android: help in local and online login and register technique in my app

i'm new to android:

I developed an app. I connected all fields with SQlite.

The theme of my app is to store data offline (in local database) and when the net is available, upload it to server.

I'm confused how to do that.

How will i connect specific account to the server and use that id and password locally to entered the app when net is not available.

Hope you got what i want to ask.