LAB 5 — LazyColumn & Room Database
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Mobile Application Development | SUZA | Semester II 2025/2026

OBJECTIVES
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- Build scrollable content with LazyColumn and LazyVerticalGrid
- Set up Room with Entity, DAO, Database
- Use Repository + ViewModel + StateFlow pattern
- Perform full CRUD from the UI

SETUP
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Add to build.gradle.kts (Module):
  implementation("androidx.room:room-runtime:2.6.1")
  implementation("androidx.room:room-ktx:2.6.1")
  ksp("androidx.room:room-compiler:2.6.1")

Top of file (Module build script): plugins { id("com.google.devtools.ksp") }

PART A — Read-Only List App
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1. Affirmation Gallery
   - Create a data class Affirmation(val id: Int, val stringRes: Int, val imageRes: Int)
   - Build a Datasource.kt with a list of 10 affirmations
   - Display using LazyColumn of Card composables (image + text)
   - Try again with LazyVerticalGrid(columns = GridCells.Fixed(2))

PART B — Student Registry (Room CRUD)
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Schema:
  @Entity students { id (PK auto), name, course, year, email }

1. Entity + DAO + Database
   Create:
   - Student entity
   - StudentDao with insert/update/delete + Flow<List<Student>> getAll()
   - StudentDatabase with singleton getDatabase(context)

2. Repository + ViewModel
   - class StudentRepository(private val dao: StudentDao)
   - class StudentViewModel(private val repo: StudentRepository) : ViewModel()
     Expose students as StateFlow<List<Student>> via .stateIn(...)
     Methods: addStudent, updateStudent, deleteStudent

3. Screens (navigate with Nav-Compose)
   a. ListScreen  — LazyColumn of students. Tap item → detail.
                    FAB "+" → AddStudent. Swipe-to-delete (optional bonus).
   b. AddStudentScreen — form with TextFields + Save button.
   c. DetailScreen    — show details + "Edit" + "Delete".
   d. EditStudentScreen — pre-fill form, update on Save.

4. ViewModel Factory
   Provide a ViewModelProvider.Factory because StudentViewModel has arguments.

5. Seed Data
   On first run, insert 3 sample students so the UI isn't empty.

VALIDATION RULES
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- Name: non-empty
- Email: must contain "@"
- Year: must be 1, 2, 3, or 4
Disable the Save button unless valid; show inline helper errors.

DELIVERABLES
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- Project "StudentRegistry" on GitHub as "mad-lab05"
- Short demo video (< 90 sec) showing: list, add, edit, delete, detail
- README.md explaining how to build & run
- Architecture diagram (draw.io / Excalidraw) in /docs