Android DB app development

I need an android app including source code which will operate in a connectivity-poor environment. The app will download data when possible (otherwise run off existing data) and on user input (drop down lists), will construct strings of data which are to be transmitted to a server via data (e.g. HTTP GET) or SMS when data networks are poor. The app will need to access phone data (phone number) and possibly interface to existing USSD or STK based services. The data to be used will include time limitations (i.e. select x from y when timestamp > z) . This will interface with a live website where data will be retrieved from and submitted to. We are basically seeking to replicate some web based templates for customers who are not always on the internet but can download data once or more times a day, and communicate via SMS or data as appropriate.