Does not handle HOTP entries
HOTP entries do not work properly as is, these items have an item "counter" that needs to be copied over as "counter" in andOTP's JSON format.
The "period" does not need be copied over, as HOTP does not use it.
In fact, when imported, the lack of "counter" makes the output data only get loaded up until the HOTP entry, at which point andOTP stops processing new items. Per: https://github.com/andOTP/andOTP/blob/8da709edcfa4b46894e35284e9c96d78d28d3ddd/app/src/main/java/org/shadowice/flocke/andotp/Database/Entry.java#L188
If you aren't sure how you want to implement it, I think I can get a pull-request created for a change.