I am creating an android ecommerce app with WP REST API and the json I get from that API, I need to store it for offline purpose. So what is a better approach save parsed data in to sqlite and just show it from there or save the json string and parse it every time it needs to be shown?
No, you must only parse before adding that to sqlite. Why to do extra same work every time. Not only it is time consuming but also memory over head for conversion.