Reliability Android when connction is off

I'm developing an App where I store my data in a DB online using HTTP POSTO and GET. I need to implement some reliability to my software, so if the user presses the button, and there is no connection, the data should be stored in something (file? sqlite?) and then when the connection is again on, send the HTTP request to send data.

Any advices or pieces of code to show me how to do this? Thanks.