How to pass data to fragment?

There are many articles teaching us how to pass the data from fragment to fragment, but most of the article or questions had implemented OnClickListener in their first fragment, which used to pass value to another fragment.

But my case is pass the data from two fragments without any button click and finally save them in different tables by clicking button in the last fragment. What can I do to achieve this??

I have tried to work it out but I get NULL value in SQLite. I think I have miss out a lot but have no idea. PLEASE help me...I've been stuck at here for more than two days...Thanks

Pass data to fragment