Debug of an existing Android app

We need to outsource a debug of Android app.

The app is dedicated to a factory. Employees have tablets where the app is deployed. The apps shows a barcode and employees have to check the barcode with a scanner (linked in bluetooth). This parts seems to work fine. At the end of the day/work, they touch a button in app to stop the work. Datas are sent to an Oracle db.

Tasks list :
- Connection fails aren't supported/managed. So if a connection to db failed, app crashes.
- Add an alert when network is deconnected or too low.
- As I said, there is a scanner for barcode (api included into the app). If this barcode is on, then we launch the app. We need to stop and restart the scanner if we want it to be detected by the app.

Note :
App has been developed with Android Studio.
Database is an Oracle Database.