[Feature Request]: Introduce support for multiple classrooms (GSoC'24 4.2)

[BenHenning]

Is your feature request related to a problem? Please describe.

The app is currently limited to only showing basic numeracy lessons, and the broader team plans to introduce lessons of other types (such as financial literacy, science, and more).

Describe the solution you'd like

Suggested Milestones

• Milestone 1: Introduce new UIs for classroom selection.
  • Deliverable 1: Introduce new feature flag for the multiple classrooms feature.
  • Deliverable 2: Update the model & domain layer to support the definition of classrooms, and specify a classroom per-topic.
  • Deliverable 3: Introduce a ClassroomController.
  • Deliverable 4: Introduce a new activity & related fragments/views/tests for a new classroom selection landing page (recommendations section should be faked out for now).
  • Deliverable 5: Update 'recently played' topic cards to include classroom information.
• Milestone 2:
  • Deliverable 1: Update the asset download script (#4885) to support classrooms.
  • Deliverable 2: Implement new recommendations logic & UI support for the classroom selection
  • Deliverable 3: Gated by the feature flag, hook up the new classroom selection page to replace the existing home activity upon profile login.
  • Deliverable 4: Ensure the existing event logs are captured in the new screen and related tests in preparation for removal.
  • Deliverable 5: Test, iterate, and work with the tech lead to finalize and launch the feature.
  • Deliverable 6: Audit home activity/fragment & recommendation tests to ensure the new utilities cover the same behaviors. Remove the old home activity/fragment.

Technical hints / guidance

Top-level components needed for supporting multiple classrooms in the app

• ClassroomListActivity.kt + presenter & layout: Top-level activity that has a row of available classrooms which is displayed as a carousel to facilitate addition of future classrooms.
  • The list of topics will be filtered based on the selected classroom.
  • The classrooms carousel shoud be sticky at the top when the topic list is scrolled.
  • When the home screen is resumed, the last classroom selection will be retained.
• ClassroomListFragment.kt + presenter & layout: Top-level fragment for the available classrooms. The classrooms are displayed in a carousel(custom view as per existing patterns, see the "last played stories" carousel).
• ClassroomController.kt: The new controller for providing classroom context and state.
• TopicListController.kt: Existing controller that will be updated to no longer surface getTopicList since this is now implemented in ClassroomController. Existing use cases and tests will need to be migrated over to ClassroomController. For the home screen, suggest defaulting to the "math" classroom so that existing functionality is maintained.
• FeatureFlagConstants.kt: Where the new feature flag for enabling multiple classrooms will be defined.
• ProfileChooserFragmentPresenter.kt: Updated to navigate the user to ClassroomListActivity.kt instead of HomeActivity when the new feature flag is enabled.
• Much of the classes under app/src/main/java/org/oppia/android/app/home: These will need to be moved to a new classroom package and generalized such that they can be used by both the home activity/fragment and new classroom views.
• The rest of the classes under home/ (including HomeFragment & HomeActivity): These will be deleted at the end of the project in favor of the new structure. The home package will actually be completely removed.

Some key technical notes

• All new components require new corresponding test files. All updated components will need their tests updated based on the changes to those components. Presenters and view models are typically exempted from testing, and are exempted from test file presence check via script/assets/test_file_exemptions.textproto.
• All references to HomeActivity/Fragment will need to be updated throughout the codebase. This may require documentation and/or test updates.
• Existing layout files will need to be updated, as needed, to support the different card tile changes.
• The new activities & fragments aren't explicitly spec'd out since they are mostly boilerplate. Existing classes should be analyzed for a reference on spec'ing these out in the proposal.
• New test textproto files should be added to demonstrate multiple classrooms in the base developer version of the app.
• Existing exploration-related event logs should be updated to contain classroomId

Suggested files to add/change

ClassroomController.kt:

class ClassroomController {
  fun getClassroomList(profileId: ProfileId): DataProvider<List<ClassroomSummary>>
  fun getTopicList(profileId: ProfileId, classroomId: String): DataProvider<TopicList>
}

TODO: Others will be added soon.

Describe alternatives you've considered

No response

Additional context

This is the high-level tracking issue corresponding to https://github.com/oppia/oppia/wiki/Google-Summer-of-Code-2024#42-multiple-classrooms-support.

[BenHenning]

NB: This issue is locked to ensure that it only contains updates for requirements. If you have questions regarding this project, please use its corresponding discussion category: https://github.com/oppia/oppia-android/discussions/categories/gsoc-q-a-4-2-multiple-classrooms-support.

