concept http://plnkr.co/edit/JXd8cERC7vHYuBfx69rj?p=preview and want to make the fields to be filled mandatory by user in fragment. Upon successful user input of fields to bind the list items in the oage accordingly.

Any suggestions to achieve this functionality.

Thanks in advance

daniel