I am creating an app with very sensitive data, so I'm not allowed to manipulate data server-side or with any DB in the cloud.
But I still want the app user to be able to save and retrieve the whole app data from local storage to avoid loosing all the data if the user cannot access the device or uninstall the app.
Exporting all data seems simple, as I can generate a JSON file and send it by email or store it on the device.
On the other hand, retrieving the data seems more complicated.
How can I get JSON data from devices files ? What do you think is the best to do the whole process ?