[BenHenning]

NB: The main issue comment has been updated to include the technical details directly rather than a link to a Gist (so that we can easily change this if needed). Please note that there are some small changes to the requirements to better align with the PRD for the feature (as some key UX confusions were cleared up that influenced the original technical design).

[theMr17]

Milestone 1

⬜ PR 1.1

Introduce a new feature flag for the multiple classrooms feature.

Starting Date	Creation Date	Merge Date
27-05-2024	27-05-2024	28-05-2024

	Tasks	Due Dates
✅	Introduce feature flag in FeatureFlagConstants.kt file.	27-05-2024
✅	Add dagger providers for the new feature flag.	27-05-2024

⬜ PR 1.2

Update the model & domain layer to support the definition of classrooms, and specify a classroom per-topic.

Starting Date	Creation Date	Merge Date
28-05-2024	31-05-2024	03-06-2024

	Tasks	Due Dates
⬜	Add ClassroomSummary & ClassroomIdList objects to topic.proto file.	29-05-2024
⬜	Update topic related objects to include classroomId & classroomTitle fields.	30-05-2024
⬜	Create test data json & textproto files for classrooms.	31-05-2024

⬜ PR 1.3

Introduce ClassroomController and modify TopicListController & ProfileManagmentController.

Starting Date	Creation Date	Merge Date
04-06-2024	10-06-2024	14-06-2024

	Tasks	Due Dates
⬜	Introduce ClassroomController to surface getClassroomList function.	04-06-2024
⬜	Add tests for getClassroomList function.	05-06-2024
⬜	Migrate getTopicList from TopicListController to ClassroomController.	07-06-2024
⬜	Migrate tests for getTopicList function.	08-06-2024
⬜	Modify ProfileManagementController to track last selected classroom.	09-06-2024
⬜	Add tests for new functions in ProfileManagementController.	10-06-2024

⬜ PR 1.4

Introduce a new activity & related fragments/views/tests for a new classroom list page.

Starting Date	Creation Date	Merge Date
11-06-2024	21-06-2024	25-06-2024

	Tasks	Due Dates
⬜	Create ClassroomListActivity, ClassroomListFragment & ClassroomListViewModel.	12-06-2024
⬜	Gate the new ClassroomListActivity.	13-06-2024
⬜	Add tests to verify the gating.	14-06-2024
⬜	Introduce Jetpack Compose Dependencies.	16-06-2024
⬜	Implement the Sticky Header and other elements of the ComposeView.	17-06-2024
⬜	Implement the Topic List UI.	19-06-2024
⬜	Add tests for the Sticky Header and other elements of the ComposeView.	20-06-2024
⬜	Add tests for the Topic List UI.	21-06-2024

Milestone 2

⬜ PR 2.1

Update 'recently played' topic cards to include classroom information and update tests.

Starting Date	Creation Date	Merge Date
08-07-2024	11-07-2024	15-07-2024

	Tasks	Due Dates
⬜	Update topic cards UI.	09-07-2024
⬜	Update tests for the UI changes.	11-07-2024

⬜ PR 2.2

Implement new recommendations logic & UI support for the classroom selection and add tests.

Starting Date	Creation Date	Merge Date
13-07-2024	18-07-2024	20-07-2024

	Tasks	Due Dates
⬜	Update the recommendation logic to include classroom information.	16-07-2024
⬜	Update tests for the logic changes.	18-07-2024

⬜ PR 2.3

Ensure the existing event logs are captured in the new screen and related tests in preparation for removal & implement new event log.

Starting Date	Creation Date	Merge Date
21-07-2024	25-07-2024	28-07-2024

	Tasks	Due Dates
⬜	Ensure that the existing event logs are captured in the new screen.	21-07-2024
⬜	Add classroomId field in ExplorationContext object and update related tests.	22-07-2024
⬜	Implement logging of start_exploration event.	23-07-2024
⬜	Add tests to verify the behaviour of the new event.	25-07-2024

⬜ Task 2.4

Test, iterate, and work with the tech lead to finalize and launch the feature.

Starting Date	Completion Date
29-07-2024	04-08-2024

⬜ PR 2.5

Audit home activity/fragment & recommendation tests to ensure the new utilities cover the same behaviors. Remove the old home activity/fragment.

Starting Date	Creation Date	Merge Date
02-08-2024	06-08-2024	09-08-2024

	Tasks	Due Dates
⬜	Verify that the new utilities cover the same behaviour.	04-08-2024
⬜	Enable the ENABLE_MULTIPLE_CLASSROOMS feature flag.	06-07-2024