Maintenance Manual

Requirements:

device with Android operation system
internet connectivity

Setup:

download the .apk file to your device and install it.
Open a Firebase project for this system.
on your PC, from the 'app' folder run 'firebase deploy' to use the remote DB, storage and functions (one time only).

note: our version uses the free plan of firebase with limited storage space and access to the DB and functions. For a scaled app you should consider to change the firebase plan.

Main app structure:

every use case in our system implemented in the following architecture.
If one wishes to change something in the system bare in mind that structure:

We designed our system in a way that each use case, has a corresponding MVVM "instance" as described in the following diagram, meaning that each use-case aUseCase has an associated view class (probably named aUseCaseFragment.java), associated view-mode class (aUseCaseViewModel.java) and associated model classes that are associated to the logic of the use-case. We belive that the use-case diagram is intuitive and a comfortable way to devide the system, while building it and on maintanence.

Activity/ Fragment - UI functionality

ViewModel - binding between the UI and the data it holds

Repositories - intended to give a good user experience so he will always see his information, thanks to this component indirect dependency on both local and remote data sources.

Model - the different data models the repositories manages
imageProcessing - component for manipulating and processing images
communication - component that bridges between the data models and the persistent data (local and remote).

Local Data Source - manages the operations on the local persistent data.

Remote Data Source - manages the operations on the remote persistent data.

Remote Functions - this component purpose is to create and update the output file for each exam - a spreadsheet.

This structure enables modularity in terms of changing the existing system.
For example:

replacing the algorithm that detects the exam and finds the students answers would require changes in imageProcessing
changing the method for calculating a student's grade would require changes in the Exam Model.

Future Versions:

There are some additions we reckon would be beneficial to the system:

Changing the format of the exam from one page only to multiple pages.
Enable the user flexibility in terms of his actions in the app. For instance, enable editing an exam answers, deleting a scan, add a grader to exam after its creation, etc.
Show user the accumulated average of solutions scanned by ALL graders