Store data in Android app for book keeping

I want to program an accounting app for Android, but I have not found a good solution to manage the storage of the data, yet.

The user should (later on) be able to specify where all the accounting data is saved, so that he can sync it via his Dropbox and access and read the data from another device.

I did look into persistent data storage in Android and I have a grasp on how I would store preferences, but SharedPreferences is no fit for this job of holding the book keeping data.

However, this data seems to be suited well by an SQLite database (which I do not know how to use, yet).

Is it possible to access and read the data saved with SQLite externally?

Or is there a better way of saving such data?