connecting to PostGIS database
Having Android clients connect directly to your database is not a good idea. Creating a web service (such as a REST service) as you mention in your comment is the way to go.
There are several reasons to take this approach:
- Exposing your database to the internet is bad from a security perspective
- Tightly coupling your app to the database is bad from a design perspective. With a separate service layer you can:
- Make changes to the data layer without having to update the app
- Add caching
- Add capacity at each layer as needed